Characterization and Mechanical Properties Improvement of Termite Mound Clay for Sustainable Construction Materials

Abstract

In this work, the characteristics of termite mound clay are studied and enhanced with the addition of alumina. The clay was washed to remove the unwanted dust particles and then sun and oven-dried at 110℃ for 8 hours. For XRF analysis, samples were crushed and sieved to 90μm, and for other tests, to 150μm. The average chemical composition results of the samples showed that 55.89% SiO₂, 14.19% Al₂O₃, 10.14% Cao, 6.58% Fe₂O₃, 1.01% MgO, 0.87% H₂O, and other trace elements had a 9.08% LOI. The chemical composition results of the samples fall under the category of high silicate clays. This result leads us to add a percentage of alumina from market to reach at least the minimum requirement for refractory materials properties. The liquid limit test established the amount of water required for the best clay plasticity prior to sample preparation. Apparent porosity decreased from 29.79% to 20.3% as Al₂O₃ content increased from 10% to 20%. This is because Al₂O₃ closes the open spaces within the samples during moulding and it could not burn off during firing but increased the bulk density value from 1.46 to 1.769 g/c³. The compressive strength also increased from 7.11 to 12.52 MPa with the increased addition of Al₂O₃. Since there were less pore spaces, the compressive strength increased, and the load-bearing cross-sectional area increased. The percentage linear fired shrinkage of the samples at 900 ℃ along the length, width, and height was decreased from 2.42 to 1.02%, 5.16 to 1.02%, and 6.09 to 0.01% respectively, with increased addition of 10 to 20 wt. % of Al₂O₃.