Performance evaluation of WMA mixtures with RAP

Abstract

Nowadays, asphalt industries are seeking for new methodologies in order to minimize global warming and emission of greenhouse gases. One of the solutions found out was the use of warm mix asphalt (WMA) technology which allows reduction in asphalt mixing, working and compaction temperature. WMA reduces the desired temperature in comparison with hot mix asphalt by 20–40°C. In addition to this issue, the lack of superior quality natural aggregate resources everywhere around the world, it is essential to use the available natural resources efficiently along with the available construction and demolition waste such as recycled asphalt pavement (RAP) if possible, without compromising in the performance of the mixtures. In this study, reclaimed asphalt pavement was used as partial replacement for conventional aggregates and binder. The RAP contents of 0%, 25% and 50% were considered. Zycotherm was used as warm mix additive which improves the pavement moisture resistance by serving as an anti-stripping agent. The mixtures were prepared with HMA @ 130°C, HMA @ 160°C, WMA @ 130°C and all these three mixtures with partial replacement with RAP. The RAP material with 0, 25 and 50% replacement was adopted for both HMA and WMA for DBM grade 2 course. Zycotherm was added by 0.1% by weight of binder in both HMA and WMA mixes. The prepared test specimens were tested for Marshall and indirect tensile strength (ITS) test. The test results indicated that the WMA blend prepared using 0.1% by the weight of binder content showed good results compared to the hot mix asphalt @ 130°C. The indirect tensile strength ratio (TSR) of mixes containing RAP is found to be higher when compared to the mixes without RAP indicating lower moisture susceptibility of the mixtures. This study demonstrated the possible use of RAP in WMA mixes with better performance than HMA.