Energy efficient sustainable concrete for multifunctional applications

There is continuous pressure on sustainable multifunctional concrete production to prevent environmental degradation severity. This material must exhibit improved mechanical performance and durability and comprise functionalities that comply with multiple benefits to fit well for structural applications. Concrete is commonly repurposed — crushed in waste concrete to form recycled aggregate (RCA), which can then be used to produce sustainable fresh concrete for low-grade applications. An innovative phase change materials (PCM) with calcium carbonate (CaCO3) reinforced-RCA (CaCO3-PCM-RCA) is prepared by immersion and injecting carbon dioxide techniques for improving its energy-efficient thermal performance. This paper examines the effect of PCM with CaCO3 on the multifunctional properties of CaCO3-PCM-RCA concrete composite with 100% RCA replacement. The synergistic effect of PCM and CaCO3 shows an unprecedented range of improved properties of RCA concrete composite compared to standard RCA concrete. These encompass an increase of 38.3% in compressive strength, excellent modulus of toughness, low energy loss coefficient, and durability while simultaneously an exceptional thermal capacity is found compared to standard RCA concrete. A dramatic reduction in water permeability by 61.3% compared to standard RCA concrete allows this unique composite material to be ideal for building applications in areas subject to flooding. By replacing virgin coarse aggregate with CaCO3-PCM-RCA composite, concrete could be found as a sustainable multifunctional material in the construction industry. •A novel CaCO3-PCM-RCA composite material is developed by immersion followed by carbonation techniques.•Multifunctional RCA concrete is developed for energy-efficient building applications.•The CaCO3-PCM-RCA concrete showed an improved compressive strength and thermal storage capacity.•Incorporating PCM and CaCO3 contributes to the water penetration resistance of RCA concrete.•The CaCO3-PCM-RCA concrete offers a new approach to developing future cooling and heating solutions for buildings to support net zero emissions in the future.