锈蚀钢筋与钢纤维混凝土粘结性能

Bond Behavior Between Corroded Reinforcement and SFRC

钢纤维混凝土具有良好的抗裂性能和韧性,现已广泛应用于土木工程。对于修复的锈蚀构件,钢纤维混凝土与锈蚀钢筋的粘结性能是影响修复构件力学性能的关键因素。本文通过中心拉拔试验研究锈蚀钢筋与钢纤维混凝土的粘结性能。试验结果表明,钢纤维的加入能够有效抑制混凝土裂缝扩展,提高混凝土的粘结刚度、粘结韧性、极限粘结强度;粘结刚度随锈蚀率的增加而降低;引入粘结韧性因子α=A_(80)/A_(peak)量化钢筋和钢纤维混凝土界面粘结韧性,计算表明粘结韧性因子α随锈蚀率增加而减小;当锈蚀率由0增加至17%时,极限粘结强度降低36.3%;基于试验结果建立以锈蚀率为参数的极限粘结强度经验公式,计算结果与试验结果吻合较好。

Steel fiber reinforced concrete has been used in civil engineering extensively, due to its fine crack resistance and toughness capacity. In the ease of corroded members repaired using SFRC, the bond behavior between corroded rebar and SFRC is a key factor for the mechanical properties of repaired members. The bond behaviors of corroded rebar and SFRC were studied through central pull-out tests in this paper. The experimental results indicate that the addition of steel fiber can restain the propagation of concrete cracks effectively, improve bond stiffness, bond toughness and ultimate bond strength. The bond stiffness decreased with the increase of corrosion rate. The bond toughness factor, α= A80/Apeak, is used to quantify bond toughness between steel fiber and SFRC, the calculation shows that the bond toughness factor decreased with the increase of corrosion rate. When the corrosion rate increased from 0 to 17%, The ultimate bond strength decreased by 36.3%. Based on the experimental results, an empirical equation, considering corrosion ratio, is proposed for predicting the bond strength, and the calculated result agrees well with the tested.