Production of Green Cement from Slag Enhanced by Egyptian Metakaolin Materials

New geopolymer-based materials offer excellent perspectives for the future; they should not be regarded as competitive materials for Portland cement, which has been the reference construction material for so long, but as alternative materials with a series of important advantages to be considered. Metakaolin (MK) produced from firing kaolin material up to 750 ºC for 2 h with a heating rate of 5ºC/min; leads to an enhancement in mechanical and microstructural properties of alkali activated geopolymer of water cooled slag material using (6:6, wt%) of sodium hydroxide and sodium silicate. In the present work the ratios of MK which will be added are less than 20% of the total mass, because of the used MK was very fine with average pore structure less than 30 mµ, which hinders the geopolymerization reaction if used as high ratio. Curing was performed under 100% relative humidity at a temperature of 38ºC and ages of 7, 14, 28 & 90 days. The properties of geopolymer specimens have been studied through measurement of XRD, SEM imaging, FTIR, compressive strength and water absorption. Results showed that the mixes of metakaolin up to 15% results in an enhancement in the mechanical properties as compared with slag control mix up to 90 days.