Compressive strength and workability of high calcium one-part alkali activated mortars using response surface methodology

Abstract

In this present experimental study, high calcium fly ash was utilized in the production of one-part alkali activated mortars. The HCFA was activated with anhydrous sodium metasilicate powder at 10 – 20 percent of the total precursor materials and cured at ambient condition. In this study, granular anhydrous sodium metasilicate has been successfully utilized to produce one-part alkali activated mortars. Thirteen mixes of one-part geopolymer mortar were designed using RSM central composite design with percentage of alkali activator and w/b ratios as parameters. Hardened density, workability, and, compressive strength was envisaged. The results showed that increasing the granular activator beyond 15% by weight of the fly ash reduces the strength and workability of the one-part alkali activated mortars. The RSM investigation helped in advancing the level of granular activator as far as acquiring ideal qualities and they were observed to be ideal at 16% of the granular activator and 0.3 w/b proportion. The model conditions were created, and the outcomes were approved through ANOVA by witnessing the model noteworthiness level of more than 95%. One-part alkali activated mortars exhibited highest compressive strength of almost 40 MPa at 28 days curing. The density of the one-part geopolymer mortars is almost the same regardless of the mixes.