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Report on the 10th International Conference on Asphalt Pavements, Quebec, Canada, 12-17 August 2006
1.1 Introduction The 10th ICAP was attended by Co van der Vusse (B&O huis) and Sandra Erkens (IW). In this report we relay our impressions, both in general and (in the Appendices) in more detail. These impressions are based on the sessions and presentations actually attended and discussions with other participants. For a more complete overview, we refer to the proceedings. 1.2 History International Conference on Asphalt Pavements, a series of conferences initiated in 1962 as the An Arbor conference series in order to disseminate research findings and new developments in the asphalt world. In 1972 the conference was held outside An Arbor, in London, for the first time, when it was in London to stress the international aim. The International Society for Asphalt Pavements became the sponsor in 1978, leading to a change in the conference name but continuity in aim. From 1962 to 2002 there has been a conference once every five years, but at the 9th conference in 2002 in Copenhagen it was decided to change to a four yearly schedule, with a symposium on a dedicated topic in between. The first symposium of that kind was held in 2004 on accelerated pavement testing, the next on pavements and environment will be held in 2008 in Zurich. The change in pace has led to the 10th ICAP conference in 2006 in Quebec, Canada. Participation 1.3 th The 10 ICAP in numbers: there were about 200 papers, in 1 key note lecture, 4 plenary sessions of 4 papers each and 45 parallel sessions on a wide variety of topics. The conference was attended by over 400 participants (350 pre-registered) from 32 countries.
The proceedings of the previous ICAP conferences are now all available on CD’s which are sold by the ISAP Scociety. 1.4 General impression The conference was well organised and both attendance and contributions came from all over the world. There is a shift from the purely road engineering to a more general outlook, where related environmental and maintenance strategies are also being considered. The average level of the contributions is high, although particularly in the classic road engineering topics there is often lack of intend, appearing as if find one just randomly started testing and hopes to find results that will be useful, rather than devising a research plan beforehand and finding the proper approach for the questions at hand. 1.5 Dutch representation, position & reputation There where 10 Participants from Dutch organisations, 6 from the Delft University of Technology (3 from Road engineering, 3 from structural mechanics), 2 from DWW (Co van der Vusse from B&O huis & Sandra Erkens from I), 1 from CROW and 1 from the R&D department of a contractor. Other contractors, engineering firms and road laboratories did not attend the conference.
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Besides the direct contribution from the Dutch or Dutch based participants, contributions and activities from the Netherlands were also referenced in various sessions and Dutch representatives played a role in the conference. Egbert Beuving (EAPA) held a plenary lecture on the developments in Europe, outlining the developments in standards and highlighting innovations. Especially the photo’s he showed on the roll pave principle resulted in reactions from the audience. Andre Molenaar (TUD) was chairman of another plenary session and his work on cracking was mentioned in the key note lecture by Reynaldo Rogue. The work done by the combination of his group and Tom Scarpas’ structural mechanics group on constitutive modelling was mentioned by various speakers like Chuck Schwarz (Univ Maryland) and Andy Collop (Nottingham pavement centre). The structural mechanics group more recent work was also referenced in moisture damage sessions. The IPG programme was mentioned several times in relation to noise reduction research efforts and ravelling in porous asphalt. 1.6 Topics targeted by ICAP ICAP targeted five main themes, each of which had several sub-themes. The division of contributions over the five main themes is shown in the Figure underneath. The historical focus on Asphalt Pavement Materials and within this theme on the topic of “in situ and laboratory characterization and modeling of pavement materials” can still be recognized, however, broadening the scope of the conference by including other topics appears to work out nicely.
8% 12% 43%
20%
Developments in Asphalt Pavement Materials Structural Design for New and Existing Pavements Pavement Performance
Pavement Investigation and Analysis 17%
Highway Operations
FIGURE: Percentage of the total number of papers that deals with a specific theme The complete list of main and sub-topics is shown on the next page. The subtopics in this list were also the themes on which papers were invited. The number of contributions on the subtopics varied from 27 to 1 while some were even omitted from the final programme because no papers were received (or at least not accepted). In the following sections the general observations per main theme are summarised, please note that these impressions are based on the presentations we attended, for a more complete overview we refer to the proceedings. These can be accessed via the CD on the V-drive (V:\I\Congressen verslag\ICAP2006) or Kennisplein. In the appendices, you find additional observations from Sandra en Co concerning the sessions each of us attended.
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Developments in Asphalt Pavement Materials 1.1 Asphalt mix design 1.2 Low-cost surfacing materials 1.3 In situ and laboratory characterization and modeling of pavement materials 1.4 Improving the performance of granular base materials 1.5 Improving the performance of asphalt binders 1.6 Reuse and recycling 1.7 Utilization of process materials and by-products 1.8 Foamed mix 1.9 Water damage in asphalt 1.10 Asphalt cracking 1.11 Asphalt reinforcement 2 Structural Design for New and Existing Pavements 2.1 Development of long-lasting pavements 2.2 Validation and implementation of the 2002 Pavement Design Guide 2.3 Effects of European standardization of truck weights and dimensions 2.4 Pavement-vehicule interaction 2.5 Low-volume road design 2.6 Accounting for frost action and seasonal effects 2.7 Life-cycle cost analysis 3 Pavement Performance 3.1 Long-term performance studies 3.2 Full-scale and accelerated pavement testing 3.3 Measuring pavement performance 3.4 Pavement instrumentation 3.5 Modeling pavement deterioration 4 Pavement Investigation and Analysis 4.1 New developments in backcalculation of pavement layer moduli 4.2 Innovative approaches to the interpretation of deflection data 4.3 Developments in non-destructive pavement analysis 4.4 Pavement profile analysis 4.5 Collection and analysis of distress data 4.6 Characteristics of safe pavements 4.7 Pavement noise 4.8 Measurement and analysis of other surface characteristics 5 Highway Operations 5.1 Partnership in pavement construction and maintenance 5.2 Performance-based contracts and specifications 5.3 Risk management in pavement construction 5.4 Quality systems 5.5 Advancement in construction techniques 5.6 Reduction of user disturbance 5.7 Preventative maintenance 5.8 Pavement preservation tools 5.9 Sustainable development List of topics addressed at 10th ICAP 1.6.1
DEVELOPMENTS IN ASPHALT PAVEMENT MATERIALS
This main topic was by far the largest theme of the conference and as such it covered a wide variety of sub-topics. An interesting observation mentioned by several people was the spin-off of the SUPERPAVE mix design system in the US. Although the system itself may have its drawbacks, the fact that the same tests are used throughout the US provides a common starting point. They feel that this facilitates sharing of knowledge and experience and thereby speeds up developments. This is an interesting observation with regard to the implementation of the European standards for AC in 2008. In interesting contribution in this respect dealt with an attempt to integrate these standards in a
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mixture design method by a Norwegian cooperation of highway agency, material suppliers and research institutes. Concerning response modelling and classical damage types, a lot of Dutch work is still mentioned as state of the art, but where concerning newer materials (half warm mixes, highly modified mixes) most of the contributions are from non-European participants (South Africa and Asia). The keynote lecture was on pavement cracking, showing that the approach in the US is still focussed quite strongly on separating the various damage mechanisms. It provided a nice overview, but limited new insights. The current focus is on energy approaches, but this doesnot really present anything new either. 1.6.2
STRUCTURAL DESIGN FOR NEW AND EXISTING PAVEMENTS
The key issue here is the mechanistic-empirical desing approach, the heart of the AASTHO 2002 guide. It is not generally applied, but it is clearly gaining momentum. The most interesting aspect is that they try to combine material, climate, structural and traffic data in one over-all approach. We do not yet have something like it, so despite all the problems and uncertainties raised in various presentations (how to get your data, how to calibrate the models), it is an interesting starting point for the increasing demand for a Euro-design code to go with the European standars for AC. Because the ME approach requires traffic spectra rather than ESALS, it triggers contributions in the area of pavement-vehicle interaction. These are of varied quality, from attempts to somehow summarize those spectra to get back to ESALS to WIM-like systems and simulations of trucks to assess the most important influences on the dynamic load. 1.6.3
PAVEMENT PERFORMANCE
Pavement performance is partially dominated by Accelerated Pavement stories, but most of them stress the need to bridge the gap between the APT and field data. An interesting topic was based on the claim that since road users care only for comfort, which is smoothness, pavement performance indicators should be related to this parameter. It is an interesting approach, but it neglects aspects like splash&spray and rutting, also mentioned as important for comfort by our users, and skid resistance which is linked to safety. With regard to pavement deterioration, the focus appears to shifting from practice-like tests to modelling. This doesnot mean that there aren’t still a number of contributions on simple performance tests or pavement-like tests, but these are mainly variation on the well-known themes. Some interesting work on rutting is presented by LCPC and OCW/Nynas (France, resp. Belgium). Several American groups are working on simulating various deterioration mechanisms like rutting and cracking. The limiting factor in these approaches appears to be the material modelling, with the input limited to tension (cracking) or compression (rutting) tests. However, these limits are acknowledged and they all claim to work towards general models. 1.6.4
PAVEMENT INVESTIGATION AND ANALYSIS
An interesting observation is that, where there would appear to be a close link between this topic and the previous, this is does not appear to be the case. Where the contributions in the previous section focus on testing and modelling from a material-based point of view, those in this section aim at pavement inspection and the link to management systems. Using Pavement inspection data for the ultimate validation or the identification of necessary modification of pavement performance models is not addressed. Another observation is that our standardized inspection routine appears to be fairly advanced. Several contributions address feasibility studies into such routines and the development of network condition databases. Concerning the registration of construction parameters, however, especially the Americans appear to have rather elaborate quality control and data storage systems. The impression
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obtained is that they use these also in there innovative contracts, which could be interesting for our current developments.
1.6.5
HIGHWAY OPERATIONS (CO VAN DER VUSSE)
Vooraf: Deelname vanuit het BOH is ingegeven door het thema Highway Operations waaronder wordt verstaan a. management models - partnership in pavement construction and maintenance - performance based contracts and specification - risk management in pavement construction - quality systems b. technical and organizational issues, including topics as - reducing of user disturbance - preventative maintenance - pavement preservation tools - sustainable development - safety issues. Deze onderwerpen zijn min of meer terug te vinden in de papers/presentaties. Daarnaast heb ik onder meer aandacht geschonken aan onderwerpen die te maken hadden met longlife pavement, performance/eigenschappen van verhardingen (stroefheid, geluid), dunne deklagen, zeer open asfaltbeton en recycling. Als waardevol zijn mij opgevallen de papers/presentaties over - het reconstrueren van een drukke autosnelweg (M4) in het verkeer door P.Scott (UK). Er is veel aandacht geschonken aan de informatie aan de gebruikers en omwonenden en dat het komt overeen met de aanpak van de reconstructie van de A10 west. Opmerkelijk was de verkeersoplossing. Overdag’s was hetzelfde aantal rijstroken (versmald) beschikbaar voor het verkeer. In de nacht werd het verkeer naar 1 rijbaan geleid en de 2 verkeersstromen (1-1) werden gescheiden door kegels. Dat is volgens de RWSrichtlijnen ondenkbaar. Toch was het aantal ongevallen niet opvallend. - innovatie en performance contracten door S.Brown (UK). Highways Agency is ruim 10 jaar geleden overgegaan op een andere werkwijze (en forse reorganisatie) waarbij meer aan de markt wordt overgelaten. Het functioneren van de weg is vastgelegd in functionele specificaties/eisen en het is een lange termijn benadering met partnership oa om de veiligheid te verbeteren. De bedrijven zijn niet snel geneigd om nieuwe werkwijzen/oplossingen te introduceren die ze nog niet goed beheersen maar wel het risico van dragen. Ze denken nu aan bdfo(peration) contracten met een duur van 30jaar. Ook wordt de aannemer in een zeer vroeg stadium betrokken bij de voorbereiding van het contract dus nog voor de inschrijving. Kwaliteit wordt zwaar meegewogen, bij nieuwbouw contracten is de verhouding 70 – 30% (kwaliteit – prijs) en voor onderhoud is dat zelfs 80 – 20% . Dit is voor RWS een belangrijk thema. - eigenschappen van het wegdek in relatie tot het gebruik is belicht door: Brillet (FR). Dat heeft bij de Fransen geleid tot het niet meer toepassen van een bepaald mengsel (SCAC) op de snelwegen ivm stroefheidsproblemen. Bovendien gebruiken zij voor een hogere stroefheidswaarde materiaal met een hoge PSV en polymeer bitumen. Fernandez ( PORT). De Portugezen overwegen om de eisen voor stroefheid te verhogen. Dit is interessant ‘’knoppen materiaal’’. - beperking van geluid is belicht door Tighe (CAN, proefvakken oa rubberasfalt), Carter (CAN, theorie ontstaan van geluid). Zie ook dunne deklagen. - analyse van de onderhoudsfrequenties irt de schade (Brillet, FR). Uitkomst van het onderzoek is inzicht in de maatgevende schade (thermal cracking 37%, stroefheid 31%). Dat inzicht heeft er toe geleid dat er nu meer VTAC/dunne deklagen worden toegepast. - interessant voor diegenen die duurzaamheid een warm hart toedragen is de paper van L. Uzarowski (CAN). Hij geeft een interessante beschouwing over duurzaamheid en pleit oa voor beperking van afval, beperking van nieuwe materialen, beperking van zware transporten en een life cycle benadering.
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- opmerkelijk is de aandacht voor preventief (klein) onderhoud aangestipt door Hein (CAN) welke het systematisch benaderd en Yilderim (USA) die inzicht gaf in het cursusprogramma van zijn door 2 universiteiten gestichte instituut voor preventief onderhoud. De cursus is bestemd voor beleidsfunctionarissen en uitvoerenden. Beide onderbouwden het nut met de stelling dat het achterwege laten van preventief onderhoud leidt een veelvoud van meerkosten later. (1$ nu ipv 4 a 10 $ later). - aan longlife benaderingen is door diverse personen aandacht geschonken: Lane (CAN). Zij legde relatie met contracten en ging in op hoe een langere levensduur bevorderd kan worden door middel van specificaties (per jaar). Zij zoeken het overigens vooral in de contract/garantieduur. Deze is nu 7 jaar. Zij streven naar 10 jaar. Haas belichtte return on investment met een interessante theorie geïllustreerd met een praktisch voorbeeld van een weg (DBFM) in Canada met een contractduur van 99 jaar. Rada (USA) ging in op het long term pavement programma (ontwerp en kwaliteitsborging). Overige onderwerpen: - dunne deklagen zijn door diverse personen (Ertman Larsen DK, Pretorius SA) belicht. De Denen doen onderzoek overigens in samenwerking met IPG (DWW) en Pretorius heeft onderzoek gedaan naar betrouwbare criteria voor dunne deklagen. - zeer open asfalt beton is door de Zwitsers onderzocht met zelfs een proefvak voor 2zoab. Ze melden belangrijke daling van het aantal ongevallen. - aan rap ofwel recycled asphalt is ruim aandacht geschonken oa in de plenaire sessie (zie Sandra) oa vanwege de voordelen voor het milieu: geen of minder nieuwe materialen, minder transportkosten, het asfalt wordt ter plaatste vernieuwd hetgeen vooral aantrekkelijk is in gebieden met een lage dichtheid van asfaltwegen ofwel zonder vaste asfaltmolens. Hosokawa (JAP) bracht een spectaculaire produktiemethode waarin in een arbeidsgang de bovenlaag werd gerecycled en een nieuwe toplaag werd aangebracht. Bij de samenvattingen is nog meer informatie te vinden.
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Specific questions asked by DWW-colleagues
1.7.1
MARKTBENADERING, DE WIJZE VAN SPECIFICEREN EN TOETSEN IN D&C
- CONTRACTEN Zou vallen onder thema 5.2 , Higway Operations-performance based contracts and specifications en 5.4 Quality systems. Brown is ingegaan op de performance contracten (zie highway operations) maar ook in andere papers is er iets van gezegd (Lane)
1.7.2
DE WIJZE WAAROP (DAARIN) MET CE
- NORMEN WORDT OMGEGAAN
Een Noors initiatief om via de CE-normen tot een ontwerpprocedure te komen, uitgewerkt door wegbeheerder, onderzoeksinstellingen en leveranciers kwam nog een beetje in deze richting (paper nr 1.1-3). 1.7.3 EUROPESE STANDAARDISERING VAN NOISE PERFORMANCE VAN PAVEMENTS. PAVEMENT NOISE, THEMA 4.7, had wel enige bijdragen die behandeld zijn in combinatie met andere onderwerpen oa dunne deklagen (zie highway operations).
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1.7.4
KLIMAAT EN WEGDEKKEN
Meest relevante bijdragen die ik heb gehoord gingen over cold-in place recycling, maar dat was niet vanuit milieu oogpunt maar pragmatisch: afgelegen wegen, lang vervoer en hoge kosten leiden tot het ter plaatse met de aanwezige materialen her-paven. Er was wel een firma aanwezig (Green ARM) die een en ander vertelden over het in een arbeidsgang recyclen van de bestaande bovenlaag en het aanbrengen van een nieuwe toplaag 1.7.5
EFFECTS OF EUROPEAN STANDARDIZATION OF TRUCK WEIGHTS AND DIMENSIONS
Thema 2.3 had geen bijdragen. De nadruk in dit hoofdthema lag op de AASHTO-design guide met zijn mogelijkheden om aslast spectra in te voeren en de worsteling hoe hier mee om te gaan en wegdek-voertuig interactie. In die laatste categorie liepen de benaderingen uiteen van uitgebreide simulaties met truckmodellen om de meest belangrijke aspecten die tot verhoging van de belasting leiden te komen (kwam toch uit op vlakheid), via WIM-inputs tot equivalente aslast beschouwingen zoals we die klassiek gebruiken. 1.7.6
PAVEMENT VEHICLE INTERACTION
Zie genoemde onder 1.7.5 1.7.7
STILLE VOEGOVERGANGEN (I.E. THORMA JOINTS)
Er was een presentatie over joints maar die ging over het dichtingsmateriaal en niet over stille voegovergangen. List of upcoming events highlighted during the 10th ICAP 1.8 Theme/topic organisation date th Advanced characterization of pavement 4 3D FEM in June 20-22 2007 and soil engineering materials Pavements Consolidating Best Practice 9th CAPSA: sept 16-19 2007 Int. conf. On heavy vehicle ISHVWD 10 & may 19-22 2008 ICWIM 5 Managing Pavement Assets ICMPA June 25-28 2008 Pavements & Environment ISAP symposium Aug 18-20 2008 Int conf on Asphalt Pavements 11th ICAP 2010
location Athens, Greece Gaborone, Botswana Paris, France Calgary, Canada Zurich, Switzerland Japan
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Appendix A Notes Sandra Note: the section number equals the topic number +1 (because of the automatic numbering of word), theme number and a chronological sequence, i.e. section 2.1.1 concerns the first main theme (1+1=2), first sub theme (1) and the first presentation attended on that topic (1). Titles are paper titles and the numbers in brackets behind third-level headers are the paper numbers on the CD. If no third level titles are given, I did not attend sessions on that topic, the titles are included to maintain the topic-related numbering. 2
Developments in Asphalt Pavement Materials 2.1 2.1.1
Asphalt mix design NORTH AMERICAN SHIFTS IN HOT MIX ASPHALT TECHNOLOGY (42)
He presents the history of hot mix asphalt technology as something strongly related to changes in vehicle technology. Presents an overview of developments in time, with rules of thumb as the initial approach, followed by Hubbard system of design after tior to the mid-1900s most asphalt mixtures were formulated using recipes although some early mix design methods were being developed. In the latter 1900s HMA design was dominated by the Marshall method of design, a method adopted in many countries throughout e 1920’s where void percentage and something equivalent to void in mineral aggregates was used. Then the Marshall design after the 1940 (no mention of the Hveem tests and design method). He also states that SHRP was basically a reaction to a rutting epidemic in the 80’s. SUPERPAVE’s performance grades include the time and temperature effects on bitumen and mix performance, allowing rut mix design. Part of SUPERPAVE’s importance is claimed to be the acceptance throughout the US of the same design method. This paved the way for the 2002 ASTHO mechanistic empirical design guide, but the general acceptance thereof is not yet at SUPERPAVE levels. An idea that is garnering general acceptance is the perpetual pavement approach, where high strains yield short life times and low strains yield perpetually lasting pavements (R: in material mechanics terms: stresses and strains in the initial response envelop do not cause damage). An approach of just replacing the top layer becomes wide spread (R: something we already do in our maintenance approach). There is a lot of attention on practical aspects like paver segregation, joint quality and construction effects (like a truck driver spraying diesel in his truck to prevent the asphalt load from sticking to it..). Most of these topics are addressed in the Netherlands as well, but from what I hear here, we are generally a bit further ahead. 2.1.2
DEVELOPMENTS IN EUROPE AND IN THE EUROPEAN ASPHALT AND BITUMEN STANDARDS (43)
Egbert presents an overview of the existing European standards, the reasons for establishing them and the route to arrive there. He relates his presentation strongly to the bitumen specs and the initiation thereof in 1990, because they are still under development. HE stresses that it takes this long because all stakeholders are part of the process. Goes on to explain thart the standards for AC will be mandatory for all Europan member states starting january 2008 (R: hopefully it will have similar benefits as SUPERPAVE, shared standard allowing more cross reference of experience and shared research). As an aim for the future he describes standards that use only functional requirements, which does not include any compositional requirements. Ideally, one standard would than be sufficient. He stresses the importance of environmental issues on the European agenda and it’s effects on mixtures via warm, half warm etc techniques. Presents two-layer laying techniques as a successful innovation (Q: our results have not been so good, weren’t they?). Finally, he also shows rollpave, quite elaborately with many photo’s (reaction in the room is incredulous), unfortunately he doesnot mention it is a Dutch initiative.
