Performance evaluation of fly ash-lime-gypsum-quarry dust (FALGQ) bricks for sustainable construction

Abstract The aim of this study is to optimize fly ash utilization by combining lime, gypsum, and quarry dust in various proportions to develop fly ash lime gypsum quarry dust (FLGQ) bricks with dimensions of 230 mm × 110 mm × 70 mm, as a potential alternative to traditional bricks. The investigation analysed the compressive strength, split tensile strength, water absorption, density, and initial rate of absorption of FLGQ bricks across different mixes. Mix 9 (M ₉ ), comprising of 35% fly ash, 10% lime, 25% gypsum, and 30% quarry dust, exhibited a 15% higher compressive strength (7.2 MPa) and 12% higher split tensile strength (0.85 MPa) compared to the superior conventional brick. Water absorption for M ₉ was reduced by 18%, enhancing the durability. Prediction models for compressive and split tensile strengths were developed using regression analysis, achieving over 92% accuracy when compared to experimental data at 28 and 56 days. Additionally, a positive correlation was observed between the 14th, 28th, and 56th days results, reinforcing the reliability of predictions in brick compressive strength. These research findings indicate that M ₉ is superior and more sustainable alternative to traditional bricks, with significant improvements in key performance metrics.