Effect of hybrid fibers, calcium carbonate whisker and coarse sand on mechanical properties of cement-based composites

Nowadays researchers are developing a new hybrid fiber reinforced cement-based composites (HyFRCC). The new HyFRCC can restrain micro-cracking, improves compressive and flexural performance of beams by addition of calcium carbonate (CaCO3) whisker, polyvinyl alcohol (PVA) fiber and steel fiber. In this work, a mix optimization procedure is shown for multi-scale HyFRCC, with steel, PVA fiber and CaCO3 whisker. The new HyFRCC is explored with addition of coarse sand to further improve its mechanical properties. Additionally, the flexural performance of beam and slabs has been investigated to optimize sand gradation and fiber combination in new HyFRCC. The compressive strength, flexural strength, flexural behavior, flexural toughness, equivalent flexural strength and deflection-hardening behavior of beams and slabs are improved with optimized content of sand gradation, fibers and CaCO3 whisker. The HyFRCC slab with 1.5% steel fiber, 0.4% PVA fiber, 1% CaCO3 whisker and optimized coarse sand showed overall best properties.