Search results for "Asphalt"

Experimental Investigation on Water Loss and Stiffness of CBTM Using Different RA Sources

2021

Cold recycling of reclaimed asphalt (RA) is a promising technique to build or to maintain roads, combining performance and environmental advantages. Although this technique has been extensively used worldwide, there is no unique and internationally-shared method to characterize cold recycled mixtures. The previous work of the RILEM TC 237-SIB TG6 successfully attempted to characterize different RA sources with both traditional parameters (gradation, bitumen content and geometrical properties) and non-conventional properties (fragmentation and strength testing). The current RILEM TC 264-RAP TG1 mainly focuses on the influence of different RA sources on physical and mechanical characteristics…

Determination by solid-phase microextraction/gas chromatography/mass spectrometry of polycyclic aromatic hydrocarbons in bitumen fumes during road pa…

1999

The Sustainability of Reclaimed Asphalt as a Resource for Road Pavement Management through a Circular Economic Model

2019

The transition of the road engineering industry to a circular way of doing business requires more efficient and sustainable resources, energy, and waste management. The rates in which reclaimed asphalt is being recycled or reused in the asphalt mixture production process constitutes a crucial parameter in this transition. This paper aims at establishing a further step towards the combined circularity and sustainability of asphalt pavements, by introducing a framework for quantifying their Material Circularity Index. The framework is based on the methodology proposed by the Ellen MacArthur Foundation and accordingly tailored for the context of asphalt pavements. This study, thus, attempts to…

Comparing the Material Circularity Index of the Italian and Spanish motorways: A case study over the Mediterranean basin

2022

Closely following the attempt of the pavement engineering industry to comply with the principles of Circular Economy (CE) while simultaneously promoting its principles, it can be detected that a significant effort is being made towards the minimization of the energy and raw materials usually utilized. In this regard, Reclaimed Asphalt (RA) is a product that exhibits a tremendous exploitation potential. Knowing that by definition CE is restorative [1], regenerative, and aims to keep products, components, and materials at their highest utility and value at all times [2], i.e. it supports the “re-circulation” of materials and energy within the same or alternative product systems and thus the e…

European National Road Authorities and Circular Economy: An Insight into Their Approaches

2020

The pavement engineering industry, having realized the significance of the impacts that it imposes on the environment through the production, construction and management of its products and assets, has been driven towards a more sustainable and circular way of operating. This has partly been through asphalt recycling, which is an area that many road authorities have prioritized. However, not all the National Road Authorities (NRAs) and/or sector stakeholders seem to be adequately familiar with the Circular Economy (CE) concept. This paper attempts to assist the transition of NRAs to a more circular way of doing business, by analyzing the current situation of CE within national/regional auth…

Compaction of Open-Graded HMAs Evaluated by a Fuzzy Clustering Technique

2015

The aim of this paper is the proposal of an expeditious procedure to be used during the execution of an asphalt layer for improving the compaction task. This procedure, based on a fuzzy clustering technique, starts from the knowledge of some information recorded by ordinary measuring instruments and provides an aid to the decision-maker on the number of roller passes needed to achieve a specific density at a certain temperature. This result can be deduced with great rapidity during the paving operations on site without waiting for the time spent in the core extraction and in the subsequent laboratory analysis. In this way it is possible to identify more precisely which aspects of the execut…

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…

Recommendation of RILEM TC237-SIB on cohesion test of recycled asphalt

2018

This recommendation describes how to evaluate the presence of potentially active bitumen in recycled asphalt (RA) materials through the cohesion test. The experimental protocol is designed according to the research performed by the RILEM Technical Committee 237-SIB ‘‘Testing and characterization of sustainable innovative bituminous materials and systems’’ with the purpose, to develop a new, simple and fast method for the characterization of RA while limiting the need for conventional rheological tests. The guidelines in this recommendation focus on the testing procedure including specimen preparation, data analysis and provide information on the preparation of a tests report.

Comparative life-cycle assessment of conventional (double lane) and non-conventional (turbo and flower) roundabout intersections

2016

Abstract This research studied and compared different construction techniques for the road subgrade, embankment and pavement of different types of roundabout intersections in order to assess their environmental sustainability. A Life Cycle Assessment (LCA) was carried out on double lane, turbo- and flower roundabouts. We considered virgin materials and reclaimed asphalt pavement (RAP) for the pavement construction. Also the environmental effects due to in situ lime stabilization of fine-grained soils were assessed in order to reduce the use of virgin material in road subgrades. The use of reclaimed asphalt pavement (RAP) can lead to a significant reduction in pollutant emissions and energy …

Analytical approach for the mix design optimisation of bituminous mixtures with crumb rubber

2018

The present paper provides a basis for defining a mix design method specifically tailored to rubberised asphalt that takes into account the behaviour of crumb rubber. An analytical approach to quantifying the recovered deformation of crumb rubber in the post-compaction phase has been developed in order to adjust the number of gyrations proposed by the Superpave method for compacting specimens of hot mix asphalt using a Superpave gyratory compactor. The maximum allowable amount of rubber has been calculated. Finally, a step-by-step protocol has been proposed in order to fabricate and compact crumb rubber modified mixtures with the gyratory compactor.