接缝修补材料对复合式路面AC层抵抗反射裂缝的试验研究

摘要

通过小梁加载试验研究不同修补策略对旧水泥混凝土路面破损接缝处沥青混凝土加铺层(AC)抵抗反射裂缝的有效性。采用3种修补材料即普通水泥混凝土(CC)、纤维增强水泥基复合材料(ECC)和 ECC 加设传力杆(ECC-dowel)，通过三点抗弯试验及微观形貌观察，分析不同复合梁的裂纹发展形式及抗变形能力。研究结果表明：CC，ECC和ECC-dowel修补材料的裂纹发展形式存在明显不同；ECC应变硬化、多点开裂的延性特征可有效防止AC层反射裂缝的产生；ECC与ECC-dowel复合梁的断裂模量、断裂能等无显著差异，说明ECC基体内纤维的桥接作用是复合梁抗变形能力的关键性因素，传力杆贡献不大。%Different joint restore strategies of the old cement concrete pavement were investigated to validate the availability on the reflection-crack resistance in the asphalt concrete(AC) layer through beam tests. In this research, three repaired materials, i.e. cement concrete (CC), engineered cementitious composite (ECC) and ECC-dowel combination were used. The crack development and flexural performance of the different composite beams were investigated by three-point-bending test and SEM. The results show that there are obvious differences in the development of the cracks between ECC and CC composite beams. ECC can effectively prevent the reflection crack due to its ductility characteristics as strain hardening and multipoint cracking. Bridging between the fibers in ECC matrix is crucial for the flexural performance of composite beam while dowel bar contribution can be neglected.