纤维对3D打印混凝土打印性能与力学性能的影响

Effects of Fibers on Printing Performance and Mechanical Properties of 3D Printing Concrete

为了研究纤维掺入对3D打印混凝土(3DPC)性能的影响,通过掺入聚乙烯醇(PVA)、聚丙烯(PP)纤维以及剑麻纤维,探究了纤维对3DPC流变性能、打印性能、力学性能以及孔结构的影响规律。流变性能测试结果表明,3DPC的静态屈服应力与三种纤维的掺量均呈线性上升关系,但纤维对3DPC流变性能的影响程度有所差异。打印性能测试结果表明PVA纤维的掺入会降低3DPC的可挤出性,但能明显提高挤出后混凝土的尺寸均匀性。力学性能与孔结构的测试结果表明,PP纤维对3DPC抗压强度有明显的提升效果,剑麻纤维对3DPC抗折强度有最显著的增强效果,而纤维掺量提高会降低3DPC表观密度,使内部孔隙率增加,从而导致高掺量纤维的增强效果弱于低掺量纤维。

In order to investigate the effects of fiber on the performance of 3D printing concrete(3DPC),the influence of fiber on the rheological properties,printing properties,mechanical properties,and pore structure of 3DPC were studied by adding PVA fiber,PP fiber,and sisal fiber.The result of the rheological property test shows that the static yield stress of 3DPC increases linearly with the content of three kinds of fiber,but the influence of fiber on the rheological property of 3DPC is different.The results of printing performance test indicate that the addition of PVA fiber reduces the extrudability of 3DPC,but it significantly improves the size uniformity of extruded concrete.The test results of mechanical properties and pore structure point out that PP fiber significantly improves the compressive strength of 3DPC,sisal fiber has the most significant strengthening effect on the flexural strength of 3DPC,and the increase of fiber content will reduce the apparent density of 3DPC and increase the internal porosity,resulting in the reinforcement effect of high fiber content is weaker than that of low fiber content.