Effect of rice husk ash on compression behavior of high-calcium fly ash geopolymer concrete

Abstract

Geopolymer concrete is an alternative material that is more eco-friendly than Portland cement concrete. To promote the use of rice husk ash which is a by-product from biomass power plants for domestic geopolymer concrete production, this research investigated the physical properties and behavior in compression of geopolymer concrete utilizing high-calcium fly ash and rice husk ash from 0 to 60 percent by mass. The 10 M sodium hydroxide and sodium silicate solutions were used as alkali activator solutions with the ratio of 1.0. Geopolymer concrete specimens were cured in ambient condition for 28 days before compression testing to determine compressive strength, modulus of elasticity, and Poisson’s ratio. The results showed that geopolymer concrete using 20-percent rice husk ash exhibited the maximum compressive strength of 25.9 MPa. Modulus of elasticity of the geopolymer concrete varied from 12,000 to 19,000 MPa as compressive strength increased. Poisson’s ratio varied from 0.19 to 0.31. Moreover, the stress-strain curves showed an increase in ductility of the geopolymer concrete using higher rice husk ash contents due to higher plastic deformation before fracture.