AN EVALUATION OF THE PROPERTIES OF CONCRETE INCORPORATING TERMITE HILL MOUNDS AS A SUPPLEMENTARY CEMENTITIOUS MATERIAL

Abstract

Concrete composite is the universal principal rich building material, but cement production contributes to CO₂ emissions. This necessitates alternatives, such as supplementary cementitious materials (SCMs), to partly replace cement while preserving its mechanical performance. The SCMs like fly ash are costly and not abundant in Nigeria. Termite hill mounds (THMs) are naturally occurring potential pozzolanic materials. This study intended to assess the mechanical performance of concrete with THM as SCM to mitigate cement dependence and SCMs cost and scarcity. THM samples were collected from five locations to study if there is a significant variation, then characterized via energy-dispersive X-ray fluorescence (EDXRF), results indicated that the material is pozzolanic; therefore, the samples were mixed together, since no significant difference observed. The concrete mixes of Grade M15, 1:2:4 ratio, 0.5 w/c ratio were prepared with THM replacements of 0% to 50% at 5% intervals. The workability was measured using the slump test as per (BS EN 12350-2:2009). Result indicated the workability peaked at 15% replacement (36 mm slump). The compressive strength performance was tested at day 7, 14, and 28 as per (BS EN 12390-2:2000). 5% replacement produced a 4.93 N/mm² increase in day 28 compressive strength performance of (18.65 N/mm² versus 16.97 N/mm² control), with a strength activity index (SAI) of 119% exceeding ASTM C618-05 requirements. Microstructure was analyzed using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). The 5% mix appeared denser indicating calcium silicate hydrate (C-S-H) formation. In conclusion, THM can enhance concrete mechanical performance at low replacement levels.