Fatigue performance of recycled asphalt mixtures : viscoelastic continuum damage approach and cost analysis

Abstract

This study aims to evaluate the fatigue phenomenon in recycled hot asphalt mixture for an asphalt surface layer. Eight mixtures were evaluated in the laboratory, and the samples were divided into two major groups: four mixtures containing neat binder and RAP from source 1 (RAP with neat binder) and four mixtures containing SBS-modified binder and RAP from source 2 (RAP with SBS-modified binder). The levels of RAP incorporation were 0%, 10%, 20%, and 30% in relation to the total weight of the mixtures. The mixtures followed the Marshall mix design methodology. The results indicate that mixtures with polymer-modified binder presented better performance, whereas the addition of RAP slightly decreased the resistance to fatigue cracking. In terms of economic analysis, the use of RAP, for all cases, leads to a reduction in production costs due to the reduction of the binder and aggregate added, with savings of up to 14.1% in the case of 30% of RAP for the SBS binder. When evaluating the economic impact of inserting RAP and its relationship with fatigue performance in the long term, it can be observed that the type of binder added impacts the results: mixtures with SBS binder present economic gains within acceptable quality parameters up to 30% RAP insertion; for mixtures with neat binder, the percentage of up to 10% RAP is advantageous.