Effects of ultra fine slag as mineral admixture on the compressive strength, water absorption and permeability of rice husk ash based geopolymer concrete

Abstract

Geopolymer concrete (GPC) is a sustainable green concrete, replaces ordinary Portland cement concrete prepared by activating aluminosilicate based industrial waste materials with an alkaline solution as an alkaline activator. In this paper rice husk ash (RHA) based GPC was prepared with varying the percentages of ultra-fine slag (UFS) and RHA, activated with an alkaline mixture of sodium hydroxide and sodium silicate with desired proportion. The ambient curing method was used at an average temperature of 27-degree Celsius. The compressive strength, the durability property of GPC in terms of water permeability and water absorption were investigated. Effects of several parameters such as the percentage of ultrafine slag, duration of curing, RHA content on water permeability, and water absorption of geopolymer concrete was studied. The result shows that the inclusion of ultra-fine slag significantly improvises the durability properties of RHA based geopolymer concrete. GPC specimens prepared with ultra-fine slag appear to have improved densification. The analysis of results shows that with a higher percentage of ultra-fine slag in rice husk ash geopolymer concrete has a substantial effect in enhancing the strength properties.