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2.1.3
DEVELOPMENTS IN HOT MIX ASPHALT IN ASIA (44)
The presentation consists of an overview n numbers (length of roads, percentage PA) of pavement developments in Asia, followed by an overview of the tests used, which are well know tests like wheel tracking (for rutting), Cantabro (for ravelling) and four point bending (for cracking). The Cantabro test and steered wheel tracking test in laboratory have been adapted to evaluate the raveling resistance of porous asphalt concrete spec. for intersections. Then it goes on to microscopic pictures of SBS modified asphalt, where they aim at high SBS contents to improve rut resistance and reduce water sensitivity. This is followed by field tests for friction, a dynamic friction tester which uses a spinning disk, similar to Wehner-Schulze, that is part of the ASTM (ASTM E1911-98) and an acousrtic field measurement with a microphone on the axle (road acoustic checker car). Basically, they seem to be vartiations on tests known and used in Europe and/or the US. 2.1.4
TRENDS AND CALLENGES IN HOT MIX ASPHALT (45)
Presentation on environmental issues in road engineering. He starts with the use of recycled asphalt, where use is driven by financial incentives (cheaper than new material), with the challenge of providing the same quality. Air quality criteria also result in an increase of warm (versus hot) mix asphalt, specifically alonf the east and west coast. The problem of run of water during heavy rain fall (because of paving/covering of most of the surface in populated areas, which limits infiltration. They look into PA to solve this for roads and parking lots, with sublayers with 40% voids which seem to work really well even in cold climates. Noise is also becoming an issue, for the approach here he refers to the Netherlands, with open surfaces rather han soundbarriers. For perpetual pavement design her refers to the website of the asphalt alliance where there is a free Monte Carlo and Wesly based design program available. 2.1.5
EVALUATION AND CHALLENGES OF THE FLOW NUMBER SIMPLE PERFORMANCE TEST (1.1-2)
Presents the old flow number test (where a differentiated fitted polynomial was used to determine the actual flow number from the test curve) and the new one, which is quite different. It looks like a triaxiaal set-up and can be run both with and without confinement. They use specimens 150mm (!) high and 100mm diameter and friction reduction between the plates (which look to be of equal or slightly smaller D than the specimen?). Because of the rather complex set-up they started out to simplify the set-up. Simplification includes simpler deformation measurements. They make flownumber mastercurves, by running tests at various temperatures and stress levels and shifting the results (exact procedure unclear, check paper). They checked the sensitivity to volumetric parameters specifically air voids and bitumen content. They used over 1000 asphalt specimens, including both DOT mixtures and mixtures from field validation studies, to compare the materials Flow Number property against the actual field performance. The results showed that the Flow Number test has potential for ranking the relative performance of asphalt mixtures, determining the performance history of asphalt mixtures (in terms of deformation resistance), determining the optimal binder content of asphalt mixtures, and examining the effects of air voids on asphalt performance, but both confined and unconfined tests did not respond as strongly as expected to low void percentages (<3%). They claim that that locally based criteria could be established to determine local performance in rutting. 2.1.6
DEVELOPMENT OF A NEW ASPHALT MIX DESIGN SYSTEM IN NORWAY (1.1-3)
Based on PROKAS project aimed at developing functional specifications, ran from 1998 to 2004. It was a combined effort of road authorities, contractors, material suppliers etc. One objective was to develop performance-based specifications for Norwegian asphalt mixtures. During the project, new test methods were tried out and useful experience regarding properties of typical “Norwegian” asphalt mixes was gained. A new mix-design procedure has been sketched based on the results from the project. In this procedure, a new asphalt binder selection system for mix design is used. The system is based on local climate conditions and traffic loadings. The method focuses on material selection and particularly binder selection. For binder content selection, they use the gyrator. For performance tests they used the Indirect Tensile Stiffness Modulus (ITSM) test and the Indentation Repeated Load Axial Test to assess the elastic modulus and deformation properties respectively. It correlates well with SUPERPAVE for conventional mixtures.
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Field samples are taken and tested to assess their performance with respect to the functional requirements as follow-up to the actual mix design. They started testing the design method and produced a number of sections with different mixtures in2005, obviously evaluation will still some time. A remark with respect to the CE- guide is made, but it is not quite clear how this fits in. NOTE: They show a table of mixture properties where PA performs more poorly that AC on permanent deformation! Check definition. 2.1.7
AGGREGATE QUALITY AND THE INFLUENCE ON THE RUTTING IN ASPHALT PAVEMENTS (1.1-4)
Conclusion is that modified binders respond better with respect to rutting (tsja), research mainly based on determining the effect of aggregate on resistance to studded tyres and that is what most of the presentation is about as well. The relation to rutting is sketchily at best. Mostly he mixes up rutting and damage due to studded tyres (might explain the weird ranking from previous speaker). 2.1.8
COMPARISON OF FIELD AND LABORATORY COMPACTED ASPHALT MIXTURES (1.1-5)
A presentation on an approach that involved image analyses and mechanical tests to asses the most representative lab compaction method. They used several compaction methods, gyratory compaction, vibratory compaction (kango hammer), slab compaction and field compaction with dead weight rollers, wheel rollers (?) and vibrating rollers and various aggregate and binder types. They analysed 4 horizontal planes per core. They focussed on the orientation of the particles in those planes (so not the 3D structure or pores). In terms of aggregate orientation, slab compacted specimens tend to mimic field compaction better than gyratory and vibratory compaction. Where moulds are used, tendency to preferential orientation was stronger. The mechanical properties of slab compacted specimens were in some cases also closer to those of field cores than those from the other compaction techniques, but the stiffness modulus and permanent deformation resistance of field cores are still considerable lower than those of any laboratory specimens. R: it appears that this was almost literally the same presentation as given at CAPSA last year??? 2.2 2.2.1
Low-cost surfacing materials DETERMINATION OF MATERIAL PROPERTIES OF BITUMEN STABILIZED MATERIALS USING TRIAXIAL TESTING (1.3-22)
Presentation on a program to characterize the behaviour of bitumen stabilized materials for use in cold in-place recycling for numerous reasons. Focuses on the results of the monotonic and long duration dynamic tri-axial tests on various mixtures with crushed rock (limestone) and millings (RAP) which were treated with two types of bitumen emulsion, as well as with foamed bitumen. It was found that for the blends with mainly RAP, the bitumen emulsion produces a mix with a slightly higher shear resistance than foamed bitumen. For the blends with less RAP the use of foamed bitumen resulted in more shear resistance than emulsion. The friction angle appears to be mainly influenced by the aggregate used and not by the type of binder. He established a transition between secondary and tertiary type response at a ratio of deviator over normal stress of 0.4/0,5 he actual level differs per mix composition and binder type. Also, there are differences between mixtures in the sense that some mixtures can deal with higher strain levels before getting into tertiary flow than others. (R:This may help to establish the usefulness of various test conditions and/or failure criteria for various materials.) 2.2.2
THREE-DIMENSIONAL VISCOPLASTIC CHARACTERIZATION OF ASPHALT CONCRETE UTILIZING PERZYNA AND HISS METHODOLOGIES (1.3-22)
Description of nn enhanced viscoplastic model for irrecoverable deformations of asphalt concrete. They moved to Perzyna type plasticity after the independent validations tests couldnot be describd with the simpler model they used. They se (and state it) a ACRe like approach, but visco-plastic rather then strain rate dependent, the adaptation the Scarpas group made shortly after finishing the original ACRe project.Their initial model did not include hardening, the more advanced model does. Incorporation of temperature and loading rate effects is via an extended time-temperature superposition principle. Model calibration was based on cyclic creep tests with full recovery under two different loading historiesThey have now predicted monotonic (i.e. constant strainrate) tests that they did not use fr model calibration and those look good.
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They aim to use it for rutting analyses, but it is still only based on compression tests so it remains to be seen of it will work. Intensions are to also incorporate tension and such. 2.2.3
OVERLAY TESTER: A SIMPLE AND RAPID SCREENING TEST FOR CHARACTERIZING CRACK RESISTANCE OF HMA MIXES (1.3-24)
Presentation on the feasibility of using the Overlay Tester (OT) as a simple test for characterizing crack resistance of an stone skeleton asphalt mixes, to prevent rut resistance design from compromising crack resistance. The OT can be run on standard size samples, typically 150 mm long by 75 mm wide by 38 mm high, which are glued on to a set of steel plates with an opening between them. The plates are moved apart repeatedly, resulting in cracking of the asphalt above. Result is a crack length versus nr of load repetitions. He states that in a series of tests, it was found that asphalt absorption by aggregate appears to have a major impact on crack resistance of asphalt mixes. Q: do we have experience with that? They claim a good correlation with both fatigue bending tests and filed performance. R: instrumentation appeared rather limited, so it appears a simple empirical performance test. Check the correlations from the paper. 2.2.4
THE PERMANENT DEFORMATION LAW OF ASPHALT MIXTURES: INVESTIGATION OF THE EFFECT OF MIX COMPOSITION AND MATERIAL PROPERTIES (1.3-46)
In the presentation first Franckens early work on large triaxial specimens is summarized, than the new EU test is described and the differences are addressed. They try to establish if they can still use the old results hen interpreting the new results. As expected, they cannot simply use the A and B values from Frankens power law for permanent deformation, because the deformation in the new test is approximately 4 times as high as predicted with the formula. Their analysis is complicated by a rather high variability in the intercept value. The power is more reproducible and showed a reasonable correlation with binder characteristics. They find logical rankings in B for variation in binder type and mix type. They excluded the gyratory compactor as a method for specimen preparation because of the variability, instead they used slab compaction. 2.2.5
FRACTURE BEHAVIOR OF ASPHALT MIXTURES USING THE DISK-SHAPED COMPACT TENSION TEST AND DISCRETE ELEMENT METHOD (1.3-47)
The presentation deals with fracture in hot-mix asphalt, using a micromechanical modeling approach that of the materials’ heterogeneous microstructure via the discrete element method. They simulate the disk-shaped compact tension (DCT) using a clustering technique that realistically portrays the heterogeneous structure over the depth of the specimen is excluded. Butt you still need to assess the properties of the constituent materials that result in the cohesion and adhesion that is exhibited. They hope to use the approach for understanding and accounting for size effects in fracture tests and the modeling of cracking in hot-mix asphalt pavements. 2.2.6
CREEP MODULUS OF ASPHALT MIXES DETERMINED IN UNIAXIAL CYCLIC COMPRESSION TEST WITH “SOME CONFINEMENT” (1.3-48)
Presentation on the effect of several variables on the value of the Creep Modulus determined in the Uniaxial Cyclic Compression Test “with some confinement”, according to EN 12697-25 standards. Using the Nottingham Asphalt Tester they studied the following variables: stress level, loading time, rest period, curing period, testing temperatures and sample size. The purpose was also to compare the “some confinement” procedure with the traditional unconfined uniaxial cyclic compression test, which is not included in the standard. The results of this study indicate that the “some confinement” procedure could have a different influence on the Creep Modulus depending on the volumetric properties of the mix being studied and the testing conditions. He presents results on SMA and PA (but he talks about dense and pourous mixtures, where I suppose PA is porous and SMA is considered dense), where PA is more sensitive to creep, both with and without confinement. Also, the creep in both mixtures increased with test frequency. They conclude that adding some confinement is necessary to prevent underestimating the resistance to rutting. The confinement here is introduced by a restraint rather than by applying pressure and this would result in different confinement levels due to
11
the different response of the materials, thus creating a difference. It is unclear whether that matches with reality or not. 2.2.7
PERMANENT DEFORMATION CHARACTERISTICS OF AGGREGATE SKELETON IN ASPHALT MIXES (1.3-67)
Presentation on a project that aims to characterize rutting resistance of asphalt mixes by characterising the performance of the bitumen, mastic and aggregates respectively. On the basis of this, models will be developed for the behaviour of each component (Q: how will you put them together for overall reponse prediction?). Mixes selected are ZOAB 0/16, SMA 0/11 and DAB 0/16, the aggregates skeletons are in some cases compacted with some water. He did not check whether the aggregate skeleton achieved is comparable to those in the asphalt mixtures. This presentation deals with characterisation and model development for the aggregate skeletons. The characterization was performed by means of triaxial testing involving both stress controlled monotonic failure tests conducted at constant confinement and permanent deformation tests conducted under cyclic and constant confinement. He shows failure tests where DAB exhibits a peak,but both SMA and ZOAB look more elsto-plastic, in all cases the deformation was dilational (i.e.: volume increase R:something that will be constrained in AC by the binder, loading it in tension). The permanent deformation of aggregate skeleton under cyclic confinement was higher than the permanent deformation under constant confinement. He also states that the stresses at 10% permanent deformation in the cyclic tests (plotted on I1sqrtJ2) for ZOAB and SMA are close to those at failure in the monotonic test, for DAC they are much lower? 2.2.8
REPEATED AND UNIAXIAL TENSILE CREEP TESTING OF ASPHALT CONCRETE (1.3-68)
Presentation on results from laboratory testing undertaken to characterize the tensile behaviour of two generic types of asphalt mixture (bitumen macadam and ???). Uniaxial tensile creep testing and repeated load creep testing have been undertaken over a range of conditions. For both mixtures, increasing the stress level and/or increasing the temperature was found to reduce the time to failure. The elastic moduli of both mixtures was found to be independent of stress level and the steady state viscous behaviour was found to be non-linear. Both approach and results are in line with the ACRe project results, this is a next step, where cyclic loading is being included. They do not yet state modelling or simulation results. 2.2.9
RUTTING PREDICTION OF ASPHALT CONCRETE MATERIALS USING A MULTI-CRITERIA VISCOPLASTICITY MODEL (1.3 – 87)
During the past few years, many efforts have been devoted to the study of rutting problems. Under high traffic loadings together with extreme environmental conditions, permanent deformations of asphalt pavements appear and become more and more severe, requiring more efforts with regard to developing suitable predictive models. In this paper, a three-dimensional elasto-viscoplastic model is developed and applied to describe the behaviour of asphalt concrete materials under cyclic loadings. The model is based on a double-criteria visco-plasticity model and focuses on the coupling of a Drucker-Prager type criterion with a customized quadratic criterion. This is in order to take into account the evolution of volumetric deformations and the role of the shear strains on the establishment of permanent deformations. The kinematic hardening law is introduced following the continuum thermodynamics framework together with Koiter's evolution law for plasticity followed by an extension to viscoplasticity using a Duvaut-Lions type formulation. The model is validated using experimental results of dynamic creep tests. A numerical method for high-cycles calculation will also be presented.
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2.3
In situ and laboratory characterization and modeling of pavement materials
2.4
Improving the performance of granular base materials
2.5
Improving the performance of asphalt binders
2.6
Reuse and recycling
2.6.1
PAVEMENT RECYCLING – THE USAGE OF ASPHALT PAVEMENT RECYCLING TO ACHIEVE TECHNICAL, ECONOMICAL AND ENVIRONMENTAL SUSTAINABILITY IN ROAD SERVICEABILITY (169)
In this presentation an overview of the techniques (quite fast, little detail) for recycling is given along with the general advantages, cost benefit, environmental benefits and such. According to him, road owners nearly always choose to use it for financial reasons (Q: is it short time benefit or also for LCA?). He highlights the growing interest in the energy consumption of construction processes, where recycling has benefits over HMA, and cold over warm recycling. He stresses that recycling offers these energy and cost benefits with no compromise on quality. (Q:does that match with experience? For cold recycling as well as warm?). The high quality of current day recycled pavements is mainly due to advances in equipment accuracy and quality, according to the speaker. He expects recycling to increase further due to budget constraints at the road owners and the focus on environment. 2.6.2
WHAT DO WE EXPECT FROM RECYCLING IN A ROAD CONSTRUCTION COMPANY? (170)
Starts by introducing the emulsion conference in France in octobre 2006. In his opinion recycling will grow mainly due to lack of materials, boh binder and aggregates are getting scarce, which makes recycling interesting. In the US they use >10% RAP, in France they have purchased a moblile plant to use 50% RAP. The standards in FRnce allow 10 % RAP in binder courses, 15 % in ( lower layers ??). He believes that the performance is the key to get more recycling accepted by road owners. 2.6.3
DEVELOPMENT AND PERFORMANCE OF ASPHALT PAVEMENT RECYCLING TECHNIQUES IN THE AMERICAS (171)
In this presentation a standard rehabilitation/overlay job on a major Ontario highway was flanked by a cold in place recyling of the original pavement, overlayed with a superpave mixture with modified binder. The standard job shows reflective cracks after a few years, but the other is still looking very good (R: uclear if anything was done to stop the cracks from coming through in the standard case, nor if polymers were used there. If not, comparison is rather unfair.) On foamed bitumen he mentions that mixing is essential for quality, not high tech foaming equipment. He states that this is the reason that the strength achieve in the field can be considerable higher than those in the lab if it wasnot mixed properly in the latter. For this reason, he pleads for using strength achieved instead of target water content as criteria, since the water content necessarily is in equilibrium with the surrounding moisture conditions and thus situation dependent. He shows data where eventually the stiffness of foamed asphalt exceeds that of HMA and claims this could be used in the design (R: it can, but only f the strength is also higher!!). A limiting factor on foamed ad other recycling techniques according to the speaer is the road authorities fixation on the cheapest bids, rather than LCA approaches. 2.6.4
EVOLUTION OF FLEXIBLE PAVEMENT RECYCLING IN ONTARIO – AN AGENCY’S PERSPECTIVE (172)
This presentation provides an overview of recycling use in Ontario from 1989 to now. Initially, central hot recycling was the key method, gradually giving way to hot in place recycling and currently a shift towards full depth cold in place recycling, often with foamed asphalt. Some quality (IRI an such) data presented shows that most CIR pavement last for at least 11 years, against 15 years for full depth reclamation, with similar performance up to 7 years of life, after that on smoothness FDR performs better than CIR, which starts to deteriorate more rapidly. As an essential factor in success, the pre-project evaluation in order to assess the suitabilityof various recycling approaches for that work is mentioned, but it is not clear what criteria they use for this assessment. The province of Ontario has a series of design manuals for these techniques, which are available trough their website (). A leading role in the implementation is attributed to the contractors in the Ontario region.
