The Effects of Steel Fiber Types and Inclination Angles on Static and Impact Pullout Behavior of UHPC

Abstract

This study investigates the effects of steel fiber types and inclination angles on pullout behavior of ultra-high-performance concrete (UHPC) under quasi static and impact loading conditions. For this purpose, three different types of steel fibers (i.e., straight, half-hooked, and hooked steel fiber) and four different types of inclination angles (i.e., 0, 30, 45, and 60°) were considered. Based on the test result, the highest average bond stress was obtained for the hooked steel fiber under both static and impact loading conditions, while the straight steel fiber showed lowest values. The average bond stress values of straight and half-hooked steel fiber were significantly improved by applying impact loading conditions. All of the inclined hooked steel fibers were ruptured under quasi static loading conditions whereas the inclined half-hooked fiber did not. The effectiveness of using the half-hooked steel fiber increased at the inclined conditions.