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  • 51. Kim, H
    et al.
    Sokolov, K
    Poulikakos, L
    Partl, Manfred
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik.
    Fatigue Evaluation of Carbon FRP-Reinforced Porous Asphalt Composite System Using a Model Mobile Load Simulator2009Inngår i: Transportation Research Record, ISSN 0361-1981, E-ISSN 2169-4052, Vol. 2116, s. 108-117Artikkel i tidsskrift (Fagfellevurdert)
  • 52. Kim, Hyunwook
    et al.
    Arraigada, Martin
    Raab, Christiane
    Partl, Manfred
    Empa Swiss Fed Labs Mat Testing & Res, CH-8600 Dubendorf, Switzerland.
    Numerical and Experimental Analysis for the Interlayer Behavior of Double-Layered Asphalt Pavement Specimens2011Inngår i: Journal of materials in civil engineering, ISSN 0899-1561, E-ISSN 1943-5533, Vol. 23, nr 1, s. 12-20Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bonding characteristics between pavement layers have an important influence on responses of pavement structures. This paper deals with this subject by analyzing the interlayer behavior of double-layered asphalt (DLA) specimens taken from an in-service motorway using a coaxial shear test (CAST) and a layer-parallel direct shear (LPDS) test. To analyze and model the influence of the interlayer condition, finite-element simulations of CAST DLA specimens were conducted. In the models, both idealized fully bonded and no-bonding assumptions were used to characterize the interlayer behavior of DLA specimens. Experimental results presented for CAST and LPDS tests demonstrate that there is a strong influence of temperature in the interlayer bonding mechanism. At lower temperatures, there is an increase on the bonding strength produced by the binder stiffening and aggregate interlocking. Further, it was observed that comparisons of CAST experimental and numerical results indicate that the interlayer can be close to the fully bonded condition at low temperatures below 20 degrees C while the interlayer, at higher temperatures, behaves between fully bonded and no-bonding idealized conditions.

  • 53. Kim, Hyunwook
    et al.
    Buttlar, W
    Partl, Manfred
    Empa, Dübendorf, Switzerland.
    Investigation of Fracture Toughning Mechanisms of Asphalt Concrete using the Clustered Discrete Element Method2008Konferansepaper (Fagfellevurdert)
  • 54. Lal, Sreeyuth
    et al.
    Moonen, Peter
    Poulikakos, Lily D.
    Partl, Manfred N.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggnadsmaterial. Swiss Federal Laboratories for Materials Science and Technology, Switzerland.
    Derome, Dominique
    Carmeliet, Jan
    Turbulent airflow above a full-scale macroporous material: Boundary layer characterization and conditional statistical analysis2016Inngår i: Experimental Thermal and Fluid Science, ISSN 0894-1777, E-ISSN 1879-2286, Vol. 74, s. 390-403Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Convective drying of macroporous materials is governed by the complex interaction between airflow above and into the material, the roughness of the air material interface and the characteristics of the material pore system. In this study, we experimentally investigate this interplay in detail and at fullscale, using porous asphalt (PA) as a model material. The characteristics of the turbulent flow in the immediate vicinity of the material surface are studied with full-scale wind tunnel experiments at three flow speeds over two types of PA with different surface porosities and surface pore sizes, and are compared to similar measurements over a smooth and impermeable reference material. It is shown that, above a certain wall-normal distance, turbulence profiles can be scaled to make them independent of the flow speed. However, at low speed, the scaling breaks down due to a combination of organized turbulent structures of high intensity and a low turbulence background. No generally valid scaling applicable at all tested air speeds is found close to the surface, where drying occurs. Hence, realistic drying experiments must be performed at full scale and for the entire range of velocities of interest.

  • 55. Lal, Sreeyuth
    et al.
    Poulikakos, Lily D.
    Gilani, Marjan Sedighi
    Jerjen, Iwan
    Vontobel, Peter
    Partl, Manfred N.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Transportvetenskap, Väg- och banteknik. Swiss Federal Laboratories for Materials Science and Technology, Switzerland .
    Carmeliet, Jan C.
    Derome, Dominique
    Investigation of Water Uptake in Porous Asphalt Concrete Using Neutron Radiography2014Inngår i: Transport in Porous Media, ISSN 0169-3913, E-ISSN 1573-1634, Vol. 105, nr 2, s. 431-450Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Porous asphalt (PA), a highly porous hydrophobic composite material, is subjected to water uptake and the process is documented with neutron radiography (NR). While the un-aged laboratory-prepared PA specimens do not show any water uptake, we observe uptake in aged PA even though the bitumen binder is a hydrophobic material. The moisture content distribution plots derived from the NR images clearly identify regions in the aged specimens where water uptake is active. Two-dimensional degree of saturation (DoS) distribution images, which are obtained by combining micro-computer tomography and NR images, identify those pores where saturated flow is certainly active. However, to clearly distinguish between saturated and unsaturated flows in the remaining wet pores, the DoS distribution images are read together with the three-dimensional PA microstructure obtained by micro-CT. It is observed that uptake begins mainly as unsaturated film/corner flow at large well-defined pores. As this uptaken water travels further into the material, the flow transforms into a combination of saturated flow and unsaturated film/corner flow. Saturated flow is seen to be mostly active in the small pores within the mastic. From the observed succession of unsaturated and saturated flows in an aged PA specimen, it can be concluded that years of environmental and mechanical loading has resulted in the stripping of binder from the aggregate surfaces and has consequently exposed patches of hydrophilic aggregate to water, which enables the capillary uptake of water. We also simulate an absolute permeability experiment and observe that relatively less tortuous and more connected paths play an important role in determining the preferential path of the uptaken water.