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2.7 2.7.1
Utilization of process materials and by-products FATIGUE BEHAVIOUR OF BITUMEN-FILLER MASTICS (1.8 – 99)
Purpose of the project is to develop or select a standard testr for fatigue in binders and/or mastics. They used a series of fillers, among which a sewage residue, in various quantities. Tests included direct tension at various strain rates and temperatures. In the test both cylindrical and hemispherical geometries were used (between flat plates and between rounded plates). The third test used was the DSR. Increase in filler content for a given filler results in both an increase in stiffness and an increase in fatigue life. For a stress criterion you see stiffening from bitumen to mastic to mixture, for strain criteria bitumen and mastic are almost the same. They did the DSR at low temperatures in order to ensure that failure was purely in fatigue, without flow. They found that various grade bitumens from a single crude source wen tested at equi-stiffness conditions showed comparable fatigue response, while the same grades from different sources tended to show different response. The fatigue tests were performed using oscillatory shear loading in the DSR at 10°C and 20°C at a frequency of 10 Hz and it shows that the fatigue is influenced by filler concentration but not by filler type. Also, no stress or strain dependency (criterion) for pure bitumen or bitumen-filler mastics was apparent in the results. 2.8
Foamed mix
2.9
Water damage in asphalt
2.9.1
DETERMINATION OF BOND STRENGTH AS A FUNCTION OF MOISTURE CONTENT AT THE AGGREGATE-MASTIC INTERFACE (1.9 – 72)
Moisture infiltration into asphalt mixes can have a negative effect on the material characteristics of the individual components and damages the bond between the components, leading to separation of the aggregates from the asphalt mixture (i.e. stripping). The phenomenon of stripping is a complicated process involving a combination of physical, chemical and mechanical processes. This paper’s focus is on damage to the aggregate-mastic bond caused by a weakening of the interface due to diffusion of moisture. The adhesive tensile strength of the interface between thin film asphalt mastic and a diabase aggregate substrate is determined via a modified version of ASTM D 4541 Pull-Off Strength of Coatings Using Portable Adhesion Testers. Experimental results of the pull-off test are linked to moisture diffusion simulations via the finite element analysis tool RoAM (Raveling Of Asphaltic Mixtures) developed at Delft University of Technology. On the basis of this combination of experimental measurements and computational analyses, for the first time, bond strength degradation as a function of the amount of moisture at the mastic-aggregate interface is established. The paper extensively describes the proposed methodology and identifies future research on the topic. 2.9.2
EVALUATION AND CORRELATION OF TENSILE STRENGTH RATIO (TSR) AND PERFORMANCE OF ASPHALT PAVEMENTS IN WISCONSIN (1.9 – 73)
The Wisconsin Department of Transportation (WisDOT) has been using the Tensile Strength Ratio (TSR) test (ASTM D-4867) to predict the potential susceptibility of asphalt mixture to moisture damage and other associated pavement deterioration. The objectives of this paper are to evaluate the relationship between the performance of asphalt pavements in the field and the TSR values measured in laboratory on the original asphalt mixtures used in constructing pavements, and to evaluate the effect of anti-stripping additives on field performance. To assess the moisture damage problem in the field, 21 existing WisDOT pavement sections built prior to adoption of the TSR parameter requirement were selected to cover a wide range of locations and aggregate sources. The TSR and the pavement performance data (Pavement Distress Index or PDI) for these projects were collected from the WisDOT Pavement Management Database. The results indicated no relationship between TSR and field pavement performance as measured by the PDI, and no relationship between TSR and specific pavement distresses related to moisture damage (surface raveling and rutting). To evaluate the effect of using anti-stripping additive, a database study was conducted. The database showed that antistripping additives do have an effect on pavement performance.
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2.9.3
NUMERICAL SIMULATION OF THE PHYSICAL PROCESSES INDUCING MOISTURE DAMAGE IN ASPHALTIC MIXES (1.9 – 165)
Very fast presentation, showing that the moisture and mechanical processes are now combined, giving damage in a moisture laden pavement which exceeds the damage by the same loads on the same material which is not influenced by moisture. She shows the ACRe constitutive data as well as data on the interface strength, have to check if this is actual test data or assumption. It was shown that based on the combination of properties a simulation could result in either adhesive or cohesive failure. 2.9.4
MOISTURE DAMAGE EVALUATION OF ASPHALT MIXTURES USING AASHTO T283 AND DC(T) FRACTURE TEST (1.9 – 166)
Bill Buttlar presents and he states that due to the rutting problems in the 80’s in the US their mixtures were made leaner, with the result that they now have a lot of cracking. Their assumption is that this is not just due to temperature and traffic stresses, but that their absorptive aggregates in combination with little binder also make the material sensitive to moisture and aging. They carried out fracture test (several types, among which ITT DSC, the disk shaped compact tension test) on dry and wetted specimens made with polymer modified and conventional binder. Visual observations and fracture test indicate more stripping in non-modified material, but TSR results contradict this. No clear overall conclusions. 2.9.5
SUITABLE TEST METHOD FOR PREDICTING EFFECT OF STRIPPING ON MECHANICAL PROPERTIES OF CANADIAN PAVEMENTS (3.3 – 167, SHOULD BE 1.9!)
Presentation on a search for a simple test to evaluate moisture sensitivity of AC mixtures, claiming that the existing tests yield different rankings of the same mixtures. \they used standard road engineering tests like ITT, DSCT, Marshall etc on dry and moisture conditioned specimens from lab prepared and field cores. First goal is to differentiate between good and bad mixtures, second to distinguish between mixtures, third a correlation with other tests and finally simple testing. Shows what looks like an extensive statically analysis, but so fast that I’m not sure. The best scoring (from the tests used) test was the Marshall stability. 2.10 2.10.1
Asphalt cracking PAVEMENT CRACKING: MECHANISMS, ANALYSIS, AND MITIGATION (KEYNOTE LECTURE)
Rogue distinguishes “classical” bottom-up fatigue cracking and thermal and top down cracking. Causes are understood, mechanisms are not, and that is the missing link to get to more accurate predictions, as well as pavement design approaches and material specifications that more effectively mitigate this form of distress. (Q: if the mechanism is not known, how can you be sure that the causes are nown?). States that researchers have made important progress that has led to a general understanding of factors that affect asphalt pavement cracking and to the identification of mechanisms that may lead to fatigue, thermal, and top-down cracking. Reviews what is known about cracking mechanisms in asphalt pavement, what challenges remain to enhance our understanding, and how we might proceed to overcome these challenges. He lists a number of assumptions and simplifications that result in differences between lab and pavement repsons, like differnces in stress conditions, relaxation in practise, healing, avering effect over time and location in pavements. He observes that: • Not all loads cause distress • Most damage is healable • Distesseis stepwise, not continuous • Permanent damage requires presence of critical conditions Based on large and variable shift factors and reverse trends (lab ranking completely different than pavement performance) indicate that important factors are not (correctly) taken into account. Discusses endurance limit (no failure beneath 70-90 microstrian) and postulates that this is not so much due to a threshold strin, but because under those levels the healing rate exceeds the damage rate.
15
Deals with the 50% stiffness limit as failure, claims gthat this is a non-fundamental criterion that introduces differences between lab and reality. Shows work from di \bennedetto from 2004 where it is clear that higher stiffeness materials tend to fail at S-values higher than 50%, approaching 100% for the very stiff ones (R: illustration of brittleness!!). Also, the stiffness at which fail;ure occurs depends on test conditions (strain/stress control, uniformity of strain field). Shows data where if fatigue threshold is not exceeded (no increase of deformation/ decrease of stiffness (R: couldnot reed vertical axis) where after rest the exact same response is observed. If the threshold is exceeded, after rest healing is observed, but to a lower level and with rapid decrease after loading is resumed. Rey claims that the threshold is a fundamental value, independent of mode of loading (strength, cyclic and creep were tried). Defines this as the Dissipated Creep |Strain Energy (DCSE) as a more fundamental damage criterion, where this is the point at which macro cracking starts/rapid degradation commences. It is basically a transition of stable energy dissipation to rapidly increasing energy dissipation. R: I’m not sure how the healing rate is taken into account, if at all. Does calim that for any mixture this approach yields a unique relation which can be used for any test, whether strain or stress controlled (if you know the energy dissipation therein?). Remarks on material and structural non-uniformities (cracks, stress redistribution etc) which coause actual situation to differ from assumed one in design. Shows figures from Kim, 2004 where you see damage move from bottom to top due to increasing layers thicknesses. (R: similar to what we showed in late nineties…). Suggests that fatigue cracks at the bottom of the pavement might not in fact occur and refers to a paper by Andre Molenaar from 2004? That also poses this question, proposing that bottom damage is more likely to be distributed in nature due to lack of stress concentrations (R: material weakness concentrations will still result in cracks, which cause their own stress concentrations). Another reason for cracking being top down rather than bottom up that he discusses is the more advanced ageing at the top, the larger and faster changing temperature at the top, causing the top to be more sensitive. So early on in a pavement l;ife distress will be due to faulty design, later on (after about 5 years) material damage might occur, with the top being most sensitive). He refers to field tests as the ultimate thruth, bu cautions that usually you don’t know all the facts about it which limits the usability. From a selection of over twenty field sections the prediction (ranking) with respect to cracking damage three were predicted incorrectly, the others performed to prediction (R: he did not specify what they used as a criterion, check paper!). 2.11 3
Asphalt reinforcement Structural Design for New and Existing Pavements
3.1
Development of long-lasting pavements
3.2
Validation and implementation of the 2002 Pavement Design Guide 3.2.1
DEVELOPMENTS AND CHALLENGES IN MECHANISTIC - EMPIRICAL PAVEMENT DESIGN METHODS (105)
He refers to Monismith’s lecture on the history of mechanistic-empirical design, which is placed on the ISAP website (check it out), as an important source for his presentation. He gives a historical overview, starting by Burmisters publications on multi-layer systems, on to the various computer codes for multi-layer analyses published through the years, among which he lists VEROAD (linked to TUD). This represents the mechanistic-component, the locally based (temperature, subgrade, traffic etc related) relations needed to go from there to the predicted pavement response/design criteria are the empirical part. He goes into more detail on OPAC 2000, a 2 layer equivalent ME code, which includes a 2 step calibration (for the local empirical component). It predicts / uses as input (?) the pavement service sate in time with separate degradation due to environmental and traffic components. Calibration involes design and evaluation by local experts, which is eventually made more ob.jective by regression analysis of predicted and actual response. The second ME-code discussed in detail is new AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG), referring to El-
16
BAsyouny&Witzac’s 2005 AAPT contribution on the topic. As implementation challenges he identifies the necessary highway agency knowledge-to-apply-correctly, distribute budgets, assess and update pavement performance indicators, calibration of traffic, materials, environmental input and distress output data. 3.3
Effects of European standardization of truck weights and dimensions
3.4
Pavement-vehicule interaction 3.4.1
CONCEPT FOR DEVELOPING A MECHANISTIC EMPIRICAL BASED CAN METHOD FOR NEW GENERATION AIRCRAFT (2.4-117)
Story on how ME is applied to assess potential damage by new aircrafts, uses FEM with \mohr Coulomb failure criterion, using superposition to get the loads, since the model is axi-symmetric and thus limited to a single wheel load. Relative effect of any pavement is expressed in a damage factor. Much of his work is initiated in response to the 2002 CROW observation that CBR was unsuited to assess plane damage capacity. Calculations are stored is a database, which is used to assess relative damage capacities for various conditions. 3.4.2
COMPARISONS OF DIFFERENT SUMMATION MTHODS TO ACCOUNT FOR FATIGUE AND RUTTING DAAGE IN AC PAVEMENT SUBJECTED TO MULTIPLE AXLE LOADS (2.4-118)
ME design uses axle loads spectra rather than ESALS, requiring a summation method. This presentation reviews various ways to account for the interaction between multiple wheel loads in an axle, to arrive on axle damage factors. His story is very chaotic, maybe the paper is better. It appaears that he determines the factors via various superposition methods, peak-peak strain, dissipated energy etc and compares them to lab tests meant to represent fatigue and rutting respectively. But the link between any test and actual pavement response is unclear and the summation is based on the assumption of linear elasticity for the material response, without differences between tension and compression response, so it looks like a lot of energy spent in a rather useless direction. 3.4.3
EFFECTS OF AXLE LOAD, SUSPENSION SYSTEM, VEHICLE SPEED AND PAVEMENT CONDITION (2.4-137)
Detailed investigation on the influence of several aspects of truck geometry on the dynamic load. They use TRUCKSIM, a model that appears to originate from mechanical engineering. I wonder if this adds anything to a two-mass-spring system in assessing the effect on the pavement? They find that pavement roughness and vehicle speed are the most important parameters. 3.4.4
THE DEVELOPMENT OF A VEHICLE/PAVEMENT DYNAMIC INTERACTION MODEL FOR A TRUCK POPULATION (2.4-138)
They try to develop a representation of heavy vehicles based on previous WIM measurements. Generall they represent the vehicles as two-mass-spring systems, where mass is know from the WIM’s. Pavement condition can also be obtained, but lateral position and spring stiffnesses are not known. They assume that the unknowns are normally distributed and use Bayesian statistics to determine them. First they assume a model, than based on the WIM data they fit the parameters. With the data they generate a fleet of trucks and check the result against the available data (or something like it…?). Based on this they describe the measured impact factors by a mean and 95% limits of these factors. Based on this, they used the model to predict these factors also for stretches of raod that were not used as input and the lines are on top of those showing the measured data. As future work he mentiones using the Dutch WIM data as actual input (does that mean that the data he showed is not really measured?).
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3.5
Low-volume road design
3.6
Accounting for frost action and seasonal effects
3.7
http://www.icap2006.fsg.ulaval.ca/english/page texte/ang-ptech-manu-2.htm - 2.72.8 Life-cycle cost analysis Pavement Performance
4 4.1 4.1.1
Long-term performance studies SUPPORTING THE DEVELOPMENT OF PERFORMANCE MODELS WITH LONG- TERM PAVEMENT PERFORMANCE DATA (106)
Discusses the Long-Term Pavement Performance (LTPP) program, a huge research program undertaken to provide data necessary to determine how and why pavements perform the way they do. In 2005 it consisted of 20GB of data. This kind of data is essential for any ME design code, because without the calibration component is not possible. Besides the distress inspections, the data set includes FWD data on test sections every 3 years, air temperature and precipitation data (can/should we combine GMS and winfrabase data?), sub-surface data build in pavement structures to assess base conditions. Furthermore, results from lab tests on HMA-mixtures are incorporated in the database. Currently, an effort to fill this in is underway as well as an effort to get traffic data, in order to couple material, structural, environmental and traffic data for response prediction and check it against the actual distress development. He stresses that I is important to use standardized definitions for distress, traffic loads etc in order obtain an objective database. In regards to the latter, WIM-techniques are mentioned. It is mentioned that over 100 reports are published based on the project and database, and that engineering students use actual data in their curriculum. It is not clear of this means the database is accessible for everyone? Might be interesting in order to decide on how we want to deal with our data? Future developments envisioned are focussed on the use of advancing material science in combination with the collected data to arrive at better models for both design and performance prediction (for maintenance). Discussion: The discussion at the end focuses on the necessity to sell these long-term, expensive data collection to politicians and the problems with it. Comercial firms are stated unwilling to invest in and contribute sensitive data to something the competition will also use. (R: show the benefits !! & find the buttons to push, i.e. vision, courage, environment) 4.2 4.2.1
Full-scale and accelerated pavement testing THREE DECADES OF DEVELOPMENT AND ACHIEVEMENTS: THE HEAVY VEHICLE SIMULATOR IN ACCELERATED PAVEMENT TESTING (108)
Presentation on South Africa’s Accelerated Pavement Testing, started in 1970 to bridge he gap between design methods and actual performance, especially for heavy loads. Their long-term goal is to develop design procedures that accurately take the environmental and traffic data into account. He gives an historical overview of the developments. From local test sections they soon went into mobile heavy vehicle simulators, which could be used in various regions to include the environmental factors. Since the early 90’s some US organisations have adopted the HVS for their APT research. He goes on to present a long list of groups using the HVS in various projects. These groups are combined in a user group in order to facilitate data sharing, unfortunately, no resulting insights are presented. Stress in motion (SIM) as a component of pavement-vehicle interaction is presented, with examples of tyre foot prints. He mentions a sensor used for variable depth deflection measurements, but doesnot go into how it works and what it is used for (may be in the paper?).
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He also presents the organizational form, stressing the involvement of industry (might be useful to see how they organize that) and shows a graph claiming that every rand invested in APT return between 2.4 and 6.3 rand. They developed design charts and design methods and are now in the proces of evaluating them, this has already shown that the material components and some other aspects need tob e adapted (especially the gap between lab and field data (Q: wasn’t that the objectve of APT??), this is currently underway and in a few years they hope to have beteer design methods. 4.2.2
DYNAMIC WHEEL LOADS ON SUPERPAVE PAVEMENTS (3.2-119)
States that wheel loads are important for design, but users care only for smoothness. So that should be incorporated in the performance prediction. Smoothness in this case is expressed in the IRI, they registered the right wheel track longitudinal profile yearly for asset of test sections. They use the profiles to asses correction factors for the dynamic effect the roughness would ad to a static wheel load. Most dynamically corrected loads are within 20% of the static value, with exceptions to over 30% difference. At higher speeds, the dynamic load increased further (R: sound logical, but it is probably dependent on the model used to get from profile and speed to load factor, so should betreated carefully). 4.2.3
RECONSIDERATION OF TIRE-PAVEMENT INPUT PARAMETERS FOR THE STRUCTURAL DESIGN OF FLEXIBLE PAVEMENTS (3.2-120)
He pleads for more realistic wheel loads, instead of limiting ourselves to uniform circular loads because that is all our software can handle. Shows some complex tyre models and the Stress In Motion system where slow moving wheels pass over steel pins and the corresponding vertical, lateral and longitudinal stresses are registered (R: essential for top-damage, like ravelling, surface cracking and to a lesser extend, rutting). He shows tat low loads (800kPa and 30kN) the contact surface is roughly circular, if the load increases the shape becomes rectangular, about twice as long in the longitudinal than the transverse direction. Measurement on actual trucks driving over SIM’s (and loading bridge) shows that the assumption of equal and symmetric distribution between the various tyres is very often incorrect, leading to wheel loads higher than assumed, with the stresses even higher because of the non-uniform distribution. Generally, the steering axle is the heaviest loaded. Based on the data, FEM simulations of multi-layer constructions using schematic wheel stress profiles (n vs m shape) (R: unfortunately with isotropic, linear elastic material properties!) and these analysis indicated that near-surface Strain Energy of Distortion (SED) may be utilised for pavement rutting studies in this asphalt layer. 4.3 4.3.1
Measuring pavement performance CORRELATION OF SMALL STRAIN STIFFNESS AND STRENGTH OF HOT MIX ASPHALT (3.3 – 98)
Presentation about a search for a “new simple performance test”, the Marshall test of this century. She looks at the Dynamic Modulus test and claims that where Marshall is a strength indicator, this test is representative for the small strain region. Unless there is a relation between this small strain stiffness and the strength, you cannot predict stress related damage by means of the stiffness results. She looks at the test as an rutting indicator, proposing that this damage is stress related. She also proposes that although rutting involves shear, it must initiate by densification in the wheel path (R: similar to what Arthur & I postulated in 2003, if shear is dominant PA would rut, son densification plays a key role in some way). She runs dynamic modulus |E*| and Simple Shear Tester (SST) shear modulus |G*| tests, adapting deformation rates in order to arrive at similar strain rates when you compensate for the geometry. Both dense and gap grade mixtures are investigated and aging protocols are applied. For young and aged specimens no correlation between stiffness and strength was found, especially for the SMA mixes. Also, the additives (cellulose fiber and fine mineral filler) used in the SMA mixtures had more effect on stiffness than on strength properties. The dynamic modulus and SST shear modulus did not rank mixtures in a similar manner, but both test methods were able to identify the same mixtures as being the softest and stiffest among the 11 studied mixtures. The same applied to the strength parameters, cohesion and indirect tensile strength.
