3D打印水泥基材料的建造性研究

Research on Buildability of 3D Printing Cementitious Materials

通过塑性强度、静态屈服应力和跳桌流动度的经时变化试验,研究了纳米黏土与减水剂协同作用对3D打印水泥基材料(3DPC)建造性的影响,并以流变性能为参考依据,建立了3DPC建造性的评价指标。结果表明,复掺纳米黏土和增黏型聚羧酸减水剂的3DPC经时塑性强度和经时静态屈服应力均随纳米黏土掺量增加而提高,纳米黏土的适宜掺量为0.8%;当静态屈服应力时变速率为2.0~4.2 Pa/s时,可实现3DPC的挤出性与建造性的协同;在可打印、可建造窗口时间内,3DPC的跳桌流动度为170~190 mm。掺用纳米黏土和增黏型聚羧酸减水剂对3DPC的流变参数进行调控是提高3DPC建造性的有效途径。

Buildability is an important performance parameter of 3D printing cementitious materials(3DPC). Effect of nano-clay and viscosity modifying polycarboxylate superplasticizer(VPCE) on buildability of 3DPC was investigated by testing time dependent green strength, static yield stress and flow table. Indexes for evaluation the buildability of 3DPC were established based on the reference of rheological parameter. Experimental results show that both green strength and static yield stress of VPCE dispersed 3DPC increase with increase of nano-clay dosage, and the suitable dosage of nanoclay is 0.8%. Synergy between extruderability and buildability can be realized when the static yield stress retention rate equals 2.0~4.2 Pa/s. During print window time, flow table value of 3DPC is 170~190 mm. It is an effective way to improve the buildability of 3DPC by rheology modifying technique based on nano-clay and VPCE.