水泥基3D打印材料基础配合比试验与质量评价

Basic mix ratio test and corresponding quality evaluation for cement-based 3D printing materials

水泥3D打印技术在土木建造工程和类岩石力学行为模拟中日渐推广,其水泥基3D打印材料方面却一直面临流动性、收缩性、可加工性等质量与成型控制方面的挑战和基础性配方缺乏的不足。首先针对水泥基3D打印实体质量评价的问题,建立了一套考虑成型全过程的6指标评估体系及其质量分级方法,包括流动性、挤出性、凝结时间、可建造性、密实性以及变形率,从打印过程、堆积成型、实体精度三方面实现对3D打印实体模型的质量评价;进而采用不同阈值范围的两阶段正交设计与打印测试进行了水泥基3D打印材料的基础性配合比试验优选,获得了一种综合打印性能较好的基础性配合比;最后对其打印成型水泥基3D实体模型进行单轴压缩试验,并评估了其类岩石力学特性,从而得到一种新型的类岩石水泥基3D打印基础性配合比,可为采用水泥基3D打印材料的工程建造和岩石工程物理模拟试验奠定基础。

Cement-based 3D printing technology is increasingly popularized in civil construction and rock-like physical simulation,yet its cement-based 3D printing materials not only is limited by the challenges in quality control such as liquidity,shrinkage,and processability,but also is lack in basic formula in concrete material.This paper firstly establishes a set of assessing system based on six indexes and corresponding quality classification method considering the whole process of solid model forming for cement-based 3D printing,including fluidity,extrusion,setting time,buildability,compactness and deformation rate.The quality evaluation of the 3D printing solid model is realized in three aspects:printing process,stacking process,and solid accuracy.Then,through the two-stage orthogonal design and printing test with different threshold ranges,the basic mix ratio of cement-based 3D printing materials,which is ideal in comprehensive printing performance,is obtained.Finally,the uniaxial compression test is carried out for the printed cement-based 3D solid model and its rock-like mechanical properties are evaluated,which can provide a new type of rock-like cement-based 3D printing material.The specific mix ratios lay the foundation for the civil construction and physical simulation test of rock engineering based on cement-based materials.