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3D打印水泥基材料层间结合性能研究
作者：吴昊一，蒋亚清，潘亭宏，王玉
（河海大学 力学与材料学院，江苏 南京 211100）
摘要：为研究冷缝对3D打印水泥基材料（3DPC）层间结合性能的影响及层间冷缝形成机制，采用直接拉伸试验评价了3DPC的层间结合性能，并运用近场动力学方法模拟了3DPC层间冷缝扩展过程。试验结果表明：上层打印时间小于水泥水化诱导期起点时间时，层间无冷缝出现，上层打印时间、纳米黏土掺量对层间结合强度影响较小；上层打印时间达到水泥水化诱导期后，随层间循环时间的延长，层间冷缝数量、连续程度和长度增加，层间结合强度降低，掺加纳米黏土可显著提高层间结合性能。通过控制上层打印时间、掺加纳米黏土可保证3DPC层间膜层具有合适的相对湿度，防止层间冷缝的形成，提高打印层间结合性能。
关键词：3D打印；层间结合性能；近场动力学；冷缝
中图分类号：TU528 文献标识码：A 文章编号：1001-702X（2019）12-0005-04
Interlayer bonding property of a 3D printing cementitious material
WU Haoyi，JIANG Yaqing，PAN Tinghong，WANG Yu
（School of Mechanics and Materials，Hohai University，Nanjing 211100，China）
Abstract：In order to analyze the effect of cold joints on the interlayer bonding property of 3DPC and the formation mechanism of interlayer cold joints，the interlayer bonding property of a 3D printing cementitious material（3DPC） was evaluated by dir-
ect tensile test，and the process of interlayer cold joints extension of 3DPC was simulated by near field dynamic method. The results indicate that there is no cold joint between printed layers when the printing time of the upper layer is less than the starting time of the hydration induction period of cement，and the upper layer printing time and dosage of nano-clay have little effect on the interlayer bonding strength. After the upper layer printing time exceeds the starting time of cement hydration induction period，the number，continuity and length of interlayer cold joints increase with the prolongation of interlayer cycle time，and the interlayer bonding strength decreases，but the interlayer bonding strength can be significantly improved by adding nano-clay. The cold joint of 3DPC can be prevented and the interlayer bonding can be enhanced by controlling the upper layer printing time and by adding nano-clay to ensure proper relative humidity between 3DPC interlayer.
Key words：3D printing，interlayer bonding property，near field dynamics，cold joint