Coordinated adjustment and optimization of setting time, flowability, and mechanical strength for construction 3D printing material derived from solid waste

Construction 3D printing (C3DP), as a green building concept, yields savings in terms of time, material, and labor costs and, hence, has become increasingly popular in recent years. The potential printing materials should have the characteristics of low cost, quick-setting, good flowability, and high mechanical strength. However, these properties are difficult to be obtained simultaneously in material adjustment. In the present study, the coordinated adjustment and optimization of setting time, flowability, and mechanical strength for a sulfoaluminate high-activity material (SHAM) were achieved, and the material was proved to be suitable for C3DP. This material was entirely prepared from industrial solid waste ingredients and thus cost-effective when used in C3DP. Optimal initial setting time (42 min), flowability (180.7 mm), and compressive strength (19.2 MPa and 97.5 MPa for 2-h and 28-d, respectively) were realized. The coordinated adjustment of these three properties was realized through cross changing the ratios of boric acid as a retarder and flowability enhancer and lithium carbonate as an accelerator. Moreover, 3D structures with different shapes were successfully printed using optimized material. This work has opened the way for the use of solid waste to prepare high value-added products and promote green building construction. (C) 2020 Elsevier Ltd. All rights reserved.