Influence of plastic coating temperature on recycled concrete brick coarse aggregate

The generation of waste from the demolition of old structures poses a significant environmental challenge. Recycling these materials as aggregates in concrete offers a potential alleviation of environmental impact. While recycled aggregates offer promise as a remedy, they are not without drawbacks. However, innovative approaches have been developed to overcome these limitations. Among these, plastic coating stands out as a particularly sustainable solution. This study investigates the influence of plastic coating temperature on recycled concrete brick aggregates (RCBA), which serve as coarse aggregates. The RCBA were coated with locally sourced polyethylene terephthalate (PET) at varying temperatures, such as 250 °C, 300 °C, 350 °C, and 400 °C. Then the physical properties of the plastic-coated recycled aggregates (PCRA) were assessed. Additionally, concrete specimens incorporating PCRA were fabricated to evaluate their influence on the mechanical properties of concrete. The results indicate that higher coating temperatures positively influenced the physical properties of the aggregate. Furthermore, at elevated temperatures, the plastic became sufficiently malleable to penetrate deeper into the permeable pores, reinforcing the weak mortar interface and thereby enhancing the mechanical properties of the concrete made with it. Additionally, mathematical models have been proposed to predict the influence of plastic coating temperature on both the physical properties of the RCBA and the mechanical properties of the concrete.