This study presents a comprehensive investigation into the feasibility of incorporating Ceramic Fines (CF), a calcium-rich industrial byproduct from the cement manufacturing process, as a partial replacement for Ordinary Portland Cement (OPC) in the production of fly ash-based interlocking bricks. CF was substituted at incremental levels ranging from 0% to 20%, and its influence on the physical, mechanical, and durability properties of the bricks was systematically evaluated. The results indicate that 10% replacement of OPC with CF yields optimal performance, achieving a peak 28-day compressive strength of 11.72 MPa. A substantial reduction in bulk density, upto 13.36%, was observed with increasing CF content, indicating the potential for lightweight applications. Water absorption exhibited a strong inverse correlation with weight density and a decrease in the initial rate of absorption further confirmed the refinement of pore structure. Durability studies under prolonged seawater and sodium chloride immersion demonstrated superior chemical resistance, with minimal weight gain and strength degradation in CF specimens.XRD Analysis revealed dominant hexagonal crystalline phases, contributing to enhanced matrix stability and reduced ion permeability. The findings substantiate the viability of Ceramic Fines as a sustainable supplementary cementations material, promoting circular economy principles while enhancing the performance and durability of interlocking masonry units.

Keywords: Ceramic fines, Fly ash, Interlocking brick, Durability, Sustainability.