钢纤维-基体混凝土界面黏结性能及影响因素分析

Influencing Factors of Interface Bond Performanceof Steel Fiber-Matrix Concrete

为优化钢纤维-水泥混凝土界面特性,文章在钢纤维混凝土中复掺聚合物乳液,通过拉拔试验获得拉拔荷载-位移曲线,计算钢纤维-基体混凝土界面黏结强度及钢纤维拔出的拉拔韧性,并分析粗集料最大粒径,钢纤维和聚合物单掺、复掺对界面黏结强度及拉拔韧性的影响规律。研究结果表明:减小基体混凝土粗集料最大粒径有助于提高钢纤维-基体混凝土界面黏结强度;掺入钢纤维后,混凝土界面黏结强度提高,拉拔韧性增加,且纤维掺量越大拉拔韧性越大;相较于钢纤维混凝土,复掺聚合物对界面黏结强度作用效果不显著甚至有所减弱,但钢纤维-基体混凝土界面得到强化,提高钢纤维从混凝土中拔出的拉拔韧性28.4%。

To optimize the interface characteristics of steel fiber-cement concrete,polymer emulsion was mixed into steel fiber reinforced concrete,the load-displacement curve by pull-out test were obtained,and the steel fibre-matrix concrete interface bond strength and steel fibre pull-out toughness were calculated.The effects of the maximum size of coarse aggregate,single admixture and compound admixture of steel fibre and polymer emulsion on the bond strength and pull-out toughness of the interface were also analysed.The results show that reducing the maximum size of coarse aggregate in the matrix concrete helps to improve the interfacial bond strength of steel fibre-matrix concrete.The interfacial bond strength and the pull-out toughness increases when steel fibre was mixed in the concrete,and the larger the fibre mixture,the greater the pull-out toughness.Compared with the steel fibre concrete,the effect of the mixed polymer on the interface bonding strength was not significant or even weakened,but the steel fibre-matrix concrete interface was strengthened,and the pull-out toughness of steel fibre increased by 28.4%.