  • 56. Morgan, G.
    et al.
    Poulikakos, L.
    Arraigada, G.
    Partl, Manfred
    Empa Swiss Federal Laboratories for Materials Testing and Research.
    Muff, R.
    In Situ Monitoring of Pavement Stresses on the A1 in Switzerland2008Inngår i: Journal of Testing and Evaluation, ISSN 0090-3973, E-ISSN 1945-7553, Vol. 36, nr 4, s. 291-299Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A large number of sensors installed as part of the European cooperative project, Eureka Logcham Footprint, are used to examine the effects of individual vehicles on the road pavement and the environment. The weigh-in-motion data recorded at the Footprint Monitoring Site near Lenzburg, Switzerland are analyzed and figures are presented which describe the nature of the traffic experienced at the monitoring site. The weighin-motion data are matched to data from a prototype stress- i n-moti on sensor from the same site and the two datasets are compared. The ability of the stress-in-motion sensor to record the contact stress distribution is discussed and procedures are proposed for describing the shape of the distribution using a relatively small number of parameters. A method for quantifying distribution shape in terms of an "m"-ness value is proposed. A finite element model of the road is constructed, validated, and used to predict the stresses and strains in the pavement related to particular contact stress distributions. It is demonstrated that, for all but the heaviest tires, the shape of the stress distribution has a significant effect on the stresses and strains within the pavement.

  • 57. Morgan, G.
    et al.
    Poulikakos, L.
    Arraigada, M.
    Muff, R.
    Partl, Manfred
    Swiss Federal Laboratories for Materials Testing and Research EMPA. Duebendorf, Switzerland.
    Stress-in-Motion Measurements of Heavy Vehicles from the Swiss Footprint Monitoring Site2008Inngår i: 5th International Conference on Weigh-In-Motion, 2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Stress-in-Motion data from the A1 motorway in Switzerland is examined. The data is classifiedby the load and stress distribution of the wheel and five examples are selected as beingrepresentative of the highly loaded wheels passing the site. A finite element model is used toexamine the effects that these five distributions have on the A1 pavement. It is concluded thatwhile there is an approximately linear relationship between pavement strain and wheel loadwhen other parameters are held constant, the effects of the stress distribution are moresignificant in the cases presented. It is also shown that the different stress distributions producesignificantly different effects on pavements irrespective of the wheel load.

  • 58.
    Olsson, Erik
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.), Hållfasthetslära (Avd.).
    Jelagin, Denis
    KTH, Skolan för teknikvetenskap (SCI), Hållfasthetslära (Inst.), Hållfasthetslära (Avd.).
    Partl, Manfred
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggnadsmaterial.
    New discrete element framework for modelling asphalt compaction2019Inngår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    During asphalt mixture compaction, loads in the material are mainly transferred through contact between the stones and the interaction between the stones and the binder. The behaviour of such materials is suitable to model using the Discrete Element Method (DEM). In this study, a new DEM modelling approach has been developed for studying the asphalt compaction process, incorporating contact and damage laws based on granular mechanics. In the simulations, aggregate fracture is handled by a recently developed method of incorporating particle fracture in DEM, based on previously performed fracture experiments on granite specimens. The binder phase is modelled by adding a viscoelastic film around each DEM particle. This surface layer has a thickness that obtains the correct volume of the binder phase and has mechanical properties representative for the binder at different temperatures. The ability of the model to capture the influence of mixture parameters on the compactability and the eventual stone damage during compaction is examined for the cases of compaction flow test and gyratory compaction. Explicitly, the influence of different aggregate gradations, mixture temperatures and binder properties are studied. The results show that the proposed DEM approach is able to capture qualitatively and quantitatively responses in both cases and also provide predictions of aggregate damage. One large benefit with the developed modelling approach is that the influence of different asphalt mixture parameters could be studied without re-calibration of model parameters. Furthermore, based on comparative DEM simulations, it is shown that the proposed approach provides more realistic force distribution networks in the material.

  • 59. Ongel, A.
    et al.
    Harvey, J.
    Partl, Manfred
    Swiss Federal Laboratories for Materials Testing and Research EMPA. Duebendorf, Switzerland.
    Assessment of Clogging in Open Graded Mixes in California2008Inngår i: International ISAP Symposium on Asphalt Pavements and Environment, 2008Konferansepaper (Fagfellevurdert)
  • 60.
    Partl, Manfred
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggnadsmaterial. Carleton University, Canada.
    Editorial2017Inngår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 18, s. 1-1Artikkel i tidsskrift (Fagfellevurdert)
  • 61.
    Partl, Manfred
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Väg- och banteknik (stängd 20110301). Empa, Swiss Federal Laboratories for Materials Science and Technology Road Engineering/Sealing Components, Duebendorf, Switzerland .
    Editorial2014Inngår i: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 47, nr 8, s. 1271-1272Artikkel i tidsskrift (Fagfellevurdert)
  • 62.
    Partl, Manfred
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggnadsmaterial.
    Introduction2018Inngår i: RILEM State-of-the-Art Reports, Springer Netherlands , 2018, s. 1-14Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An overview on the background and motivation for this report on the achievements of the technical committee RILEM TC 237-SIB on Testing and Characterization of Sustainable Innovative Bituminous Materials and Systems is presented, together with a short summary on the scope of this voluntary international team effort. Challenges and key research paths towards modern “green” asphalt pavements are addressed, focusing on general aspects associated with the increasing variety of approaches and their implication on testing and characterization of innovative asphalt pavement materials. As example for the complexity of the experimental challenges and the potential necessity to break free from traditional testing patterns, selected specific aspects of reinforced asphalt pavements are considered and discussed. It is emphasized that testing must be consistent with the purpose of the reinforcement, answering the key questions in what respect, under what conditions and in what loading direction reinforcement should be achieved and tested. This “garbage-in-garbage-out” awareness is also valid for all other fields dealing with testing and characterization of innovative bituminous materials and systems, of course. 

