Novel Concrete Mix for 3D Concrete Printing with Special Functions

Rapid modernization of society has accelerated concrete production, making it the second most consumed material on Earth, with an estimated two billion tons being produced each year. Although the use of concrete is booming, several adverse effects of its use have become evident, including its large carbon footprint and the waste it generates. However, deeper investigations have shown that the majority of emissions are from the results of the operational phase of a building through heating and cooling. Another limitation of concrete use in modern construction is that the degree of architectural freedom is restricted to standard geometric structures. To address some of the limitations of conventional concrete construction, the proposed research develops a novel concrete material that possesses better thermal insulation properties, which can decrease energy consumption during the building’s operational phase, and is applicable for 3D concrete printing (3DCP), which removes the need for formwork, increases building design flexibility, and can improve the environmental effect. The proposed 100% expanded perlite aggregate concrete mixture was found to obtain a unit weight of 1,703 kg/m³ and achieve a thermal conductivity reduction percentage of approximately 62% while sustaining a compressive strength of 42 MPa at 28 days. Experimental analysis was conducted to evaluate and tune the proposed material’s printability for 3DCP. Additionally, to investigate the environmental impact of 3DCP compared to conventional concrete construction, a cradle-to-gate life-cycle assessment (LCA) study was done, which highlighted 3DCP ability to decrease negative environmental impacts. Lastly, building energy modeling was utilized to evaluate the environmental impact of the proposed concrete mixture and quantify its energy performance during the building's operational phase. Ultimately, this work's findings support the advancement of 3DCP technology and push for investment in 1) more sustainable, printable concrete material; 2) reinforcement strategies specific to 3DCP; and 3) the adoption of 3DCP as a viable technology for building construction.