Influence of iron making slags on strength and microstructure of fly ash geopolymer

Two types of iron making slag namely granulated blast furnace slag and granulated corex slag has been added in the range of 0–50% into a fly ash based geopolymer system respectively. The effect of slag addition to the geopolymerization reaction and consequent structural rearrangement has been studied using Isothermal Conduction Calorimeter and Fourier Transform Infrared Spectroscopy. The effect of corex slag is found to be similar to that of the granulated blast furnace slag. In both the cases, the main reaction product is C–S–H gel (C = CaO, S = SiO2, H = H2O). An attempt has been made to correlate the reaction, structure and properties. It is found that corex slag, which is generated by a different process of iron making, gives the similar kind of result as granulated blast furnace slag in fly ash based geopolymer. Thus it can be safely used as substitute of granulated blast furnace slag in alkali activated or geopolymer system.