Structural performance evaluation of concrete mixes containing recycled concrete aggregate and calcined termite mound for low-cost housing

Abstract

Alternative substitutes to convectional building and construction materials which pose environmental challenges, will be a bonus to the construction industries. This research investigates the suitability of calcined termite mound as partial substitute for cement and recycled concrete aggregate as aggregates substitute in the production of concrete. Termite mound clay in its natural state was obtained, calcined, and pulverized to the fineness of 75 µm. Various concrete mixes were formulated in which Ordinary Portland cement was partially replaced with Calcined Termite Mound (CTM) from 0% to 25% replacement at a step size of 5%, and recycled concrete aggregates (RCA) was also used as a partial replacement of the coarse natural aggregate (NA) at 20%, 40%, 60%, 80% and 100% by weight replacement. Compressive strength test, setting time test, slump test, scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR), were used to characterize the test materials and the concrete specimens. The results show that addition of either RCA or CTM will lead to reduction in the compressive strength. However, when RCA is combined with CTM, the optimum combinations suitable for structural load bearing members were found to be 60% RCA, 40% NA with 5% CTM. Other comparable mixes were also discovered.