3D打印水泥基材料工作性分析与表征

ANALYSIS AND CHARACTERIZATION OF 3D PRINTING CEMENT-BASED MATERIALS WORKABILITY

3D打印水泥基材料的工作性关系到原材料输送、挤出和堆积工艺的难易和效果,还会影响到硬化后制品的外观质量、强度和耐久性能,是材料设计过程中必须考虑的重要性能。本文结合打印工艺流程和要求,分析了3D打印各工艺阶段中水泥基材料工作性特点,提出了3D打印水泥基材料工作性表征主要包括流动性、堆积性和触变性三个方面。按照现有水泥基材料工作性评价方法进行了相关试验,并讨论了这些试验方法用于表征3D打印水泥基材料工作性的适用性。结果表明把砂浆稠度法和胶砂流动度法相结合使用,利用胶砂流动度、砂浆稠度值、振动触变度可以全面评价3D打印水泥基材料工作性;流变试验获得屈服应力、粘度和触变环面积,也可以较为全面地表征3D打印水泥基材料工作性。

3D printing cement-based materials workability is related to the effect of raw materials feeding,extrusion and accumulation,and moreover,it also has a great effect on the appearance quality,strength and durability of the hardened products.So workability of 3D printing cement-based materials is a major property that must be considered in the process of material design.In this paper,based on the 3D printing process and requirements,cement-based materials workability in each stages of 3D printing process is analyzed,and the characterization of the 3D printing cement-based materials workability is presented as flowability,buildability and thixotropy.The applicability of Chinese national standard test methods to the workability characterization of 3D printing cement-based materials is discussed through a series of tests.The results show that the parameters such as fluidity of mortar,consistency of mortar and vibration thixotropy obtained by standard test methods can well characterize the 3D printing ce原ment-based materials workability.And the parameters such as yield stress,viscosity and thixotropy loop area obtained by the rheological test can also well characterize the 3D printing cement-based materials workability.