Enhancing mechanical performance of twin-pipe printable concrete using a binary binder system

Abstract

A twin-pipe pumping (TPP) system has been developed for the set-on-demand purpose of 3D printable concrete, where a static mixer is used to merge two streams (primarily a Portland cement-based mixture and a limestone powder-based mixture) before extrusion. Although the limestone-based suspension works as an accelerator carrier for high mixing efficiency, inert limestone powder would perform as a weak region. To improve the mechanical performance of the final printed element using TPP, the weak limestone-based mixture was replaced by a newly developed calcium sulfoaluminate (CSA) cement-based mixture in this study. Results indicated that the mechanical strength in different loading directions was improved using the PC/CSA system.