Comparative feasibility analysis of fly ash bricks, clay bricks and fly ash incorporated clay bricks

Recycling of industrial waste-like fly ash into construction materials is attaining more momentum nowadays towards enhancing the characteristics and performance of materials in terms of strength and durability. This article attempts to present the effect of fly ash inclusion on the properties of bricks by means of a comparative feasibility analysis of fly ash bricks (FB), clay bricks (CB), and fly ash incorporated clay bricks (FC). Twelve brick specimens were made using fly ash (15-100 %), clay (5-25 %), lime (5-30 %), gypsum (2 %), sand (30-50 %), and water in different proportions followed by sun-drying and firing methods for the experiment. Sieve analysis, X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy Dispersive X-ray Fluorescence (EDXRF), Fourier-transform infrared spectroscopy (FTIR), compressive strength, and efflorescence tests were performed to study the properties of brick specimens. Various factors such as the effect of drying, heating temperature, and percentage of ash addition on the bricks were also observed. The laboratory results indicated that out of the above-mentioned three bricks, FB showed better performance than CB and FC. The compressive strength and water absorption values for FB were found in the range of 8.50-12.18 MPa and 10.84-13.11 %, respectively. Thus, based on the experimental observations and results, the mix design FB-3 (25 % fly ash, 20 % lime, 2 % gypsum, 53 % sand) exhibited the optimum compressive strength of 10.25 MPa with a water absorption value of 11.16 %. This mix design can be recommended as a substitute for conventional bricks against aggressive environment contributing immensely towards solid waste management and sustainable development.