The technology of 3D printing concrete has undergone rapid development in the last few years due to its lower environmental impact than that of conventional concrete. To investigate the fresh and the hardened behavior as well as the microstructure of 3D printing cementitious materials (3DPC) containing nano-CaCO₃ (NC), four replacement ratios of NC to binder from 1 to 4% are investigated. 3DPC without NC was used as a control specimen. The workability, such as fluidity, extrudability, printability limit, and deformation under self-weight, and the flexural and compressive strength of 3DPC are tested. The strength development of 3DPC is compared with that of the cast specimens. The hydration products and the microstructure of specimens were also investigated by derivative thermogravimetry (DTG), thermogravimetry analysis (TGA), scanning electron microscopy (SEM), and backscattered electron (BSE) imaging. The results indicate that the fluidity, extrudability, printability limit, and deformation under self-weight demonstrate a decreasing tendency to increase the NC content. This is attributed to the large specific surface area of NC, which increases the mixtures’ consistency. Adding 2% of NC exhibited about 7.2, 39.1, and 22.5% higher compressive strength than that of the control mixture at 7, 28, and 90 days. The enhancement of strength of 3DPC with NC can be ascribed to the filler effects and the seeding effects of NC. Furthermore, NC refines the pore structure and improves the microstructure of 3DPC due to its filler effects and accelerating effects.

3D打印混凝土技术由于其对环境的影响小于常规混凝土，因此在过去几年中得到了飞速发展。研究含有纳米CaCO ₃的3D打印胶凝材料（3DPC）的新鲜，硬化行为以及微观结构（NC），研究了NC到粘合剂的四个替换比例为1-4％。没有NC的3DPC被用作对照样本。测试了3DPC的可加工性，例如流动性，可挤出性，可印刷性极限和自重下的变形，以及3DPC的抗弯和抗压强度。将3DPC的强度发展与铸件的强度发展进行了比较。还通过导数热重分析（DTG），热重分析（TGA），扫描电子显微镜（SEM）和背散射电子（BSE）成像研究了样品的水合产物和微观结构。结果表明，自重下的流动性，可挤出性，可印刷性极限和变形表现出增加NC含量的下降趋势。这归因于NC的较大比表面积，这增加了混合物的稠度。在第7、28和90天，添加2％的NC的抗压强度比对照混合物高约7.2、39.1和22.5％。NC增强3DPC的强度可归因于NC的填充效应和晶种效应。此外，由于其填充作用和促进作用，NC可改善3DPC的孔结构并改善其微观结构。