Effect of fiber-fiber interaction on the strength properties of short fiber reinforced cements

Abstract

A general modification to the models used for the study of the effect of fiber volume on the strength properties of short fiber reinforced cements is presented. It considers the composite as a mix of cement paste, fibers, and voids. The matrix contribution to the strength of the composite is expressed as a function of the void and fiber volume fractions. A modification to the strength contribution of the fibers is proposed based on the reduction of interfacial surfaces due to fiber-fiber and fiber-void interactions. Furthermore, the void volume fraction is related experimentally to the fiber volume fraction. The effect of these modifications on the different measures of strength and toughness in fiber-reinforced cements is briefly discussed. The experimentally observed nonlinear variation of the bending strength of wood fiber reinforced cement (WFRC) with fiber volume fraction can be predicted by applying the proposed modifications to the rule of mixtures traditionally used to predict that strength.