| 摘要: |
| 为了揭示3D打印挤出形状和尺寸对成型混凝土性能的影响机制，对比了模具成型、同挤出流量条件下不同挤出形状（三角形、方形和圆形）成型、同挤出形状条件下不同挤出尺寸成型、同挤出形状和同尺寸下不同打印条排列成型的混凝土断面形态、力学性能和空间孔隙分布，分析了不同挤出形状和尺寸条件下打印试件的层/条缺陷特征，探讨了打印试件孔隙率与其力学性能的对应关系.结果表明：层间和条间缺陷会显著影响打印试件的密实度，在同挤出流量条件下，由于层/条间的压紧作用，挤出形状呈三角形的打印试件具有最少的层间缺陷和最佳的力学性能；同形状的打印试件随着挤出尺寸的增大,其缺陷降低、力学性能提高；在挤出形状和尺寸均不变的情况下，打印口交错排列可提升打印试件力学性能13%～47%. |
| 关键词: 3D打印 水泥基复合材料 挤出形状 挤出尺寸 孔隙分布 |
| DOI：103969/j.issn.1007 9629202006008 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目（52079123） |
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| Influence of Extruded Strip Shape and Dimension on theMechanical Properties of 3D Printed Concrete |
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SUN Xiaoyan1, LE Kaidi2, WANG Hailong1, ZHANG Zhicheng1, CHEN Long1
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1.College of Architecture Engineering, Zhejiang University, Hangzhou 310058, China;2.Zhongjun Group Southeast Regional Company, Shanghai 201805, China
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| Abstract: |
| To figure out the influence mechanism of extruded strip shape and dimension on the performance of 3D printed concrete, the strip shapes of triangle, square and circle at the same extrusion flow rate, the extrusion diameter, and the printing arrangement using a same shape were typically selected to compare with the mold forming specimens on the fracture surface, mechanical performance and the spatial pores distribution. The characteristics of layer/strip defects in printed specimens at different shapes and dimensions of extruded strip were analyzed in detail and the spatial distribution of pores was discussed, the relationship between porosity and mechanical properties was clarified. The experimental results indicate that the compactness of printed concrete is mainly determined by the intersectional defects between layers and strips. At the same extrusion flow rate, the specimen stacked with triangle extrusion strip achieve the lowest porosity and the best mechanical properties. With the increasing dimension of extruded strip, the defects in printed concrete is decreased, resulting in an increase of mechanical property. At the same shape and size, the strengths of printed concrete can be improved by 13%47% due to the dislocation arrangement of upper and lower strips. |
| Key words: 3D printing cement based composite extruded strip shape extruded strip dimension pore distribution |
