CRCP冲断区域后续开裂及影响因素分析

摘要

In order to study the reasons and influence factors of subsequent cracking in punch-out areas, cement concrete which is constituted by cementing materials, aggregates and their interfaces were taken into consideration. Firstly, compressive strength test and flexural tensile strength test in meso-scale were simulated by using PFC2D software, and elastic modulus and flexural tensile strength were obtained. Secondly, considering the characteristics of continuously reinforced concrete pavement ( CRCP) punch-out area and combining the elastic modulus and flexural tensile strength which were obtained from compressive strength test and flexural tensile strength test, the mechanics model of CRCP in macro-scale was established by the finite element method software and the subsequent cracking of CRCP punch-out area under vehicle load, temperature and moisture gradient was analyzed. Lastly, influence factors of the constitution factors of concrete in meso-scale and pavement factors in macro-scale on subsequent cracking of CRCP punch-out area were analyzed. The results based on the study of two scale model for macro-scale and meso-scale indicate that cement content, cement strength and interface stiffness of aggregate and cementing materials have large influence on subsequent cracking of CRCP punch-out area, vehicle overload and void at the bottom of pavement are the main reasons for subsequent cracking of CRCP punch-out area.%为了对冲断区域后续开裂产生原因及影响因素进行研究，首先考虑水泥混凝土细观上是由胶凝材料、集料及其界面组成的非均匀材料，采用PFC2D软件从细观尺度上进行水泥混凝土抗压强度和弯拉强度数值模拟试验，得到水泥混凝土的弹性模量和弯拉强度；然后考虑连续配筋混凝土路面( CRCP)冲断区域特点，利用有限元软件建立CRCP宏观受力分析模型，结合混凝土细观研究所得弹性模量和弯拉强度，对车辆荷载、湿度梯度和温度梯度作用下的冲断区域路面板后续开裂进行研究；最后分析水泥混凝土细观结构组成参数和宏观影响因素对冲断区域后续开裂的影响。研究结果表明：水泥掺量、水泥强度及集料和胶凝材料界面刚度对冲断区域路面板后续开裂影响较大，车辆超载和板底脱空是冲断区域路面板后续开裂的主要原因。