Effect of Fiber Strength and Fiber-Matrix Interface on Crack Bridging in Cement Composites

This article proposes a new theory for predicting the crack-bridging performance of random short fibers involved in cementitious composites. The current theoretical model for estimating crack bridging performance of random short fiber reinforced cement composites under tension is limited to specific constituent properties: friction-dominant fiber-matrix interface and complete fiber pull-out from matrix without rupture. The new theory extends this model by accounting for two often-encountered features in practice: fiber strength reduction and rupture in composites, and chemical bond–dominant fiber-matrix interface. The new theory was verified to capture important characteristics in bridging performance in comparison with composite tensile test data. As a result, the new theory forms an important foundation for developing high-performance random short fiber reinforced cement composites.