  • 63.
    Partl, Manfred
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggnadsmaterial.
    Towards improved testing of modern asphalt pavements2018Inngår i: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 51, nr 6, artikkel-id 166Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    During the last 50 years, Rilem was continuously active in pre-standardization efforts aiming at gradually improving scientific and technological testing and analysis methods for refined understanding and characterization of bituminous binders and asphalt, both under well-defined laboratory and performance driven in-field conditions. This paper intends to highlight and provide a short overview on the international activities of Rilem’s to date 18 technical committees (TC) on asphalt and bituminous binders. After some general background information, underlining the specific complexity of asphalt pavement materials in terms of rheological behavior and basic structural functioning, it is shown that these activities resulted in numerous recommendations, state of the art reports and conference proceedings, all produced on a voluntary basis by scientific and technical commitment of individual experts. This wealth of results was created by the TCs following an own systematic methodology for many years which, at the end of the day, allowed building up activities through the new TCs of today in a much more specialized but at the same time also more diverse way. In view of this new flexibility and keeping in mind the previous success story of Rilem towards improved testing of asphalt pavements, future developments, challenges and interdisciplinary issues regarding bituminous road materials are outlined as potential starting point for future TC initiatives.

  • 64.
    Partl, Manfred
    et al.
    EMPA, Swiss Federal Laboratories for Materials Testing and Research, Road Engineering and Sealing Components, Dübendorf, Switzerland.
    Canestrari, Francesco
    Grilli, A.
    Gubler, R.
    Characterization of Water Sensitivity of Asphalt Mixtures with Coaxial Shear Test2008Inngår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 9, nr 2, s. 247-270Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The CoAxial Shear Test (CAST) performs fatigue test under simultaneous action Of dynamic loading, temperature cycles and water, and modulus test on wet or dry specimen. Both a dense graded and an open graded mixture were studied at different air void content. The water sensitivity of both mixtures was determined by comparing fatigue performance of dry and wet tests. Additionally the effects of water action, temperature and loading cycles were also investigated by comparison of modulus test before (undamaged specimen) and after (damaged specimen) each fatigue test. The introduced Water Sensitivity Index for fatigue test confirms that water damage in asphalt pavements is considerably related to air voids. Finally, the modulus test analysis allowed explaining also the different consequences of environmental factors on viscoelastic properties of asphalt mixtures by using the Standard Linear Solid model.

  • 65.
    Partl, Manfred
    et al.
    Empa, Swiss Federal Laboratories for Materials Testing and Research, Road Engineering/Sealing Components, Dübendorf, Switzerland.
    Flisch, A.
    Jönsson, M.
    KTH.
    Comparison of Laboratory Compaction Methods Using X-ray Computer Tomography2007Inngår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 8, nr 2, s. 139-164Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Changes and differences in homogeneity of asphalt concrete specimens during Marshall and Rolling-Wheel compaction are investigated by means of standard air-void content determination (AV) and X-ray Computer Tomography (CT). Following an earlier study on Gyratory compaction with the same objective and material, this study, again, focuses on expert. mental aspects serving as a basis for laboratories and producers to optimize compaction procedures and devices. The results demonstrate that X-ray CT is a powerful tool leading to a better understanding of compaction mechanisms, In this way, X-ray CT may be considered very suitable for developing improved laboratory compaction methods and procedures.

  • 66.
    Partl, Manfred
    et al.
    Road Engineering/Sealing Components Laboratory, EMPA Duebendorf, Duebendorf, Switzerland.
    Pasquini, E.
    Canestrari, Francesco
    Virgili, A.
    Analysis of Water and Thermal Sensitivity of Open Graded Asphalt Rubber Mixtures2010Inngår i: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 24, nr 3, s. 283-291Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This research investigates the water and thermal sensitivity of two open graded mixtures prepared with asphalt rubber binder, one mixture containing lightweight aggregates (expanded clay) replacing a part of coarse fraction. Fatigue tests using the CoAxial Shear Test (CAST) apparatus were performed in both dry and wet conditions with and without temperature cycles. Results showed that fatigue resistance of the studied materials was only little affected by water and temperature cycles and superior to traditional open graded mixtures produced with SBS modified bitumen only. The results were also validated and modelled by means of an elasticity-based damage model.

