Rheology, fiber distribution and mechanical properties of calcium carbonate (CaCO3) whisker reinforced cement mortar

Calcium carbonate (CaCO3) whiskers are a new kind of microfiber used in cementitious composites and have proved to provide excellent effect on strengthening and toughening. In order to further improve the mechanical properties of CaCO3 whisker-reinforced cementitious composites, rheological properties of fresh mixtures and the CaCO3 whisker distribution in the hardened matrix were investigated. The yield stress and plastic viscosity increased with an increasing content of CaCO3 whisker and a decreasing water-cement ratio. Also, the rheological properties were affected by the distribution of CaCO3 whisker in the matrix. The largest increments in flexural and compressive strength were 27.59% and 12.60% for the mortars with CaCO3 whisker contents of 2.0% and 1.5%, respectively. The properties responsible for the mechanical response were explained in terms of the effects of CaCO3 whisker reinforcement, the distribution of CaCO3 whiskers, and the porosity as well as pore size distribution.