Hybrid effects of alumina and silica nanoparticles on water absorption of geopolymers: Application of Taguchi approach

The effect of amorphous nanosilica and crystalline nanoalumina on water absorption behaviour of geopolymers was considered at two and seven days of water curing regimes. Taguchi approach was used to design the experiments and the results were analysed by factorial analysis and analysis of variance (ANOVA). ANOVA results were used to find optimized mixture proportions. The results show that the degree of completion of geopolymeric reactions is the key factor affecting on the percentage of water absorption. While nanosilica particles support a denser geopolymeric paste, unreacted nanoalumina particles act as nanofillers and reduce water demands. The main important operational factor was oven curing temperature where increasing the temperature to 90 oC resulted in lower percentages of water absorption at both two and seven days of water curing regimes.