  • 67. Partl, Manfred
    et al.
    Sokolov, K.
    Kim, H.
    Evaluating and Modeling the Effect of Carbon Fiber Grid Reinforcement in a Model Asphalt Pavement2008Annet (Fagfellevurdert)
  • 68. Piber, H.
    et al.
    Canestrari, F.
    Ferrotti, G.
    Lu, X.
    Millien, A.
    Partl, Manfred
    Swiss Federal Laboratories for Materials Testing and Research EMPA. Duebendorf, Switzerland.
    Petit, C.
    Phelipot-Mardelle, A.
    Raab, C.
    RILEM Interlaboratory Test on Interlayer Bonding of Asphalt Pavements2009Inngår i: ADVANCED TESTING AND CHARACTERISATION OF BITUMINOUS MATERIALS, VOLS 1 AND 2 / [ed] Loizos, A; Partl, MN; Scarpas, T; AlQadi, IL, 2009, s. 1181-1189Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The RILEM TG 4 organized an interlaboratory test in order to compare the different test procedures to assess the interlayer bonding properties of asphalt pavement. The pavement was composed of two layers. Three different interface conditions were chosen. The first pavement was laid without interface treatment and the others with two different types of emulsion. 14 laboratories from 11 countries participated in this study and carried out shear or torque tests on 1400 cores. The maximum shear or torque load and the corresponding displacement were measured and the shear or torque stress was calculated as a function of the following parameters: diameter, test temperature, test speed, stress applied normal to the interface and age of the specimen. This paper presents the results of this study in terms of precision and correlations regarding the parameters.

  • 69. Piber, H.
    et al.
    Partl, Manfred
    Raab, C.
    RILEM Interlaboratory Test on Pavement Performance Prediction and Evaluation2009Inngår i: ADVANCED TESTING AND CHARACTERISATION OF BITUMINOUS MATERIALS, VOLS 1 AND 2 / [ed] Loizos, A; Partl, MN; Scarpas, T; AlQadi, IL, 2009, s. 1191-1200Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The former RILEM TC 182 PEB organized 1997 an international inter-laboratory test on pavement performance, prediction and evaluation. The aim was to predict the expected damages after 10 years on the basis of traffic and climatic data. Two sections in Austria and Portugal were constructed and test samples were cut from the pavement and send to the different laboratories. 13 laboratories of 12 countries participated in the study and gave performance predictions according their own methods and standards. The report which summarizes the results in detail is available on the RILEM web site. RILEM TC 206 ATB TG 4 continued the long term observation. Unfortunately, only the Austrian section in Villach could be monitored as planned, since the Portuguese section had problems in the data supply. In 2007 the Austrian road administration stopped the observation of the test section in Villach. The paper summarises the actual road condition and compares it to the predicted performance.

  • 70. Piber, H.
    et al.
    Partl, Manfred
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Byggnadsmaterial.
    Raab, Christiane
    Interlaboratory tests on pavement performance prediction and evaluation-rutting2013Inngår i: RILEM State-of-the-Art Reports, Springer Netherlands, 2013, Vol. 9, s. 257-302Kapittel i bok, del av antologi (Fagfellevurdert)
    Abstract [en]

    The former RILEM TC 182 PEB organized 1997 an international interlaboratory test on pavement performance, prediction and evaluation. The aim was to predict the expected damages after 10 years on the basis of traffic and climatic data by testing samples that were cut from the newly constructed road. On esection in Austria was monitored as planned until 2007. Thirteen laboratories from 12 countries participated in the study and provided performance predictions for both sections according to their own methods and standards. This chapter summarises the road condition after this long term performance observation and compares it to the rutting results from those laboratories which performed dynamic rutting tests on more than one pavement layer and based their prediction on their own test results and models without relying on national requirements. © RILEM 2013.

  • 71. Poulikakos, L.
    et al.
    Arraigada, M.
    Morgan, G.
    Heutschi, K.
    Anderegg, P.
    Partl, Manfred
    Empa, Swiss Federal Laboratories for Materials Testing and Research, Dübendorf, Switzerland.
    Soltic, S.
    In Situ Measurements of the Environmental Footprint of Freight Vehicles in Switzerland2008Inngår i: Transportation Research Part D: Transport and Environment, ISSN 1361-9209, E-ISSN 1879-2340, Vol. 13, nr 4, s. 274-282Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Eureka Logchain Footprint is an ongoing European cooperative project aimed at developing methods to identify road and rail vehicles through their environmental "footprint" as characterised by their dynamic load, noise, ground borne vibrations, and gaseous emissions. Part of the project involves the installation of road and rail footprint monitoring stations throughout Europe. This paper reports the results of the first road station built on the A1 motorway in Switzerland on a flexible asphalt pavement. Individual vehicle data on weigh in motion, noise and vibration sensors were measured in situ. Methods for the incorporation of gaseous emissions from vehicles are discussed. The results indicate that the various footprint parameters need to be assessed separately to determine the environmental impact of heavy vehicles.

  • 72. Poulikakos, L.
    et al.
    Heutschi, K.
    Arraigada, M.
    Anderegg, A.
    Partl, Manfred
    Swiss Federal Laboratories for Materials Testing and Research EMPA. Duebendorf, Switzerland.
    Comparison of WIM, Noise, Vibration Data from Heavy Vehicles2008Inngår i: 5th International Conference on Weigh-In-Motion, 2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A European cooperative project aims to develop an innovative and cost effective method toidentify road and rail vehicles by means of their environmental "footprint" as characterized bydynamic load, noise, ground borne vibration and gaseous emissions induced by the vehicle.This characterization can produce a method for a ‘true’ bottom up allocation of effects ofvehicles on infrastructure and environment. An important part of this project is the installationof road and rail Footprint Monitoring Sites (FMS) throughout Europe. This paper presents theresults from the Swiss FMS where the environmental Footprints of heavy vehicles aresystematically collected and compared.

