1 a New Micromechanics Design Theory for Pseudo Strain Hardening Cementitious Composite

Micromechanics design theory has realized Random Short Fiber Reinforced Cement Composites (RSFRCC) showing Pseudo Strain Hardening (PSH) behavior with over 5 % of strain capacity under tension. Nevertheless, this existing theory is currently limited to specific constituent properties, which does not account for chemical bond and fiber rupture. This article presents a new design theory which eliminates this restriction, achieving fiber rupture type PSH-RSFRCC with high performance hydrophilic fibers like Polyvinyl-Alcohol (PVA) fibers. Uniaxial tensile tests are conducted employing PVA fiber composites, the results of which support the validity of the proposed theory. Furthermore, parametric study employing the proposed theory quantitatively evaluates the effects of composite’s micromechanics parameters, such as bond strength and fiber strength, on composite performance. This parametric study reveals that continuously increasing the degree of fiber rupture (fiber rupture intensity) enhances the strength performance of composites but not energy performance. However, an optimum rupture intensity exists for maximizing energy performance, which is critical for PSH behavior. The consistency between theoretical predictions and experimental results consequently demonstrates that the proposed theory can be practically utilized as a powerful and comprehensive tool for PSH composite design. 1Kajima Technical Research Institute, 2-19-1 Tobitakyu, Chofu-shi, Tokyo 182-0036, Japan. 2Prof. and Dir., ACE-MRL, Dept. of Civ. and Envir. Engrg., Univ. of Michigan, Ann Arbor, MI 48109-2125.