表层嵌贴CFRP-混凝土结构的黏结性能研究

Bond Behavior of Near-surface-mounted CFRP to Concrete Structure

为研究嵌贴的CFRP与混凝土间的黏结性能及黏结滑移关系,对22个嵌贴CFRP加固混凝土棱柱体试件进行了单剪拔出试验,考察了混凝土强度、槽宽、槽边距、树脂保护层厚度、及构件截面尺寸等因素对嵌贴CFRP-混凝土界面的黏结承载力、破坏模式、黏结刚度、黏结滑移关系等性能的影响;在试验结果基础上提出了含残余摩擦段的三段式黏结滑移关系模型,进而明确了混凝土强度与槽边距等因素与峰值黏结应力等模型特征参数的相关性,最终在上述工作基础上建立了首次考虑混凝土强度、槽宽、槽边距等多因素影响的黏结滑移关系模型。研究结果表明:所考察的各因素对嵌贴CFRP与混凝土界面的黏结性能及黏结滑移关系存在显著影响;运用最小二乘法得到的含特征参数的黏结滑移关系模型对界面断裂能的预测精度优于现有其他模型;所建立的考虑多因素影响的黏结滑移关系模型预测的峰值黏结剪应力与文献试验实测值的相关系数为0.65,预测精度较高。

The bond behavior and bond-slip relationship of near-surface mounted(NSM)carbon fiber reinforced polymer(CFRP)to the concrete interface were studied.Simple shear pull-out tests were conducted on 22 specimens,which consist of concrete prisms and NSM CFRPs,to investigate the influence of concrete strength,groove width,edge-to-groove distance,epoxy cover depth,and sectional dimension of specimens on the bond capacity,failure mode,bond stiffness,and bond-slip relationship of NSM CFRP systems.A three-segment bond-slip model containing the residual friction branch was proposed on the basis of the test results.The correlations between the characteristic parameters of the model and factors such as concrete strength and groove width were analyzed and determined.Based on the above works,a bond-slip constitutive model that considers the influence of multi-factors such as concrete strength,groove width,edge-to-groove distance was established for the first time.The results show that the factors studied have a significant influence on the bond of NSM CFRP to concrete.The present bond-slip constitutive model with characteristic parameters obtained by least squares method showed better agreement with the interfacial fracture energy from literature than existing models.The correlation coefficient of the peak bond stress predicted by the multi-factor bond-slip constitutive model and the actual values from literature is 0.65,suggesting a relatively good agreement.