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She suggests that the different material responses to mechanical loading in the compressive modulus |E*| and SST shear modulus |G*| are due to different loading and orientation. Generally she concludes that the tests seem able to rank mixes of similar composition, but if the composition changes the ranking doesnot work. Also field cores versus lab cores result in different result, be it due to compaction/composition differences or different ageing patterns. As a suggestion she sates that maybe both stiffness and strength are needed to characterize all AC mixtures, so two tests instead of one. 4.4
Pavement instrumentation
4.5
Modeling pavement deterioration
4.5.1
MODELING OF RUTTING IN ASPHALT FLEXIBLE PAVEMENT (3.5 – 10)
Goal was to understand rutting and to develop a usefull countering strategy. Asphalt was modelled viso-elasto-plastic with von Mises as bounding surface (R:means tensile strength equals compressive strength!). Mohr-Coulomb was used for the sub-layers. Parameters were determined by back calculation from strain measurements at the bottom of the AC layer in full scale rut tests. They model rutting in 2D with ABAQUS. They found that a super single cuases morelk rutting than dual wheels (how schematised?). This paper presents a finite element analysis modeling of rutting. The behavior of the asphalt concrete is described using an elasto-viscoplastic constitutive relation, while an elastoplastic constitutive relation is used for the lower layers. The model allows for taking into consideration the influence of both the loading period and the temperature. The numerical model is validated on accelerated pavement tests realized at LAVOC laboratory. Results show that rutting increases with the increase in the contact pressure and in axle load with a dominant role for the axle load. Wheel wander significantly affects the development and profile of rutting. Rutting due to the asphalt layer is generally accompanied by a pavement uplift. 4.5.2
A SIMPLE APPROACH FOR DESIGN AGAINST REFLECTIVE CRACKING IN ASPHALT CONCRETE OVERLAYS (3.5 – 143)
Very fast, complex story that is supposed to explain a very simple method. It is meant to replace the current Californian design method for AC overlays on concrete, which is a fixed thickness irrespective of conditions. So it’s clearly an improvement. They did fem analysis and couple the results to N-values using an elaborate regression relation (Read paper). 4.5.3
TOP-DOWN CRACKING ANALYSIS AND CONTROL FOR ASPHALT PAVEMENTS (3.5 – 144)
Presentation based on the proposition that longitudinal cracks are load-induced. \they build a lab set up to measure the tyre stresses, by mounting a wheel in a frame under an actuator and pressing it down on an instrumented AC slab (R: static!). He presented a shear stress analysis, but it was unclear (bad English) if it was measured (how do you measure shear stress??) or calculated, it looked like typical multi layer output, but could be linear FEM with the stresses from the tyre experiments imposed. He postulates that shear stress is the cause of any top-down cracking and that to avoid it the stress has to decrease or the strength increased. (R: I wonder how he wants to do the former..?) 4.5.4
A VISCOELASTOPLASTIC CONTINUUM DAMAGE MODEL OF ASPHALT CONCRETE IN TENSION (3.5 – 177)
They use a Schapery-modified approach, with input from frequency sweep data from the unixial tension test in frequency sweep and monotonic failure tests. They validate the model with tension tests at other conditions, among which random cyclic signal tension tests. They found very different rankings of tests on mixes with various binders when compared to ALF full scale results (concerning fatigue), they tried various tests and eventually found a reasonable ranking with strain controlled tests. They couple this to the relatively thin ALF pavement, which they motivate with thin and thick pavement simulations like we did for ACRe, where it shows damage initiating at both top and bottom for thick and purely at the bottom for thin pavements. R: potential problem is that their model is calibrated solely in tension, so predominantly non-tension states of stress in the
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pavement will be coupled to an incorrect response, so for example rutting can not be studied with this model. 4.5.5
RISK EVALUATION OF SURFACE-INITIATED CRACKING IN ASPHALT PAVEMENTS BY MEANS OF FUNDAMENTAL LABORATORY TESTS AND NUMERICAL MODELING (3.5 – 178)
Presentation on a combined experimental and numerical approach to surface cracking, where they take the coupled effect of temperature and traffic, using field measurements to determine extreme temperature gradients and traffic loads, after which they run cyclic tensile tests where the lower and upper stress levels are coupled to the thermal and combined thermal and traffic stresses respectively. R: I’m not sure why the deal with both aspects simultaneously, from a modelling point of view you should separate them, but they seem to intend to use the test as a performance test where they want to take not only the temperature sensitivity into account, but also the effect of traffic. 4.5.6
USE OF SHEAR TEST DATA FOR MIX DESIGN, PERFORMANCE ANALYSIS, AND RUT DEPTH PREDICTION (3.5 – 179)
Elaborate story on the process of test selection, showing among others a sheet with simple shear data on field compacted, slab compacted and gyratory compacted specimens, where the field compacted where lowest, than slab and finally gyrator with the last showing considerable scatter. The various considerations arfe mentioned, the conclusions are not, but apparently they decided to use th simple shear test at constant height (R; not surprising, since they developed it). He mentions a multiplication factor to get from SST-CH to rutting shear strain, based on FEM analyses discussed in the paper, but doesnot explain how it works (R:check paper). It was used in a waarnty project where the contractor ended up getting a bonus because the rutting after 5 years of surface life was less than 0,5 inch (12,5 mm). He also shows some mix design results whee the new mixture performs much better in the test than a number of CALTRANS rut resistant mixes, it doesnot appear to be used yet. Would be interesting to see if by negelecting the volumetric deformation component they have created a potentially great mix which cannot perform like that in the pavement or not? They used a M-E type approach using the shear stress at the edge of the wheel at 2” depth (Q why there?), compare it to some FEM approach and the Asphalt Institute subgrade strain criterion for rutting (Q: that is secondary rutting, does it compare?) He presents slides showing rut depth versus ESALs for various mixtures, but it is not quite clear if it are shear test data, or curves based on them somehow, I guess the latter since the test has neither rut depth nor ESALS in it. 4.6
Performance indicators for pavement management
4.7
Lessons learned from pavement performance programs
5
Pavement Investigation and Analysis 5.1
New developments in backcalculation of pavement layer moduli
5.2
Innovative approaches to the interpretation of deflection data
5.3
Developments in non-destructive pavement analysis
5.4
Pavement profile analysis
5.5
Collection and analysis of distress data
5.6
Characteristics of safe pavements
5.7
Pavement noise
5.8
Measurement and analysis of other surface characteristics
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6
Highway Operations 6.1
Partnership in pavement construction and maintenance
6.2
Performance-based contracts and specifications
6.3
Risk management in pavement construction
6.4
Quality systems
6.5
Advancement in construction techniques
6.6
Reduction of user disturbance
6.7
Preventative maintenance
6.8
Pavement preservation tools
6.9
Sustainable development
6.10
Safety issues
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Appendix B Notes Co van der Vusse
Verslag van het 10e ICAP Congres te Quebec van 14-17 augustus 2006 Co van der Vusse Vooraf: Deelname vanuit het BOH is ingegeven door het thema Highway Operations waaronder wordt verstaan a. management models - partnership in pavement construction and maintenance - performance based contracts and specification - risk management in pavement construction - quality systems b. technical and organizational issues, including topics as - reducing of user disturbance - preventative maintenance - pavement preservation tools - sustainable development - safety issues. Deze onderwerpen zijn min of meer terug te vinden in de papers/presentaties. Daarnaast heb ik er onder meer aandacht geschonken aan onderwerpen die te maken hadden met longlife pavement, performance/eigenschappen van verhardingen (stroefheid, geluid), dunne deklagen, zeer open asfaltbeton en recycling.
Maandag 14 aug 2006. Opening en plenair. Presentatie van Rey Roque (zie verslag sandra). Hij gaf een overzicht van de ontwikkelingen sinds ca 1960. Er is veel veranderd. Belangrijkste mechanismen zijn fatigue - thermal cracking – low temperature cracking. Vergeleek de traditionele fatigue approach (continue verloop van het kwaliteitsverlies) met de critical condition approach (stapsgewijze verloop van de kwaliteit). Zolang de microstrain beneden de kritische grens blijft (treshold) herstelt de stijfheid van de constructie. Op een bepaald moment verlaagt het kwaliteitsniveau door veroudering. Bij dikkere constructies wordt de spanning kritisch aan de bovenkant van de constructie. Dus alleen herstel schade aan de bovenzijde (=deklaag).
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Hij pleit voor onderzoek naar de mechanismen die daaraan ten grondslag liggen. Ik vraag me af wat we daarmee opschieten. Wat kunnen we met al die kennis die waarschijnlijk gekoppeld is aan bepaalde mengsels en klimaatverkeersomstandigheden. Nb de noord amerikanen rekenen ook klimaatinvloeden (temperaturen vb winter – 30 zomer + 30gr) tot environment.
6.11
Parallelsessies 13.30 – 15.00
Current State of Porous Asphalt in Switzerland L. D. Poulikakos Swiss Federal Laboratory for Materials Testing and Resarch, Empa, Switzerland
ABSTRACT: As of January 2004, 131 km of Swiss motorways are paved with porous asphalt with heterogeneous composition and performance. This paper gives an overview on long term insitu performance as well as some specific technical aspects of maintenance and rehabilitation. Swiss standards, mix design, binder types and a selection of typical results of mechanical tests performed on cores will be discussed. These cores were chosen based on feedback from the individual local road authorities and vary in terms of binder type, age and performance. KEYWORDS: Porous Asphalt, mix design, maintenance, mechanical tests, hydraulic permeability Er is ervaring met 151 km porous asphalt. De oudste toepassing is 13 jaar oud. Zij schatten de levensduur op 15 jaar. De geluidsreductie is 4 a 6 dba, dat roept de vraag op naar de referentie. Boven 600m wordt het niet toegepast vanwege het gebruik van sneeuwkettingen (=schade aan wegdek). Poulikakos meldt een grote daling van het aantal ongevallen. Na afloop de Nederlandse ervaring gedeeld (minder ongevallen maar ernstiger afloop vanwege de hogere snelheden, onveiligheid per saldo gelijk). Gemodificeerde bitumen is standaard in tegenstelling tot Nederland ivm onduidelijkheid over eigenschappen bij hergebruik. (bij 2zoab wordt het bij ons wel in de bovenste laag toegepast tegen afdruipen). De doorlatendheid wordt getest (pr EN 12697-19), lijkt op een laboratorium test. (15l/min).
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Development of sustainable thin noise reducing surface layers in Denmark H. Ertman Larsen, Danish Road Directorate, Danish Road Institute, Denmark ABSTRACT: There is great need to develop effective noise reducing pavements which are durable, safe and cost-effective and which reduce the disturbance of the road user and the neighbours of the road. The noise can be reduced either at source during propa-gation or at the receiver. An effective and sustainable way to reduce noise and avoid an-noyance is to decrease the emission from the source. The noise is generated when the tires roll on the pavements. The type and structure of the road pavement is important for the determination of noise level emitted. Like porous pavements, thin layer pavements have a noise reducing potential on urban roads as well as on highways. In Denmark, a project on urban roads was started in 2003 and in 2004 the first test sections were in place on a highway. The goal was to develop and test thin durable asphalt layers as noise reducing pavements under Nordic conditions and under different traffic condi-tions. The project hypothesis, pavement types, and measurement program are high-lighted and the first promising data from test pavements are presented. Also in 2004, a research project on thin open surface layers started as a co-operation between the Dan-ish Road Institute (DRI) and the Road and Hydraulic Engineering Institute in the Neth-erlands (DWW) called the DRIDWW noise abatement program. This new project fo-cuses on optimizing noise reduction and finding the long term noise reducing effects of thin layers. The project plan for this new project will also be presented. KEY WORDS: Traffic noise, thin surface layers. Geluidproduktie is een aanzienlijk probleem geworden. De limiet is 55 dba (europese richtlijnen). Bij 28% van de wegen speelt het geluidprobleem. Uitleg van ontstaan van de geluidoverlast: 1. contact band – wegdek 2. luchtverplaatsing (circulatie in/op deklaag door rollende band). Afgezien van zoab vanwege de korte levensduur (zou 7 jaar zijn, wij hebben andere ervaringen), problemen met rafeling en de gladheidsbestrijding. Focus op dunne deklagen. Gebruik gemaakt van ervaringen uit frankrijk (studie uit 1990) en met Nederland wordt samengewerkt (IPG). De Denen hebben onderzoek gepleegd in 2003/2004. Onderzoek wordt vervolgd zowel in Nederland als in Denemarken (Herning experiment).
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Noise Reducing Asphalt Pavements: A Canadian Case Study Tighe S Department of Civil Engineering, University of Waterloo, Ontario, Canada ABSTRACT: Over the last 20 years, many highway jurisdictions have experimented with different asphalts that include blended recycled rubber particles as a way to re-use old tires as well as to monitor the effects of rubber in possibly reducing the aging effects in asphalt pavements. While there have been many claims of noise reduction from different agencies over the years, there was limited conclusive documentation and testing to support the claims. In late 2003, the University of Waterloo’s Centre for Pavement and Transportation Technologies (CPATT) and the Regional Municipality of Waterloo embarked on a partnership to first design noise reducing pavement test sections and then secondly to conduct controlled noise testing on four different types of asphalt mixes. The four different surface courses were placed in lengths of 600m. The overall 2.4 km test area was closed to traffic and four different test vehicles were driven through the test area at different control speeds with noise meters recording noise levels both at the tire/pavement interface as well as at monitoring stations off the roadway. Noise level test results have indicated that the special premium pavement mixes do achieve a reduction in measured noise. The paper will elaborate on the types of materials used, the testing protocol, the measured noise results and the conclusions which will be of use by other municipalities in assessing the merits of using premium surface course asphalts to reduce noise in urban, noise-sensitive environments. Susan is verbonden aan de universiteit Waterloo welke diverse onderzoeken uitvoert en beschikt over uitgebreide onderzoeksfaciliteiten (laboratorium en een testlocatie). Er zijn 4 proefvakken onderzocht waarvan 2 met rubberasfalt (rubberized open friction course/rORC, ruberized open graded course/rOGC, 1 SMA en 1 controle vak/hotlaid/HL3) Het geluid is onderzocht bij verschillende snelheden, verschillende deklagen en op 2 manieren * nabij (50cm) het rollende wiel (aanvoertuig, proximity method)\ * microfoon op 15m afstand in de berm (pass by)
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Daarnaast is het geluidsabsorptievermogen van de verharding in het lab gemeten. De resultaten zijn in het bovenstaande figuur weergegeven. Er was wel een indicatie van de kosten beschikbaar (resp 100 –100 – 65 –45) maar gemeld werd dat nader onderzoek nodig was
INFLUENCE OF TEXTURE ON TIRE/PAVEMENT NOISE A. Carter, École de technologie supérieure, Montreal, Quebec, Canada ABSTRACT. Tire/pavement noise has become a major factor in the choice of the pavement for the decision maker of the Quebec department of transportation. A literature review was done to understand the tire/pavement noise generation mechanism and to identify the methods, both in laboratories and in the field, currently use to measure the tire/pavement noise. To rank Quebec’s usual pavement by their noise level, 19 different sections were tested with a CPX noise trailer. Texture was also measure on the same sections; texture was measured with an ARAN van, a TM2 and the sandpatch method. The results have shown that the PCC sections are not noisier or quieter than the HMA sections. The transverse tining PCC sections were the noisiest for the concrete and one of the EG-10 was the noisiest for the HMA sections. A good correlation was found between texture and noise level for the PCC sections; the higher the texture, the higher the noise level. For the oldest HMA sections studied, the same relation was found. However, for the HMA surface treatment sections, there was also a good correlation, but this time the noise level decreases when the texture increases. For the HMA mixes, the noise level increase when the percent passing the 5mm sieve increases. This suggests that limiting the percent passing on the 5mm sieve might be a way to reduce the noise level on the HMA sections. KEY WORDS: Noise, Pavement, Texture, HMA, PCC In Canada wordt geen zoab toegepast vanwege de enorme hoeveelheden sneeuw (300 cm /jaar).
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Alan legt het ontstaan van verkeerslawaai op drie manieren - door contact band en wegdek - door luchtcirculatie op en in het wegdek nabij de band - in de band door de vervorming Beton zou niet zoveel geluid produceren, het ligt vooral aan de frequentie. Deze conclusie leidde tot vragen/ongeloof. Kennelijk zit de hinder voor mensen niet in het volume alleen maar ook in de frequentie.
15.30 –17.00 Innovative Surfacings: What’s New In New Zealand? David Faulkner, Managing Director Fulton Hogan Ltd, Christchurch, New Zealand
ABSTRACT: The paper discusses recent innovations, new technology and current projects that are specifically targeted at the next generation of pavements, for a wide range of areas covering environmental (eg Low-noise surfacings, asphalt recycling and utilization of processed materials and byproducts), developments in surfacing materials, maintenance and construction practices, data collection (eg seal texture measurement using digital imaging), and other related topic areas. Modern computer-controlled sprayers have been developed to apply bitumen at rates that vary transversely across the lane width and are being used when chipseal surfaces have insufficient macrotexture in the wheeltracks as well as a preventative measure for binder rise in the future. Ultra high-pressure watercutting has been adapted for use on road surfaces, to improve both macrotexture and microtexture of surfacings, to rejuvenate the surface to that of a near new surfacing. This paper presents results from initial research into these surfacing treatments as well as in-service performance results from up to 5 years monitoring of other innovative treatments discussed in the paper. In order to ensure the programme of treatments is always optimised, a holistic approach to solving skid and texture deficiencies on sealed roads has been developed, and this approach is described in the paper. The paper discusses the technical and environmental aspects of the treatments that make them sustainable, and the implications for the road authorities and contractors. The paper concludes with the author’s vision of the next generation of cost effective, smarter pavements. KEY WORDS: Macrotexture, Watercutting, Microtexture, Surfacing Treatments NZ is overgegaan op het meer inschakelen van de markt. Nu, na 10 jaar, zijn ze er aan gewend. Er is een sterk Asset Managementteam. De Road Authority definieert de gewenste outcome, bepaalt beleids- en performance maatregelen, voert uitbestedingsprocedures uit die kwaliteit en innovatie door de bedrijven aanmoedigen. De bedrijven ontwikkelen goede kwaliteitssystemen en onderhoudsstrategieën, innoveren door research en development en leveren de verwachte services en performance. Vervolgens is uitgebreid verslag gedaan over oppervlakbehandelingen; het aanbrengen en onderhoud daarvan. Er is een onderhoudsmethode getoond waarbij water met hoge druk het oppervlak reinigt/als het ware bouchardeert. Deze technieken zijn nmm vooral
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bedoeld op wegen met lage intensiteiten. Grote landen met een relatief kleine bevolking hebben veel te maken met dit type wegen. (hoge ontwerpsnelheden, weinig verkeer, relatief veel oppervlakteschade). Hij noemde nog een mogelijkheid van textuurmeting door digitale fotografie. In de toekoms zal NZ vooral te maken krijgen met - meer recycling - meer open asfalt technologie - focus op stroefheid en stille wegdekken - strategie leidend tot het maximeren van de levensduur en het reduceren van het gebruiken van grondstoffen die niet hergebruikt kunnen worden.
Refinement of Mix Design Criteria for 4.75mm Superpave Mixes R. West, National Center for Asphalt Technology, Auburn, Alabama, USA ABSTRACT: Pavement applications for which small aggregate size HMA mixtures are well suited include surface courses for low and medium volume roads, leveling mixes for correcting pavement profiles, thin overlays for pavement maintenance, patching, and parking lots. Advantages of these mixtures are that they can be placed at low spread rates, provide a smooth surface and tight joints, and can be feathered along edges without raveling. Potential limitations for small aggregate size mixtures may include concerns with permanent deformation, scuffing, skid resistance, durability, and cost. In 2002, the 4.75 mm nominal maximum aggregate size designation and criteria were added to the AASHTO Superpave specifications to fit the need for small aggregate size mixtures. The 4.75 mm mix criteria were based on a combination of experience, limited laboratory research, and engineering judgment. However, a number of agencies and contractors have had many years of good experience with small aggregate size mixtures that fit the 4.75 mm NMAS size designation, but do not meet some of the Superpave mix design criteria. Nine states are participating in this pooled fund study. In the laboratory phase of this study, test results show that design asphalt contents can be controlled by modifying design air voids and/or the number of gyrations. VFA seems to be a key indicator of permanent deformation and tensile strength ratio. Also, percent natural sand has a significant effect on volumetrics and performance. KEW WORDS: Superpave, Mix Design, Low Volume Roads, 4.75 mm NMAS Dit ging met name over speciale mengsels (AASHTO) voor wegen met lage intensiteiten en het volume binder effect. De AASHTO-mengsels waren ontworpen op een (te) beperkt onderzoek. De herziening van de criteria voor deze mengsels is gebaseerd op aanvullend onderzoek waarbij getest is op rutting, permeability, stripping en aging.
Chip Sealing Systems: Improving Early Age Chip Retention Anton Kucharek McAsphalt Industries Limited, Scarborough, Ontario, Canada
ABSTRACT: A number of solutions aiming at better chip retention have been tried over the years, such as using quick-set polymer-modified emulsions, using smaller and cleaner chips or modifying certain aspects of construction practices. This paper is intended to take an in-depth and more systematic look at various technical aspects that can have an impact on improving early
29
chip retention by an asphalt emulsion. A group of asphalt emulsions have been selected for this laboratory study, containing both anionic and cationic types and having different types of polymer modifications. Curing of the emulsions is studied by assessing the development of film strength in the binder layer by rheological measurements and by the Frosted Marble Cohesion test. Subsequently, chip retention on a variety of stone types is assessed by means of the Sweep Test for Surface Treatments. The outcome indicates that the CRS type emulsions and certain polymer systems show advantages in improving early chip retentions. KEY WORDS: Chip retention, surface treatments, emulsion curing, asphalt emulsion, chip seal Ging weer over oppervlakbehandeling op basis van emulsie nu ook geschikt voor wegen met een hoge intensiteit. Onderzocht zijn 10 emulsies (de meeste gemodificeerd) en 3 steensoorten. Er werd getest op cohesie (frosted marble cohesian test) en ook de sweeptest werd geduid. CRS (cationic rapid set) emulsies scoorden het hoogst op cohesie.
