| 1. |
- Kuttah, Dina K, 1975-, et al.
(författare)
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Performance Assessment of Hot-Asphalt Mixtures Produced with By-product Aggregates under Repetitive Heavy Traffic Loading
- 2019
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Ingår i: Journal of materials in civil engineering. - : American Society of Civil Engineers (ASCE). - 0899-1561 .- 1943-5533. ; 31:6
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Tidskriftsartikel (refereegranskat)abstract
- Given the importance of overcoming the challenges associated with the management of nonrenewable resources, and to solve the industrial waste stream problems, this article presents the results of fundamental research conducted to assess the rutting and fatigue cracking performance of hot asphalt mixtures with high percentages of by-product aggregates. For this purpose, two full-scale flexible pavement test sections were constructed and tested at the accelerated loading facilities at VTI (Swedish National Road and Transport Research Institute). The accelerated test aimed at evaluating the performance of two developed asphalt mixtures, designated as mix 1 and mix 7, and made up of 98% of industrial by-products (namely, steel slag, foundry sand (WFS), and reclaimed asphalt pavement, in addition to biobased additives). The test sections were constructed in an indoor facility and loaded with a heavy vehicle simulator (HVS) equipped with a half-standard truck axle with dual wheels. The two road sections were constructed using the same construction materials obtained from the same source, as follows: asphalt surface layer of 50-mm thick, 70-mm thick granular base layer, and 160-mm thick subbase layer on top of a 2.6-m thick sandy subgrade soil. Horizontal asphalt strain sensors were embedded in the pavement test sections to assess the mixture's resistance to fatigue and cracking and the laser surface profiler measurements were used to evaluate the rutting performance under controlled testing conditions. For comparison purposes, the long-term rutting developed in the sections paved with mix 1 and mix 7 was compared to the rutting observed in a previous similar HVS test carried out on a 70-mm thick asphalt surface layer section made only with natural virgin aggregates.The test results showed that mix 1 and mix 7 may suffer from higher rutting at the beginning when the road is open to traffic, as compared to asphalt mixtures of natural aggregate, but subsequently the alternative mixtures resisted the rutting development better with the increase of traffic loading as compared to the conventional asphalt mixtures. The horizontal strain measurements at the bottom of the asphalt layer during testing showed that failure began as cracks initiated at the bottom of the asphalt layer of mix 7 and started to propagate to the surface of the asphalt layer in the last stage of the HVS traffic loading of the test. No fatigue cracking was observed in the asphalt surface paved with mix 1 at the end of heavy vehicle simulation (HVS) testing. The study demonstrated that the adopted by-product hot mix asphalt (HMA) mixtures can substitute the conventional HMA material under the given heavy traffic loading and environmental conditions.
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| 2. |
- 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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| 3. |
- Porot, Laurent, et al.
(författare)
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Characterisation of complex polymer modified bitumen with rheological parameters
- 2021
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Ingår i: International Journal on Road Materials and Pavement Design. - : Taylor & Francis. - 1468-0629 .- 2164-7402. ; 22:S1, s. S297-S309
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Tidskriftsartikel (refereegranskat)abstract
- The use of modifiers for bituminous binders has become common practice to enhance the performances of asphalt materials. As a result, the binder becomes more complex, with various phase morphologies. Conventional testing methods may not always be suitable. As example, the European standardisation committee is looking at different ways to characterise Polymer modified Bitumen. The RILEM Technical Committee 272-PIM ‘Phase and Interphase behaviour of innovative bituminous Materials’, with its Task Group TG1, is evaluating different test methods for complex binders. The aim is to evaluate how these tests could address complex bituminous binders. An inter-laboratory programme was conducted with 17 laboratories. Seven binders were evaluated; two were neat bitumen and two PmB. In addition to the conventional property measurements, an extensive effort was made on investigating various rheological parameters obtained from Dynamic Shear Rheometer measurements. Some initial results are presented and discussed in view of the future revision of the European product standard EN 14023 for PmB.
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| 4. |
- Porot, Laurent, et al.
(författare)
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Complex Bituminous Binders, Are Current Test Methods Suitable for?
- 2022
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Ingår i: Proceedings of the RILEM International Symposium on Bituminous Materials. ISBM 2020.. - Cham : Springer Science and Business Media B.V.. ; , s. 37-43
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Konferensbidrag (refereegranskat)abstract
- The asphalt industry is constantly working to enhance the performances of asphalt materials, introducing innovative and more sustainable solutions. In this context, the incorporation of materials, such as additives, polymers, is more and more used to improve the properties of neat bitumen. This leads to even more complex bituminous binders, raising the question, are the current specifications and test methods appropriate for complex materials? To deal with this, the RILEM Technical Committee 272-PIM ‘Phase and Interphase behaviour of innovative bituminous Materials’ with its Task Group TG1 is looking at the efficiency of various test methods for complex binders with an extensive inter-laboratory program with 17 laboratories. It includes seven different binders, two neat bitumen, two polymer modified bitumen and three binders with liquid additives, emphasising on compositional and physical changes at different conditions. The focus is low temperature; while a complementary experimental program encompasses as well as testing at intermediate and high temperatures. The outcomes of the work will provide indications on how robust the current binder characterisation techniques are and establish technical recommendations for future test methods specially designed for complex binders. Some first results are presented hereby. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.
