Strength Properties of Fiber Reinforced Concrete by Means of a Homogenization Approach

Abstract

Addition of steel fiber to concrete results in a composite with enhanced strength properties than conventional concrete. Experimental studies have shown that fibers improve the biaxial compressive and uniaxial tensile strengths of concrete. This study investigates the strength properties at the macroscopic level of the reinforced material by means of a micromechanical reasoning which implements the static approach of limit analysis homogenization theory. Within this framework, the macroscopic strength criterion can be theoretically determined from the knowledge of the failure conditions of individual constituents, namely, concrete matrix and fibers. Adopting a Drucker-Prager failure criterion for the concrete failure properties, and assuming an isotropic spatial distribution for the fibers, an approximate static-based model is formulated for the homogenized strength properties. The expression of the latter is provided together with the corresponding geometric interpretation in the space of macroscopic stresses. The accuracy of the proposed model is assessed by means of comparison with available data. The predictions of the analytical model are found to compare well with the available experimental results.