This is attributed to that the higher CC/SH ratio causes the decrease of aluminosilicate content of GBFS leading to a decrease in the intensities of bands of geopolymers (O–Si–O bond bending vibration, symmetric stretching vibrations of the Si–O–Si(Al) bridges, Si (Al)–O anti symmetric) and hydration products (bending H–O–H vibration, and stretching of O–H groups).