Effect of reclaimed asphalt pavement on performance of rubberised asphalt mixtures

Abstract

The utilisation of crumb rubber (CR) and reclaimed asphalt pavement (RAP) has proven to be an economical, environmentally sound and effective way of increasing the performance of asphalt mixtures. The objective of this study was to evaluate the use of CR in high RAP content asphalt mixtures. The RAP content was 0%, 20%, 40% or 60% and CR (0%, 10% and 20% by weight of bitumen) was blended with the unmodified binder using a wet process. The performance characteristics of these modified asphalt mixtures were investigated through a series of laboratory tests such as the indirect tensile strength, moisture susceptibility, resilient modulus, rutting resistance and fatigue behaviour. The results of the experiments indicated that the fatigue life of the mixtures decreased with an increase in RAP content. The addition of CR led to an increase in the fatigue life of the mixtures. Also, as the percentage of RAP in the mixtures was increased, the rut resistance of the CR-modified mixtures substantially increased. Statistical analysis showed that the addition of RAP and CR had a significant effect on reducing the permanent deformation of the mixtures. According to the results, 10% CR and 40% RAP could be used without a significant reduction in the performance of the mixture.