化学外加剂对3D打印水泥基材料抗冻性的影响

为探究3D打印成型水泥基材料的抗冻耐久性，制备了不同外加剂掺量的水泥基3D打印试件，通过加速冻融试验研究3D打印试件的质量损失和动弹性模量变化。结果表明，随着速凝剂掺量的增加，水泥基材料3D打印试件的质量损失增大，相对动弹性模量降低，抗冻耐久性变差。引气剂的加入可以减轻但无法完全阻止3D打印试件的表面剥落破坏，且未能明显减轻试件的内部损伤。随着增稠剂掺量的增加，3D打印试件的表面剥落量增大，相对动弹性模量的降低速率减缓，试件的内部损伤有所减轻。本研究对于3D打印水泥基材料用化学外加剂的选择、油墨材料组成设计及3D打印制品的服役性能评价均具有一定的指导意义。

The influence of chemical admixture on the frost resistance of 3D printed cement-based materials

In order to study the frost-resistant durability of 3D printed cement-based materials, 3D printed cement-based specimens with different dosage of chemical admixture are prepared. Weight loss and dynamic elastic modulus are studied by accelerated freeze-thaw test. The results show that the weight loss of 3D printed specimens increases with the increase of accelerator dosage, while relative dynamic elastic modulus decrease and frost-resistant durability deteriorates. The weight loss decreases with the presence of air entraining agent. But the presence of air entraining agent cannot completely prevent the surface spalling failure of 3D printed specimen, and does not significantly reduce the internal damage of 3D printed specimen. The weight loss increases and relative dynamic elastic modulus decreases with the increase of thickening agent dosage. The addition of thickening agent helps to release the internal damage of 3D printed specimen. This study has guiding significance for the selection of chemical admixture for 3D printing of cement-based materials, the designing of ink materials composition and the evaluation of service life of 3D printed products.