Feasibility of Using Coal Ash for the Production of Sustainable Bricks

In this research study, environmentally friendly unburnt coal ash (CA) bricks were investigated as an alternative to conventional burnt clay bricks. In this research study, various physical and mechanical properties of unburnt CA bricks were investigated. The unburnt CA bricks were prepared by using 60% CA and 10% lime by weight. In these unburnt CA bricks, varying cement contents (5%, 10%, and 15%), sand contents (10% and 15%), and quarry dust contents (5% and 10%) by weight were used. A forming pressure of 29 MPa was applied through an automatic pressure control system either for 3 s or 6 s. The prepared bricks were moist cured for 28 days. The experimental results exhibited that unburnt CA bricks with 10% cement, 10% sand, and 10% quarry dust subjected to forming pressure for 3 s exhibited the highest compressive strength of 19 MPa and flexural strength of 2.1 MPa. The unburnt CA bricks exhibited reduced water absorption, reduced efflorescence, and lower weight per unit area than the conventional clay bricks. A cost comparison of unburnt CA bricks and clay bricks exhibited that unburnt CA bricks are cost-effective compared to clay bricks.