冻融循环下BFRP筋与混凝土黏结强度试验研究

Experimental study on bond strength between BFRP bars and concrete under freeze-thaw cycles

为了研究冻融循环作用下BFRP筋与混凝土黏结强度,对不同冻融次数(0、10、20、40次)和不同混凝土强度等级(C30、C35、C40)共36个试件进行冻融循环试验和中心拉拔试验。试验结果表明:未经冻融循环的试件和冻融循环40次(C30)试件发生拔出破坏,其余冻融试件均发生劈裂破坏;随着混凝土强度等级提高,脱胶强度和黏结强度逐渐增加;随着冻融循环次数增加,BFRP筋与混凝土的黏结强度和峰值滑移呈现出先增加后减小的趋势,而脱胶强度随冻融循环次数增加逐渐减小。

To study the bond strength between BFRP bars and concrete under freeze-thaw cycles,freeze-thaw cycles test and central pull-out test were carried out on 36 specimens with different freeze-thaw times(0,10,20,and 40 times)and different concrete strength grades(C30,C35,C40).The experiment results show that all the specimens fail due to the splitting failure of the concrete except for the specimens without freeze-thaw cycles and specimens adopting C30 concrete with 40 freeze-thaw cycles,which exhibit pulling-out failure.With the increase of strength grade of concrete,the debonding strength gradually increases,but the ultimate bond strength does show a proportional increase.With the increase of freeze-thaw cycles,the ultimate bond strength and peak slip between BFRP bars and concrete show an increasing trend followed with decreasing,while the debonding strength gradually decreases.