Geopolymer concrete is an environmentally - friendly alternative to normal concrete that can significantly reduce the emission of CO2 into the atmosphere for its utilization of by-products from industries. This paper is focused on alumino-silicate source materials like Ground Granulated Blast Furnace Slag (GGBS) used as a binder material. Due to scarcity of river sand manufactured sand (M-sand) acts as fine aggregate. This paper investigates the engineering properties and microstructural studies by using XRD, FTIR and SEM for geopolymer concrete (GPC) mixed with GGBS cured under ambient temperature. The test results revealed that, high early compressive strength is achieved in 28 days by 85 %, XRD results show the formation alumino-silicate and C-S-H gel, and FTIR results show that presence of Si-O-Al bond characteristics. The dense formations of the geopolymer matrix had been observed from the SEM analysis. © 2020 by Advance Scientific Research.