  • 73. Poulikakos, L.
    et al.
    Heutschi, K.
    Arraigada, M.
    Soltic, P.
    Jordi, P.
    Partl, Manfred
    Swiss Federal Laboratories for Materials Testing and Research EMPA. Duebendorf, Switzerland.
    Can Environmental Footprint of Vehicles be used for Road Pricing?2008Inngår i: 7th European Congress and Exihbition on Intelligent Transport Systems and Services, 2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The movement of additional goods associated with a single market in Europe will increase rail and road freight traffic and the resulting impact on the environment and infrastructure. To reduce this impact, a better understanding of the dynamic interaction between freight vehicles and the infrastructure and environment is required. The European cooperative project Eureka Logchain Footprint E!2486 aims to develop an innovative and cost effective method to identify road and rail vehicles by means of their environmental "footprint" as characterized by dynamic load, noise, ground borne vibration and gaseous/particle emissions induced by individual vehicles. Switzerland has been a partner in the Footprint project since 2004. The Swiss participation included the installation of the novel Footprint Monitoring Site (FMS) on the A1 motorway in June 2005. This paper presents results from the monitoring of footprint parameters and compares these parameters with the parameters currently used for heavy vehicle fee.

  • 74. Poulikakos, L.
    et al.
    Morgan, G.
    Muff, R.
    Partl, Manfred
    Swiss Federal Laboratories for Materials Testing and Research, Dübendorf, Switzerland.
    Doupal, E.
    Calderara, R.
    Interpretation of Accelerated Laboratory Testing of the Prototype Modulas Stress in Motion (SIM) Sensor with the MMLS3 Load Simulator2008Inngår i: Journal of transportation engineering, ISSN 0733-947X, E-ISSN 1943-5436, Vol. 134, nr 10, s. 414-422Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    With modern heavy vehicles using higher inflation pressures and higher axle loads the dynamic measurement of the tire-pavement contact force/stress is essential not only for tire development but also in road research for the investigation of factors which may lead to excessive damage of pavements. In this paper the results of laboratory tests with a prototype stress in motion (SIM) quartz sensor trafficked with a one-third scale load simulator (MMLS3) are presented. The tests were designed to vary parameters such as tire inflation pressure, speed, ambient temperature, lateral position, and angle to direction of travel in a controlled environment in order to isolate the influence of these parameters on the SIM sensor results. All other controllable variables remained constant while the target parameter was varied. Tire inflation pressures were calculated from these data. The laboratory tests show that the prototype sensor promises to be an effective investigative tool for SIM measurements.

  • 75. Poulikakos, L.
    et al.
    Partl, Manfred
    Empa, Swiss Federal Laboratories for Material Testing and Research, Dübendorf, Switzerland.
    Evaluation of Moisture Susceptibility of Porous Asphalt Concrete Using Water Submersion Fatigue Tests2009Inngår i: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 23, nr 12, s. 3475-3484Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Porous asphalt concrete due to its open structure is exposed to water and therefore susceptible to water damage. Effect of water, temperature and frequency on mechanical properties of porous asphalt concrete was investigated. An innovative test method developed in Switzerland is used to mechanically test 150 mm diameter cylindrical cores from eight materials in dry state and while being submerged under water. Although the conventional indirect tensile strength ratio delivers useful data about the water sensitivity of porous asphalt specimen, the coaxial shear test provides vital information about the development of fatigue damage in the material. Application of coaxial shear test (CAST) for a twin lay porous asphalt as well as conventional porous asphalt shows a reduction in complex modulus due to fatigue loading after each thermal cycle and due to detrimental effects of water Submersion. Moisture susceptibility results using CAST reflected the field inspections of surface degradation. In addition, investigation of the microstructure has given insight into the mechanical behavior of selected materials.

  • 76. Poulikakos, L
    et al.
    Partl, Manfred
    Empa, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Road Engineering/Sealing Components, Dübendorf, Switzerland.
    Investigation of Porous Asphalt Microstructure using Optical and Electron Microscopy2010Inngår i: Journal of Microscopy, ISSN 0022-2720, E-ISSN 1365-2818, Vol. 240, nr 2, s. 145-154Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    P>Direct observations of porous asphalt concrete samples in their natural state using optical and electron microscopy techniques led to useful information regarding the microstructure of two mixes and indicated a relationship between microstructure and in situ performance. This paper presents evidence that suboptimal microstructure can lead to premature failure thus making a first step in defining well or suboptimal performing pavements with a bottom-up approach (microstructure). Laboratory and field compaction produce different samples in terms of the microstructure. Laboratory compaction using the gyratory method has produced more microcracks in mineral aggregates after the binder had cooled. Well-performing mixes used polymer-modified binders, had a more homogeneous void structure with fewer elongated voids and better interlocking of the aggregates. Furthermore, well-performing mixes showed better distribution of the mastic and better coverage of the aggregates with bitumen. Low vacuum scanning electron microscopy showed that styrene butadiene styrene polymer modification in binder exists in the form of discontinuous globules and not continuous networks. A reduction in the polymer phase was observed as a result of aging and in-service use.

