固废基硫铝酸盐胶凝材料用于建筑3D打印的特性与过程仿真

为了解决建筑3D打印材料的性能、成本及技术应用等问题，通过以工业固体废弃物为原料制备了硫铝酸盐胶凝基质材料，配以促凝剂、缓凝剂等形成的建筑3D打印粉体，并应用多物理场耦合软件对同一喷嘴结构不同水灰比（W/C）下喷出浆体速度及质量的影响规律进行仿真计算。结果表明：以工业固体废弃物为原料能成功制备达到GB-2007-R525的硫铝酸盐胶凝材料，且经过外加剂改性后凝结时间可控制在10～30 min，2 h抗压强度15～20 MPa，后期强度稳定；水灰比高于0.6，打印浆体出现堆叠、坍塌的现象，影响打印精度及打印构件质量；水灰比低于0.4，喷射浆体会出现拖尾，影响打印速度，最终确定水灰比在0.5附近较适合相应尺寸喷嘴的3D打印应用。

Characteristics of solid-waste-based sulfoaluminate cementitious material being used in 3D printing and process simulation

To obtain high performance, low cost and extend technology application, industrial solid wastes were used to prepare sulfoaluminate cementitious material (SCM), which was then processed into three-dimensional (3D) printing materials by using a suitable accelerator and retarder. Multidiscipline coupled-field analysis was used to determine the influence of slurry velocity and the quality that results from different water-cement ratios with the same nozzle diameter. It was proved that the SCM prepared from industrial solid wastes could meet the national standard GB-2007-R525. After improving their properties, the SCMs exhibit advantages of a controlled setting time of between 10 and 30 min, a rapid hardening and an early stable strength. The hydrated-specimen compressive strength reached 15-20 MPa after 2 h of curing. When the water-cement ratio of the 3D printing-material slurry exceeded 0.6, stacking and collapse phenomena might be resulted. When the water-cement ratio was below 0.4, the jetted slurry showed tailing phenomena that could affect the printing speed. A water-cement ratio of~0.5 with its corresponding nozzle size was most suitable for 3D printing applications.