3D printing of geopolymer-based concrete for building applications

PURPOSE: Three-dimensional (3D) printing technology allows geometric complexity and customization with a significant reduction in the structural environmental impact. Nevertheless, it poses a serious threat to the environment when organic binders are used. Binder jet printing of alkali-activated geopolymer precursor can represent a successful and environmental-friendly alternative. DESIGN/METHODOLOGY/APPROACH: The present work reports about the successful 3D printing of metakaolin-based alkali-activated concrete, with dimensional integrity and valuable mechanical behavior. FINDINGS: The geometric behavior was studied as a function of alkali activator flow rate, and the minimum geometric deviation with complete saturation was recorded at 103 mg/s. The printed specimen is characterized by a modulus of rupture as high as 4.4 MPa at 135 mg/s. PRACTICAL IMPLICATIONS: The 3D printed geopolymer-based concrete can be potentially used in a wide range of structural applications from construction to thermal insulation elements. ORIGINALITY/VALUE: The analysis of the 3D geopolymer-based concrete printing system and material conducted in this paper is original.