Search results for "ASPHALT MIX"
showing 10 items of 24 documents
Image analysis for detecting aggregate gradation in asphalt mixture from planar images
2012
Abstract The mechanical properties of bituminous mixture strongly depend on the gradation of the aggregate that represents the mineral skeleton of the mixture, since for open and gap-graded mixtures, stresses due to vehicles in movement on the pavement are mainly transmitted through their contacts. Internal structure of bituminous mixture is, therefore, of great interest for road and infrastructure engineering and it is appropriate to study it with recently developed image analysis method. The purpose of this study was to finalize an effective analysis of asphalt section image for automatically extracting aggregate gradation without the need of separation of the bitumen from the aggregate. …
Investigating the Multi-Recyclability of Recycled Plastic-Modified Asphalt Mixtures
2023
Although the benefits of asphalt recycling have been scientifically proven and several best practices are being implemented, further research is required in specific and specialized areas. One of these circumstances is the recycling of Reclaimed Asphalt Pavements (RAPs) that contain asphalt modifiers such as elastomers and/or plastomers. Following the principles of the circular economy and considering the sustainability implications of asphalt mixtures, this paper deals with the multi-recyclability of asphalt mixtures containing 50% RAP with and without a recycled plastic asphalt modifier and rejuvenating agent. The recycled plastic asphalt modifier was made of hard recycled plastics and wa…
Performance-based characterization of recycled polymer modified asphalt mixture
2021
Due to the introduction of secondary materials, the asphalt mixtures to be designed and tested in our laboratories are constantly becoming much more complex than traditional asphalt mixtures making difficult to use conventional laboratory procedure and/or predict expected results. This study proposes a comprehensive characterization of asphalt mixture modified with recycled polymer compound by using both wet and dry process proposing adjustments to laboratory mixing and sample compaction procedure. Accordingly, three AC20 Hot Asphalt Mixture (HMA) were designed and their conventional and performance related properties were assessed by looking at a) Indirect Tensile test (ITS) a) moisture da…
Towards a new mix design method for asphalt mixtures containing rap
2016
Recycling is one of the most important aspects to conceive the new construction or rehabilitation of sustainable road infrastructures. Even if Reclaimed Asphalt Pavement (RAP) is commonly used in the practice, its presence may lead to some critical aspects due to the physical and chemical phenomena occurring during the new mix process. For instance, the formation of RAP clusters during a new mix may inhibit the uniform distribution of the virgin binder as well as cause changes in the design grading curve of the mixture. Indeed, laboratory results demonstrate that small-size RAP particles stick together forming clusters. The amount of clusters depends on different parameters observed: The pe…
Life Cycle Assessment of Asphalt Mixtures with WMR
2023
This study aimed at providing pavement specialists with international average values of greenhouse gas emissions (GHG) and energy consumption related to the manufacturing of asphalt mixtures (cradle-to-gate), with and without waste and secondary materials for roads (WMRs). In order to achieve this goal, TG leaders first referred to current standards to define a methodology for obtaining benchmark values according to ISO 21678:2020. Then, a data collection tool was designed and provided to a group of international partners to build a life cycle inventory for asphalt mixtures including data from materials up to plant manufacturing (A1–A3). Partners were asked to provide information for any ty…
ENVIRONMENTAL IMPACT OF BIO-BASED ASPHALT MIXTURES: LIFE CYCLE INVENTORY, LIFE CYCLE ASSESSMENT AND RECOMMENDATIONS
Bio materials with reclaimed asphalt: from lab mixes properties to non-damaged full scale monitoring and mechanical simulation
2019
Three innovative environmentally friendly pavement materials, designed with 50% of Reclaimed Asphalt and three different biomaterials (2 bio-additivated bitumens and 1 bio-binder), were produced in an industrial plant. These mixes were tested in lab and also at full scale using an Accelerated Pavement Test facility. The asphalt mix viscoelastic properties were measured in lab and their intrinsic viscoelastic response were simulated. These rheological models are used to simulate the pavement mechanical response using both elastic and viscoelastic multilayer codes. Hence, full scale measurement performed during the full scale test at an early stage (without damages) can be compared with these…
An investigation of the mechanical properties of rubber modified asphalt mixtures using a modified dry process
2017
Incorporating recycling tyres into asphalt mixtures contributes to solving a serious environmental problem as well as the potential of improving the mechanical performance of asphalt mixtures. The recycled tyre rubber is added by two technologies known as the dry process (when rubber particles are treated as an aggregate modifier) and the wet process (when rubber particles are treated as a binder modifier). Although, the dry process is easier and requires minimal or no modification in the asphalt plant, the inconsistency in field performance makes the dry process not widely used. The main reason for this is believed to be the lack of interaction between the rubber particles and binder. In o…
Increasing the Circularity of asphalt mixtures: Integrated Sustainability and Circularity Assessment as a progress monitoring tool towards more Circu…
2021
Sustainability and Circular Economy (CE) are two concepts that lately have been profoundly linked to each other. The road engineering industry has gradually been adapting practices that are considered both circular and sustainable. However, not all of these practices entirely consider the whole life environmental and circularity assessment and implications of asphalt mixtures.; which in turn leads to doubtfully circular and sustainable approaches. For this reason in this thesis, after analysing the ways that National Road Authorities implement and communicate CE through questionnaires and web searches, a Material Circularity Index quantifying framework, based on the proposed methodology of …
Feasibility of using more polishable aggregates in dense-graded asphalt surface mixture: Case study of dolomite
2022
This study aimed to evaluate the feasibility of using more dolomite aggregates in asphalt surface mixtures that are typically used by West Virginia Division of Highways (WVDOH). The laboratory test results indicated that increasing dolomite content in asphalt surface mixtures resulted in a faster deterioration rate at the early polishing stage. In addition, asphalt surface mixtures containing more than 50% dolomite coarse aggregates would significantly reduce roadway safety. The field test results validated that dolomite shall not exceed 50% of coarse aggregate in asphalt surface mixture if the projected traffic volume is greater than 3.0 million equivalent single axle loads (ESALs).