Fracture characteristics of asphalt mixtures containing asphalt millings with geosynthetic fragments

Abstract

The increasing cost of asphalt and environmental concerns have created a greater interest in exploring the possibility of incorporating higher percentages of reclaimed asphalt pavement (RAP) materials in asphalt mixtures. However, increasing the RAP content can adversely affect some of the properties of asphalt mixtures, including their cracking resistance potential. Consequently, finding a solution that accommodates incorporating higher RAP contents into the asphalt mixture is crucial. Moreover, geosynthetics has gained significant popularity as an anti-reflective cracking system in asphalt pavements, which may lead to the possibility of milling asphalt layers with geosynthetic interlayers. Thus, research studies need to be conducted to understand the characteristics and behaviour of RAP obtained from asphalt layers with geosynthetic interlayers (referred herein as GRAP). The objective of this study is to investigate the cracking characteristics of asphalt mixtures containing different percentages (0, 15, and 30%) of RAP and GRAP material using cross-shear tests. Results indicated that the addition of GRAP into the asphalt mixture by about 30% significantly improves the performance of asphalt mixtures against crack initiation and propagation compared to those asphalt mixtures containing only RAP. Overall, it can be inferred that the presence of geosynthetic fragments could increase the possibility of incorporating higher percentage of RAP in asphalt mixtures.