Mechanical properties, resistance to fire and durability for sulfate ions of alkali activated cement made from blast furnace slag-fine metakaolin

Abstract

The characterization of alkali activated cement prepared by blending blast furnace slag (BFS) and fine metakaolin (FMK) is studied. MK of particle size 45 μm and blain area 6530 cm2/kg is used by 20, 40, 60 and 80% replacement of BFS in the production of alkali activated cement. The utilized alkaline activator is mixture of NaOH and Na2SiO3 with various molar ratios. The prepared specimens are cured under humidity conditions up to 90 days. All specimens are characterized regarding setting times, compressive strength and water absorption. The formed hydrates are studied using XRD analysis, FTIR spectroscopy and SEM technique. The durability of the prepared geopolymer is determined via studying the fire resistance at 300o, 600o and 800 oC and sulfate ions attack after time intervals extended up to 1 year. The results indicate that the specimens made from 60% BFS and 40% FMK and activated by (1:1) NaOH and Na2SiO3 were revealed the best overall behaviour.