The research aims at proposing an innovative application of using Fourier transform infrared (FTIR) to examine the microstructure of a new no-cement SFC binder paste, which is fabricated with mixture of ground granulated blast furnace slag (GGBFS). Type F fly ash, and circulating fluidized bed combustion (CFBC) fly ash.15% CFA is used as the main activator to trigger the hydration of various mixtures of GGBFS and FFA. The results show that CFA mainly consists of portlandite (Ca(OH)2) and anhydrite (CaSO4) which attributes to the hydraulic property of SFC powder. The main hydration products of the hardened paste are ettringite (AFt) and calcium aluminum silicate hydrate (C-A-S-H) gel. An increase in FFA addition leads to the higher degree of AFt precipitation induced by an increase of active alumina