  • 77. Poulikakos, L.
    et al.
    Takahashi, S.
    Partl, Manfred
    Swiss Federal Laboratories for Materials Testing and Research (EMPA), Road Engineering/Sealing Components, Dübendorf, Switzerland.
    Coaxial Shear Test and Wheel Tracking Tests for Determining Porous Asphalt Mechanical Properties2007Inngår i: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 8, nr 3, s. 579-594Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Performance oriented test procedures are compared and discussed with respect to their suitability for porous asphalt optimization and for development of improved mix design. Coaxial shear tests and wheel tracking tests were carried out in order to compare the properties of both theoretically and empirically designed porous asphalt specimens. The specimens were produced using an improved theoretical mix design approach for porous asphalt. This method is based on a packing theory for aggregate grading optimization, reducing the post compaction effects on the pavement under traffic. The problems with porous asphalt arise from premature aging and therefore laboratory aging of the mix was used for the simulation of in-situ condition. As presented in this paper the test results vary significantly with aging as seen in the rutting behavior and shear modulus. The packing theory leads, in many cases, to porous asphalt mixes with superior quality as compared to traditional standard mixes provided that the influence of the binder is considered accordingly.

  • 78. Raab, C.
    et al.
    Partl, Manfred
    Department of Road Engineering and Sealing Components, Empa, Duebendorf, Switzerland.
    Influence of Tack Coats on the Adhesion Properties of Asphalt Pavements2008Inngår i: EFFICIENT TRANSPORTATION AND PAVEMENT SYSTEMS: CHARACTERIZATION, MECHANISMS, SIMULATION, AND MODELING / [ed] AlQadi, IL; Sayed, T; Alnuaimi, A; Masad, E, 2008, s. 517-527Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper summarizes the results of a laboratory study in which a common cationic tack coat was used between two layered slabs. The slabs were produced with a roller compactor and the adhesion of cores taken from the slabs was evaluated by means of direct shear testing according to Leutner. Furthermore, a common cationic, but not polymer modified, tack coat was compared to a polymer modified one. To evaluate the limits of the application of tack coats dirt and moisture was applied between the two layers before and after the application of a tack coat. For comparison the tack coat was applied on one side of the slab only, when the other stayed untreated. Besides, the influence of tack coats on fine milled surfaces and the influence of curing time on the adhesion were also investigated.

  • 79. Raab, C.
    et al.
    Partl, Manfred
    Swiss Federal Laboratories for Materials Testing and Research EMPA. Duebendorf, Switzerland.
    Influence of the gap width between the shearing rings on interlayer shear bond testing2009Inngår i: Proceedings of second International Conference environmentally friendly Roads, ENVIROAD 2009, 2009Konferansepaper (Fagfellevurdert)
  • 80. Raab, C.
    et al.
    Partl, Manfred
    Swiss Federal Laboratories for Materials Testing and Research EMPA. Duebendorf, Switzerland.
    Interlayer Bonding of Binder, Base and Subbase Layers of Asphalt Pavements: Long-Term Performance2009Inngår i: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 23, nr 8, s. 2926-2931Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    With bond testing of asphalt layers becoming a more important topic as well as in research as in every day pavement construction, the question of long term behaviour of bonding properties has come up. In recent research it has been shown that the bonding properties between surface and binder courses seem to improve with time considering that the surface course does not show distress phenomena and that the traffic volume does not exceed the traffic considered for pavement design. That bond failure is not only a question of the top layers is a well known fact; therefore the long term properties of the lower layers are also of interest. The paper focuses on the effect of long term behaviour of bonding properties of the lower pavement layers (binder or base and subbase courses) presenting the results of an extensive Swiss study. The study compares the bonding properties determined with the layer parallel shear test (LPDS) according to Leutner of high volume roads after a 9-13 years period. It was found that for rehabilitations or old constructions an improvement cannot be expected and especially in case of old constructions seems to depend on their service life. For the bond between lower layers decreases of shear force values down to 50% are possible.

  • 81. Raab, C
    et al.
    Partl, Manfred
    EMPA Swiss Federal Laboratories for Materials Testing and Research. Dübendorf, Switzerland.
    Investigation into a long-term interlayer bonding of asphalt pavements2008Inngår i: Baltic Journal of Road and Bridge Engineering, ISSN 1822-427X, E-ISSN 1822-4288, Vol. 3, nr 2, s. 65-70+Ia+IIa+IIIaArtikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In recent years adhesion testing of pavement layers has gained more and more importance throughout Europe. In a lot of projects the bonding properties are determined after construction and many countries have developed standard requirements which the obtained bonding values have to fulfil. The paper focuses on the question of long-term behaviour of bonding properties and presents the results of an extensive Swiss study. The study compares the bonding properties determined with the Layer Parallel Direct Shear Test (LPDS) according to Leutner of 14 high volume roads from the years 1993-97 to the values for the same road sections determined 9-13 years later. In addition, a second study conducted on a circular track investigated the differences between the bonding properties in the wheel path and outside the wheel path. It could be shown that in most cases the bond improves due to compaction and settlement caused by the traffic. Problems arise, resulting in a reduction of shear forces, when the pavement shows distress phenomena. The difference between the bonding properties in the wheel path and outside it could be demonstrated in the circular track study, whereas the differences on the road depend on many factors and often seem to be eliminated over the years.

  • 82. Raab, C.
    et al.
    Partl, Manfred
    Swiss Federal Laboratories for Materials Testing and Research EMPA. Duebendorf, Switzerland.
    Laboratory Study on Interlayer Bonding Using Cationic Tack Coats2009Inngår i: ADVANCED TESTING AND CHARACTERISATION OF BITUMINOUS MATERIALS, VOLS 1 AND 2, 2009, s. 3-12Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper summarizes the results of a laboratory study in which a cationic tack coat was used between two layered specimens. The specimens were produced with a roller compactor and the adhesion of cores taken from the specimens was evaluated by means of direct shear testing according to Leutner. To evaluate the limits of the application of tack coats dirt and moisture was applied between the two layers before and after the application of a tack coat. In addition, the influence of tack coats on fine milled surfaces and the influence of curing time on the bonding properties were investigated. It could be shown that especially in the case of dirt and moisture common phenomena on construction sites-tack coats have a great potential to secure and improve adhesion properties. Contrary to the benefit of tack coats on dirty and wet surfaces the advantage of tack coats on fine milled surfaces is doubtable.

