The influence of silicate content of alkali activator on the physical, mechanical and microstructure properties of paste phase of alkali activated cements (AC) were studied. The AC paste was produced by activating the Red Mud and ground granular blast furnace slag with a ratio of 25:75 (RM: GGBS) by using combination of sodium Hydroxide (SH) and Sodium Feldspar (SF) as alkali activators. The silicate content was varied from 0.2 to 1.2. Initially the test specimens were casted and cured at ambient temperature and tested for itscompressive strength at the age of 3, 7 and 28 days. It can be noticed that the compressive strength of test specimens were found to increase with increase in silicate content up to 0.8. The optimum value of compressive strength was found to be 44.52MPa corresponding to age of 28 days and silicate content of 0.8.Further, it can also beobserved that the compressive strength of specimens increases with age. The variation of silicate content was found to have significant influence on porosity and water absorption properties. Micro structural and mineralogical characteristics were determined using SEM/EDAX and XRD analysis

Alkali activated Cement (AC), Red Mud (RM), Ground Granular Blast Furnace Slag (GGBS), Sodium Hydroxide (SH), Sodium Feldspar (SF), Silicate ratio, Compressive strength, SEM and XRD