A ROOM TEMPERATURE CURED FLY ASH BSED GEOPOLYMER COMPOSITION FOR CONCREATE AND BUILDING MATERIALS AND A PROCESS THEREOF

摘要

In the present invention there is disclosed a room temperature cured fly ash based geopolymer composition .for concrete and building materials and a process for manufacturing the same, wherein the mix comprising composite binder of fly ash and ground granulated blast furnace slag (18-20% by weight), activating solution (7-8% by weight) of sodium silicate and recycled sodium hydroxide/sodium carbonate, chemical admixtures (0.18-0.20% by weight), aggregates (71-74.5% by weight) and polycarboxylate based superplasticizer (0.3-0.8% by weight). Optionally, industrial grade sodium hydroxide is used as a part of activating solution. In the process of the present invention, preheated low calcium fly ash and ground granulated blast furnace slag are inter-grind in a ball mill to obtain a composite mix binder, preparing the activating solution consisting of silicate, hydroxide and carbonate wherein carbonate and silicate used in a ratio of 1.5-2.51 and silicate and hydroxide used in a ratio of 1- 3: 1, mixing the activating solution containing superplasticizer with dry concrete ingredients consisting of composite mix binder, fine and coarse aggregate in a pan mixer and adding chemical admixture at the final stage of mixing. The doughymix so obtained is then cast in the mould and cured at ambient temperature. Various products such as solid and hollow blocks, bricks and structural beam elements are made out of present invented geopolyrner mortar and concrete. The salient. features of invented geopolymer concrete are: high early strength, low drying shrinkage, low permeability, low water absorption, low thermal conductivity and good chemical and fire resistance. The products made out of the present invention meet the existing specifications/guidelines and comparable with cement concrete and burnt clay/fly ash bricks.