An overview of geopolymers derived from industrial by-products

Large amount of industrial wastes are being released from various industries like power generation industry, iron making industry, steel making industry, mining industry, etc. These wastes like fly ash, bottom ash, blast furnace slag, metakaolin, etc poses various difficulties in their disposal. To overcome these waste management issues, the best solution is to utilize these waste products for some other applications. On the other hand cement industry have been found to be highly energy intensive industry acting as a major source for carbon dioxide emission leading to some serious environmental hazards like global warming, however, due to the need of high infrastructure the use of cement is unavoidable. Therefore, the approach can be to find the best alternative of the conventional Ordinary Portland Cement concrete which can provide better or comparable strength and durability properties and is economical and easy to prepare. The intense amount of work on geopolymeric binders derived from these industrial by-products have proved its utility having similar strength and durability properties that of conventional concrete. This alkali source provider, in the presence of alkaline medium forms geopolymerization products, that have comparable or even better characteristics than Calcium-Silicate-Hydrate products of conventional concrete. This paper presents a concise review of various studies that have indicated the utilization of various industrial waste products in the synthesis of geopolymers. It has been observed from the studies that various industrial by-products such as fly ash, bottom ash, metakaolin, volcanic ash, etc. can be used effectively as source material for geopolymerization. Also despite of comparable properties to cement concrete the limitations that are resisting the use of geopolymers in actual industrial applications are also discussed. (C) 2016 Elsevier Ltd. All rights reserved.