Mechanical and durability performance of concrete mixtures incorporating bentonite, silica fume, and polypropylene fibers

Abstract

Cement demand has steadily increased around the world, negatively impacting the environment by consuming a substantial amount of energy, depleting raw materials, and contributing to climate change. Supplementary cementitious materials (SCMs) can be a potential way to deal with environmental issues by providing an alternative to the cement industry, resulting in more efficient, sustainable, and long-lasting concrete while keeping the environment safe for subsequent generations. The effect of individual and combined integration of bentonite and silica fume as a partial replacement for cement in concrete mixes with polypropylene fibers (PPF) was investigated by determining the mechanical and durability properties of concrete mixes. Binary mixes, containing either bentonite or silica fume as a partial replacement of cement, were prepared along with ternary mix incorporating both the SCMs. Additionally, PPFs were added to the ternary blends in increments of 0.25%, resulting in nine distinct concrete mixtures. Compressive, splitting tensile and flexural strength tests were carried out to study the hardened concrete properties. UPV, sorptivity, porosity, water permeability, abrasion resistance, acid attack resistance, and chloride penetration tests were performed to examine the durability properties. The experimental results exhibited that the addition of silica fume and bentonite resulted in enhanced compressive, splitting tensile and flexural strengths. The durability properties of SCM concrete mixtures also improved compared to the control mix. The microstructure investigation depicted a denser concrete in the case of SCM incorporated mixes. PPF mixes showed satisfactory performance up to a certain percentage of PPF (i.e., 0.5%).