Comprehensive Durability and Environmental Benefits of Recycled Brick Powder Concrete after Long-Term Curing
Abstract
Waste bricks from construction demolition occupy a large amount of land and cannot be effectively utilized as resources. Processing them into powder for use as a cement substitute can effectively reduce carbon emissions and dispose of solid waste. This study assessed how recycled brick powder (RBP) particle size and replacement rate impact concrete’s fundamental mechanical properties, and explained the reaction process of RBP in combination with microscopic analysis. Freeze–thaw cycling, sulfate exposure, elevated temperatures, and natural carbonation were investigated to assess RBP’s role in concrete durability. A life-cycle assessment (LCA) of the recycled brick powder concrete (RBPC) production process was conducted to evaluate its environmental benefits. Results indicate RBPC’s compressive and tensile strengths decline with increasing replacement rate and particle size, and increase with the extension of curing age. When the replacement rate of fine RBP was 5%, the concrete exhibited improved durability, including enhanced freeze–thaw resistance (10.05% increase in compressive strength), sulfate resistance (8% increase in compressive strength), high-temperature resistance (90.79% strength retention after exposure to 400°C), and carbonation resistance (45.8% reduction in carbonation depth). Higher replacement rates led to a deterioration in durability. RBP significantly reduced the environmental impacts of concrete production, showing an almost linear decrease with increasing replacement rate: for every 5% increase, the carbon emissions, energy consumption, and environmental cost per cubic meter of concrete were reduced by approximately 21.68 kg, 74.85 MJ, and USD 3.01, respectively. Concrete with 5% RBP replacement rate showed the highest comprehensive mechanical–environmental benefits. This research delivers theoretical guidance that supports the prolonged and practical utilization of RBP in engineering applications.