Suitability of Anthill Soil as a Supplementary Cementitious Material

Cement is the most utilised construction material and the second most consumed commodity in the world after water. It has been reported that the heavily energy-intensive processes that are involved in its production contribute about 7 to 10% to the total global anthropogenic carbon dioxide (CO2), which is the main cause of global warming; and are expensive economically. It is however possible, that energy and cost efficiency can be achieved by reducing on the amount of cement, and in its place utilizing Supplementary Cementitious Materials (SCMs), which require less process heating and emit fewer levels of CO2. This work aimed to provide an original contribution to the body of knowledge by investigating the suitability of Anthill Soil (AHS) as an SCM by testing for pozzolanic or hydraulic properties. Cement was replaced in concrete with AHS by weight at 0%, 5%, 7.5%, 10%, 15%, 20%, 25%, and 30% steps at the point of need. The 0% replacement was used as the reference point from which performances were measured. The chemical composition analysis by X-ray diffraction (XRD) showed that AHS contained the required chemical composition for pozzolans, while the compressive strengths achieved were above strength classes that are specified as being suitable for structural applications. The increase in compressive strength over time, density and workability behaviors of AHS were consistent with the characteristics of SCMs. All results across the tests showed good repeatability, highlighting the potential of using AHS as an SCM in concrete to enhance the sustainability and economic aspect of concrete, while at the same time improving its properties in both the wet and hardened states.