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| 5. |
- Porot, Laurent, et al.
(författare)
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Multiple Stress Creep Recovery Test to Differentiate Polymer Modified Bitumen at High Temperature
- 2022
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Ingår i: Journal of Testing and Evaluation. - : ASTM International. - 0090-3973 .- 1945-7553. ; 51:4, s. 2168-2178
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Tidskriftsartikel (refereegranskat)abstract
- The constant demand for high-performing and more reliable roads has led to an increasing use of complex bituminous binders such as polymer-modified bituminous binders, which has become a widespread practice for asphalt pavement. As a result, specification and testing have evolved to better distinguish between quality materials. In recent years, more focus has been devoted to better evaluating the rutting resistance of bituminous binders. The multiple stress creep recovery (MSCR) test has gained popularity over the last decade, especially for polymer-modified binders, bringing more advantages in discriminating amongst quality binders such as polymer-modified bitumen. Within the International Union of Laboratories and Experts in Construction Materials, Systems and Structures technical committee 272, Phase and Interphase of Behavior of Innovative bituminous Materials, and its TG1 task group, several binders were thoroughly evaluated, including two non-modified and two polymer-modified bituminous binders, under various testing conditions to address the high-temperature behavior. Five laboratories performed MSCR on short-term aged binders after performing the rolling thin film oven test, in the same temperature conditions for all binders. Despite the limited data set, the variability between laboratories was reasonable. The MSCR results were compared with softening point temperature, high-temperature performance grade criteria, |G*| / sin delta, and equi-modulus temperature. MSCR was able to distinguish between complex binders better as compared with conventional parameters. It generates multiple useful parameters, amongst which percent recovery and non-recoverable creep compliance are the most relevant. This paper presents the analysis of MSCR results and comparison with other test methods.
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| 6. |
- Poulikakos, Lily D., et al.
(författare)
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Impact of temperature on short-and long-term aging of asphalt binders
- 2016
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Ingår i: RILEM Technical Letters. - : RILEM Publications SARL. - 2518-0231. ; 1, s. 6-9
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Tidskriftsartikel (refereegranskat)abstract
- Properties of asphalt concrete after aging are important parameters in determining the long-term performance of these materials. With the popularity of reduced temperature mixtures the question remains how this reduced temperature in short-term aging affects the long-term properties. This paper focuses on developing a robust and fundamental understanding of the effect of temperature on aging by connecting the chemistry of bitumen to its mechanics. To this end, round robin experiments are being currently conducted within 8 laboratories using four binders of the same grade 70/100 pen from different crude sources. In developing chemo-mechanical characterization techniques at the nano-and micro-scale, the material’s variability from crude-source to crude-source and its sensitivity to temperature needs to be taken into consideration. Furthermore, the development of uniform speci-men preparation procedures for these bituminous materials at the nano-and micro-structural level is the focus. The chemical characterization is per-formed using Fourier transform infrared spectroscopy (FTIR). For the mechanical characterization rheological data is used using the dynamic shear rheometer (DSR) as well as conventional tests, e.g. needle penetration and softening point using the ring and ball method. It is shown that the short-term aging temperature affects the increase in softening point, while the consequent effect on long term aging is less pronounced.
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| 7. |
- Wang, Di, et al.
(författare)
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Multiple stress creep and recovery test for bituminous binders : influence of several key experimental parameters
- 2023
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Ingår i: International Journal on Road Materials and Pavement Design. - : Taylor & Francis. - 1468-0629 .- 2164-7402. ; 24:Sup1, s. 290-308
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Tidskriftsartikel (refereegranskat)abstract
- The Multiple Stress Creep and Recovery test is recognised to better characterise the high-temperature property of bituminous binders than the traditional methods, especially for polymer modified bitumen (PmB). However, some experimental parameters may affect the test results, such as the preloading, measurement location, stress level. In this study, the effects of these parameters were evaluated through an interlaboratory experiment. Four bituminous binders were short-term aged and analysed by five different laboratories. The variability in most results met the requirements of the European standard, while some failed to pass the American precision criteria. The preloading at 0.1 kPa with ten cycles was found to have a recordable impact on PmB samples, but a less significant effect was observed for the unmodified ones. With the measurement locations, the influence is limited compared to other parameters. As for stress sensitivity, higher stresses lead to remarkable differences.
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