| 1. |
- Ghafoori Roozbahany, Ehsan, 1982-, et al.
(författare)
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Fracture testing for the evaluation of asphalt pavement joints
- 2013
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Ingår i: International Journal on Road Materials and Pavement Design. - : Informa UK Limited. - 1468-0629 .- 2164-7402. ; 14:4, s. 764-791
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Tidskriftsartikel (refereegranskat)abstract
- Asphalt joints are inevitable parts of every pavement. Although much attention is dedicated to the construction of such joints, reliable tools for assessing the mechanical properties of joints for design and performance assessment are still scarce. This is particularly true for cold joints when attaching a new hot pavement to a cold existing pavement as in the case of large patches for pavement repair. This paper intends to evaluate different new or modified static fracture testing methods for ranking existing joint construction techniques. Some of these testing methods, such as indirect tensile test, direct tensile test and 4-point bending test are familiar in the field of asphalt pavement characterisation, but have scarcely been used for assessing the quality of joints so far. These three test types were adopted and evaluated for joints and the test results were analysed with finite element (FE) software ABAQUS. Different joints for testing were prepared in the laboratory using a special specimen construction procedure. The results suggest that joints with inclined interfaces seem to show more promising behaviour than vertical joints. It was confirmed that starting compaction from the hot side of the joint generally produces better results than compaction starting from the cold side of the joint. Pre-heating of the joint surface and using a bond sealant appears to provide the best results.
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| 2. |
- Witkiewicz, Patryk, et al.
(författare)
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Långtidseffekter av biobindemedel i asfalt
- 2024
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Ingår i: Sammanställning av referat från Transportforum 2024. - Linköping : Statens väg- och transportforskningsinstitut. ; , s. 413-414
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The road network is an essential and integrated part of the transport infrastructure in today’s society. Nowadays, most roads are paved with asphalt mixtures. The petroleum-based bitumen is used as a binder to hold the asphalt mixture together. As a petroleum-derived product, bitumen has a relatively high environmental impact and carbon footprint. For a green transition, the use of bio-based materials from renewable resources, such as plant-based biomass, in asphalt mixtures has been investigated as a potential next-generation solution. Despite some promising results so far, knowledge gaps still exist in understanding the fundamental material behaviours and properties of the new bituminous binders and asphalt mixtures containing bio-based components. This is mainly because the bio-based components have different chemical compositions compared to bitumen and they may affect the binder behaviour and mixture performance in a different way, particularly the long-term performance. This study will investigate a specific type of bio-based material – a plant-based bio-oil – for its use in bituminous binders and asphalt mixtures as a partial replacement of petroleum-based bitumen. The study will focus on a specific and significant knowledge gap, namely the understanding of how the presence of bio-oil affects the ageing behaviour of bituminous binders and asphalt mixtures. Ageing is an important aspect to consider when evaluating the long-term performance of asphalt materials, which undergo ageing due to various factors, including exposure to sunlight, air, temperature fluctuations, etc. This ageing process can significantly affect the mechanical properties of pavement materials and thus the durability of roads. This contribution will present an experimental investigation into the ageing behaviour of bio-extended bituminous binders and asphalt mixtures, aiming to enhance our understanding of their long-term performance and durability.
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| 3. |
- Zhu, Jiqing, 1987-, et al.
(författare)
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Durability assessment of bio-extended bituminous binders by rheological characterisation after long-term ageing
- 2024
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Ingår i: 8th E&E (Eurasphalt & Eurobitume) Congress, Budapest, Hungary, 19-12 June, 2024.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The pursuit of sustainable road infrastructure is prompting extensive research into the utilization of bio-extended bituminous binders. This paper investigates the durability of bio-extended bituminous binders (both unmodified and polymer-modified) containing a plant-based bio-oil, aiming to assess their long-term performance. The research employed laboratory-scale tests and advanced rheological techniques to evaluate viscoelastic properties of the binders after long-term ageing. Accelerated ageing protocols were used to simulate prolonged exposure to environmental factors, including the Rolling Thin Film Oven Test (RTFOT) and Pressure Ageing Vessel (PAV) test. Dynamic Shear Rheometer (DSR) tests measured the shear modulus and phase angle of the binders under various conditions while Bending Beam Rheometer (BBR) tests measured the flexural creep stiffness at different low temperatures. Various performance indicators and specification parameters were analysed for the investigated binders regarding their resistance to both fatigue cracking at intermediate temperatures and thermal cracking at low temperatures.The results indicate that the bio-extended binders passed all the analysed criteria after RTFOT+PAV ageing. Using the investigated bio-oil in bituminous binders had largely a positive effect on the ΔTc and did not affect the standard performance low-temperature grade significantly. The bio-extended binders followed the same relationships between several durability-related performance indicators as the reference binders did. Certain slight negative effects could be noticed at low temperatures when the bio-oil content was high, but a further verification on the asphalt mixture scale will be necessary to assess if these effects are significant enough to impact the asphalt mixture performance in practical applications.
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