Modeling of Tensile Stress-strain Relation of Pseudo Strain Hardening Cementitious Composites

This study proposes a new comprehensive theoretical approach for predicting tensile stress-strain relation of Random Short Fiber Reinforced Cement Composites (RSFRCC) showing Pseudo Strain Hardening (PSH). This approach is grounded on solid basis of micromechanics, which describes PSH phenomenon in terms of constitutive properties of fiber, matrix, and fiber/matrix interface. The proposed modeling requires theoretical treatment of inelastic strain due to multiple cracking. This modeling is achieved by employing a probabilistic description of initial flaw size distribution, which should be known for predicting stress-strain relation. This study proposes a practical method for this identification using the tensile test result of a reference composite. Comparison with test data indicates that the proposed model is capable of reasonably reproducing stress-strain relation of “similar” composites. Such composites have configuration (matrix mix proportion, mixing process and age) similar to the reference one but different in fiber volume fraction and fiber length. Finally, it is indicated that the proposed theory can be a potentially powerful tool for tailoring composites in order to satisfy targeted structural performance. 1 Sr. Res. Engr., Kajima Technical Research Institute, 2-19-1 Tobitakyu, Chofu-shi, Tokyo 182-0036, Japan. 2 Optimal Computer Aided Engineering, Inc., 39555 Orchard Hill Place, Novi, MI 48375 3 Prof. and Dir., ACE-MRL, Dept. of Civ. and Envir. Engrg., Univ. of Michigan, Ann Arbor, MI 48109-2125.