Surface Treatments in Asphalt Pavements - A Systems View S. Senadheera Department of Civil Engineering, Texas Tech University, Lubbock, Texas, USA
ABSTRACT: Many highway agencies of the world use surface treatments in their pavements, both as preventive maintenance treatments and as wearing courses in new construction and rehabilitation. The primary advantages of surface treatments are their low cost and rapidity of construction, both of which are extremely important to highway agencies. This paper looks at surface treatments in pavement engineering from a systems viewpoint by discussing the characteristics of surface treatments including its proper use, design, materials selection, contractor expertise, construction processes, quality control, pavement performance and most importantly, training of personnel. Much has been said about the construction of surface treatments being an “art” rather than a “science”. However, to understand the role of surface treatments in pavement engineering, it is important to adopt a systems approach that takes into consideration all the factors indicated above. The personnel involved in surface treatment work are often called upon to make decisions that will have major impacts on the performance of surface treatments and the pavement as a whole. The author has gleaned information and knowledge from a wide array of research projects he has conducted for the Texas Department of Transportation, including two comprehensive constructability reviews of surface treatments in preventive maintenance and new construction of asphalt pavements. Both these studies adopted a systems approach and involved the development and delivery of training programs to pavement professionals. In addition, the author has conducted research studies involving the selection of materials for surface treatments, and on quality control and quality assurance of asphalt binders in these applications. KEY WORDS: Surface treatments, chip seal, systems approach, constructability Wederom oppervlak behandeling op het menu. Dit maal een systeem overzicht . En de constatering dat er sprake is van een ontwikkeling van chip sealing naar surface treatment. (ik leg dat uit als van techniek naar functie). Er is systematisch onderzoek gedaan naar de componenten -selectie van projecten en ontwerp - constructie en acceptatie - performance 30
- voortdurende verbeteringen Het systeem maakt het mogelijk om de opp.behandelingensystematisch te analyseren teneinde het proces makkelijker te beheersen en te repliceren.
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Dinsdag 15 aug Plenaire zitting 8.3 - 10.00 zie ook verslag sandra NORTH AMERICAN SHIFTS IN HOT MIX ASPHALT TECHNOLOGY Gerry Huber; Heritage Research Group (Indianapolis, USA) ABSTRACT: The history of hot mix asphalt technology in North America has been closely tied to the need for transportation and changes in vehicle technology. Prior to the mid-1900s most asphalt mixtures were formulated using recipes although some early mix design methods were being developed. In the latter 1900s HMA design was dominated by the Marshall method of design, a method adopted in many countries throughout the world. Indeed, the Marshall method is the closest to a “universal” mix design method. In the late 1900s changes in the asphalt industry and widespread performance problems created a desire to develop updated material specifications and a new mix design method. Performance-graded asphalt binders and Superpave mix design was the result of this research. Asphalt mixture formulation and pavement structural design remain separate operations in highway design with only general connections between them. Conservative pavement thickness design has been a result of this imperfect connection. Thicker pavements minimize the effect of HMA properties on structural failure of pavements. Guidelines have been developed for perpetual pavements which minimize or eliminate fatigue failure in pavements. Today, research efforts seek to tie mix properties and pavement structural response. Progress is being made and the future holds promise that structural design will be done with mixture specific properties. NOTE: The full manuscript will be available on the second version of the CD.
Nmm voldoen we aan de door Huber genoemde criteria voor de perpetual award te weten - Levensduur constructie > 35 jaar - de constructiedikte bij benadering constistent - Vernieuwing van de deklaag meer dan 13 jaar. DEVELOPMENTS IN EUROPE AND IN THE EUROPEAN ASPHALT AND BITUMEN STANDARDS Egbert Beuving; European Asphalt Pavement Association (Brussels, Belgium) ABSTRACT: In May 2006 the new harmonised European Standards for Bituminous Mixtures were published. This means that 30 European Countries will have to use these new standards starting in January 2008 and conflicting national standards have to be withdrawn by that date. There are now European standards for Asphalt concrete, Asphalt concrete for very thin layers, Soft asphalt, Hot rolled asphalt, Stone mastic asphalt, Mastic asphalt, Porous asphalt and for Reclaimed asphalt. Next to these product standards there is a European Standard for Type Testing and one for Factory Production Control. Beside this there are also 43 European standards for test methods. The standards that were recently published are called the first generation standards. At this moment the standardisation committee for Bituminous Mixtures is now already discussing the second generation standards. These standards will be Performance Standards, describing the performance required of the mixtures without having requirements for composition and constituent materials. All relevant characteristics will to be
32
described using performance characteristics; the mixtures could be produced in a hot, warm, half warm or cold way. The fist generation of European Bitumen standards were published in 1999 and they are being revised at this moment. The European Standardisation Committee for Bitumen is now working on the second generation of Bitumen standards. Several activities took place and are taking place to find the best test methods to characterise performance related bitumen properties. Other European developments that will be presented are: - Noise reduction by using porous asphalt, double layer porous asphalt and thin and ultra thin layers; - The use of two-layer asphalt pavers; - Paving pre-fabricated asphalt layers from a roll; - Trends in the use of low temperature asphalt mixes. NOTE: The full manuscript will be available on the second version of the CD.
Ontwikkelingen in Europa onder invloed van de verschuiving van meer werk naar de markt hetgeen tot uiting komt in contracten en met name in de ontwikkeling van functionele specificaties. Hij laat de historie zien en komt uit bij de nieuwste richtlijnen. IN 2007/2008 worden de Europese standaards van kracht. Strijdige nationale richtlijnen dienen ingetrokken te worden. In 2009/2010 komen er nieuwe standaards voor bitumen. Belangrijke thema’s: milieu/environment,energie en CO2reductie, stankreductie op asfaltmolens, warmasfalt. Nieuwe ontwikkelingen: sma, open asfalt, 2 laags open asfalt, dunne deklagen, zeer dunne deklagen, asfalt op rol, high module asphalt, warm asfalt mengsels. Hij besteedde veel aandacht aan het RTF- rollpave experiment.
DEVELOPMENTS IN HOT MIX ASPHALT IN ASIA
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Atsushi Kasahara; Hokkaido Institute of Technology (Sapporo, Japan) ABSTRACT: Paved road construction has become national policies of urgent implementation in Asian. The pavement technologies of Asian countries have been developed based on AASHO road test and products of SHRP. The level of the technologies is the total strength of asphalt mix supply capability, paving machinery production, paving technology, labor skills, asphalt plant capacity and etc. Large volume of road construction job being daily taken in China, India and other countries will rapidly accumulate technical expertise and improve actual pavement technology. The increase of traffic volume has been causing serious problems; increase in number of traffic accidents and in traffic noise level in residential areas near to highways and busy streets. It is now the utmost important issue among other things to address the problems. For many years already the road authorities and the industry as well as the academics in Japan have studied and implemented porous asphalt concrete pavement, some fruits of which are widely shared worldwide. There are emerging new changes toward the future now. The followings ought to be noted as the major achievements of Japanese technologies regarding the porous asphalt concrete; 1) Cantabro test and steered wheel tracking test in laboratory have been developed to evaluate the raveling resistance of porous asphalt concrete, which is essential at the intersection of busy streets. 2) SBS high-content modified asphalt is widely used to raise resistance of water sensibility and rutting resistance. The Japanese manufacturing base of the material has made it possible to produce the very high quality of the modified asphalt. 3) Dynamic friction tester developed in Japan and now taken as ASTM E1911-98 has been used to measure friction properties of porous asphalt concrete as a function of speed. Road acoustic checker car is also used to measure contact noise between tires and pavement surface. NOTE: The full manuscript will be available on the second version of the CD.
Kasahara meldde opmerkelijke ervaringen met open asfalt in Japan. Een daling over 1 jaar van 2535 naar 416 ongevallen. De stroefheid wordt gemeten met een DF-tester, een alternatief van de SRT. Ook hier weer meting van de doorlaatbaarheid (1 ml/15sec als norm?). TRENDS AND CHALLENGES IN HOT MIX ASPHALT Kent Hansen; NAPA (Lanham, USA) ABSTRACT: The Hot-Mix Asphalt (HMA) industry in the United States has faced and met many challenges over the years. The rapid increase in the price of oil over recent years has resulted in an increase in the price and availability of all construction materials including asphalt and aggregates. Obviously the quantity of aggregate used in a mixture cannot be significantly reduced and reducing the asphalt content would have a detrimental effect on the durability and performance of HMA mixtures. Therefore, the HMA industry is looking to maximizing the use of recycled asphalt in mixtures while maintaining the quality and performance of the mix, as well as meeting ever more stringent environmental standards. Warm mix asphalt (WMA) has gained a great deal of interest in the US as a way to reduce energy consumption and reduce environmental concerns. Many WMA trials have been constructed across the US. Environmental issues related to stormwater runoff from impermeable surfaces such as pavements has required the industry to examine technologies
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such as porous pavements with stone recharge beds to reduce runoff. Road noise affects the quality of life for residents living near high-speed roads. The industry has been working with agency partners to provide guidance on surface types that will reduce noise and is working to get surface type considered as part of a noise mitigation strategy. Sustainability and life cycle costs are improved with Perpetual or Long Life HMA pavements. Because of the performance history of these types of pavements, they have become widely accepted, and research is being conducted to verify mechanistic design criteria. NOTE: The full manuscript will be available on the second version of the CD.
Hansen ziet in de sterke stijging van de olieprijzen kansen/uitdagingen voor de hot mix asphalt sector. Met name zal er nadruk komen op recycled materiaal. 15% rap (recycled asphalt) is al normaal en gedacht wordt aan 20%. Toepassing van rap is iets voordeliger (ook life cycle?). Pma (polymeer gemodificeerd asphalt) wordt toegepast. Er zijn proeven met 2 laags zoab met 40% holle ruimte in de 2e laag. Hij deed het congres de aanbeveling om 2zoab toe te passen zoals in Nederland. (Wij, RWS, hadden er geen verhaal, dat deden anderen wel voor/over ons, in gunstige zin).
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Parallelsessies 10.30 – 12.00 Factors Affecting Flexible Pavement Performance Based on the LTPP SPS-1 Experiment K. Chatti Department of Civil and Environmental Engineering, Michigan State University, East Lansing, MI, USA. ABSTRACT: This paper is a summary of results from a study on the relative influence of design features on the performance of in-service flexible pavements. The data used in this study were from the SPS-1 experiment of the Long Term Pavement Performance program. This experiment was designed to investigate the effects of HMA surface layer thickness, base type, base thickness, and drainage on the performance of flexible pavements constructed under different site conditions (subgrade type and climate). Based on various statistical analyses conducted on the data, base type was found to be the most critical factor affecting fatigue cracking, roughness (IRI), and longitudinal cracking (in the wheel path). The best performance was shown by pavements with asphalt-treated bases. When combined with base type, drainage also plays an important role in improving pavement performance, especially in terms of fatigue and longitudinal cracking. Base thickness has only secondary effects, mainly for roughness and rutting. In addition, climate was found to have significant effects, in that longitudinal cracking in the wheel path and transverse cracking seem to be associated with wet-freeze environments, while longitudinal cracking non-wheel-path seems to be dominant in Freeze climates. Also, in general, pavements built on fine-grained soils have shown the worst performance, especially in terms of roughness. Although most of the findings from this study support the current understanding of the influence of design factors, the study provides an overview of the interactions between design and site factors as well as new insights on various design options. KEY WORDS: pavement performance, design factors, site conditions, LTPP, SPS-1 experiment Long term performance pavement sps1 (special pavement study) Een experiment met: 12 testsites onderzocht op ontwerp 18 locaties met verschillende omstandigheden (ondergrond etc). Gelijke verkeersomstandigheden zijn gekozen om dit als variabele te neutraliseren. Ook in vries-dooi situaties zijn meegenomen.. concl. Funderingslagen van de constructie is de dominante factor voor vermoeidheidsschade/scheuren, langsonvlakheid en langsscheuren. De dikte ervan heeft secondaire effecten op het ontstaan van onvlakheid en spoorvorming. Wegen in vries-dooi omstandigheden vertonen een slechtere performance.
Modeling Long-Term Flexible Pavement Performance of Ontario Highways Lane B., P. Eng. Ministry of Transportation of Ontario, Canada
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ABSTRACT: The Ministry of Transportation of Ontario (MTO) uses several multiple performance indices in the newly implemented MTO Second Generation Pavement Management System (PMS/2). These indices can be used jointly or individually to assess pavement performance in terms of overall Pavement Condition Index (PCI), ride comfort index (RCI), International Roughness Index (IRI), and Distress Manifestation Index (DMI). Each of the evaluation indices may be used to address current pavement serviceability and predict future trends in functional adequacy, such as pavement structural strength and distresses. This study presents the long-term flexible pavement performance observed in the field after reconstruction or rehabilitation, as represented by a number of pavement maintenance and rehabilitation (M&R) strategies that are commonly used for preservation of the Ontario highway network. Historical construction records and provincial contract documents indicate that all of the 1,732 pavement sections in the provincial network have experienced at least one if not several significant rehabilitation activities since 1985. The long-term pavement performance trends of these pavement sections have been reported annually by PCI, RCI and DMI, for the past twenty years. The paper concludes with discussions and recommendations to modify the existing pavement performance prediction models that are currently used in the PMS/2 through correlation with the actually observed pavement performance trends for each type of pavement rehabilitation/reconstruction treatment. KEY WORDS: Pavement Performance, Evaluation, Indices, Modeling, Prediction. Het ministerie doet het routine maintenance. Verkeersklassen: hoog = 500000/jaar (ca 1500/dag, bij ons wordt het hoog bij 1500/uur) , laag = 50000/jaar (ca 150/dag) Opvallend is de kennis mbt de verwachte levensduur en er is een indrukwekkende dataverzameling. Enige noties mbt warranties/garantie - de termijn is 7 jaar - de eisen zijn per jaar gespecificeerd - over de 7 jaren periode moet de performance gelijk of beter zijn als die van het gemiddelde van100 overeenkomstige wegvakken. Over de ontwikkeling van een langere periode: - om 10 jarige krommes te kunnen ontwikkelen is het PMS gebuikt voor het vergaren van historische performance data. Er zijn sigmoidale modellen voor kwaliteitsverlies verharding. Door de registratie van de historie van het onderhoud en de confrontatie met de huidige situatie is inzicht verkregen in het verloop van de kwaliteit waardoor er beter voorspeld kan worden. Vraag over toegang tot pms data => contractanten kregen gegevens over de wegvakken die onder garantie vielen. Die was 7 jaar, 12 jaar is beter. De werkwijze is een bedreiging voor de werkgelegenheid bij het ministerie. echter de specificaties (voorschriften/richtlijnen) blijven. gebleven 7
Analysis of road maintenance sequences according to the evolution of
distresses F Brillet, Laboratoire Central des Ponts et Chaussées (LCPC), Bouguenais, France ABSTRACT: Within the framework of the preventive maintenance policy carried out on the
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French national network, the pavements are subject to systematic distress monitoring programs and condition indicator measurements: sideways force coefficient, transverse unevenness and macrotexture. The methodology, which was formalized in 1992 as the “Quality Image of the National Roads” (IQRN), includes particularly a triennial survey of the different distresses, with calculation of a total index. The analysis of such data made it possible to define laws of evolution for distresses, depending on the initial structures, traffic and successive maintenance operations. In order to complement this approach, a joint analysis of the pavement evolutions and maintenance sequences was undertaken. The work presented here analyses statistically the relations existing between the evolution of the observed distresses and the decisions made about maintenance. It also deals with the lifespan of a surfacing before being overlaid, according to observed pathology, and the choice of the technique used to answer this pathology. The selection considers asphalt pavements excluding cement stabilised bases. The study shows that there are implicit rules, more or less marked, concerning the priority given to maintenance, and the choice of the technique used (surface dressings, thin or thick asphalt overlays), according to the encountered problems (skid resistance, plastic deformation, fatigue or thermal cracking). KEY WORDS: Pavement, Deterioration, Maintenance, Decision rules Analyse van onderhoudsfrequenties/levensduren volgens de evolutie van schade. Monitoring programma: 30.000 km elke drie jaar, vakken van 200 m. Grote organisatorische verandering in het beheer: 13000km wordt overgedragen aan 11 regionale eenheden. Dat doorkruist het onderzoek. Onderzoek is gebaseerd op 2600 secties van 200m. Er zijn 6 type deklagen onderzocht. De uitkomst is inzicht in de omvang van de verschillende schadetypes: - thermal cracking 37% - plastische deformatie 7% - vermoeiing 21% - draagvermogen 4% - stroefheid 31% VTAC (dunne deklaag 2 a 3 cm) wordt nu meer toegepast.
Return on Investment Analysis for Long Life Asphalt Pavements Haas, R. Department of Civil Engineering, University of Waterloo, Ontario, Canada ABSTRACT: It is becoming increasingly necessary in life cycle analysis (LCA) of infrastructure assets, including pavements, to take a longer term approach than in past, conventional practice. This is largely for reasons of ensuring sustainability and assessing the future impacts of today’s decisions. Life cycle analysis can be primarily in terms of life cycle cost analysis (LCCA) but can also include considerations of resource conservation, environmental impacts, energy balance, etc. A reasonable time horizon for life cycle analysis should involve short, medium and long term periods, in the order of 25, 50 and 100 years, respectively. Conventional LCCA compares competing alternative investment strategies and can involve a range of stakeholders, from the elected level to the public at large to suppliers and consultants. Ofthe methods available, present worth of costs is almost exclusively used in the pavement field.
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However, when medium to longer term life cycle periods are involved, rate-of-return and costeffectiveness formulations can be applicable and should be considered. A numerical example is provided which shows how an agency can determine the internal rate of return (IRR) for an investment alternative involving a long life different pavement design and a life cycle period of 50 years. Conventional LCCA for calculating present worth of costs will undoubtedly continue to be used in the pavement field as a primary tool. However, going beyond conventional LCCA and using a rate-of-return or cost-effectiveness formulation, especially for medium to longer term life cycle periods, should be given more consideration. Voor lcc moet uitgegaan worden zeker service level. (level of service=los). Er zijn meerdere lcca-methoden: kosten-baten analyse, internal rate of return, equivalent uniform annual costs, kosten-effectiviteit en de huidige waarde. Nu denken in andere tijdvakken: korte termijn = 25 j, middenlange termijn = 50j, lange termijn = 100j. Kosteneffectiviteit staat centraal. Keuze van rentevoet is belangrijk. 4% (ned). Voorbeeld highway 407 in ontario. (etr = electronic tollroad). Er is een boek over. Het is een lange termijn concessie (99 jaar). Grapje van ralph => nu nog maar 92 jaar te gaan. De bank wordt er wijzer van. Verdient snel haar investering terug. vraag over prijsstijging: dat is the snake in the grass. uitgaan van gangbare prijzen bij de raming en gunning. stijging onderhoudskosten door olieprijzen => er wordt vanuit gegaan dat ook de inkomsten toenemen (groei verkeer). er zijn performance modellen gebruikt gebaseerd op veel data.
13.30- 15.00 DETERMINING SUBGRADE RESILIENT MODULI FOR PAVEMENT DESIGNS John Emery Geotechnical Engineering Limited, Toronto, Ontario, Canada
ABSTRACT: Many agencies are currently moving from well-established empirical pavement design procedures to the AASHTO mechanistic-empirical guide, which requires representative resilient moduli for mechanistic-based design. This case study reports on the use of a highcapacity falling weight deflectometer and dual mass dynamic cone penetrometer, as well as a parallel laboratory testing program, to determine representative subgrade moduli for a major design-build urban expressway in Edmonton. It was found that the resilient moduli of samples prepared at optimum water content, or less, according to AASHTO T307-99 were extremely high, deviating from the typical Mr ~ 10 CBR (MPa) by more than a factor of 2. Additional tests completed on a sample soaked for two days before testing and samples prepared at water contents consistent with conditions corresponding to the soaked CBR revealed that two days soaking was insufficient for the fine-grained soil to soften enough to cause a substantial loss in material stiffness, with the resilient modulus of samples prepared at water contents corresponding to the soaked CBR relating well to the relation Mr ~ 10 CBR. Good agreement was
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also found to exist with results obtained in the laboratory and those estimated from the in-situ tests. Considerable care must be taken with respect to selecting representative field moisture contents for preparing laboratory Mr-samples. KEY WORDS: Modulus, subgrade, falling weight deflectometer, dynamic cone penetrometer De AASHTO guide for design of pavementstructures stamt uit 2002. Belangrijke factoren in het onderzoek zijn de ondergrond, milieu/environment, het verkeer en de afwatering. De ondergrond, het klimaat en de afwateringscondities zijn bepalend voor de schade. Het grootste deel van de schade ontstaat in de lente ((de winters zijn koud, de lentes zijn nat en de zomers zijn droog).
