Sustainable Use of Raw Sand Residue in Production of Fired Clay Bricks

The purpose of this study is to assess the feasibility of using mirror and glass industry residues as a partial replacement for clay in clay brick production, with a focus on sustainable and eco-friendly techniques. Clay was mixed with raw sand residue (RSR) in various ratios: 87.5/12.5, 85/15, 82.5/17.5 and 80/20 wt%, extruded with the appropriate amount of moisture, dried at 110 °C and fired at temperatures from 850 to 1050 °C. Extensive analytical techniques, including thermogravimetric analysis, X-ray diffraction (XRD) mineralogical analysis, chemical characterisation using energy-dispersive X-ray analysis (EDX) and X-ray fluorescence (XRF), and scanning electron microscopy (SEM) morphological analysis, were employed to characterise the raw materials. Mechanical and thermal properties of the fired bricks were assessed, encompassing linear shrinkage, apparent porosity, apparent density, water absorption, thermal conductivity, dilatometry analysis, bending strength, compressive strength and freeze–thaw resistance. The results demonstrated that the incorporation of RSR as an additive yielded lightweight bricks with adequate strength, particularly when fired at lower temperatures. Notably, a clay–RSR mixture containing 12.5% RSR and fired at 1050 °C displayed an optimal balance between mechanical performance and porosity, exhibiting a porosity of 13%, an apparent density of 2 g/cm3, a thermal conductivity of 0.55 W/m K, and a compressive strength of 55 MPa. Furthermore, compressive strengths of the RSR replacement bricks ranged from 25 to 45 MPa, indicating the material's potential as a sustainable alternative to reduce clay consumption in brick production. The findings of this study highlight the promising potential of mirror and glass industry residues as an eco-friendly substitute in clay brick production.