Title : Development and optimization of locally enhanced burnt clay brick tiles using the rule of mixtures and recycled waste additives
Abstract:
Nigeria’s construction sector is increasingly dependent on imported ceramic and burnt clay brick tiles, with local production meeting only about 11% of national demand, a situation that undermines national self-sufficiency and places significant pressure on foreign exchange reserves. Industry analyses project that tile imports could rise to USD 2.1 billion by 2025, highlighting the heavy reliance on foreign products despite the country’s abundant clay deposits and large volumes of agro-industrial waste such as rice husk ash, sawdust, and waste glass. These waste resources, which often create environmental challenges when improperly disposed of, present viable opportunities for value-added local production if effectively utilized. In this study, burnt clay brick veneer tiles were developed and optimized by incorporating recycled waste additives and applying the Rule of Mixtures as a predictive modeling framework. Clay samples were collected from Anambra and Ogun States, while rice husk ash, sawdust, and waste glass powder were obtained from local industries, processed, and introduced as additive materials. The clay–waste mixtures were molded and fired at standardized temperatures between 900 °C and 1100 °C to produce brick veneer tiles. The Rule of Mixtures was used to estimate mechanical and thermal properties prior to experimental validation, thereby minimizing the trial-and-error approach common in traditional studies. Laboratory tests were performed to evaluate compressive strength according to ASTM C67 standards, as well as bulk density, water absorption, and thermal conductivity, with the results analyzed using ANOVA and regression models to compare predicted and measured performance. The findings revealed that waste glass powder enhanced vitrification and improved compressive strength and durability, rice husk ash increased thermal resistance through its insulating properties, and sawdust reduced density while improving thermal behavior by introducing controlled porosity, though careful optimization was required to maintain strength. Overall, the optimized tile formulations demonstrated superior performance compared to conventional clay tiles and were competitive with imported products, with the added advantage of lower production costs through the use of local materials and waste. A cost–benefit analysis confirmed the economic feasibility of large-scale adoption, while the integration of predictive modeling with sustainable waste valorization offers one of the first systematic frameworks in Nigeria for producing eco-optimized burnt clay brick tiles. These results highlight the potential for reducing import dependence, supporting local industries, promoting environmental sustainability, and advancing the thematic goals of Environment, Housing, and Regional Development.
Keywords: Bricks; Tiles; Clay; Waste; Recycling; Mixtures
