Hardened properties of 3D printable ‘One-Part’ Geopolymer for construction applications

Abstract

This paper reports the hardened properties of an extrusion-based 3D printable ‘one-part’ geopolymer for construction applications. To date, all of the 3D printable geopolymers reported in the literature had ‘two-part’ mix formulations, made by using liquid activators. In contrast, the 3D printable geopolymer developed in this study has a ‘one-part’ (just-add-water) mix formulation, made by using a small amount of solid activator instead of the commonly used liquid activators. Handling a small amount of solid activators instead of large quantities of user-hostile liquid activators significantly enhances commercial viability and large-scale application of the 3D printable geopolymers in construction industry. Effects of print-time interval on the inter-layer strength, along with compressive and flexural strengths of the developed 3D printed ‘one-part’ geopolymer in different directions were investigated. Specimens were printed with 2 and 15 min delay times (print-time intervals). Compressive, flexural and inter-layer strengths of the 3D printed ‘one-part’ geopolymer were measured. The results showed that the print-time interval had a significant effect on the inter-layer strength of the 3D printed ‘one-part’ geopolymer. However, the effect of the print-time interval on the compressive and flexural strengths of the 3D printed ‘one-part’ geopolymer was negligible. The results also showed that the compressive and flexural strengths of the 3D printed ‘one-part’ geopolymer depended on the loading direction.