In order to understand the factors contributing to strength (geopolymerization) for higher grade of geopolymer concrete, characterization of concrete specimens is needed. Fly Ash (FA) and Ground Granular Blast Furnace Slag (GGBS) based geopolymer concrete is tested for 28 days' compressive strength. And the mixes were characterized by adopting various physical-chemical method Fourier Transform Infra-Red (FTIR) spectroscopy. This knowledge helps to understand the contribution of ingredients of mix to strength and derived properties from the mix in a better way.These short-term micro analyses of FTIR were then compared to that of M45 grade of conventional concrete (CC). The molar ratio of hydroxide solution considered in the investigation is 10 M. (c) 2021 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 2nd International Conference on Manufacturing Material Science and Engineering.