The influence of mineral additive type and water/binder ratio on matrix phase rheology and multiple cracking potential of HTPP-ECC

Engineered Cementitious Composites (ECC) exhibit pseudo strain-hardening behavior by fine multiple cracking with controlled tight crack width mechanism. The optimization of interaction between fiber and matrix is the main design strategy of ECC. Mineral additives are preferable in the design of ECC due to technical and economic advantages. In this study, the influence of mineral additives on normal strength grade ECC (compressive strength range: 20-50 MPa) procured with a recently developed fiber known as high tenacity poly-propylene (HTPP) have been experimentally studied. Composites incorporating ground granulated blast furnace slag (GBFS) and fly ash (FA) were prepared at three different Water/Binder (W/B) ratios (0.31, 0.34, 0.37). Matrix phase rheology of composites characterized. The tensile stress-strain relationship, crack width distribution, fiber bridging stress - crack opening relation, matrix fracture toughness and compressive strength values have been experimentally determined. The role of mineral additives on multiple cracking has been discussed. Furthermore, energy and strength based pseudo-strain hardening indices of composites have been calculated by using ECC micromechanical theory.