Sasobit再生沥青混合料的设计与性能

Design and performance of Sasobit warm mixed reclaimed asphalt mixture

为了对温拌再生沥青混合料(WMRA)的路用性能进行评估,设计了回收沥青路面材料(RAP)掺配率分别为10%、30%、50%的WMRA和热拌再生沥青混合料(HMRA),构建了WMRA的最佳拌和温度、击实成型温度与新集料加热温度的确定方法,并按照规定的温度制作Marshall试件,通过进行Marshall试验、车辙试验、低温弯曲试验、残留稳定度试验和冻融劈裂试验,评估了HMRA和WMRA的Marshall指标和路用性能。研究结果表明:当RAP掺配比例较小时,WMRA和HMRA的空隙率非常接近,得出Sasobit的降温幅度在15℃左右;随着RAP比例的提高,WMRA和HMRA的新集料加热温度逐渐提高,沥青老化程度增加,进而导致混合料性能发生变化,致使空隙率(VV)和动稳定度(DS)增大,低温弯曲应变降低;Sasobit温拌剂的掺入,能降低新集料的加热温度,减弱沥青老化,进而降低混合料VV,使低温性能有所提升,同时Sasobit材料本身又能提高沥青低温粘度,进而提高了混合料的高温性能;通过路用性能试验,所有WMRA的高温性能和水稳定性均满足中国规范要求,部分混合料的低温性能稍低于规范要求。

In order to evaluate road performance of warm mixed reclaimed asphalt （WMRA）, asphalt mixtures using different content （10%, 30%, 50%） of RAP （recycled asphalt pavement） were selected, and WMRA and Hot mixed reclaimed asphalt mixture （HMRA） were designed consequently. Besides, the methods to determine the optimal mixed temperature and compaction temperature of WMRA as well as the heating temperature of new aggregates were proposed. Then the WMRA mixtures were made into Marshall specimens to perform the following tests, including Marshall test, rutting test, low temperature bending test, residual stability test and freeze-thaw splitting test. Finally, Marshall indicators and pavement performance of HMRA and WMRA were evaluated. The results show that when the RAP content is low, the VV between WMRA and HMRA is very close, indicating that cooling temperature of Sasobit is 15 ~C; With the increase of RAP content, heating temperatures of virgin aggregate for WMRA and HMRA are gradually rising and asphalt aging degree also increases, leading to performance changes of mixture as follows： both VV and DS increases, and low temperature bending strain decreases; with Sasobit mixed into mixture, the heating temperature of the virgin aggregates and the asphalt aging degree can be reduced. Besides, the VV of mixture is also reduced and the low temperature performance is improved, At the same time, Sasobit itself can improve the low temperature viscosity of asphalt and also improve the high temperature performance; high temperature performance and water stability performance of all WMRA meet Chinese specification requirements, and low temperature performance of partial mixture is slightly lower than the specification requirements. 10 tabs, 7 figs, 13 refs.