Halloysite reinforced 3D-printable geopolymers

This study investigates the role of halloysite nanotube as a mineral-based thixotropic admixture to 3D printable geopolymer mortar. The first part of this paper focuses on the fundamental characterization of the thermal evolution of halloysite at 30-1000 degrees C. In the second part, we show how the calcination and concentration of halloysite influence the fresh and hardened properties of 3D-printable geopolymer mortar. It was found that regardless of thermal treatment, using only 1-2 wt% halloysite can significantly increase the rheological prop-erties and buildability of the mortars without compromising their mechanical strength. However, the setting time of geopolymer only accelerated when highly reactive dehydroxylated halloysite was used. Compared with mold-cast specimens, the mechanical properties of 3D-printed specimens were lower at early ages due to their higher surface dehydration; however, the gap became closer over time.

Automated summary

This study investigates the role of halloysite nanotube as a mineral-based thixotropic admixture to 3D printable geopolymer mortar. The first part of the study focuses on the thermal evolution of halloysite at different temperatures. The second part examines how calcination and concentration of halloysite affect the properties of 3D-printable geopolymer mortar. It was found that the addition of 1-2 wt% halloysite significantly improves the rheological properties and buildability of the mortars without compromising their mechanical strength.