Selected Test Methods for Assessing Fresh and Plastic-State 3D Concrete Printing Materials

Materials’ requirements for 3D concrete printing centre around printability and buildability. The concrete must be pumpable, extrudable, yet retain its shape after extrusion (fresh state) and stack over each other without yielding and buckling failure (plastic state). The nature of 3D printed concrete materials has driven research into adapting various test methods to assess these requirements. This study reports selected test methods evaluated for 3DCP in its fresh and plastic state – rheometry, unconfined compression tests, gravity-driven (slug) tests and slow penetration tests. The study further highlights their correlations, applications, and practicality for the two main types of printable materials – enhanced-thixotropic and accelerated-hydration concrete.