Permeability indices and corrosion resistance of geopolymer and Portland cement concretes

Abstract

Along with the strength and durability of construction materials, the environmental aspects of using these materials have to be taken into consideration. Geopolymer concrete is a new generation of ‘green’ concrete, mainly made from waste materials and aluminosilicate binder. The main objective of this work was to study the permeability indices such as water penetration depth, water absorption and voids ratio as well as the corrosion resistance of geopolymer concrete. The parameters considered were the molarity of the alkaline activator (sodium hydroxide), the alkaline solution binder ratio, the binder material content, curing temperature, cement addition and silica fume addition. The performances of geopolymer concrete and hydraulic Portland cement concrete were also compared. From the test results, in terms of the permeability indices, the optimum parameter values were found to be a molarity of 16, an alkaline activator to binder ratio of 0·40, binder materials content of 450 kg/m3 and a curing temperature of 70°C for 48 h duration. The addition of cement or silica fume was found to improve the performance of the geopolymer concrete. At the same compressive strength, the geopolymer concrete achieved better water permeability resistance and corrosion resistance than Portland cement concrete.