Strain Localization in High Performance Fiber Reinforced Cementitious Composites

High Performance Fiber Reinforced Cementitious Composite (HPFRCC) is a cementitious composite, which consists of a specifically tailored cementitious matrix reinforced with short discrete fibers that have a proper geometry and enhanced bond properties in order to improve tensile properties of the overall composite. Despite all of its beneficial properties HPFRCC has not yet found its way into the engineering practice largely due to the lack of adequate numerical models. To this end, the main objective of this research was to develop and implement a combined analytical-numerical algorithm that can capture a stress-strain response and inception of strain localization in elastic-plastic HPFRCC. Multi-directional fibers are embedded into a matrix and modeled as a linear elastic material, while the resulting composite is described by a two-invariant non-associated non-linear Drucker-Prager hardening plasticity model. A diagnostic strain localization analysis was conducted for several uniaxial tension and uniaxial compression tests on a non-reinforced cementitious composite as well as on the HPFRCC. It was found that the presence of fibers delayed the inception of strain localization in all tests on the HPFRCC. Furthermore, it appears that the onset of strain localization in uniaxial tension on HPFRCC detects the inception of distributed cracking, while the onset of strain localization in uniaxial compression detects the onset of more localized cracking.