高低温循环作用后CFRP与混凝土的黏结性能试验研究

Experimental Research on Bond Performance of CFRP and Concrete after High and Low Temperature Cycling

摘要: CFRP加固混凝土结构处于室外环境条件时会遭受高低温循环作用，为了研究CFRP与混凝土在高低温循环作用后的黏结性能，本文针对36个黏结试件进行了高低温循环作用后的单剪试验。首先利用表面粘贴(externally bonded, EB)，混合粘贴(hybrid bonding, HB)及开槽粘贴(externally bonded reinforcement on grooves, EBG)技术将CFRP布粘贴在混凝土棱柱体试块表面；然后将其中27个黏结试件置于高低温循环作用下(−20˚C～60˚C，60%湿度)，经历50次、100次、150次高低温循环作用后在室温环境中进行单剪试验，剩余的9个试件作为对比试件养护后直接进行单剪试验。试验结果表明：随着高低温循环次数增加，CFRP与混凝土极限黏结承载力呈降低趋势，且高低温循环作用对EBG试件极限承载力影响最显著，经历150次高低温循环后，其极限黏结荷载降低了50.30%。

Abstract: Carbon fiber reinforced polymer (CFRP) strengthened concrete structures may be under harsh and changing environmental conditions including temperature cycles. In order to investigate the bonding performance of CFRP and concrete under temperature cycles, a total of 36 concrete prisms bonded with CFRP were tested. Firstly, three techniques named externally bonded (EB), hybrid bonding (HB) and externally bonded reinforcement on grooves (EBG), were used to attach CFRP sheets to the surface of concrete prism specimens. Then 27 of the specimens were subjected to temperature cycles of −20˚C~60˚C and constant relative humidity of 60%. After 50, 100 and 150 temperature cycles, these specimens were tested using the single-lap shear test method at ambient conditions. The remaining 9 specimens were tested using the single-lap shear test method after curing used as reference ones. The test results show that with the increase of the temperature cycles, the ultimate bond load of CFRP and concrete decreases. Moreover, temperature cycles affect the ultimate bearing capacity of EBG bonded specimens significantly. After 150 temperature cycles, the ultimate bond load of this specimen is reduced by 50.30%.