Physicochemical and Thermomechanical Performance of Eco-Friendly Unfired Clay-Biopolymer Composite Bricks

Abstract

The rapid growth of the global population, coupled with increasing pollution levels, highlights the urgent need for sustainable and eco-friendly construction materials, such as unfired clay bricks. However, their widespread adoption remains limited due to certain performance drawbacks, particularly in thermal insulation, a critical factor in addressing climate change challenges. In this study, a plant-based waste-derived biopolymer was incorporated into unfired clay bricks to enhance their physicochemical and thermomechanical properties. The biopolymer was added at six different weight fractions (0%, 1%, 3%, 7%, 15%, and 20%) to systematically evaluate its impact on bulk density, porosity, capillary water absorption, thermal conductivity, specific heat capacity, and compressive strength. The results revealed a gradual decrease in porosity as the biopolymer content increased, leading to a 41% improvement in thermal conductivity at 20 wt%. However, the optimal balance between thermal efficiency and compressive strength was achieved at 7 wt% biopolymer; this result has been verified through a combination of experimental methods and modeling. Additionally, TRNSYS simulations confirmed the enhanced thermal performance, demonstrating a 9.74% increase in time lag and a 16% reduction in decrement factor, both of which contribute to optimizing building energy efficiency. Overall, this approach not only helps reduce environmental pollution but also enhances insulation capacity while lowering heating and cooling demands, thereby improving overall building performance. Biopolymer-reinforced unfired clay bricks thus represent a promising solution for advancing a low-carbon and sustainable construction industry, aligning with the United Nations Sustainable Development Goals (SDGs) for climate change mitigation and responsible resource management.