再生沥青低温抗裂性能评价

Evaluation of Low Temperature Cracking Perfermance of Recycled Asphalt Binder

基于弯曲梁流变试验和频率扫描试验,对再生沥青的低温抗裂性能进行评价.通过目标性能等级(PG)试验确定再生剂的最佳掺量,采用差别变量(ΔTc)、Glover-Rowe(G-R)常数以及主曲线分析评价再生调和沥青在不同老化状态下的低温抗裂性能.ΔTc和G-R常数结果表明:老化时间显著影响再生沥青的抗裂性能;相较于新沥青,再生沥青对于老化过程更为敏感;沥青路面回收旧料(RAP)掺量越高,再生沥青的抗裂性能随老化时间的衰减幅度愈大;为了保证再生沥青在长期老化条件下的抗裂性能,必需使用最佳用量的再生剂,并且RAP沥青质量分数应严格限制在30%以下.主曲线分析结果表明:再生剂和新沥青对于RAP老化沥青流变性能的恢复作用是不同的,再生剂主要减小老化沥青的劲度,新沥青主要改善老化沥青的相位角,但新沥青的改善作用随老化时间的增加而减弱.

Bending beam rheometer（BBR）tests and frequency sweep tests were conducted to investigate the low temperature cracking performance of recycled blends incorporating polymer-modified binder,RAP binder and recycling agent at different aging conditions.The optimum content of the recycling agent was determined by the target performance grading（PG）tests.TheΔTcand the Glover-Rowe（G-R）parameter results show that aging time significantly affects the cracking resistance of the recycled blends.And compared to the virgin binder,the recycled blends tend to be more sensitive to aging process.The aged modified binder has detrimental effect on long-term anti-crack property of the recycled blend,and in order to achieve similar performance to the virgin binder,the RAP binder content of the recycled blends containing the optimum dosage of recycling agent should be strictly limited below 30%.In addition,the master curve results reveal that the effects of the recycling agent and virgin modified binder on the viscoelastic nature of aged modified binder are not consistent.The recycling agent can significantly reduce the stiffness of the aged binder,while the virgin binder mainly improves the phase angle of the aged binder.