Impact of Reduced Activator Concentration and Curing Method on Compressive Strength of Metakaolin/Fly Ash-based Geopolymer Mortar

The demand for cement is increasing each year, but the manufacture of 1 tonne produces an equal number carbondioxide (CO2) gas which directly related to increase in global warming. Therefore, we need a substitute material, namely geopolymer. This material has relatively superior properties compared cement. However, one drawbacks geopolymers that production costs are more expensive pre-cast because it requires chemical solutions such as sodium hydroxide (NaOH) and silicate (Na2SiO3) activate precursor. research was conducted replace specific ratio alkali activator with water reduce use alkaline while reducing costs. experiment carried out by replacing solution at certain amount different curing method. Mechanical properties, X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy characterization were used analyze effect additional compressive test result shows maximum content can 20% mass fly ash-based 30% metakaolin-based geopolymers, sealed bare conditions before strength decreased sharply. Substitution 10% geopolymer increases 17.20 MPa. Compressive results showed optimal condition due O-C-O bonds representing carbonate (Na2CO3), affects geopolymers.