An approach to investigate the fiber-cementitious composites bond-slip mechanisms

The composite behavior of fiber-reinforced cementitious composites is generally governed by the total contribution of individual fiber interacting with the cementitious matrix for which fiber-matrix bridging phenomenon is the main mechanism that would influence the energy absorption capacity of the material. This would mean that the overall characteristics of fiber-reinforced cementitious composites can be predicted if the fiber pullout behavior could be better understood. Fiber pullout tests are commonly proposed in the study of fiber-matrix bonding behavior, but such a test is always difficult to perform because it is highly reliant on the configuration design and there is no valid and standard testing technique to date. The specially designed fiber pullout testing fixture presented herein was shown to be able to evaluate the fiber-matrix bond-slip characteristics. The testing results clearly demonstrated that fiber with less deformity was shown to give higher dissipated pullout energy but lower maximum pullout load, whereas more heavily deformed fiber would result in a higher maximum pullout load but with less dissipated pullout energy that is due to fiber fracture during the pullout process. This article has provided an important insight on how fiber shape could influence the ductility of fiber-reinforced cementitious composites.