钢纤维改性橡胶混凝土与变形钢筋的粘结性能

本试验共设计制作4组钢纤维(钢纤维体积率分别为0%、0.5%、1.0%、1.5%)改性橡胶混凝土粘结试件,采用中心拉拔试验的方法,系统研究了钢纤维体积率的变化对粘结破坏形态、初始粘结强度、极限粘结强度以及粘结滑移曲线的影响规律。研究结果表明:随着钢纤维体积率的增大,与橡胶混凝土相比,初始粘结强度分别提高了5.37%、8.35%、0.89%,极限粘结强度分别提高了9.44%、16.49%、12.91%。适量掺入钢纤维可以显著改善粘结试件的破坏形态。上升段、下降段以及残余段共同组成钢纤维改性橡胶混凝土的粘结滑移曲线,且粘结滑移曲线的饱满程度以及上升段斜率随着钢纤维体积率的增加而增加。基于试验结果,建立了钢纤维改性橡胶混凝土与变形钢筋的粘结滑移本构方程,该方程能为其在结构设计中提供一定的参考。

Bonding Properties of Steel Fiber Modified Crumb Rubber Concrete and Deformed Bar

Four groups of steel fiber(steel fiber volume fraction is 0%, 0.5%, 1.0%, 1.5%, respectively) modified crumb rubber concrete(SFCRC) bond specimens were designed and made in this experiment. The influence of steel fiber volume fraction on bond failure mode, initial bond strength, ultimate bond strength and bond-slip curve was systematically studied by central pull-out test. The results show that with the increase of the steel fiber volume fraction, the initial bond strength is increased by 5.37%, 8.35%, 0.89%, and the ultimate bond strength is increased by 9.44%, 16.49%, 12.91%, respectively, compared with crumb rubber concrete. Adding appropriate amount of steel fiber significantly improves the failure form of bond specimens. The rising section, the descending section and the residual section together constitute the bond slip curve of steel fiber modified crumb rubber concrete. The fullness extent and rising section’s slope of the bond-slip curve increase with the increase of steel fiber volume fraction. Based on the experimental results, the bond-slip constitutive equation of steel fiber modified crumb rubber concrete and deformed steel bar is established, which provides a certain reference for its structural design.