The Effect of U-Type Expanding Agent for Concrete (UEA) on the Microstructural and Mechanical Properties of Mortar Fabricated Through Alternate 3D Printing

In this paper, we proposed an alternative 3D printing process for construction materials based on the idea of upgrading from “black and white printing” (printing from one material) to “color printing” (printing from multiple alternative materials). The plan was to reduce the amount of energy-intensive and polluting construction materials (e.g., cement) and use a combination of industrial solid waste and cement to build structures that meet safe service requirements. Two different alternative materials of alkali-activated slag and conventional cement were used, and it was found that column-by-column printing was beneficial to refine the interface, resulting in better flexural strength. After establishing the feasibility of the alternative printing, the architectural alternative 3D printing device was designed and fabricated, and the effect of u-type expanding agent for concrete (UEA) on the performance of the alternatively printed products was evaluated. It was found that 2% by mass of UEA would create an interlocking structure, which was beneficial for strength enhancement. The study contributed to the advancement of alternative 3D printing technology.