Performance evaluation of temperature effect on hot in-place recycling asphalt mixtures

Hot in-place recycling (HIR) is a novel technique to rehabilitate the surface layer of the pavements, in which recycling agents are commonly utilized to restore the binder rheological properties of reclaimed asphalt pavements (RAP). Considering the energy consumption and smoke issue, the heating temperatures for HIR containing 100% RAP mix are usually controlled around 110 °C, which is significantly lower than that for the traditional hot mix asphalt (HMA). To evaluate the effect of temperature on the performance of 100% recycled asphalt mixtures after the HIR process, the materials obtained from an HIR project were remixed and compacted at different temperatures (110 °C, 120 °C, and 130 °C). The asphalt mixture performance tester, asphalt pavement analyzer test, Superpave indirect tension tests, and moisture susceptibility tests were conducted to evaluate the performances of the HIR mix. The staged extraction tests were used to identify the mobilized RAP binders under different temperatures. It was revealed that mixtures heated with a higher temperature exhibit better cracking and moisture resistance performances. It was also found that a larger proportion of the RAP binders can be activated to coat the aggregates at a higher mixing temperature, which may increase the rutting potential.