Enhancing the durability of concrete with construction and demolition waste aggregate through its functionalization with phase change materials (paraffin)

Incorporating construction and demolition waste aggregate (DW) into concrete addresses environmental concerns by reducing the demand for virgin materials and diverting waste from landfills. However, the high porosity of DW negatively impacts the durability of concrete. In this work, DW was functionalized by impregnating it with paraffin to fill its inherent pores. Additionally, the phase change characteristics of paraffin were utilized to partially infiltrate the interfacial transition zone pores, thereby minimizing the connected porosity within the concrete. This work focuses on the durability of concrete containing DW and functionalized DW, examining factors such as chloride ion penetration, sulfate magnesium attack, freeze-thaw cycles, and carbonation resistance. The findings reveal that concrete with 100 % functionalized DW achieved a 31.5 % improvement in durability, exhibited zero carbonation depth, and demonstrated excellent resistance to freeze-thaw cycles, highlighting the effectiveness of this approach in enhancing concrete performance.