不同RAP掺量下热再生沥青混合料性能衰变规律

Performance Decay Law of Hot Recycled Asphalt Mixture with Different RAP Content

本文采用自主研发的全寿命分析仪对沥青混合料分别进行0、4、8、12个月的模拟老化,采用冻融劈裂试验、动态蠕变试验和半圆弯曲试验,研究不同RAP掺量下热再生沥青混合料长期老化后各项性能的衰变规律.结果表明:在12个月模拟老化后,RAP掺量为30%时沥青混合料的流变次数达到最大,RAP掺量的提高使得TSR衰减幅度变大且断裂能下降.50%RAP掺量时再生料TSR衰减幅度比新拌料大7.9%,流变次数和断裂能较新拌料分别减少38.6%和61.7%.长期老化作用下RAP掺量对沥青混合料疲劳寿命衰减的影响不明显,但会降低其应力敏感性.

The asphalt mixture was simulated aging for 0,4,8 and 12 months by a self-developed life analyzer.Freeze-thaw splitting test,dynamic creep test and semi-circular bending test were used to study the decay law of various properties of hot recycled asphalt mixture with different RAP content after long-term aging.The results show that after 12 months of simulated aging,the rheological times of asphalt mixture reach the maximum when the RAP content is 30%.With the increase of RAP content,TSR attenuation amplitude increases and fracture energy decreases.With 50%RAP content,the TSR attenuation of recycled aggregate is 7.9%larger than that of new aggregate,and the rheological times and fracture energy are reduced by 38.6%and 61.7%respectively.Under long-term aging,the effect of RAP content on fatigue life attenuation of asphalt mixture is not obvious,but it will reduce its stress sensitivity.