A Study on Using Reclaimed Asphalt Pavement (RAP) in the Construction of New Roads in the State of Qatar

Abstract

In the State of Qatar, road engineers started using RAP in the base course of asphalt pavement from past few years. The use of RAP not only replaces the quantity of virgin aggregate and binder, it also improves the overall stiffness of asphalt mixture due to the addition of aged asphalt binder. Considering the economic and environmental benefits of RAP, in this study, a mix design was developed for asphalt mixtures containing different proportions of RAP and evaluate the performance of RAP blended asphalt mixtures. Based on obtained properties, it was attempted to optimize the use of RAP content in the base course of asphalt pavement. In this study, the asphalt mixtures were produced with three different RAP contents (15, 25 and 35%) and the behavior of these mixtures was benchmarked with conventional mix (0% RAP). The RAP blended asphalt mixtures were tested using several experimental protocols. First, the stiffness modulus of RAP mixtures were determined using AASHTO test method. The high and low temperature distress characteristics of mixtures were determined using Hamburg wheel tracker and semi-circular beam bending test. Based on the stiffness and performance properties, a suitable RAP content and the ways to increase the use of RAP content was recommended.