Successful implementation of extrusion-based 3D printing (3DP) of concrete requires knowledge of material flow behavior during pumping and extrusion and its influence on shape stability of printed elements. Limited emphasis exists on flow behavior and process-induced variations in material properties (rheology and composition) during printing. This paper delineates the effect of flow behavior and process-induced variations on shape stability. A comprehensive review of material flow behavior during pumping and extrusion is discussed, and its influence on shape stability of 3DP elements is highlighted. The extent of shearing in print material is shown to govern process-induced variations during pumping and extrusion. During extrusion, the degree of filtration and consolidation plays a significant role on shape stability. Accurate assessment of process-induced changes in material properties is required to ensure steady and continuous flow of material during 3DP and secure proper shape stability of printed elements.

成功实施混凝土的基于挤压的3D打印（3DP），需要了解泵送和挤压过程中的材料流动行为及其对印刷元件形状稳定性的影响。在印刷过程中，对流动行为和材料特性（流变学和组成）的过程引起的变化的关注有限。本文描述了流动行为和过程引起的变化对形状稳定性的影响。讨论了泵送和挤出过程中材料流动行为的全面综述，并重点介绍了其对3DP元件形状稳定性的影响。显示出印刷材料中的剪切程度决定了泵送和挤出过程中过程引起的变化。在挤出过程中，过滤和固结程度对形状稳定性起重要作用。