  • 83. Raab, C.
    et al.
    Partl, Manfred
    Swiss Federal Laboratories for Materials Testing and Research EMPA. Duebendorf, Switzerland.
    Long-Term Interlayer Shear Performance of Asphalt Pavements2008Inngår i: Proceedings of 2nd Transportation Research Arena TRA, 2008Konferansepaper (Fagfellevurdert)
  • 84. Raab, C
    et al.
    Partl, Manfred
    Swiss Federal Laboratories for Materials Testing and Research EMPA. Duebendorf, Switzerland.
    Long-Term Interlayer Shear Performance of Base and Subbase Layers in Asphalt Pavements2009Inngår i: Proceedings of Sixth International Conference on Maintenance and Rehabilitation of Pavements and Technological Control Mairepav6, 2009, s. 646-653Konferansepaper (Fagfellevurdert)
  • 85. Raab, C.
    et al.
    Partl, Manfred
    Section Road Engineering/Sealing Components. Duebendorf, Switzerland.
    El Halim, A.
    Effect of gap width on interlayer shear bond results2010Inngår i: International Journal of Pavement research and Technology, ISSN 1996-6814, Vol. 3, nr 2, s. 79-85Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Since the 1990s the Leutner shear test has become the most important device for testing the interlayer shear bond of asphalt pavements. The test device was originally designed by R. Leutner in the late 1970s, but since different countries and laboratories have made modifications or have built their own equipment. Besides others the gap width between the shearing rings has been a matter of modification. Recently this question also appeared in the process of European standardization. This paper shows the results of a laboratory study in which the gap distance was varied between 0 and 5mm. It was found that the influence of the gap width depends on the asphalt concrete type of the two layers (mixture type, max. aggregate size, and binder content). In most cases the gap width is negligible, in some cases maximum shear force and stiffness value decreases with increasing gap width. In addition to the shear values at the interface, shear tests were conducted in the material itself. Therefore, the difference between in-layer and interlayer shear properties and behavior is also discussed in more detail.

  • 86. Raab, C.
    et al.
    Partl, Manfred
    Swiss Federal Laboratories for Materials Testing and Research EMPA. Duebendorf, Switzerland.
    El Halim, A.
    Evaluation of Interlayer Shear Bond Devices for Asphalt Pavements2009Inngår i: Baltic Journal of Road and Bridge Engineering, ISSN 1822-427X, Vol. 4, nr 4, s. 186-195Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    For testing the bond between asphalt pavement layers quite a variety of methods were proposed and used during the last 30 years. In many publications some of these test methods and devices were described by presenting photographs and sketches. Often photographs show the functioning of the devices only insufficiently and detailed information regarding the test devices (e.g. gap width) and test conditions (e.g. loading function, normal force) are difficult to retrieve. The following paper summarises the test methods and devices for the determination of the bond between asphalt pavement layers regarding shear testing. Direct and simple shear tests from all over the world are presented and their mode of operation shown. Furthermore, the range of applications is described and information regarding test evaluation and results are given.

  • 87. Rabaiotti, C.
    et al.
    Partl, Manfred
    Swiss Federal Laboratories for Materials Testing and Research EMPA. Duebendorf, Switzerland.
    Caprez, M.
    APT device evaluation for road research in Switzerland: test campaign on a Swiss Highway with the MLS102008Inngår i: Proceedings of 3rd Int. Conf. on Accelerated Pavement Testing, 2008Konferansepaper (Fagfellevurdert)
    Abstract [en]

    APT facilities and testing devices have a long tradition in road research in Switzerland. Since the beginning of the seventies the Swiss Codes for road design have been strongly affected by the results of 7 test campaigns carried out on more than 35 pavement structures tested with the “Rundlauf” circular test track. The APT device MLS10, developed by the University of Stellenbosch in collaboration with Empa and the Institute for Geotechnical Engineering of the ETH Zürich has now being evaluated for replacing the “Rundlauf” circular test track. Some of the main advantages of the MLS10 are that it allows for a real road structure to be tested in situ, and in a much shorter time scale than with the “Rundlauf”.The machine capabilities have been long and accurately tested on a real Swiss Highway section. The mechanical properties of the road structure have been monitored and analyzed with a newly developed static deflection measurement device “ETH DELTA”. The test track surface conditions, the layer thickness, composition, and in situ conditions as well as the temperatures in different depths have also been collected. The results show that the MLS10 is able to reproduce the real loading conditions on an existing road structure, and it allows for the residual service life of a real road construction to be estimated.

  • 88. Santagata, F.
    et al.
    Ferrotti, G.
    Partl, Manfred
    Department Materials and Systems for Civil Engineering, Swiss Federal Laboratories for Materials Testing and Research (EMPA).
    Canestrari, Francesco
    Statistical investigation of two different interlayer shear test methods2009Inngår i: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 42, nr 6, s. 705-714Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The performance of multi-layered pavement systems strongly depends on interlayer bonding. In order to evaluate this parameter, some countries have developed their own test method. However, different devices generally provide different results due to the test conditions. In this article, the statistical investigation of two interlayer shear test methods is shown considering different asphalt materials and different specimen preparation techniques. Both test methods provided comparable results showing the same ranking in interlayer shear stress for different test conditions and the same level of precision in terms of scatter of the results. Moreover, the repeatability limit was found to be dependent on the test method, the pavement material and the compaction technique. It is worth noting that this extensive experimental investigation paves the way for the incoming European Standardization process involving the two shear test methods.

