| 1. |
- Partl, Manfred, et al.
(författare)
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Analysis of Water and Thermal Sensitivity of Open Graded Asphalt Rubber Mixtures
- 2010
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Ingår i: Construction and Building Materials. - : Elsevier BV. - 0950-0618 .- 1879-0526. ; 24:3, s. 283-291
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Partl, Manfred, et al.
(författare)
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Characterization of Water Sensitivity of Asphalt Mixtures with Coaxial Shear Test
- 2008
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Ingår i: International Journal on Road Materials and Pavement Design. - : Informa UK Limited. - 1468-0629 .- 2164-7402. ; 9:2, s. 247-270
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
- Porot, Laurent, et al.
(författare)
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Bituminous binder
- 2018
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Ingår i: Testing and Characterization of Sustainable Innovative Bituminous Materials and Systems. - Cham : Springer Netherlands. ; , s. 15-74
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Bokkapitel (refereegranskat)abstract
- One of the most important aspects of asphalt pavement deterioration is the ingress of water in pavement which leads to loss of the material characteristics, even material integrity with loss of aggregates. Thus the behaviour of asphalt mixture under moisture conditions is one of the key parameter for specifications. It’s a complex phenomenon which is influenced amongst other things by materials properties with wetting, cohesion and adhesion of bituminous binder and by environmental conditions with temperature, moisture, loading and layer type. It has been a research subject for a very long time and still not precisely described. A large number of test methods is available to estimate the affinity between aggregates and bituminous binders. These test methods can be subdivided in different ways; a first distinction can be based on the presence or absence of water during the test procedure. If water is present, the evaluation is in fact referred to as water sensitivity or moisture damage testing. Another distinction can be based on the type of sample that is evaluated. The test sample can be loose aggregates coated with a bituminous binder or a compacted asphalt mix sample. Lastly the individual components, bitumen and aggregate, can be tested separately through intrinsic properties. Furthermore, test results can also be based on the quantification of the test results, whether this is based on a qualitative or a quantitative evaluation. In RILEM TC 237 SIB, TG1 the main purpose was to evaluate common test methods, used to assess the affinity of bitumen to aggregate surfaces, to determine, if possible, the repeatability and reproducibility and to give recommendations for improvement. In this study both binders and aggregates have been considered. Three bituminous binders, two unmodified from different sources, one polymer modified binder, and four aggregate types, with different mineralogy, have been selected. The test methods considered in the study include the rolling bottle test, the boiling water stripping test and the bitumen bond strength test; also surface energy was investigated. This chapter presents the results of these tests and their accuracy.
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| 4. |
- Santagata, F., et al.
(författare)
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Layer Characteristics Affecting Interlayer Shear resistance in Flexible Pavements
- 2008
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Ingår i: 2008 Journal of the Association of Asphalt Paving Technologists, Vol 77. ; , s. 221-256
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 5. |
- Santagata, F., et al.
(författare)
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Statistical investigation of two different interlayer shear test methods
- 2009
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Ingår i: Materials and Structures. - : Springer Science and Business Media LLC. - 1359-5997 .- 1871-6873. ; 42:6, s. 705-714
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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