EFFECTS OF NANO SILICA ON THE STRENGTHS OF GEOPOLYMER CONCRETE CURED AT AMBIENT TEMPERATURE

The mineralogical and chemical composition of fly ash, in general depends on the source of coal and types of power plants. Yip and Deventer [5] have observed that higher molarity with low alkaline content and elevated curing temperature at early ages enhanced the high early strength of geopolymer systems. Oh et al. [6] have noticed that the presence of calcium compound in the source material plays a vital role because the Ca2+ was capable of acting as a charge-balancing cation with in the geopolymeric binder. Bakharev [7] concluded that says Ca2+ compound in the source material forms Ca–Al– Si amorphous structures. Oh et al. [8] stated that the Ca2+ available in blast furnace slag was able to create a coexistence of geopolymeric gel that leads to the increase of mechanical strength of geopolymer materials. However, Shaikh et.al[9] have showed better results in terms of strength and durability by incorporating nano silica in conventional cement concrete or high volume fly ash concrete and it was found as an effective additive towards the mechanical development. Tanakorn et al.[10] have reported that the usage of nano silica and nano aluminium oxide in geopolymer paste for high calcium based fly ash for a particular 10 molar concentration enhanced geopolymer mechanical property. However, research on the effects of nano silica on the properties of geopolymer concrete is scarce in literature. Therefore, this study aimed to investigate the effect of nano-silica on the properties of fly ash geopolymer concrete. In order to determine the optimum quantity of nano-silica in the different types of geopolymer concrete, experimental work was carried out on flyash, GGBS blended flyash geopolymer concrete. The strength development of geopolymer concrete samples containing different proportions of Nano silica cured at room temperature curing were studied.