Mechanistic and Economic Impacts of Using Asphalt Rubber Mixtures at Various Vehicle Speeds

Abstract

In the application of hot-mix asphalt pavement (HMA), tension at the bottom of the HMA layer creates one of the most challenging distresses to pavement structures, fatigue cracking. Adding rubber to the asphalt mix can extend the life of a pavement and provide an end use for old tires that would otherwise end up in a landfill. It is already known that the initial construction cost of an asphalt rubber mix will be higher than that of a conventional mix. However, the purpose of this article is to investigate if the reduced layer thickness and improved fatigue life will offset the initial cost. After completing a mechanistic analysis using the FHWA software package named 3D Move (University of Nevada, Reno, NV), the pavement thickness required to last for 50,000,000 cycles (the estimated endurance limit) was found to be much less for asphalt rubber mixes as opposed to the reference HMA. The cost to construct one lane mile of the reference mix pavement designed for 113 kph traffic was $190,031, while the cost for asphalt rubber mix at the same speed came out to be $187,629. This is a $2,402 difference. Additionally, the cost to construct 1.6 km of lane of the reference mix and asphalt rubber mix for four more different vehicle speeds was calculated. Overall, analysis showed that Asphalt Rubber (AR) modified asphalt mixtures exhibited significantly lower cost of pavement per 1,000 cycles of fatigue life per mile compared to the conventional HMA mixture.

Investigation of Strength and Fatigue Life of Rubber Asphalt Mixture

“…where the N f is the fatigue life, which can be expressed by Equation ( 12): 12) can be transformed into Equation (13).…”

“…Most of the design methods of asphalt pavement structures in the world use the mechanics-experience method, which uses mechanical methods to calculate the load response of the pavement structure. It uses homogeneous and isotropic linear elastic mechanics as the mechanical model for structural response calculation [ 9 , 10 , 11 , 12 , 13 ]. The strength, stiffness, and fatigue parameters are essential parameters in calculating the load response and establishing the mechanical model, which plays a vital role in the design of the pavement structure.…”

A Review of the Utilisation of Recycled Waste Material as an Alternative Modifier in Asphalt Mixtures

“…Recent studies have proven the economic advantage of adding tires to asphalt binders since recycled tires markedly reduce the need for using new materials [16]. The use of waste materials for asphalt stabilisation is regarded as a smart strategy for sustainable development.…”

“…Furthermore, the crushed concrete in several types of research confirmed that the recycled concrete aggregates (RCA) are applicable for reuse on the roads, concrete pavement when it is replaced with a proper percentage of new aggregate [11][12][13][14]. The use of recycled materials as an eco-friendly substitute has performance, economic and environmental benefits [15,16]. Figure 1 shows the waste hierarchy applied to pavement materials.…”