Mechanical properties and acid attack test of hybrid fiber reinforced high performance concrete for fly ash based mineral admixture

Abstract

The scope of the present investigation the mechanical properties and acid attack test of hybrid fiber reinforced high performance concrete (HFRHPC) for Fly ash (FA) based mineral admixture. HFRHPC is prepared by adding crimped steel fibers and polypropylene fiber to the concrete to make it a composite mixture. It derives benefits from each of the added fibers and exhibits significant response. A constant proportion of 0.25% for polypropylene fibers (PF) and varying proportions of 0%, 0.5%, 0.75% and 1.0% for crimped steel fibers (SF) making a total fiber volume fractions of 0%, 0.75%, 1.0% and 1.25% were used to develop hybrid fiber. Four replacement levels for hybrid fibers by volume of the binders and four partial replacement levels for FA (0%, 10%, 20% & 30%) by weight of cement have been considered for three different water binder ratios (0.275, 0.325 & 0.375). An aggregate binder ratio of 1.75 was kept constant. This study shows that hybrid fiber may improve the mechanical properties of fly ash-based high-performance concrete. Acid attack tests have been conducted to measure the durability of HFRHPC. Cubes have been cast, cured, and immersed in 5% concentrated solutions of Hydrochloric acid (HCL), Magnesium sulphate (MgSO4), and Sulphuric acid (H2SO4) for 30, 60 and 90 days and then tested to record the residual compressive strength of HFRHPC produced with the fly ash mineral admixtures. It was observed that a combination of 1.25% hybrid fibers and 10% FA as cement replacement resulted in enhanced mechanical performance and acid resistance.