A stochastic micromechanical framework for hybrid fiber reinforced concrete

Abstract A stochastic micromechanical framework is presented to predict the probabilistic behavior of the hybrid fiber reinforced concrete (HFRC). The proposed framework consists of the stochastic descriptions for the material's microstructures, deterministic micromechanical model for HFRC and maximum entropy based stochastic simulation program. The HFRC is represented as multiphase composite composed of the aggregate, the interfacial transition zone (ITZ), the bulk cement paste and different types of fibers. Multi-level homogenization schemes are presented to predict the material's effective properties, where the effects of aggregates, ITZs and multi-types of fibers are quantitatively calculated. By modeling the volume fractions and properties of constituents as stochastic, we extend the deterministic framework to stochastic to incorporate the inherent randomness of effective properties among different specimens. Maximum entropy based simulation procedures are employed to characterize the material's probabilistic behavior, including different order moments and the probability density function. Numerical examples including limited experimental validations, comparisons with existing micromechanical models, commonly used probability density functions and the direct Monte Carlo simulations indicate that the proposed models provide an accurate and computationally efficient framework in characterizing the material's effective properties. Finally, the effects of different fibers and ITZs on the materials' macroscopic probabilistic behaviors are investigated based on our proposed stochastic micromechanical framework.