Effects of using pulverized termite mound (PTM) as partial replacement of fine aggregate on the durability properties and microstructure of concrete

The unrestrained use of non-renewable natural resources used in the production of structural concrete raises sustainability concerns. The use of appropriate waste and non-conventional materials is encouraged to address some of these concerns. Understanding the relationship between the durability properties and microstructure of such a material will increase innovation in its use and mitigate some of the environmental issues associated with concrete production. This paper presents the results of a study conducted to evaluate the durability and investigate the microstructure of concrete with fine aggregate partially replaced by pulverized termite mound (PTM). Durability was evaluated by sorptivity and water absorption coefficient tests. Scanning electron microscopy (SEM) was used to study the microstructure of the concrete specimens after 28 days of curing. The results show (i) that the durability of the PTM concrete specimens, as measured by the water absorption coefficient, improves progressively with PTM content, (ii) that the durability of the PTM specimens, as evaluated by sorptivity, improves up to a PTM content of 70%, and (iii) that the microstructure of the concrete specimens has smaller pores compared to the control, which follows the trend of the sorptivity results. Therefore, for practical purposes, the use of PTM mounds as a substitute for fine aggregate in the production of structural concrete should be limited to 70 %.