Bonding Mechanisms and Strength of Steel Fiber–Reinforced Cementitious Composites: Overview

Abstract

The bond characteristics between steel fiber and a cementitious matrix play a crucial role in controlling the performance of steel fiber–reinforced concrete (SFRC). The bonding mechanisms of SFRC have attracted considerable attention over the last four decades and are still active research. This overview provides a state-of-the-art understanding of the major mechanisms governing the pullout behavior of steel fibers. Characteristics of different types of bond and their functions have been explained in detail. Primarily important are bond strength in each of its likely failure modes. Different factors affecting the bond strength include geometry, orientation and embedded length of fiber as well as matrix strength. A review of existing analytical papers investigates the bond mechanisms between steel fiber and cementitious matrix. The review shows that the most successful method to improve bond slip is to reinforce concrete with pre-deformed fibers. This review also provides useful information on how fiber geometry influences pullout behavior from the matrix for a known relative strength between the two constituents. The theory of bonding and its related parameters is surveyed. Finally, recommendations for future research and optimum applications of SFRC are considered.