Search results for "warm mix"
showing 7 items of 7 documents
Binder design of high RAP content hot and warm asphalt mixture wearing courses
2015
Reclaimed Asphalt Pavement (RAP) has shown great potential for being used in the construction or maintenance of roads. However, RAP is usually downgraded to lower pavement layers and the percentage of RAP used in wearing courses is still moderate (≤30%). The research and results contained in this paper focus on the definition of binder recipes aimed at increasing the percentage of RAP in hot and warm mix asphalt wearing courses. A review of current internationally used blend design methodologies is presented followed by case studies aimed at defining binder recipes for high RAP content asphalt mixture wearing courses to be further used for mix design and production in asphalt plants. Binder…
Quantitative assessment of the parameters linked to the blending between reclaimed asphalt binder and recycling agent: A literature review
2020
Abstract The lack of understanding the mechanisms governing the interaction between reclaimed asphalt binder (RAb) 1 and recycling agents is one of the technical issues that still need to be resolved when high amount of reclaimed asphalt (RA) 2 is used in a new recycled asphalt mixture (RAM). Due to important role of RAb in that interaction and increased used of RA, it becomes necessary to have a way to classify RA, as any other material used in asphalt mixture production. It is very important to determine how much RAb is active by itself (DoA) 3 , but also to determine how much RAb can be considered available for a mix design of RAM (DoAv) 4 when a recycling agent is used. Finally, since t…
Design considerations of high RAP-content asphalt produced at reduced temperatures
2018
In many countries recycling of reclaimed asphalt pavement (RAP) for road surface layers is limited to a maximum of 10–30%. This is due to technical limitation of common asphalt plant but also to specifications that are still restrictive when it comes to increasing RAP in surface courses. The mistrust in this practice is mainly related to uncertainty in performance of these mixes as well as to existing fundamental issues with the mix design, especially when production temperatures are lowered. This paper analyses some of the factors affecting the design of warm asphalt mixtures for surface course layers containing 50% RAP, and suggests a framework to justify the common assumption of full ble…
Life cycle assessment of low temperature asphalt mixtures for road pavement surfaces: A comparative analysis
2018
The increasing fuel consumption demand, the accelerated pressure imposed by the depletion of 5 scarce raw materials and the urgent environmental protection requirements are forcing the change of 6 pavement industry and academia community’s research endeavors towards the development of low 7 emissions road paving technologies able to significantly reduce mixing and compaction temperature as 8 well as the consumption of virgin raw materials. One set of relatively recent technologies in the field of 9 pavement materials that aims at addressing those concerns are the warm mix asphalt (WMA). In fact, 10 they have the potential to allow the reduction of energy consumption and airborne emissions d…
Energy and Environmental Life Cycle Assessment of asphalt pavements: A Scenario Analysis for Urban Roads
2018
This paper aims at calculating the life-cycle energy and the environmental impacts pertaining to roads management, including materials production, transportation, construction, maintenance, and rehabilitation. A life-cycle approach is applied to assess energy and environmental impacts of a typical Italian urban road, according to the ISO 14040 series. In more detail, the Authors assess the energy and environmental profile of different optimized scenarios of bituminous mixtures. The aim of scenario analysis is to identify the less impacting scenario from an energy and environmental point of view. For each analysed scenario, the contribution of each life-cycle step to the total impacts and th…
Thermo-rheological analysis of WMA-additive modified binders
2020
AbstractThermo-rheological characteristics of unmodified and modified bitumen have significant impacts on the mechanical response of asphalt. This study investigates the impacts of an organic and a chemical Warm Mix Asphalt additive on bitumen thermo-rheological and mechanical characteristics. Modified binders with different concentrations of each additive were studied and analysed comparatively to a 40/60 penetration grade bitumen. Frequency sweep tests were performed at different ageing levels to characterise the Linear Viscoelastic properties. The multiple stress creep and recovery, linear amplitude sweep (LAS) and low temperature creep stiffness tests, together with the Glover–Rowe (G–R…
A life cycle scenario analysis of different pavement technologies for urban roads.
2019
In the past, lowest price was the award criterion, given that structural capacity and safety were assured. In the last years, environmental, energy, and long-term impacts have been introduced (climate change, resource depletion, energy consumption, generated solid waste, discharged water, and emissions). Unfortunately, the introduction of new pavement technologies and materials (i.e., waste plastics) affects maintenance and rehabilitation processes and call for accurate and timeliness studies and criteria. Consequently, this paper presents an energy and environmental assessment of an Italian urban road and considers different material-related scenarios that fully comply with emerging techno…