Abstract

The construction industry’s heavy reliance on conventional burnt clay bricks has caused serious environmental degradation, including topsoil depletion, high energy consumption, and substantial greenhouse gas emissions. This paper provides a comprehensive review and analysis of compact green sand bricks that incorporate fly ash—an industrial by product of coal fired thermal power plants—as a sustainable alternative. The study synthesises findings from recent experimental investigations into fly ash–cement–sand composite bricks, examining their mechanical properties, durability characteristics, and environmental performance. Results from multiple studies indicate that optimised fly ash–sand brick mixes can achieve compressive strengths ranging from 9.13 MPa to 28 MPa, with water absorption values below 20 % and negligible efflorescence [1, 7]. Life cycle assessment studies demonstrate that fly ash bricks can reduce carbon dioxide equivalent emissions by over 80 % compared with conventional sand block manufacturing [4]. The pozzolanic reactivity of fly ash, combined with appropriate curing regimes—particularly steam curing—enhances early age strength development and microstructural densification [1, 12]. This paper concludes that compact green sand bricks with fly ash represent a technically viable, economically attractive, and environmentally superior alternative to traditional clay bricks, thereby contributing to circular economy principles in the construction sector