表面开槽碳纤维布-混凝土界面抗剪性能试验

Experimental study on interfacial shear behavior of CFRP-concrete with surface groove

为探究表面开槽法对碳纤维布(carbon fibre reinforced plastics,CFRP)-混凝土界面抗剪性能的影响,开展了表面开槽法CFRP-混凝土单剪试验,研究槽宽深比(0.5、1.0和1.5)和沟槽形状(矩形、正梯形和倒梯形)对CFRP-混凝土界面抗剪性能的影响,重点探究失效模式、断裂能、平均剪应力等指标,并提出表面开槽黏结界面抗剪设计方法。结果表明:较未开槽粘贴法,表面开槽法失效模式由Ⅱ类剥离破坏转变为Ⅵ类断裂破坏,界面断裂能最大提高136.4%,充分发挥CFRP布的抗拉强度和利用率;槽宽深比与平均剪应力成正相关,且存在最优值;正梯形沟槽的平均剪应力分别较倒梯形和矩形沟槽提高10.1%和11.8%。表面开槽法具有较好的抗剪性能,提出的设计方法可用于指导其黏结界面抗剪设计。

To investigate the effect of surface groove method on the interfacial shear behavior of CFRP-concrete,a series of simple shear tests on CFRP-concrete specimens with surface groove method were carried out,focusing on the effects of groove width-depth ratio(0.5,1.0 and 1.5)and groove shape(rectangle,normal trapezoid and inverted trapezoid)on the interfacial shear behavior of CFRP-concrete,especially the failure modes,fracture energy,and average shear stress.The bond interfacial shear design method of surface groove was proposed.The results show that the failure mode of surface groove method is changed from classⅡdebonding failure to classⅥfracture failure,with the interfacial fracture energy increased by 136.4%,giving a full play to the tensile strength and utilization ratio of CFRP sheets.Furthermore,the groove width-depth ratio is positively correlated with the average shear stress,presenting an optimum volume,and with the average shear stress of normal trapezoidal groove improved,10.1%and 11.8%higher than that of the inverted trapezoidal groove and rectangular groove respectively.As the surface groove method performs better shear behavior,the proposed method can be used to guide the shear design of bonding interface.