Feasibility of Producing Conventional and Lightweight Insulating Bricks Using Water Treatment Plant Clay Residues and Local Waste Materials in Basra, Iraq

This study investigates the physical, chemical, and mineralogical properties of clay deposits in Basrah, southern Iraq, aiming to develop high-performance insulating and lightweight bricks. A total of three representative clay samples were collected from the major sites of the Great Basrah Project, Al-Hartha, and Umm Qaser, and were characterized using grain size distribution, Atterberg limits, X-ray diffraction, and X-ray fluorescence. Bricks were manufactured using different clay-based mixtures with additions of recycled glass (5–15%) and paper waste (2–5%), and the mixtures were fired at 950°C and 1050°C to evaluate the effect of each additive on the final brick properties. The results indicate that each clay source produced different physical and mechanical responses depending on the additive type and firing temperature. The addition of recycled glass, particularly at higher firing temperatures, enhanced density and compressive strength while reducing water absorption, producing Class A bricks in the Great Basrah Project. Al-Hartha mixtures showed satisfied the specification limits, whereas Umm Qaser mixtures showed comparatively lower performance. In contrast, the addition of paper waste increased porosity and reduced density, resulting in lightweight bricks with thermal insulation but lower mechanical strength. Efflorescence decreased at higher firing temperatures in most mixtures. Overall, the results suggest that the examined clay mixtures, when combined with suitable additives and firing conditions, can produce thermally efficient lightweight bricks that comply with Iraqi, American, and British standards.