2D Investigation of Bonding Forces of Straight Steel Fiber in Concrete

Abstract

The joint behavior of steel fiber and concrete in Steel Fiber Reinforced Concrete (FRC) member is based on the fact that a bond is maintained between the two materials after the concrete hardens. If a straight steel fiber is embedded into concrete, a considerable force is required to pull the steel fiber out of the concrete. If the embedded length of the steel fiber is enough, the steel fiber may yield, leaving some length of the fiber in the concrete. The bonding force depends on the friction between the steel fiber and the concrete. It is influenced mainly by the shape of steel fiber and the concrete mix properties. The effect of parameters such as end condition of fiber (smooth or hooked-end), embedment length, (W/C) ratio, paste phase of FRC, steel-micro fiber, and curing conditions on fiber-matrix pull-out behavior must be determined. By considering the friction at the fiber-matrix interface during the fiber extraction process, analytical models which consider Poisson’s effects on both fiber and matrix might be developed, and knowledge of the initial extraction stress of the fiber provides the residual normal stress at the fiber-matrix interface. The importance of this research lies in possibility to evaluate the bonding and friction forces of steel fiber in Steel Fiber Reinforced Concrete (SFRC) in the case of straight steel fiber. This evaluation will be done using 2D computer simulations including bonding and friction forces at the interfacial surface between the straight steel fiber and the concrete.