Performance Evaluation of Recycled SMA Mixtures with Warm-mix Agent

The purpose of this paper is to study the pavement performance of warm-mix recycled SMA mixture. This paper presents a comparative study on performances of aged mixture and warm-mix recycled SMA adding regenerator and warm-mix agent. The results of air void content show that the best mixing temperature of warm-mix recycled SMA mixture is 140 degree centigrade. The Marshall stability, flow number, Marshall residual stability, indirect tensile strength ratio after freezing and thawing and dynamic stability before and after recycling are obtained from laboratory tests. The performance of recycled mixtures is better than aged mixture in all indicators except dynamic stability. The fatigue life of warm mix-recycled modified SMA mixture is 1.5 similar to 2.6 times as the aged ones in various stress levels. All indicators meet specification requirements. The conclusion is that the fatigue properties and long-term performance of warm-mix recycled SMA mixture can be improved after recycling with small sacrifice in rutting resistant. The introduction of warm mix agent extends the construction period in winter of the hot in-place recycling and reduces the secondary aging.