Formulating eco-friendly geopolymer foam concrete by alkali-activation of ground brick waste

Abstract

This study investigates ground brick waste powder as a primary precursor to develop eco-friendly geopolymer foam concrete (BGFCs) using a chemical foaming method. The effect of alkali content on the reaction kinetics of brick powder is studied and correlated with the properties of BGFCs. The reaction rates and the formation of crystalline phases of BGFCs were identified by Fourier Transform Infrared Spectroscopy and X-Ray Diffraction test method, respectively. It is found that increasing the alkali content (Na2O) in the mix has significantly enhanced the reaction kinetics of brick powder with the rapid formation of geopolymer gel in the matrix. This has resulted in the enhancement of mechanical properties and rapid setting in BGFCs. For instance, the increase in Na2O concentration from 1:40 to 1:12 has increased the compressive strength of BGFC by 245%. The corresponding initial setting times were reduced from 315 min to 140 min. The rapid setting of geopolymer mixture has resulted in a fine, regular, and homogenous distribution of air voids in the BGFCs. Finally, carbon emission calculations were conducted to assess the environmental impacts of developed BGFCs and compared with Ordinary Portland cement (OPC) foamed concrete. It is found that the developed BGFCs could significantly reduce the carbon emission up to 60% compared to their OPC counterparts.