Design and Instrumentation Plan for a Long Life Pavement in Ontario B. Lane, Pavements and Foundations Sections, Materials Engineering and Research Office Ministry of Transportation Ontario Downsview, Ontario, Canada
ABSTRACT: Transportation agencies are under increased pressure to extend pavement service life and reduce delays to the travelling public. These demands have resulted in the development of perpetual pavements, also referred to as long life pavements, which have an increased time interval between resurfacing, with a corresponding increase in structural value. A perpetual pavement is a flexible pavement designed from the bottom up to resist structural failure, minimize cracking and rutting, and last for 50 years or more with only periodic renewal. In 2006, the Ministry of Transportation Ontario (MTO) begins construction of its first perpetual pavements, with extension of Hwy 406, near Thorold and reconstruction of Highway 402, near Sarnia, Ontario. The Hwy 402 project will be constructed in three sections: a 4 km trial section of perpetual pavement with rich bottom mix as the lower binder; a 4 km trial section of perpetual pavement with Superpave 25 mm as the lower binder; and a control section of conventional flexible pavement. The perpetual pavement trials and control section will be instrumented, to better understand how the different pavement structures react and perform under various traffic loadings and environmental conditions. This paper describes the pavement design for each trial section on Hwy 402, the requirements for the rich bottom mix, and the instrumentation plan for installation of moisture probes, temperature gauges, earth pressure cells, and asphalt strain gauges which will be placed at different depths within the asphalt pavement structure. A long-term monitoring program will also involve annual Falling Weight Deflectometer testing, roughness and rutting measurement, and manual distress surveys. KEY WORDS: Perpetual pavements, long life pavements, instrumentation Lane spreekt van long life pavement als de levensduur 50 jaar of meer is. Bij dikke constructies openbaart zich schade alleen aan de bovenzijde. Het is van belang om de deklaag zo sterk mogelijk te maken = bestand tegen slijtage en spoorvorming. Onderzocht is een SMA met een ontworpen levensduur van 19 a 21 jaar uitgevoerd op HWY 402 lang 11,3 km bij sarnia/.ontario. Constructie was 80 hma, 200 beton, 150 mm stabilisatie), AADT 2295, 25% vrachtverkeer. Beproefd zijn/worden A. 240 mm asphalt en 550 mm fundering B 340 mm asphalt en 550 mm fundering. Beschreven wordt met name hoe zo’n proef opgezet en gemonitoort wordt.
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The Precision and Accuracy of Mechanistic-Empirical Pavement Design Theyse H. L. CSIR Built Environment, Pretoria, Gauteng, South Africa
ABSTRACT: The availability of mechanistic-empirical pavement design methods is increasing internationally. Although mechanistic-empirical design does offer some insight into pavement behaviour and performance, at least more so than empirical design methods, they remain mere models of the real-life pavement and are not perfect by far. Recently these design methods have evolved to include two aspects, the basic engineering knowledge and models incorporated in the method and the computational simulation techniques that are often used to introduce spatial and time variability in the design process. It is the opinion of the author that the introduction of the computational simulation techniques has shifted the focus of researchers and the developers of mechanistic-empirical design methods from the core engineering models that determine the accuracy of these methods to the simulation techniques that are merely computer coding exercises but do not improve the accuracy of the design methods. The paper provides an overview of concepts such as variability, precision, accuracy, bias or error and design risk in the context of pavement design. A simple classification of mechanistic-empirical design methods is also provided and the main components of these design methods are discussed in general. The effects of variability and error on the design accuracy and design risk are lastly illustrated at the hand of a simple mechanistic-empirical design problem, showing that the engineering models alone determine the accuracy of these design methods. KEY WORDS: Mechanistic-empirical design, Computational simulation, Variability, Accuracy, Design risk. Theyse zet grote vraagtekens bij de mechanistic-empirical design methodes. Hij heeft onderzoek gedaan naar afwijkingen in het ontwerp door afwijkingen in de input (tot 20%). Dit leidde tot merkbare fouten in het ontwerp (7% onjuist). Dat de computer nu gebruikt wordt bij het ontwerpen van mengsels maakt het niet beter als de input niet goed genoeg is. Hij riep overigens op om alvorens tot onderzoek over te gaan eerst goed na te denken over de noodzakelijke input en de effectiviteit van de output.
Conceptual Framework for Material Characterization in MechanisticEmpirical Flexible Pavement Design Y. Mehta Department of Civil and Environmental Engineering, Rowan University, Glassboro, New Jersey 08028 USA
L. Myers ABSTRACT: A conceptual framework for determining the type and amount of data necessary to successfully conduct materials characterization as part of mechanistic-empirical (M-E) flexible pavement design is presented. The framework will serve as an example approach for state highway agencies assembling data catalogs for routinely used asphalt mixtures for implementation of M-E flexible pavement design. This approach is particularly useful for agencies that plan to pool efforts regionally to obtain the necessary M-E flexible pavement design inputs; however, an understanding of local materials limitations is critical to the success of using this approach. Materials inputs for M-E flexible pavement design include volumetric binder/mix properties, dynamic complex modulus, creep compliance and indirect tensile strength. The first step in forming the conceptual approach was to identify what some state transportation agencies are already doing to prepare for M-E pavement design implementation. Based on a review of the
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various methods, an approach was formulated that consists of site evaluation of existing conditions, laboratory testing to obtain materials inputs, and analysis of inputs and resulting predicted performance. The final step consists of development of a database that contains mixture properties to be used as a materials catalog and consequently reduce the testing effort. Material datasets for a given location can be developed to identify the local or regional-specific inputs to M-E analysis. The framework was tested based on a case example with four mixtures from three northeastern US states and predicted rutting performance data was evaluated. KEY WORDS: Pavement design, mechanistic, empirical, framework, catalog. Gaat over de mechanistic-empirical pavement design guide (MEPDG). Maakt onderscheid in verschillende ‘’omstandigheden/klimaat cq landschaps’’ kenmerken te weten kust – vlakte – berg - woestijn en dat bij 3 verschillende verkeersklassen (hoog midden laag). Vat samen dat een grotere dikte niet altijd leidt tot minder schade en noemt een catalogus voor veelgebruikte mengsels ten einde het ontwerp proces te stroomlijnen. Het framework bepaalt het type en de hoeveelheid informatie nodig om te komen tot input voor MEPDG. 15.30 - 17.00
IMPROVEMENT OF THE SURFACE CHARACTERISTICS REGARDING THE SAFETY AND COMFORT OF THE USERS Francois Brillet Laboratoire Central des Ponts et Chaussées – Nantes – France ABSTRACT The main concerns of the construction financing authorities and people in charge of road maintenance in the industrialized countries concentrate on the improvement of the safety of the users and on the comfort of road displacements, but also with respect to the bordering populations. A judicious choice of the structures (durability), but especially of the nature of the wearing course, makes it possible to offer a combination of better conditions of adherence while authorizing a significant reduction of the noise level and a better division of the space for the various road users. A database on the skid resistance performances (CARAT) allows to consolidate the state of knowledge on the performance of pavement surfacing and to contribute to developing and evaluating new products. The influence and the durability on skid resistance of a particular family, including the composition, grain size, nature of the binder and polishing strength of the aggregate, is examined. Use of a highly skid-resistant surfacing on more hazardous sites, coupled with application of the micro-encrustation technique designed to enhance early-age skid resistance, is also detailed herein. Current trends with respect to road maintenance surfacing choices are indicated. The article closes with a look at the prospects for new techniques to enable increasing the durability of surface characteristics and thus spacing the schedule of maintenance interventions. KEY WORDS: Pavement noise, safety, skidding resistance, road driving comfort.
Brillet gaf inzicht in de franse werkwijze mbt het meten van stroefheid (carat, meting met adhere trailer). Stroefheid wordt uitgedrukt in de breaking force coefficient. De stroefheid van de verschillende deklagen is gemeten bij verschillende verkeers/snelheidsklassen. Het heeft er toe geleid dat deklaag type SCAC niet meer wordt gebruikt op hoge snelheidswegen. Voor een hoge stroefheidwaarde is een hoge PSV en polymeer bitumen vereist. LCPC heeft een Franstalige brochure (nr 255).
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EVALUATION OF THE RELATION BETWEEN FUNCTIONAL PROPERTIES OF ASPHALT PAVEMENTS AND TRAFFIC SAFETY A. Fernandes Department of Civil Engineering and Architecture, CESUR, IST, Technical University of Lisbon, Portugal
ABSTRACT: The main objective of this paper is to analyse the relationship existing between the functional properties of asphalt pavements and traffic safety. The paper’s content is based on preliminary studies about the Portuguese experience, performed for an ongoing PhD programme at the Technical University of Lisbon. Although accidents haven’t a unique cause because of the many factors involved, the current diversity of materials and pavement technology, in particular relative to the wearing courses, allows a wide range of solutions to be used and once again raises the discussion on the interaction existing between pavement properties and traffic safety. These recent and innovative techniques often result in increased costs, but their competitiveness compared to traditional techniques is assured by the fact that they provide more in-depth information on the behaviour of traffic. The main conclusions of the paper are related to international and the Portuguese experience on the relationship existing between skid resistance and traffic safety (braking distance, aquaplaning and vehicles losing control). These conclusions will be useful for future research, performed on a select group of roads of the Portuguese national road network, in order to support a new methodology for the design of functional pavement wearing courses based on traffic safety criteria. KEY WORDS: Road, pavement, traffic safety, skid resistance, texture.
Gebruik gemaakt is van kennis uit Britse onderzoeken. Allereerst is een ongevallen analyse uitgevoerd. Uit Britse en Amerikaanse onderzoeken blijkt dat in 28 a 34% de weg een rol speelt bij ongevallen. (de mens scoort het hoogst/94 a 95% en het voertuig 8 a 12%). In Portugal vindt 18% der ongevallen plaats bij nat wegdek. 15,5% der ongevallen heeft een ernstige afloop. Het onderzoek heeft er toe geleid dat de interventiewaarde hoger wordt deze waarde wordt in het PMS ingevoerd.
Evaluation of Automated Distress Collection Techniques: An Ontario Case Study Tighe S Department of Civil Engineering, University of Waterloo, Ontario, Canada
ABSTRACT: Pavement management systems (PMS) rely on consistent and repeatable distress data collection. Traditionally, such data has been collected through manual surveys, which are subjective, tedious and time consuming. Ideally, the data would be collected at travel or high speed, using state-of-the-art image capture equipment. The Ministry of Transportation of Ontario (MTO) has initiated a study with the University of Waterloo to determine which of these units or systems, if any, are applicable to Ontario needs and if so whether they can replace the existing manual approach which has been used for many years. The work plan has involved a comprehensive literature review, progressing to an identification of the most promising technologies and then the design and execution of a field experiment to compare and assess the automation technologies vis a vis the manual method. A set of recommendations/guidelines for high speed data collection and use in MTO’s PMS2 is expected to be the primary outcome. A preliminary investigation was conducted to determine significant differences or similarities between the performance of sensor-based and image-based pavement condition assessment, as part of a research effort sponsored by the Ministry of Transportation of Ontario, Canada. A data management plan for consistent data compilation was put in place to allow efficient data 43
manipulation. Second, a suitable set of similar distresses was selected as response variables of interest to design and conduct statistical experiments. Then, advanced analysis of variance was carried out to allow statistical data comparisons among companies and both automated technologies. The final step was to discuss the results and make recommendations. Overall, the results from this study indicate that there are no significant differences among contractors’ measurements using sensor-based equipment; however, there are significant differences among measurements taken using digital image-based technology. The implications of such outcomes are discussed in detail, including the specifics regarding methodology implementation in order to encourage practitioners to benefit from the preliminary investigation. In a broader perspective, this paper provides an opportunity for road agencies to revisit selection decisions concerning the acceptance or rejection of pavement data collected by a wide range of contractors. Een opmerkelijk verhaal in die zin dat in het land waar de Aran geproduceerd wordt de universiteit van Waterloo onderzoek doet naar de zin en van automatische schade registratie en beoordeling. Maar het is altijd goed om te evalueren. Het vastleggen van de schade kan op beeldmateriaal en met sensoren geschieden. Er zijn tests uitgevoerd op een 3-tal locaties waarbij de handmatige opname vergeleken is met de geautomatiseerd. De bevindingen van Tighe: - elke company heeft zijn eigen best practices, in de praktijk komen veel afwijkingen voor. - zorgvuldig gebruik van specificaties en goede richtlijnen, aangevuld met toepassing van benchmarking en calibratie kwaliteitsborgingstechnieken kan het hoofd bieden aan de vele afwijkingen die in de studie gevonden zijn.
Automated paving with data from road surface profiling Ekdahl P. Ramböll RST, Malmö, Sweden
uitgevallen
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Woensdag 16 augustus 8.30 – 10.00 Plenair DEVELOPMENTS AND CHALLENGES IN MECHANISTIC - EMPIRICAL PAVEMENT DESIGN METHODS Ralph Haas; University of Waterloo (Waterloo, Canada) ABSTRACT: The design of asphalt pavements was essentially empirical until about the 1950’s, at which time fundamental or theoretically based principles started to appear (see ICAP1, 1962). Over the next several decades, advances in applying these principles to what came to be called mechanistic-empirical (M-E) design were implemented in many countries. This presentation begins with a review of the evolution of M-E design, including the key role of computational advances in the process. Pros and cons of the various categories of M-E methods are identified, up to and including the new AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG). The presentation then steps back and defines what the basic performance outcomes of any pavement design method should be in terms of predicting serviceability – age; and/or service life; and/or number of traffic roads to terminal serviceability; and/or accumulation of damage over the service life – given that the inputs have been identified and characterized and levels of reliability established. However, mechanistic analysis itself only calculates such responses as stresses, strains and deflections at various points in the pavement structure, for variations in loads, temperature, material properties, etc. The challenge is to relate these responses to the basic outcomes noted above – which means calibration to the various inputs and to measured or observed in-service performance. Further, considering the many factors and their interactions affecting pavement performance, the calibration challenge also requires designers to identify which factors are most critical, how to actually carry out the calibration and how to implement it into practice. A still further challenge relates to understandability, complexity vs. simplicity and ongoing improvement needs. Finally, the presentation speculates on what the future challenges might involve, and whether M-E methods may be succeeded by or augmented through advances in micro-mechanical modelling. NOTE: The full manuscript will be available on the second version of the CD.
ralph haas geeft overzicht van de mechanistic empirical design methode. gestart in de 60-er jaren (chevron, shell en later veroad/tu delft) implementation challenges (options en factors): opac 2000 met oa 2 lagen model, een voorspellingsmethode met verkeer en klimaat als variabelen mepdg aashto 2002 design guide. challenges: agengies kopen in (all staff), vermijd gebruik van ME pakketten als black boxes. blijf je verstand gebruiken. PRODUCTS AND BENEFITS FROM THE LONG-TERM PAVEMENT PERFORMANCE PROGRAM Gonzalo Rada (1), Gary Elkins(1), Aramis Lopez (2); (1) MACTEC Engineering & Consulting, Inc., (Beltsville, USA); (2) U.S. DOT, Federal Highway Administration (McLean, USA)
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ABSTRACT: The Long-Term Pavement Performance (LTPP) program is the most comprehensive research program ever undertaken to provide data necessary to determine how and why pavement perform as they do. It was envisioned that from those data, new pavement design, management and maintenance systems would be developed to extend pavement life. Towards that end, nearly 2,500 test sections were established on in-service pavements throughout North America. Besides performance monitoring, the data collected on those test sections includes information on the environment, traffic, inventory, materials, maintenance and rehabilitation. Those data are stored in what is called the LTPP pavement performance database, the program’s principal product. Performance monitoring of the test sections began in 1989, and after nearly two decades of data collection, many valuable insights, innovations and products continue to emerge from the LTPP program. They include advancements in pavement and traffic data collection techniques, data quality control tools and materials testing protocols. Numerous improvements in existing pavement design procedures and maintenance practices have also resulted from the analysis of LTPP data. Indeed, the mechanistic-empirical design guide that resulted from the NCHRP 1-37A project, for example, would not have been possible without the LTPP data. Even more insights, innovations and products are expected to emerge from the LTPP program in the coming years as its focus shifts from data collection to data analysis and product development. This paper details the benefits realized from almost 20-years of data collection as well as those that are anticipated in the years to come. NOTE: The full manuscript will be available on the second version of the CD.
Gonzala Rada: produkten en voordelen van de long term pavement performance programma (ltpp). Doelstellingen: evaluatie van ontwerp methodes (2500 test sites). veel info beschikbaar (meer dan 500000 distress databases. veel profile sets (120000).. deflectie data (16000) enz. dit maakt een nieuw mepdg mogelijk. dus is er behoefte aan een goede data collection technique, een manual voor distress, profile, deflection, traffic, climate. met aandacht voor qc (kwaliteit contract) qa (kwaliteitsborging). naar mate er meer data werden verzamelt begon ltpp te analyseren. ltpp focust op dataverzameling en analyse en op produktontwikkeling SUPPORTING THE DEVELOPMENT OF PERFORMANCE MODELS WITH ACCELERATED LOADING DATA Jean-Michel Piau; LCPC (Nantes, France)
Uitgevallen
THREE DECADES OF DEVELOPMENT AND ACHIEVEMENTS: THE HEAVY VEHICLE SIMULATOR IN ACCELERATED PAVEMENT TESTING Benoit Verhaeghe 1 CSIR Built Environment (Pretoria, South Africa ABSTRACT: Since the 1970s, the South African Heavy Vehicle Simulator (HVS) Programme has had a major technological and economic impact on the design, construction and maintenance of South African roads. It has impacted, for instance, on the development of
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national and regional pavement design standards and guidelines, the development of material specifications and guidelines, the development of human resources, capacity building in the road construction industry, the development of innovative products and designs, and the provision of cost-effective infrastructure engineering solutions. A historical overview of technological developments associated with the Heavy Vehicle Simulator (HVS) and related technologies/instrumentation will be presented. This will cover the period from concept initiation in the late 1960s, to the current state-of-the art HVS Mk-IV Plus and HVS-A Mk-V. An overview of the research activities, outcomes and impacts of the various HVS programmes will also be presented. Although this overview will predominantly focus on the South African experience, other international HVS research programmes will also be addressed. The latter will include studies undertaken by the Partnered Pavement Research Center (California), the U.S Army Corps of Engineers Engineering Research and Development Center (CRREL and WES), as well as the Swedish and Finnish HVS-Nordic program and the Florida DOT HVS test programs, and the sharing of knowledge and experience amongst the HVS users. The presentation will also address the management of the HVS research programme, including the involvement of the road construction industry in the activities of the programme and the transfer of technology to practitioners. It will conclude with an overview of lessons learned from over thirty years of experience in accelerated pavement testing, and discuss the way forward. It is evident that this programme has had a major impact on pavement technologies in South Africa. NOTE: The full manuscript will be available on the second version of the CD.
