Characterization of diatomaceous earth to evaluate its potential as a resource for Geopolymer concrete development

Abstract

Researchers have become interested in cutting-edge geopolymer technology and the creation of geopolymer composites as a means of achieving sustainability in the production of concrete. In this study, the feasibility of using diatomaceous earth from Nakuru, Kenya, as a source for geopolymer concrete was evaluated. The chemical and physical analysis of diatomaceous earth were carried out using standard techniques. Thermogravimetric (TGA) and Differential Scanning Calorimetry (DSC) analyses were performed on the diatomite for thermal characterization. The Sodium silicate/Sodium hydroxide alkaline activated diatomite-based brick specimens were moulded, and their mechanical and physical features were determined using standard test procedures. The diatomaceous earth’s chemical composition showed that silica (SiO2) was the predominant component, with 88.12%. Calcium oxide (CaO) was 4.26% and alumina (Al2O3) was 4.25%. There were also trace levels of other oxides such as MgO, K2O, TiO2, MnO, Fe2O3, and P205. The thermogravimetric analysis showed a loss on ignition of 5.68 % and that its softening point is higher than 950 °C. The particle size analysis and the Atterberg limit test showed that the diatomaceous earth from Nakuru, Kenya, is a cohesive and medium plastic silt, with an average particle size of less than 50.4 μm. The diatomite-based specimens had an average compressive strength of 22.98 MPa, a density of 1.38 g/cm3 and water absorption of 9.32 %. The chemical composition suggests that it is comparable to Class F pozzolan. The mechanical, physical and durability performance falls within the acceptable limits provided in literature. This research showed that Kenyan diatomite can be successfully employed as a silica source in geopolymer formulations, providing hopeful approaches to utilizing and recycling the resource