摘要
内聚力模型(CZM)在沥青混凝土开裂研究中得到了广泛应用,但采用内聚力模型对再生沥青混凝土断裂的研究还很少.本文采用随机算法和坐标控制法建立包含旧集料和新集料的再生沥青混合料半圆弯拉模型,将模型分为集料同分布模型和集料随机分布模型两类.研究-10℃时不同RAP掺量(0、25%、50%、75%、100%,质量分数)对再生沥青混合料SCB试件应力强度因子KIC、断裂能GF和抗裂指数ICR的影响.研究结果表明:无RAP掺入的SCB试件具有较好的断裂性能;随着RAP掺量增大,应力强度因子KIC、断裂能GF和抗裂指数ICR均减小,表明RAP的掺入会削弱沥青混合料的低温断裂性能;采用有限元模型得到的断裂参数与室内试验结果一致;相比于集料同分布模型,集料随机分布模型各评价指标的变异性系数整体更大,表明集料分布状态对开裂结果有一定影响;当计算样本足够多时,这两类模型获得的抗裂参数变化规律一致,可有效评价再生沥青混合料断裂性能.
Abstract
Cohesive zone model(CZM)has been widely adopted in the cracking studies of hot mix asphalt,but there are few studies focused on the cracking of reclaimed asphalt mixture based on CZM.In this paper,the stochastic algorithm and the coordinate control method were used to establish the semicircular bending model of the reclaimed asphalt mixture including the RAP aggregate and the virgin aggregate,and the model was divided into two types,i.e.,the identical distribution of aggregates and the random distribution of aggregates.The effect of RAP(0,25% ,50% ,75% ,100% ,mass fraction)was investigated on the fracture parameters at-10℃,including stress intensity factor(KIC),fracture energy(GF)and cracking resistance index(ICR).The results show that specimens without the incorporation of RAP exhibit the superior fracture resistance in terms of KIC,GF and ICR.With the increase of RAP mass fraction,KIC,GF and ICR all decrease remarkably,indicating the low-temperature fracture resistance is degraded.The fracture parameters obtained by using the finite element model are consistent with those of the laboratory tests.Compared with the identical distribution model of aggregates,the variability coefficient of each evaluation index of the random distribution model of aggregates is larger,indicating that the distribution state of aggregates shows a certain influence on the cracking results,and sufficient calculation time is the key to accurate calculation.When there are enough calculation samples,the changes of the fracture parameters of the two types of models are consistent,which can effectively evaluate the fracture performance of recycled asphalt mixture.
基金项目
国家自然科学基金资助项目(52008405)
湖南省自然科学基金资助项目(2021JJ30845)
维普
万方数据