Microstructure of Geopolymerized Building Brick Under Atmospheric Curing

This research work has been carried out to tailor the development of different type of microstructure in geopolymerized fly ash building brick. During the experimental, work alkaline activator containing both soluble sodium silicates (1:1 solution) and sodium hydroxide (1:1 solution) in presence of anions has been used to improve the reactivity of fly ash. Fly ash and alkaline activator in different weight % are mixed on 100 kg scale followed by water for preparation of the wet mix. Then the wet mixture has been used in casting of brick (230X75X11mm size) by hydraulic press applying 15-20 ton of compaction pressure and then shifted for atmospheric curing at 35oC. Compressive strength, and microstructure of the bricks have been investigated. The raw mix consisting of 87% of fly ash and alkaline activator has been used by maintaining Na2O/(Al2O3+SiO2) ratio of 0.025 to 0.038 to manufacture building materials ranging in crushing strength of 6 to 12 MPa. The structural changes, i.e. crystalline structure of geopolymerized building brick under the scanning electron micrograph have been observed.