benoit verhaege over 30 jaar ontwikkeling en resultaten van de heavy vehicle simulator in accelerated pavement tests. hij toont een enorme mobiele testwagen. de resultaten zijn echter niet reproduceerbaar er was tijd over die werd gebruikt voor vragen. molenaar => hoe onderbouw je de noodzaak van onderzoek nu er meer en meer dbfm contracten worden gesloten. => fhwa; er is support van de agencies, wel veel verloop in het personeel. met de dataverzameling is goed werk geleverd en dat zal wel veranderen. => blijf werken aan de politici. vertel het verhaal elke keer (haas)
Parallelsessies 10.30 – 12.00 Evaluating Innovative Pavement Technologies Through Laboratory and Field Testing Tighe S Department of Civil Engineering, University of Waterloo, Ontario, Canada
ABSTRACT: New and improved pavement technologies are developed through laboratory investigations, construction and maintenance, theoretical analyses, long term performance studies such as SHRP and C-SHRP, and integrated programs of laboratory and field research. It is the latter which is the subject of this paper. 47
In 2002, the advancement of pavement technology in Canada was given a quantum boost by the largest research funding ever provided to the field, $9 million in total. The support package has been provided from The Canada Foundation for Innovation (CFI), Ontario Innovation Trust (OIT), Ontario Research and Development Foundation (ORDCF), and several private and public sector partners. The first major initiative to occur under this support is an integrated laboratory and field research program involving new state-of-the-art testing equipment, and new expanded field and central laboratories and central and satellite field test sections. This paper concentrates on how the test track is being used in combination with the laboratory to improve Canadian pavement design, construction and management. Results obtained from the central laboratory in combination with the field test track and satellite test tracks are providing useful information for CPATT partners. Furthermore, they are providing an excellent opportunity to train and educate a new generation of pavement engineers. The paper also provides several conclusions and recommendations on the future opportunities for further advancements in pavement technologies. ze spreekt en passant de zorg uit voor het op peil brengen/houden van kennis bij jonge mensen. toestroom van jonge mensen in de sector loopt niet zo. universiteit waterloo heeft een groot lab en een ruime testlocatie. ze pleit voor een geïntegreerde aanpak = lab en field. noemt ook wheigh in motion. toont de opzet en resultaten van onderzoek van verschillende mengsels (veldonderzoek) belast met dumpers geladen met klei (40 egals zwaar). mengsels: hl32, superpave, sma, para, hl 34?. de gradatie is identiek behalve bij sma. er is een performance analyse gemaakt, stroefheid is gemeten, de schadeontwikkeling is gemonitoort. het onderzoek geeft bouwstenen voor training van hoger opgeleid personeel = bouwsteen voor leadership in future. toekomstige stappen: educatie, training, professionaiteit, betrokkenheid
Performance of the FHWA’s ALF Modified-Binder Pavements Xicheng Qi, Ghazi Al-Khateeb, and Aroon Shenoy Turner-Fairbank Highway Research Center / SaLUT 6300 Georgetown Pike, McLean, VA 22101-2296, USA
ABSTRACT: In the summer of 2002, twelve (12) full-scale lanes of pavements with various modified asphalts were constructed at the Federal Highway Administration’s (FHWA) Pavement Testing Facility (PTF) in Virginia. The primary goal of the study is to use FHWA’s two Accelerated Loading Facility (ALF) machines to validate and refine changes being proposed in the Superpave binder specification to properly grade modified binders. In December 2002, ALF loading began on the pavements to induce two primary modes of failure: rutting and fatigue cracking. Currently, rut testing has been completed at 64 °C on all 12 lanes. Fatigue testing at 19 °C is underway and scheduled to be complete by early 2006. The pavement performance is being compared to both binder and mixture parameters. This paper presents an overview of the pooled fund study, rutting and fatigue cracking performance and correlation analyses with the laboratory testing results obtained to date. KEY WORDS: Superpave, modified-binders, APT, rutting, fatigue. xicheng qi van fhwa (turner fairbank highway research centre). performance of the ALF. aanleiding was de aanscherping van superpave (eerst shrp/1993) - 5 bindmiddelen en 2
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agregaten. research doelstelling = constructie - spoorvorming - vermoeiingsscheuren lage temperatuursscheuren. mooie plaatjes van de resultaten van de proeven
DEVELOPMENT OF RELIABLE PERFORMANCE CRITERIA FOR ULTRA THIN AND THIN ASPHALT FRICTION COURSES FJ PRETORIUS ARCUS GIBB Consulting Engineers, Cape Town, South Africa, Email:
[email protected] ABSTRACT: Ultra-thin and thin asphalt friction courses (UTFC’s called hereafter) are in essence a special group of open graded asphalt mixes with more continuously graded mastic tails. UTFC’s generally get paved in layer thickness of 12 mm to 25 mm and a special thick modified tack is used to ensure optimum adhesion to the “substrata” and durable waterproofing of the lower interface. Compared to conventional continuously graded wearing courses and surfacing seals, UTFC’s offer enhanced functional properties with regard to wet weather friction/skid resistance, splash/spray reduction, prevention of aquaplaning, noise reduction, and prevention of bleeding and surface ravelling. These mixes are typically developed as proprietary products lacking proper or universally accepted product specifications which generally guide satisfactory performance. Therefore, in order to ensure that these enhanced functional properties are maintained throughout the design life, it is essential that applicable mix and layer performance criteria be developed and verified. The paper describes the accelerated pavement testing device (Model Mobile Load Simulator) and other performance testing techniques (and minimum aggregate requirements) developed to verify the functional performance of these specialised products. It further recommends draft performance criteria levels for different application areas i.e. different traffic levels, vehicle speeds, road function. The paper also summarises the outstanding research work needed to comprehensively verify both durability and functionality of these products under various field conditions. KEY WORDS: Friction courses, functional properties, skid resistance, performance criteria
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betrouwbare performance van dunne en zeer dunne deklagen door Pretorius Hij verwees naar ervaring in Nederland en Denemarken! Ook bij dunne lagen wordt gedacht aan sproei-reductie. Bij lagen van 12-25 mm wordt een tacksealing/kleeflaag toegepast. Doel/eigenschappen bij de dunne deklaag = stroefheid, sproeireductie, geluidreductie, duurzaam en substrate waterproof. Gebruik is gemaakt van de LCSdrainometer ivm de onderlingverbonden holle ruimtes. Het ruwheid van het oppervlak wordt met de sandpatchmethode gemeten. Conclusies: strikte performance criteria zijn nodig om de functionaliteit en duurzaamheid over de gehele levensduur zeker te stellen, het MMLS3 APT apparaat en de ontwikkelde protocollen vertonen een goede correlatie met de performance op locatie, een ontwerp set prdukt performance criteria was ontwikkeld voor beoordeling met de MMLS-APT voor verificatie van het produkt, accuratere performance criteria en representatievere APT-protocols thans doorlopend bestudeerd/ontwikkeld
Direct Measurement of the Impact of Heavy Loads on Thin Membrane Pavements Cowe Falls L. University of Calgary, Department of Civil Engineering, Calgary, Alberta, Canada
ABSTRACT: Road authorities in resource based economies are frequently challenged by the demands of heavy equipment operators requiring access to remote sites during sensitive spring thaw conditions. Access to these sites is rarely along high volume, structurally engineered pavements and many secondary pavements suffer premature deterioration as a result. To overcome this, agencies impose restrictions to overloads that can result in substantial costs to operators as equipment is broken down and re-assembled onto multiple flatbeds for transportation over provincial roads. This paper presents the results of field study of the loads imposed by heavy oilfield cranes (with hydraulic suspensions and super single tires) on thin membrane asphalt pavements in Alberta. Three 150m test road sections (thin asphalt wearing course, bituminous surface treatment and granular surface) were built and instrumented for strain at the bottom of the asphalt layer, surface deflection, and subgrade pressures. Temperature and moisture profiles are also measured. Field testing involved controlled speed experiments of standard axle configurations and heavy (12,000kg) axle vehicles with and without hydraulic suspensions. This paper presents a description of the test road design, instrumentation, and testing plan; followed by some of the preliminary results and findings from the first response measurement focusing on vertical stress in the subgrade, longitudinal interfacial strain, and surface deflection of the Hot Mix Asphalt (HMA) section of the test road. KEY WORDS: Thin membrane pavement, response, heavy loading Leuke presentatie door lynne cow falls over een onderzoek in Alberta naar de impact van zwaar verkeer op dunne menbraam verhardingen. Het speelde zich af in het gebied waar een enorm olie-houdend zand reservoir aanwezig is hetgeen door de stijging van de olieprijzen nu exploitabel is. Regelmatig moeten er zeer zware mobiele kranen van de licht geconstrueerde wegen gebruik maken. Er is een proefvak gemaakt (110 mm hma, 300 mm granular base course en 150 mm gestabiliseerde ondergrond) de spanningen in de constructie te meten en na te gaan of er schade en zo ja welke zou optreden. Bij passage van de zwaarste kraan a 93 ton bezweek het proefvak. Er is nu veel inzicht gekregen.
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13.30 – 15.00 Optimization of Joint and Crack Sealant Selection Criteria based on Laboratory and Field Performance T. Worms Engineer in Training UMA Engineering Ltd, 1479 Buffalo Place, Winnipeg, Manitoba, Canada R3T 1L7 12-215 Garry Street, Winnipeg, Manitoba R3C 3Z1
ABSTRACT: The optimized selection of joint sealants can extend pavement service life and reduce annual maintenance and rehabilitation needs particularly in regions which experience extreme climatic conditions. Early sealant materials were not subjected to standardized testing procedures and many failed as a result. Since then, several empirical test procedures have been proposed and a few have been adopted into approved standards, by bodies such as the American Society for Testing and Materials (ASTM). Variability within the sealants, their application methods, and the empirical nature of the test methods made it difficult to predict sealant behaviour in the field. The purpose of this research was to develop a performance-based laboratory testing approach, and to investigate and rank the performance of eight types of hot-pour joint and crack sealants for applicability of use in Manitoba. The research is a joint effort between the Manitoba Department of Transportation and the University of Manitoba. The project involved laboratory testing of sealants to verify fundamental properties and performance simulation under cyclic loading at three test temperatures +30ºC, 0ºC and -30ºC. The results of the laboratory tests indicated that ASTM Type I (high modulus) sealants exhibited higher initial resistance to loading and also experienced adhesion failure at both the 0ºC and -30ºC test temperatures. The ASTM Type IV (low modulus) sealants generally exhibited lower resistance to load and three of the eight sealants did not show signs of failure at any of the three test temperatures. In an effort to optimize the sealant selection criteria, the laboratory performance is compared with field performance in a controlled field trial. The trial involved evaluation of the failure rates of sealants on an asphalt pavement section on the TransCanada highway, which is the primary highway connecting Canadian provinces. KEY WORDS: Sealants, Field and Laboratory Performance, Performance-based test 51
Voegconstructie door tanya worms. Zou interessant kunnen worden ivm onze belangstelling voor voegovergangen van asfalt. Het ging echter over de sealant, het dichtingsprofiel. Ze deed verslag van het onderzoek van 4 type sealants in de Canadese klimaatomstandigheden = +30gr tot +30gr. Er is een specificatie ASTM D6690. Ik heb Tanya gevraagd naar ervaringen met volledige asfalt voegconstructies maar die waren haar niet bekend.
Compaction of HMA with a Vibratory Pneumatic Tire Roller Scherocman J. Consulting Engineer, Cincinnati, Ohio, USA
ABSTRACT: A new method to compact Hot Mix Asphalt (HMA) pavement was recently developed in Japan. This system consisted of a relatively small, seven tire pneumatic tire roller that can be operated in the vibratory mode--a vibratory pneumatic tire (VPT) roller. It was previously found that the VPT roller could achieve the required level of density in a HMA mix using fewer roller passes and that the roller achieved a more uniform degree of density throughout the thickness of the HMA pavement layer. In 2005, three additional test sections were constructed to further evaluate the capabilities of the VPT roller. The first project was at the Bakersfield Airport in California where the density achieved with the VPT roller was compared with the density obtained with a static pneumatic tire roller that weighed more than twice as much. The second trial was conducted in Georgia where various roller combinations were tested. It was determined that both the mainline pavement density and the longitudinal joint density were easily achieved when the VPT was included in the roller train. The third project was located in Japan where it was confirmed that the use of the VPT roller would provide for a uniform density distribution throughout the depth of the pavement layer. The combination of the kneading action of the pneumatic tires and the vibratory force applied through the pneumatic tires provides “the best of both worlds” regarding the compaction of HMA mixtures. KEY WORDS: Compaction, density, pneumatic tire roller, kneading action, uniformity.
De bandenwals. Dit type (met vibratory pneumatic tire) is ontwikkeld in Japan. Scherocman deed verslag van proeven met deze wals. De verdichting in de asfaltlaag is meer homogeen, het onderste deel van de laag is beter verdicht. De wals is makkelijke te transporteren door het lichtere gewicht en de geringere afmetingen, de verdichtingskosten zijn lager omdat ipv 3 conventiele walsen er 2 bandenwalsen nodig zijn.
Pavement Preventive Maintenance Concepts and Techniques Hein, D. Applied Research Associates Inc., Toronto, Canada
ABSTRACT: Many pavement owner/agencies are now focusing on maintaining the overall value of their roadway assets and are striving to make better-informed decisions on how they allocate funding to minimize the deterioration of their assets. This new form of management referred to as Asset Management has clearly identified the benefits of strong pavement preventive maintenance programs compared to the commonly used “worst-first” repair approach.
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A strong pavement preventive maintenance program offers an opportunity to help close the gap between pavement maintenance needs and optimal pavement condition to better serve the traveling public. An effective pavement preventive maintenance program encompasses a full range of techniques with the goal of enhancing pavement performance in a cost-effective and efficient manner. A framework of mix-of-fix strategies, which includes a balance between pavement preventive maintenance work along with pavement rehabilitation and reconstruction, can assist a road agency to maintain an overall acceptable pavement condition while meeting the needs of the traveling public. This concept, as simple as it seems, has not been fully accepted by roadway agencies, who continue to react to problems after they occur rather than to prevent them from occurring in the first place. This paper describes the concepts of pavement preservation and outlines several typically pavement preservation techniques. KEY Words: Preventive maintenance, municipal, asset management, pavement management. Preventief onderhoud door David Hein. Preventief onderhoud is - een onderdeel van de instandhouding van de verharding - het instandhouden van de waarde voor de gemeenschap - verlengd de levensduur - verbetert de verkeersveiligheid - tijdige toepassing van de maatregel. Het bespaart kosten. Maatregelen: - dunne warm asfaltlagen - novaship (viaral etc) - hot in place recycling - micro surfacing - sealing (beperkt occidatie) - oppervlakbehandeling - surface texturization (micro milling). Schadeverschijnselen: oxidatie, bleeding/zweten, spoorvorming, scheurvorming. Opmerkelijk vind ik de aandacht die aan dit onderwerp (terecht) geschonken is. Hein gaf een prima overzicht.
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Pavement Preservation Training Yetkin Yildirim Texas Pavement Preservation Center
ABSTRACT: Pavement preservation is a maintenance strategy that allows highway agencies to adopt cost-effective and efficient programs to sustain roadways and extend pavement service life. However, due to lack of knowledge amongst policy makers and transportation professionals, such maintenance is undervalued compared to other projects. Training is needed at all levels: decision makers, highway administrators, engineers and construction workers. This paper uses the current initiatives at the University of Texas at Austin (UT) as a model for available ways of disseminating information about preventive maintenance and offers suggestions for improvement to the area. The Center for Transportation Research at UT has been actively involved in communicating the idea and importance of preventive maintenance to industry professionals and students. In addition the Texas Pavement Preservation Center, in conjunction with University of Texas’ Center for Transportation Research (CTR) and Texas A&M University’s Texas Transportation Institute (TTI), was recently established to promote the use of pavement preservation strategies to provide the highest level of service to the traveling public at the lowest cost. The goals of the TPPC are to offer a means for promoting awareness of pavement preservation as a feasible and practical maintenance strategy by providing training courses in preservation methods, to operate as an information clearinghouse for the latest preservation techniques and procedures, and to provide TxDOT with a strategic research plan for supporting long-term pavement performance. Although some forms of training exist, much more needs to be done. This paper describes available ways of disseminating information about preventive pavement maintenance and offers suggestions for improvement. This paper isolates groups that should be targeted for training and identifies viable and available training options. KEY WORDS: Pavement preservation, preventive maintenance, pavement management systems Ook hier weer aandacht voor preventief onderhoud vanwege het vaak miskende belang (stelling dat het op tijd uitgevoerd onderhoud 1 dollar kost en het (te)laat uitgevoerd onderhoud 4 a 5 dollar kost. Dus de factor 4 a 5 duurder is. 2 universiteiten hebben het initiatief genomen om om Texas Pavement Preservation Center te stichten. Het richt zich op training op alle niveau te weten de politici, de belastingbetalers, de technici en arbeiders. Texas is overigens een grote ‘’chip sealing staat. Een bijzonder initiatief. Website: www.utexas.edu
15.30 -17.00 Development of Hot In-Place Transforming of Dense Graded Asphalt Mixture to Porous Asphalt Concrete Hosokawa H Green ARM Co., Ltd., Tokyo, Japan
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ABSTRACT: A totally new concept technology of hot in-place transforming dense graded asphalt concrete to two layers of porous asphalt as the surface layer and mastic gap asphalt which supports the layer, which is different from hot in-place recycling. Thus the new technology has been named as Hot In-Place Transforming technology. It is a train of five automobile machines, two Pre-Heaters, Heater&Miller, Separator and Mixer&Tandem-Paver to be followed by conventional rollers. The key technology developed is Separator equipped with a screening device, which separates hot asphalt coated aggregates in accordance with their size. Hot air is used as an air mat rather than jet air, which the latest Hot In-place Recycling machinery uses, for even heating needed for efficient aggregate separation. It adopts a tandem paving technology, which paves through one pass for two layers of different grades of asphalt mixture. The machines were successfully demonstrated on Route 77 in Okinawa, Japan in late summer of 2005. The train was operated smoothly at a speed of 2m/min. and through one pass porous asphalt was paved, which offers to users high quality service of better safety and lower noise. The required water permeability of porous asphalt and surface roughness were satisfied. It was also confirmed the huge reduction of greenhouse gas emission including carbon dioxide through all the rehabilitation processes compared with the conventional mill and fill method should be possible by the technology. KEY WORDS: In-place, recycling, transforming, asphalt, porous. Hot in place transformatie van dicht asfalt beton in open asfaltbeton door Hisashi Hosokawa. Er is een trein van 7 werktuigen die het bestaande dichtasfalt beton omzet in open asfalt beton. (heaters, frees, oplader, screener, mixer, verspreider, verdichter(s).
Na bewerking zijn de 2 bovenste lagen vernieuwd. Het is een zeer nieuw procede. Na afloop gediscussieerd met Hosokawa en zijn directeur over dit mirakel. Ik vroeg me af wat de levensduur en de kosten waren. Voor de levensduur ging hij uit van 7 jaar voor het zoab en de kosten waren nog moeilijk in te schatten omdat met name de afschrijving van de machines nog bepaald moet worden, dat is afhankelijk van de freqentie waarmee de machines ingezet kunnen worden. Ik heb gesteld dat ze voor ons interessant worden als ze de deklaag kunnen leveren voor 2 €/m2 per jaar lcc
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Asphalt Pavement Rehabilitation: Using Sustainability in DecisionMaking L, Uzarowski Golder Associates Ltd., Whitby, Ontario, Canada
ABSTRACT: Road networks, whether they are in the developed world or in the developing world, are a cornerstone of economic development. As the world population continues to increase and the earth’s ability to sustain this growth is decreasing, the principles of sustainability must be incorporated into all aspects of the planning, design, construction, rehabilitation and maintenance of road networks. The impact of development on world ecosystems is a function of growth in population, increasing affluence (such as measured by income per capita) and technology (as measured by emissions per unit of production). Population growth and increasing affluence are realities, thus, the levers available to us to help slow the continual depletion of limited resources must focus on improvements in technology. Over the past 25 years, applied pavement research has given the pavement design engineers powerful tools to incorporate greater innovation into pavement rehabilitation schemes. This paper describes a resource management tool that can assist highway agencies, planners, contractors and design engineers in identifying mechanisms whereby social, financial and environmental issues can be integrated into the management and planning of road rehabilitation works. The process described is a simple rational process for incorporating the principles of sustainability in a meaningful way into selecting the optimum road rehabilitation design. This tool for evaluating the sustainability of alternative road rehabilitation treatments will allow all stakeholders to achieve economic benefits through increased engagement of local communities and reduced negative environmental impacts in the longterm delivery of serviceable road networks. KEY WORDS: sustainability, pavement rehabilitation, waste reduction Duurzaamheid als factor bij de beslissing over asfalt rehabilitatie. Uzarowski ging in op de trends te weten de hogere temperatuur, transport is voor 28% verantwoordelijk voor het broeikas effect, de snelle groei van de wereldbevolking zet door, iedereen verlang meer welvaart, het wereld ecosysteem wordt in toenemende mate beïnvloed door de groei van de wereldbevolking, toename welvaart en meer technologie. Per hoofd van de bevolking heeft US 12 ha, Canada 8 ha, Italië 6 ha. (Nederland schat ik op ca 0,4 ha). Er zijn al goede vorderingen gemaakt
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Hij noemt de volgende evaluatie criteria: - life cycle costing - minimalisatie afval - totale projectkosten - minimaal gebruik van nieuwe materialen. - minimale zware transporten - beperking van energiegebruik Hij sluit af met conclusies: denken in duurzaamheid is kritisch voor de wegennetten, het moet de beslissers beïnvloeden in alle aspecten van planning, ontwerp en gebruik, verhardingsontwerpers met zich hun verantwoordelijkheid bewust zijn, recycling technieken bieden veelbelovende mogelijkheden, de kwantificeren van duurzaamheid moet ingevoerd worden.
