Alkali activation of compacted termite mound soil for eco-friendly construction materials

Abstract

This investigation prospects the feasibility of optimizing the mechanical behavior and dimensional stability of termite's mound soil through alkaline activation. The raw aluminosilicate (termites' soil) was used without any pre-thermal treatment and natural occurring potash was used as the alkaline activator. Different activation level and different initial curing temperature were adopted to examine the effect of the initial temperature and the activator concentration on the Alkali Activated Termite Soil (AATS). Similarly, Scanning Electron Microscopy (SEM)/Energy Dispersive X-ray Spectroscopy (EDS), X-ray Diffraction (XRD) and Fourier Transform Infra-Red Spectroscopy (FTIR) were conducted to characterize the microstructure, to determine the crystallinity of the constituents and to identify the functional groups present within the specimens. These characterizations were carried out on the specimens at 15 days after their moulding. The compressive strength was determined for 7, 15 and 90 days to illuminate the fundamental of the optimization process. Results showed that the optimal initial curing temperature was 60°C for the oven-dry regime at 3wt% activator with compressive strength of 2.56, 4.38 and 7.79 MPa at 7, 15 and 90 days respectively. From the mechanical performances results, the alkali stabilized termite's soil can be used as masonry elements predominantly submitted to compression. The repercussions of the results are analyzed for potential applications of the Alkaline Activation techniques as an environmental-friendly approach to obtain renewable and sustainable building materials at low cost with low energy consumption henceforth replicable in most of the regions.