The influence of various basalt mineral and sodium hydroxide concentration on the physical properties and characterization of geo-polymer products

Environment friendly product has a major concern nowadays. The use of cement as a binder to make concrete cannot be negligible since cement production has contributed to the increasing of CO2 emissions. To produce 1 ton of cement, approximately 1 ton of CO2 is also released from the process. Rock geo-polymer cement as one categories of cement is known to be more environmentally friendly than Portland cement. Basalt rock has an opportunity for a material substitute in geo-polymer cement production. Variability influence of basalt and sodium hydroxide concentration on the physical properties and characterization of Geopolymer products are observed in this research. The raw materials used are basalt, sodium hydroxide, sodium silicate, and water. Geo-polymer is made by adding basalt as much as 2.5 %, 5 % and 7.5 % with basalt grain size of 80, 150 and 270 mesh. This research shows that the greater variation of sodium hydroxide concentration, the smaller compressive strength produced; however the absorption considered becomes greater. Geo-polymer with addition sodium hydroxide 2.5 % with basalt grain size of 270 mesh has a highest compressive strength and the lowest absorption rate. Characterization of the sample using XRF and XRD have indicated that the sample has the highest SiO2 compound content of 48.731 % with 2.5 % sodium hydroxide in the 270 mesh, while the phases formed were Albite Na(Si3Al)O-8, Cristobalite (SiO2), Forseterit (Mg2SiO4), Anorthite Ca(Al2Si2O8) and Magnetide (Fe3O4).