  • 89. Santagata, F.
    et al.
    Partl, Manfred
    Swiss Federal Laboratories for Materials Testing and Research (EMPA), Dübendorf, Switzerland.
    Ferrotti, G.
    Canestrari, Francesco
    Flisch, A.
    Layer Characteristics Affecting Interlayer Shear resistance in Flexible Pavements2008Inngår i: 2008 Journal of the Association of Asphalt Paving Technologists, Vol 77, 2008, s. 221-256Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The evaluation of interlayer shear resistance is important to better understand how multi-layered pavements behave under traffic conditions. This paper focuses on the characterization of the interlayer shear behavior in flexible pavements through experimental investigation and analysis of two parameters that affect interlayer bonding: the influence of air void content of the two mixes in contact and the contact surface roughness of double-layered asphalt concrete specimens. Two different shear test devices (LPDS and ASTRA equipment) were used to evaluate interlayer resistance, whereas air void content and roughness characteristics at the interface were measured by using both traditional and innovative techniques. In particular, a non-destructive method, X-ray Computer Tomography (CT), was used to investigate interlayer air void content and interlayer roughness after compaction of the upper layer. The results were able to show that air void content influences interlayer shear resistance in a non-linear way. As far as contact surface roughness is concerned, profile comb, laser profilometer and X-ray CT were used and further elaborated with advanced techniques such as fractal theory and spectral analysis. The results showed how higher macro-texture leads to an increase in LPDS and ASTRA interlayer shear resistance.

  • 90. Valtorta, D.
    et al.
    Poulikakos, L.
    Connery, E.
    Partl, Manfred
    Road Engineering/Sealing Components Laboratory, EMPA Duebendorf, Switzerland.
    Mazza, E.
    Accelerated Aging of Bituminous Binders Using a High Frequency Torsional Rheometer2007Inngår i: Advanced Engineering Materials, ISSN 1438-1656, E-ISSN 1527-2648, Vol. 9, nr 1-2, s. 121-128Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A high frequency torsional rheometer (HFTR) is used to monitor the aging process of bituminous binders. The device measures the changes in the dynamic behavior of a rod performing torsional vibrations at a specified resonance frequency. The aging of a straight run bituminous binder 180/200 were characterized using the HFTR by quantifying the rheological changes that the material undergoes during exposure to air pressure and temperature in terms of the variation of the complex shear modulus. Experiments and numerical calculations were used to study the binder properties in the surface zone of the specimens that was directly exposed to heat and oxygen. Dynamic mechanical analysis (DMA) was used to measure the rheological properties of bituminous binders and asphalt mixes. The results shows that the top surface layers of the specimen were considerably stiffer than the internal layers which are not directly exposed to air.

  • 91. Valtorta, D.
    et al.
    Poulikakos, L.
    Partl, Manfred
    EMPA, Swiss Federal Laboratories for Material Testing and Research, Switzerland.
    Mazza, E.
    Rheological Properties of Polymer Modified Bitumen from Long-term Field Tests2007Inngår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 86, nr 7-8, s. 938-948Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The possibility to monitor aging of pavements and bituminous binders directly on the operative field, under their typical environmental conditions, can contribute to better understand the factors influencing the aging process, can be used for material optimization and to improve the performance behavior of bituminous binders. The high frequency torsional rheometer (HFTR) described in this paper is a useful device to study the time evolution of the theological properties of bituminous binders during field tests. In comparison with prevailing rheometers, the HFTR is inexpensive and, due to its portability and operative frequency (5 kHz) that allows measurements to be unaffected by traffic induced low frequencies, is a useful tool for continuous monitoring of field tests. The HFTR device and the measurement technique are described in this paper. The extraction of the theological parameters from the experiments is made through analytical and finite element models that reproduce the particular conditions of the field tests. In this study, the long-term aging of an asphaltic plug joint of a highway bridge is investigated with an HFTR over three consecutive years of exposure to environmental conditions. The evolution of the theological properties of the plug joint material, containing styrene-butadiene-styrene polymer modified bitumen, is quantified in terms of the complex shear modulus G*, showing a progressive material hardening and an increase in the temperature susceptibility of the binder

  • 92. Virgili, A.
    et al.
    Partl, Manfred
    Road Engineering/Sealing Components Laboratory, EMPA Duebendorf.
    Grilli, A.
    Santagata, F.
    Damage model for Environmental Conditioned Fatigue Test with CAST2008Inngår i: Fatigue & Fracture of Engineering Materials & Structures, ISSN 8756-758X, E-ISSN 1460-2695, Vol. 11, nr 31, s. 967-979Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this paper is to suggest a unified test method that allows investigation into the different effects and contribution of water damage and temperature cycles on fatigue performance of asphalt mixtures by means of a CoAxial Shear Test (CAST). A continuum damage approach, based on the elasticity theory, is chosen to determine the damage level of each tested specimen. The proposed mathematical model allows the simulation of the modulus evolution in the fatigue test and takes into account the temperature cycles. In this way, a unique scalar damage factor determines the damage process severity in each specimen and allows a rational comparison between each different condition.

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