Strength and microstructural characterization of silica fume blended concrete with increased curing period

Abstract

With rapid urbanization and an exponential surge in population, the need and demand for concrete structures have increased, and industrial waste has also increased. Due to this, the adverse effects on the environment have started to show. Utilizing industrial byproducts in concrete, such as silica fume (SF), not only contributes to the reduction of industrial waste, but also mitigates the adverse environmental effects. The present investigation is mainly focused on the influence of SF on the strength and microstructure of concrete with an increased period of curing. In this study, SF is used as a substitute for cement in varied proportions of 0 %, 10 %, 20 %, 30 %, and 40 %. This investigation determines the mechanical parameters of concrete, such as compressive, split tensile, and flexural strength, at curing periods of 28, 56, and 84 days. The results indicate that a 10 % substitution of cement with SF as the optimum dosage. In this investigation, scanning electron microscopy is performed to examine the microstructure of the concrete samples that contributed to the variation in strength characteristics with an increased period of curing. Microstructural analysis has revealed that the incorporation of SF in the concrete matrix with an increased period of curing has led to the decrease in voids and an increase in hydration products. The incorporation of SF in the concrete matrix led to the densification of the microstructure. With increased period of curing, the strength parameters have enhanced due to the pozzolanic reaction between SF and the free lime present in the concrete matrix.