Manufacture of geopolymer fly ash bricks using class C fly ash
Fly ash is a thermal waste of coal firing thermal plants and its accumulation near power plants causes severe pollution problems. Therefore, its utilization as a raw material for brick making will be a very beneficial solution in terms of economical and environmental aspects which in case also reduces the use of clay brick that costs the nation heavily losing valuable top soil. Alonely usage of this thermal waste in brick production causes difficulties in early strength development, limiting their use to certain applications. Geopolymerization whereas makes full use of fly ash by using them as key reactants in synthesis of aluminosilicate gel binders in brick production. Geopolymers can be synthesized by mixing aluminosilicate reactive materials (Class C Fly ash) in strong alkaline solutions (Mixture of Sodium silicate and Sodium hydroxide). In this experimental investigation, fly ash geopolymeric bricks (230x110x75mm) were produced by dry hot oven curing at 60ᵒC for 24 hours. The compressive strength of these bricks were determined at the ages of one day. Test results have revealed that the compression strength values of these bricks ranged between 5 and 15Mpa with low water absorption. Since cement is hardly used, these bricks were produced at affordable cost with reduction in emission of carbon dioxide. Hence these bricks are ecofriendly and does not involve in global warming.