钢纤维增强混凝土非线性疲劳方程及应用

Nonlinear Fatigue Equation for Steel Fiber Reinforced Concrete and Its Application

根据混凝土疲劳破坏机制及钢纤维增强机理,建立了基于基体和界面过渡区性质的钢纤维增强混凝土非线性疲劳方程,并应用得到的方程分析了钢纤维长径比和体积掺量的影响。结果显示:钢纤维对基体的增强作用大于其对界面过渡区的增强作用,是钢纤维增强混凝土S-N曲线呈现明显非线性性质的原因;钢纤维提高基体初裂后的荷载承受能力及对界面过渡区的增强作用使其对高周疲劳性能有一定的改善作用;在讨论的纤维体积掺量、长径比范围内,纤维对基体、界面过渡区的增强作用随纤维特性参数的增大而增大。

According to the failure mechanisms of concrete under fatigue loading and the reinforcing mechanism of steel fiber, a nonlinear fatigue equation based on properties of both matrix and interface transition zone was proposed for steel fiber reinforced concrete and used to analyze effects of fiber volume content and aspect ratio on fatigue behavior. Results show that the effect of steel fiber on matrix is much more evident than that on interface transition zone, which may account for a bended shape of S-N curve for steel fiber reinforced concrete; steel fiber also improve high-cycle fatigue behavior of sted fiber reinforced concrete for it exerts beneficial effects on interface transition zone and the load-bear ability of matrix after first-crack; in the range of fiber volume content and aspect ratio discussed, the extent of improvement of steel fiber on both matrix and interface transition zone increases with the increase of steel fiber characteristic parameter i. e. the product of fiber volume content and aspect ratio.