Toward Locally Sourced Cement Alternatives: One-Part Alkali-Activated Materials for West African Construction

Abstract

This work explores how alkali fusion enhances the reactivity and strength development of a metakaolin-based one-part AAM activated by soda ash, as well as the feasibility of utilizing rice husk ash and waste glass as auxiliary precursors in a one-part metakaolin and NaOH system. X-ray diffraction, thermogravimetric analysis, isothermal conduction calorimetry, and compressive strength testing were conducted. Soda ash and metakaolin were alkali-fused at 800°C and 900°C. The results show that alkali fusion improves the reactivity of the soda ash and metakaolin system, with cumulative heats of 190 J/g sample and 175 J/g sample, respectively; however, strength development remained insufficient for practical application. Alternative systems incorporating rice husk ash, waste glass, and a combination of both with sodium hydroxide provided compressive strengths ranging from 1.06 MPa to 2.44 MPa. These results indicate that there is potential for one-part alkali-activated materials using metakaolin and rice husk ash to be employed as cement bricks, which have a minimum code requirement of 2 MPa.