Preparation and Characterization of Low Cost Geopolymer Cement

Abstract

Effect of some artificial pozzolana such as ground granulate blast furnace slag (GGBFS), cement kiln bypass dust (CKD), silica fume (SF), and fly ash (FA) on geopolymer composition and its resistance to sulphate attack was studied. Various mixes are prepared using different liquid/solid ratios (L/S) by weight. Sodium hydroxide pellets (SH) and commercial sodium silicate liquid (SSL) are used as an activator which was dissolved in the mixing water. The hydration characteristics of the different mixes have been tested via determination of bulk density, total porosity, combined water, compressive strength, and XRD analysis at different time intervals from 1 up to 180 days in water. The results show that the combined water content of the alkali-activated GBFS pastes gradually increases up to 180 days in all mixes. The bulk density increases and the total porosity decreases, as a result of addition of the pozzolanic materials. The compressive strength also increases up to 180 days. All mixes showed good stability of its compressive strength values in 5 % MgSO 4 solution. The data show that SF1 (85% GGBFS+15% SF) activated by (0.5 mol/kg SSL, and 2.5 M SH), and S3 (100% GGBFS) activated by (0.5 mol/kg SSL, and 2.5 M SH) are the most appropriate binding materials (geopolymer cement) that have good different properties so that they can be used as alternative binding materials to the ordinary Portland cement.