锈蚀钢筋与纤维水泥基材料的界面黏结性能

Interfacial Bond Behavior between Corroded Reinforcement and Fiber Reinforced Cementitious Materials

针对2种用于结构修复的纤维水泥基材料(超高韧性水泥基复合材料UHTCC和钢纤维混凝土SFRC),以钢筋锈蚀率(质量分数,下同)为参数,通过中心拉拔试验,研究了清理干净的锈蚀钢筋与纤维水泥基材料的黏结性能.结果表明:由于纤维的桥接作用,UHTCC和SFRC试件均呈现出劈裂-拔出破坏模式;随着钢筋锈蚀率的增大,UHTCC试件的相对黏结应力-平均滑移曲线下降段渐趋平缓,SFRC试件的曲线下降段斜率基本保持不变;在相近的锈蚀水平下,UHTCC试件的黏结强度和残余黏结强度均高于SFRC试件;当钢筋锈蚀率约为14%时,2种试件的黏结强度分别下降至初始强度的81%和88%;钢筋锈蚀对纤维水泥基材料的残余黏结强度影响较小.

Interfacial bond behavior between corroded rebar cleaned up and fiber reinforced cementitious materials were investigated through central pullout tests.Two kinds of materials were used in the tests,including ultra-high toughness cementitious composite（UHTCC）and steel fiber reinforced concrete（SFRC）.The variable considered was corrosion ratio.The experimental results reveal that all the UHTCC and SFRC specimens show splitting-pullout failure mode depending on the fiber bridging action.With the increasing corrosion ratio,agentle descending branch of relative bond stress-average slip curves is obtained for UHTCC samples whereas the slope of descending branch is almost comparable to SFRC specimens.At a similar corrosion ratio,UHTCC sample has higher bond strength and residual bond strength compared with SFRC specimen.When the corrosion ratio is high up to about 14%（by mass）,the bond strength descends to 81% and 88% of the initial strength for UHTCC and SFRC samples,respectively.Moreover,the effect of corrosion on the residual bond strength is little.