A homogenization approach to macroscopic strength criterion of steel fiber reinforced concrete

The present study aims to investigate the strength properties of the fiber reinforced concrete (FRC) by means of a micromechanics approach combining the static approach of limit analysis and the homogenization theory. The macroscopic strength criterion for FRC can be theoretically obtained from the knowledge of the strength properties of the individual constituents, namely, concrete matrix and fibers. Adopting a Drucker–Prager failure condition for the concrete matrix and assuming a simplified geometrical model for fiber orientations and length, an approximate static-based model is formulated for the overall strength properties. Explicit analytical expressions have been derived emphasizing the reinforcing contribution of fiber addition.Additionally, numerical solutions are computed by means of finite element tool implementing an elastoplastic step-by-step algorithm. The main objective of the numerical approach is twofold: qualify the relevance of the analytical results and investigate the influence of real fiber morphology on the composite strength properties.