A Critical Review on the Utilization of Fly Ash in the Production of Bricks

Abstract

The increasing demand of power supply worldwide requires setting up of more and more thermal power plants. But the wastes produced from these power plants are posing major challenges of their disposal. One such residue is fly ash, which is posing major difficulty in the form of accumulation which requires a huge land area for their disposal. For environmental safety and sustainable growth, extensive studies are being carried out on better consumption of fly ash for production of different construction materials like mortar, concrete, brick or blocks, etc. This study is an up-to-date review of earlier studies on use of fly ash in brick making which can be used for construction purposes. Bricks produced using cement/lime as binder and geopolymer technique have been considered. Compressive strength of the fly ash-based bricks produced by different researchers was studied. Durability properties including water absorption and efflorescence have also been discussed. It is found that the highest compressive strength of 27 MPa is achieved when class C fly ash, sand and 10 mm aggregate are used with cement as binder. Water absorption as low as 3–4% with slight efflorescence is found when bricks are produced using casting pressure with cement/lime as binder. In case of geopolymer bricks, the highest compressive strength of 70 MPa is obtained when 12 M sodium hydroxide is used followed by temperature curing of 60 °C for 24 h. The lowest water absorption of bricks developed by geopolymerization is found to be 3.5% when fly ash and highly alkaline activator without any filler material are used. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.