Investigation on the inclusion of reclaimed diluted epoxy asphalt pavement materials into hot mix asphalt

Abstract

Designing long-life pavements and pavements with reclaimed asphalt pavement (RAP) materials are two main strategies to improve pavement sustainability. The recyclability of a proven long-life pavement material such as epoxy asphalt has now become one concern in promoting the use of epoxy asphalt binder in road pavements. Since epoxy asphalt binder is an expensive material, road agencies have practiced diluting it with conventional binder and achieved pavements with good performance. In this study, the performance of hot mix asphalt (HMA) containing reclaimed diluted epoxy asphalt materials (hereinafter referred to as “diluted epoxy RAP”) was investigated. Two percentages of diluted epoxy RAP (40% and 80%) were incorporated as replacements of virgin coarse aggregates and compared with that of asphalt mixtures containing same content of reclaimed undiluted epoxy asphalt (hereinafter referred to as “epoxy RAP”). Due to lack of materials in the field, diluted epoxy RAP and epoxy RAP materials were artificially manufactured in the laboratory. Results showed that the use of either diluted epoxy RAP or epoxy RAP up to 80% as replacement for the virgin coarse aggregates in HMA had no negative effects on its Marshall stability, tensile strength, and moisture susceptibility. Improvements of mixtures performance were noticed in asphalt mixtures containing 40% diluted epoxy RAP, suggesting that diluted epoxy RAP binder might be partially blended with the conventional binder during mixing. This was further confirmed by binder tests on blends of diluted epoxy RAP binder and conventional binder. It is concluded that the inclusion of diluted epoxy RAP materials in HMA as replacement of virgin coarse aggregates is feasible.