Fly ash based geopolymer concrete: structural properties

Abstract

The worldwide consumption of concrete is expected to increase in order to meet the increasing demand of infrastructures, especially in countries like India and China. Globally, the cement production contributes about 7% of the world's CO2 gas emission. Therefore, it is vital to develop alternative binders in order to reduce the green house gas emission by concrete production. Fly ash based geopolymer is an alternative binder that uses an industrial by-product instead of cement. Thus, it has the potential to substantially reduce the CO2 emission associated with concrete production. Fly ash is reacted with an alkali to create geopolymer which binds the aggregates together to produce geopolymer concrete. Studies have shown that geopolymer concrete has good engineering properties. This paper describes some structural properties of geopolymer concrete essential for its application to reinforced concrete structures. The properties include bond strength of geopolymer concrete with reinforcing steel, strengths of geopolymer concrete beams and columns, and its residual strength after exposure to fire. The behaviours of geopolymer concrete members are compared with those of Ordinary Portland Cement (OPC) concrete members. The comparison shows that the structural properties of geopolymer concrete members are similar or superior to those of OPC concrete members. Results of the analytical works show that the current design provisions used for OPC concrete structural members are applicable for conservative design of geopolymer concrete members.