基质沥青混合料宏观断裂微波自愈合性能

Study on macro fracture microwave self-healing properties of bituminous mixtures

为研究微波加热对沥青混合料宏观断裂自愈合性能的影响,文章选取70#基质沥青制备AC-13型混合料试件,采用半圆弯曲(semi-circular bending,SCB)试验测试其初始断裂强度,然后采用微波加热促使其自愈合,根据其弯拉强度恢复程度评价其自愈合性能。首先对集料和沥青胶结料微波加热条件下的升温速率进行了对比,然后分析了微波作用时间、微波强度和混合料温度对沥青混合料自愈合性能的影响规律。结果表明:混合料经微波诱导加热热量分布不完全均匀,微波加热温度不能超过100℃;试件表面温度受微波加热时间与微波强度共同影响,但两影响因素之间交互作用不显著;微波加热时间、微波强度的增长对混合料自愈合有促进作用,但并非加热时间越长、微波强度越大越好;加热后的混合料温度是决定沥青混合料自愈性能的根本原因,最佳温度为80℃。

To research the effect of microwave heating on the self-healing performance of asphalt mixture macro fracture,the 70#matrix asphalt was selected to prepare the AC-13 type mixture specimens,and the initial fracture strengths of mixture specimens were tested by semi-circular bending test(SCB),and then microwave heating was used to induce their self-healing,and their self-healing performance was evaluated according to their bending strength recovery.Firstly,the heating rate under the condition of microwave heating of aggregate and asphalt binder was compared,and the influence of microwave radiation time,microwave intensity and mixture temperature on the self-healing performance of asphalt mixture was analyzed.The results show that the heat distribution of the mixture is not completely uniform after microwave induction heating;microwave heating temperature should not exceed 100℃;the surface temperature of the specimens was affected by the microwave radiation time and the microwave intensity,but the interaction between the two influencing factors is not significant;the increase of microwave radiation time and microwave intensity can promote the self-healing of the mixtures,but it does not mean that the longer the radiation time and the greater the microwave intensity,the better the effect;the fundamental factor that determines the self-healing performance of asphalt mixture is the mixture temperature after heating,and the best temperature is 80℃.