An investigation on the effect of curing conditions on the mechanical and microstructural properties of the geopolymer concrete

Abstract

Geopolymer concrete represents the future of green and sustainable concrete. It has a large impact on the construction industry owing to its better performance than that of conventional Portland cement concrete. This study aimed to identify the effect of curing conditions on the physical, mechanical, and microstructural properties of specimens using ambient curing and oven-curing. In the experimental analysis, we tested slump and setting time for physical properties, density and drying shrinkage for chemical properties, compressive strength, indirect tensile strength, modulus of rupture, Poisson’s ratio, and elastic modulus for mechanical properties, rebound strength, and UPVT for nondestructive and x-ray diffraction, and thermogravimetric analysis for microstructural analysis. After the experimental analysis, it was concluded that the density, Poisson’s ratio, and dry shrinkage were higher for ambient-cured specimens than for oven-cured specimens, whereas the compressive strength, indirect tensile strength, modulus of rupture, and elastic modulus of oven-cured specimens were higher than those of ambient-cured specimens. The nondestructive tests, rebound tests, and UPVT show that the oven-cured specimens are better in quality and strength than the ambient cured specimens. In microstructural analysis, x-ray diffraction showed that the oven-cured specimens had a lower intensity of mineral oxides than the ambient-cured specimens in microstructural analysis. The matrix of the ambient-cured specimens was thermally stable up to 800 °C and retained 92% of its original mass, whereas the matrix of the oven-cured specimens retained 94% of its mass up to 800 °C in the thermogravimetric analysis.