Geopolymer via Pressing Method: Aluminosilicates/Alkaline Solution Ratio as the Determining Factor

Abstract

Abstract Aluminosilicates/alkaline solution (FA/AA) ratio has a great influence on the morphology and mechanical properties of geopolymer fabricated via pressing method. The aim of this paper is to evaluate the effect of FA/AA ratio on the performance of pressed geopolymer. The geopolymer mixtures were prepared at FA/AA ratio of 4.5-7.0 and compacted with uniaxial hydraulic press. The resultant specimens were cured at room temperature (30°C) for 7 and 28 days. The physical properties of the specimens were measured by porosity and water absorption analysis. The microstructure and strength of pressed geopolymers were determined. The results revealed that the pressed geopolymer with FA/AA ratio of 5.5 had the lowest porosity and water absorption. Furthermore, SEM micrographs proved that FA/AA ratio of 5.5 yielded the formation of well-compacted structure. Maximum compressive strength of 78.54 MPa was achieved.