Laboratory characterization of hot mix asphalt fumes during mixing linked with mechanical performances de la Roche C. Laboratoire Central des Ponts et Chaussées, Bouguenais, France
ABSTRACT : A feasibility study has been carried out in order to estimate in laboratory the fumes emission potential during hot mix asphalt production in relation to manufacturing parameters. Temperature, binder content as well as some proceeding kinetics parameters have been studied through an experiment plan. The laboratory mixer was equipped with a stack for gas emission sampling in normalized conditions. A polycyclic aromatic hydrocarbons (PAH) sampling system has been designed and a continuous total organic compounds (TOC) analyzer has been used for hot mix asphalt fumes. Classical laboratory characterizations have been performed in order to estimate material performances. Among the possible ones, complex modulus of recovered binder or mix seems the most relevant as its result reflects mechanical properties as well as binder oxidation and ageing. The study performed allows to link potential fume emissions to mixing parameters for hot mix asphalts, in relation with mix mechanical properties.
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KEY WORDS : Hot mix asphalt fumes, TOC and PAH emissions, Complex modulus. Onderzoek naar de emissie van bitumen tijdens het produktieproces gerelateerd aan de parameters/eigenschappen. Resultaat: het effect van bitumineuze materialen op de emissie van bitumen volgens de verschillende productiefactoren zijn geïdentificeerd, een laboratorium karakteriserings methode is ontwikkeld gekoppeld aan de performances (mechanisch en milieu) met voldoende betrouwbaarheid om verschillende formules van materialen te ontwikkelen in het laboratorium. Ik legde later een andere link nl de invloed van de emissie van bitumen op veiligheid en gezondheid van het produktie personeel bv in tunnels (bv westerschelde tunnel).
Traffic-Induced Vibrations: Damping Pavement TheoreticalExperimental Study G. Dondi DISTART/Strade, University of Bologna, Bologna, Italy ABSTRACT: Vibration phenomena produced by road traffic are very interesting in terms of induced annoyance in the human body and in buildings, especially in urban historical areas. An accurate study of vehicle-pavement-building interaction thus becomes a primary requirement. By means of a finite differences technique, the authors developed a numeric analysis in order to evaluate the propagation and reduction of traffic-induced vibration. Numerical data validation, which was obtained from a deep experimental phase on a two lane rural road, consisted in: • vibration survey with triaxial velocimeter of buildings near road; • selection of the most efficient design solutions for pavement improvements and their effectiveness evaluation on reduction of vibrations in buildings. Collected data underwent an in-depth analysis, which provided particularly interesting and significant results regarding “damping” pavements design, with particular attention to laying and maintenance technologies. KEYWORDS: Vibration, buildings, numerical models, pavements
Grandi heeft het ontstaan, het meten en het ontwerpen van maatregelen behandeld. De case betreft een (bekende) Italiaanse situatie in oude steden met hoge gebouwen, smalle straten (soms met ‘’kinderkopjes’’) en zwaar verkeer. De zware trillingen zijn zeer hinderlijk voor de bewoners. Er is een model ontwikkeld waarmee de trillingen voorspeld/berekend kunnen worden. Tevens is een ‘’mat’’ ontwikkeld die, aangebracht in de ondergrond, de trillingen effectief dempt.
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Donderdag 17 aug Plenair 8.30 – 10.00 PAVEMENT RECYCLING – THE USAGE OF ASPHALT PAVEMENT RECYCLING TO ACHIEVE TECHNICAL, ECONOMICAL AND ENVIRONMENTAL SUSTAINABILITY IN ROAD SERVICEABILITY Steven Damp; Miller Paving Ltd. (Markham, Canada) ABSTRACT: Across North America over the past number of years, the Asphalt Recycling and Reclaiming industry has witnessed a huge growth in the demand for and usage of recycled pavements by road owners. These owners have been turning to recycling in ever increasing numbers to achieve the combined benefits of reducing costs, producing high quality pavements and reducing the environmental impacts of constructing and maintaining their pavement assets. The environmental impacts of recycling asphalt are far less than those of producing virgin mixes. The underlying principle of asphalt recycling is that the existing road is the source of material to produce the new pavement. With a minimum of reprocessing, existing materials replace virgin materials tonne for tonne in recycled mixtures with all the inherent environmental benefits of reduced quarrying and hauling. The energy consumption of recycled pavements can be as little as 25% of the energy needed to produce similarly performing hot mix materials. Recycling asphalt is less costly than producing virgin materials and it is these cost savings that has always driven and sustained the industry. The savings are holding true for all of the traditionally recognized forms of asphalt recycling. The high world oil prices have impacted the cost of producing virgin materials by driving up the costs of three key components: asphalt cement, aggregates and fuel. With asphalt recycling utilizing substantially less asphalt and fuel to produce a tonne of pavement material, the cost of recycled pavements has been rising at a much slower pace than that of virgin materials. Every year a greater percentage of road budgets are being allocated to pavement rehabilitation in an effort to deal with the continuing deterioration of our roads. Recycling technologies offer the long lasting pavements owners are demanding, while using materials that they already own. Performance of recycled pavement has stemmed from advancements made not only in the workmanship and construction of these pavements, but also in the knowledge and expertise gained in process selection, pavement engineering and materials design. Advancements made in equipment design have been significant in recent years. Virtually all quality asphalt recycling incorporates some form of additive material to beneficiate the mix Owners are continually turning to asphalt pavement recycling as a key component in their pavement management systems because it is just the right thing to do. They are realizing the triple benefits of reducing the overall costs of constructing and maintaining their pavements, of producing some of the highest quality pavements ever and of contributing in a major way to the benefit of our environment by reducing the overall environmental impacts of road construction.
Steven Damp hield een pleidooi onderbouwd met onderzoeken voor het toepassen van recycled asfalt. ‘’Stenen en bitumen zitten duizenden jaren in de grond, zouden ze na 30 jaar verblijf bovengronds niet meer deugen?’’. Er zijn intussen meerdere technische mogelijkheden (cold planing, hot plant, hot in place, cold recycling in place, cold central
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plant recycling, full depth treatment/application granular. De binder is goed herbruikbaar met een minimale toevoeging van rejuvenation (verjonging). Hij noemkt 3 keys nl engineerring, equipment en workmanship. WHAT DO WE EXPECT FROM RECYCLING IN A ROAD CONSTRUCTION COMPANY? François Chaignon COLAS S.A. (Morristown, USA) ABSTRACT: 1. Recycling in road techniques In this part, we will present the existing techniques to maintain and keep a road network in good condition; Cold and hot in place or in plant recycling. We will present also a unique approach to combine recycling techniques and road design with environmental approach. 2. Recycling in other fields Through the experiences in countries around the world where the COLAS group is present, a description of opportunities and final projects will be shown. Either by the optimization of the existing road operations (aggregates quarry, hot mix plants and other), or by the creation of new entities, the very important local positioning of the COLAS group allows the answers of this new market. 3. Conclusions Recycling is a new approach of the market and the employees, often concerned about the future find their way, being themselves more and more recyclers at home.
Volgens Francois wordt in USA 10% hergebruikt en in Frankrijk 50%. In Frankrijk mag 10% in de deklaag en 15 % in de binderlaag worden toepgepast. Hij noemt glocalisation als fenomeen; dat is het wereldwijd gebruiken van locale materialen. Voor de markt zijn belangrijke:aspecten: investeringen, lange termijn ontwikkelingen, performances ( steeds meer maar met kwaliteit) en duurzaamheid DEVELOPMENT AND PERFORMANCE OF ASPHALT PAVEMENT RECYCLING TECHNIQUES IN THE AMERICAS John Emery; JEGEL (Toronto, Canada) ABSTRACT: Enhanced asphalt pavement reclaiming and recycling techniques such as cold in-place recycling (CIR), full depth reclamation (FDR) and hot in-place recycling (HIR) are increasingly important to improved life-cycle performance and cost-effective pavement maintenance and rehabilitation, particularly with escalating energy costs. Practical applied materials, design and construction with CIR (emulsion and foamed asphalt), FDR (foamed asphalt and lime/foamed asphalt) and HIR (third generation equipment with recirculating forced hot-air and low level radiant heating) is used to illustrate the processing features, overall design procedures (pavement section evaluation, reclaimed pavement properties, mix design methods and quality assurance), construction requirements, appropriate specifications and anticipated performance. Experience with CIR and FDR has generally been very positive and cost effective, particularly with regard to thermal and reflective cracking mitigation. Comparative performance monitoring of third generation HIR indicates that comparable performance to conventional asphalt overlays is achieved with significantly reduced energy requirements and fewer traffic delays. Innovations with CIR and FDR such as higher ESALs use, mechanistic pavement design parameters and probabilistic life-cycle costing are
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described with implementation guidance. Advances in HIR applied asphalt technology such as rejuvenator characterization and selection, and performance evaluation of the recycled mix, in an overall systems approach to optimized HIR, are presented. It is also shown how CIR, FDR and HIR can form important components of long-life asphalt pavements.
Hij bepleitte met name het gebruik van schuimbitumen. . EVOLUTION OF FLEXIBLE PAVEMENT RECYCLING IN ONTARIO – AN AGENCY’S PERSPECTIVE Tom Kazmierowski, Susanne Chan; Ontario Ministry of Transportation (Toronto, Canada) ABSTRACT: In consideration of present and anticipated future environmental and resource challenges, flexible pavement recycling provides an important alternative to conventional pavement rehabilitation. The Ministry of Transportation of Ontario (MTO) encourages the use of pavement recycling to provide economical rehabilitation techniques that conserve nonrenewable resources including road-building materials and energy, while minimizing Green House Gas (GHG) emissions, limiting pollution and reducing waste. This paper describes MTO’s experience in adopting innovative pavement recycling techniques, focusing in on the recent improvements and current practices. Detailed discussion on these technologies and their impact on long-term pavement performance are presented, as well as a historical perspective of the ministry’s pavement recycling program achieved over the past 10 years. Finally, the paper concludes by discussing how transportation agencies can move towards a sustainable future by incorporating flexible pavement recycling into their capital construction program.
Allereerst geeft Kazmierowki een indruk van Ontario, 12 miljoen mensen, 1 miljoen km2. sinds 1995 is 37 km2 verharding recycled., het grootste deel (30 km2) met full depth reclamation. Het verloop van de kwaliteit is nauwkeurig geregistreerd (PavementConditionIndicator). N a 10 jaar is dat gemiddeld 72 (op 100). Hij noemt als criteria voor duurzame verharding - veilige, efficiente, milieu vriendelijke verhardingen die voldoen aan de behoefte van de hedendaagse gebruikers zonder de toekomstige generatie te belasten. - de in-situ recycling technologieën richten zich op de belangrijkste criteria voor duurzame verhardingen. > Optimaal gebruik van de natuurlijke bronnen > Beperking van energie gebruik > Beperking van broeikasgas emissie > Beperking van (lucht) verontreining > Verbetering van gezondheid, veiligheid en risicopreventie > Verzekering van een hoog niveau vancomfort en veiligheid.
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Parallelsessies 10.30 – 12.00 Practical Aspects of Maintaining a Busy Old Motorway, While Keeping Traffic Moving Scott P. L. BSc (Eng), CEng, MICE, MIHT, Dip TE Highways Agency, England
Abstract: The M4 motorway, close to London Heathrow Airport, Windsor and Slough, needed maintenance. This major maintenance scheme which cost £13million; involved a three-lane dual carriageway 4 kilometres long. . No major work had been carried out on it since 1970, and it carries 160,000 vehicles per day into and out of London, with the main flows between 6am and 10.00pm. There were substandard features that included discontinuous hard shoulders, which meant that hard shoulders could not be used for traffic management to keep traffic flowing. Little or no work could be carried out during the day without causing enormous congestion as it is very close to the M25, the main London orbital motorway. The road runs through high-density residential areas, which made noisy nighttime working an issue. All this makes this road to be almost unmaintainable. A contract duration of 20 weeks was set as the maximum that road users, businesses and residents could tolerate. As a consequence, the design was changed and re-scoped to achieve a pavement design life of some 10 years before the next major maintenance whilst keeping the traffic moving in the meantime. This included a very large free vehicle recovery operation. A comprehensive communications strategy was also developed for the scheme, which commenced nine months in advance of works starting on site. This communication strategy and plan made a significant contribution to the whole scheme being a success. Traffic delays were almost held to the norm. This paper discusses how the works were tailored to suit the constraints, the comprehensive approach to informing the Road Users, Stakeholders, Press and residents, and how current practices within the Highways Agency have changed. KEY WORDS: MAINTENANCE, COMMUNICATIONS, STRATEGIC, TRAFFIC. Een interessante presentatie over de aanpak en uitvoering van het groot onderhoud van een deel (3,7 km) van de M6, een verbindingsweg tussen de M25 (rondweg londen) en Heathrow (vliegveld). AADT 160000. Er was 30 jaar geen grootonderhoud uitgevoerd. De deklaag moest worden vernieuwd en de ‘’las’’ tussen het oude profiel en de langgeleden gemaakt verbreding moest worden vernieuwd. Keermuren en geluidschermen zijn vernieuwd en verkeerssystemen zijn geupgrade. Oorspronkelijke uitvoeringduur 45 weken. Op gezag van het bestuur is dat teruggebracht tot 16 weken. Vertoont overeenkomsten met de aanpak van de A10 west. 1 jaar voor uitvoering is gestart met overleg met gebruikers, bedrijven en hulpdiensten. 6 maanden vooraf is de informatie campagne gestart met hearings en een informatiebus. 1 maand voor het werk is dat geïntensiveerd met een informatie in bibliotheken en leaflets. HA laat kwaliteit meewegen bij de gunning en had een verhouding van 65-35 voor kwaliteit versus prijs (2 enveloppensysteem). Opmerkelijk is de uitvoeringsvariant. Er werd s’nachts gewerkt op een rijbaan (normaal) en het verkeer werd geleid over de andere rijbaan (2 stromen, gescheiden door kegels). Dat wordt bij RWS niet geaccepteerd vanwege de veiligheidsrisico’s/kans op frontale botsingen. (alhoewel de afloop niet ernstig hoeft te zijn bij lage snelheden). Er weren 13
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sleepwagens ingezet (24 uur/7 dagen) (kosten ca 1,2 m€). verkeershinder: meer dan 1000 verstoringen van de verkeersstroom en meer dan 200 ongevallen (niet ernstig).
Innovative Pavement Solutions under New Procurement Systems in the United Kingdom Brown S. F. Nottingham Centre for Pavement Engineering, University of Nottingham, United Kingdom
ABSTRACT: The procurement of new construction or major maintenance schemes on the motorway and trunk road network in the UK has dramatically changed in the last ten years following a Government Private Finance Initiative. From an engineering point of view, the introduction of private sector responsibility has been a catalyst to encourage change, with much more emphasis on achieving certain levels of performance, although some new ideas have not been without problems. The contractor/consultant consortia often carry more risk than in a traditional contract where designs and specifications are more prescriptive. However, some of these forms of contract have encouraged innovation, particularly by bringing in ideas from other countries and adapting them to the UK situation. Case studies describing the above innovative solutions, as well as premature pavement failures due to the introduction of new materials and construction techniques are presented. KEY WORDS: Procurement, privatisation, highway construction and maintenance, innovation, pavement management. Brown presenteerde zonder sheets omdat zijn laptop nog in zijn koffer zat en die koffer bevond zich ergens tussen Londen en Quebec (chaos door security-problemen, dreiging van bomaanslagen op vliegtuigen). Highways Agency is ruim 10 jaar geleden overgegaan op een andere werkwijze waarbij veel meer aan de markt wordt overgelaten. Het functioneren van de weg is vastgelegd in functionele eisen/specificaties en het is een lange termijn benadering met partnership oa om de veiligheid te verbeteren. Het gaat gepaard met het overbrengen van risiko’s naar de markt. Er is spanning tussen het lange termijn onderhoud en innovatie. De bedrijven zijn niet snel geneigd om nieuwe werkwijzen/oplossingen te introduceren die ze nog niet goed beheersen maar wel het risico van dragen. Ze denken nu aan bdfo(peration) contracten met een duur van 30jaar. Ook wordt de aannemer in een zeer vroeg stadium betrokken bij de voorbereiding van het contract dus nog voor de inschrijving. Kwaliteit wordt zwaar meegewogen, bij nieuwbouw contracten is de verhouding 70 – 30% (kwaliteit – prijs) en voor onderhoud is dat zelfs 80 – 20% . Dit is voor RWS een belangrijk thema.
The Pay Adjustment When Using the Vacuum Sealing Method Versus the Saturated Surface Dry Method of Determining Bulk Specific Gravity Jason P. Bausano & R. Christopher Williams Ph.D. Iowa State University Town Engineering
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Ames, IA 50011
[email protected] (515) 708-2441 (515) 294-4419
Brett A. Williams Rockroad Construction
ABSTRACT: A number of test methods are available to measure the bulk specific gravity (BSG) of laboratory compacted hot mix asphalt (HMA). The most commonly used test methods (ASTM D 2726 and AASHTO T 166) were designed for use with specimens that did not contain open or interconnected air voids. The current methods for addressing coarse and open-graded mixes (ASTM D 1188 and AASHTO T 275) can lead to erroneous bulk specific gravity measurements. Thus a non-destructive vacuum sealing method (ASTM D 6752) was developed to address HMA mixtures that contain open or interconnected air voids. The objective of this paper was to analyze air voids (AV) and to establish specific limits for bonus and penalty adjustments while evaluating the effect of the test method employed to determine the BSG measurements since the BSG is used in calculating AV. One hundred and forty field compacted roadway cores from twenty-eight paving projects throughout the State of Michigan were evaluated using the vacuum sealing method and conventional saturated surface dry (SSD) method of determining the BSG of compacted HMA. The results show that there is a significant statistical difference in pay adjustments when coarse mixes are tested with a vacuum sealing method as compared to the SSD method of determining the BSG. Water drainage occurring in coarse mixes with interconnected air voids may be responsible for giving inaccurate measurement of the BSG when using the SSD method. The nominal maximum aggregate size (NMAS) also affects the pay adjustment when using the vacuum sealing method. As the NMAS increases, the pay deduction increases based upon air voids. KEY WORDS: Bulk specific gravity, pay adjustment, vacuum sealing
Dit bleek te gaan over de relatie tussen kwaliteit en betaling met name 2 manieren waarop holle ruimte wordt bepaald. Het is te vergelijken met onze kortingsbepalingen waarmee bij een mindere kwaliteit (verdichting cq holle ruimte) korting wordt opgelegd.
Monte Carlo Based Simulation for Managing Risk in End-Result Construction Specifications William G. Buttlar Department of Civil and Environmental Engineering, University of Illinois at UrbanaChampaign ABSTRACT End-Result Specifications for asphalt pavement construction offer potential benefits over method-related specifications and can be used in conjunction with or replacement of traditional Quality Control (QC)/Quality Assurance (QA) specifications to encourage contractor innovation, reduce agency testing burden, and enhance pavement quality. Unlike other manufacturing sectors, the measure of pavement quality is not as simple as quantifying defective items. The quality of pavements is assessed with imperfect measuring tools operated by human operators, who may inadvertently or intentionally introduce measurement variability and/or bias. Payment bonuses and penalties determined based on imperfect measurements would involve risk, which must be understood. Existing methods for assessing risk in pavement construction-related ERS contracts do not properly consider all of the factors affecting risk, and therefore, the
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administration of such contracts had the undesirable attribute of unknown risk levels. This paper details the development of a simulation tool which can be used to analyze risk and develop ERS systems with user-managed risk levels. The program, called Simulated Risk Analysis (SRA), computes the risk of overpayment (agency risk) or underpayment (contractor risk) as a function of many factors, including: sample size, production and measurement variability, bias, pay formula and pay caps, specification limits, and considers the quality assurance and third-party testing scheme used. In general, SRA can be used to develop a better understanding of how changes in individual ERS specification parameters can effect the payment risk for the contractor and agency. This knowledge can be used to explore the possibility of developing desirable changes in an existing ERS, such as reducing sample size, reducing risk, optimizing tolerance limits, changing pay factor equations, and the pros and cons of pay factor equations with payment caps. Specific examples of how the Illinois Department of Transportation’s existing ERS for Superpave HMA could be modified to reduce contractor and agency testing are presented. KEYWORDS: End-Result Specification, ERS, Risk, Construction, Asphalt, Pavement, Monte Carlo, Simulation Een interessante presentatie. Er is ondermeer een vergelijking gemaakt van ers (end result specification) en prs (performance related specification) met behulp van SRA (simulated risk analyse).
de bottom-line: de belangrijkste aspecten voor de ontwikkeling van specificaties zijn - houd specificatie zo simpel mogelijk - om risico’s relatief in balans te houden
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- om te verzekeren dat gekwantificeerde risico’s niveau bekend zijn bij beide partijen.
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