冻融循环和界面持续应力作用下CFRP-混凝土界面的粘结性能研究

Bond performance study of CFRP-concrete interface under freeze-thaw cycling and sustained interfacial stress

通过对12根试验梁进行冻融循环作用下预应力CFRP板加固钢筋混凝土梁的界面粘结性能试验研究,考察了CFRP板初始应力水平、冻融循环次数及混凝土强度等因素对CFRP-混凝土界面粘结性能的影响。试验结果表明:随着冻融循环次数的增加,加固试件界面粘结应力的劣化速率逐渐增大,薄弱环节逐渐由混凝土保护层向粘结界面发展;CFRP板初始应力和冻融循环的耦合作用对粘结界面的劣化效应较单一的冻融循环作用更加显著,而且随着CFRP板初应力水平的增加,这种劣化效应会逐渐加剧;混凝土强度等级为C60的预应力CFRP板加固试件在冻融侵蚀作用下的界面粘结性能退化速率较C30加固试件更加显著。

Interfacial bond performance experiments of total 12 reinforced concrete beams,which were strengthened with prestressed CFRP plates, were conducted under freeze-thaw cycling. The influences of CFRP initial stress level,freeze-thaw cycling times and concrete strength on the interfacial bond performance of the strengthened specimens were analyzed. Experimental results show that with the increasing of freeze-thaw cycling times,the degradation of interfacial bond stress is gradually significant and the weak zoom transforms from concrete to bond interface gradually. The coupling effect of initial stress and freezing-thaw cycling on the interfacial bond performance is severity to the signal effort of freeze-thaw cycling,and it becomes worse with the increasing level of initial stress level. The degradation of strengthened specimens with concrete strength of C60 under freeze-thaw cycles is more significant than that of specimens with concrete strength of C30.