碳酸锂对3D打印水泥基材料早期性能影响研究

Influence of lithium carbonate on early age behaviour of 3D printing cement-based materials

3D打印水泥基材料需要良好的形状保持能力,早期性能的发展对3D打印水泥基材料的配合比设计与优化调控至关重要。研究了碳酸锂掺量对3D打印水泥基材料流变特性、湿胚强度、可建造性的影响规律。研究发现:碳酸锂的加入使得砂浆湿胚强度和静态屈服应力呈现指数级增长,随着碳酸锂的掺量达到2‰、3.5‰、5‰,其初凝时间分别为94、62、39 min;龄期为10 min时碳酸锂掺量为5‰砂浆的静态屈服应力值是未掺入碳酸锂的4倍;碳酸锂掺量为0、2‰、3.5‰、5‰的打印层数分别为26、22、28、32层。当静态屈服应力值达到3544 Pa,砂浆的挤出性变差对可建造性造成了负面影响,底层砂浆强度的快速发展则能够提高可建造性。

3D printing mortar requires good shape retention ability,while early strength development is crucial to the mix ratio design and optimization control of 3D printing mortar.The influence of the content of lithium carbonate on the rheological properties,wet embryo strength and constructability of 3D printing cement-based materials was studied.The results show that the addition of lithium carbonate makes the early strength and static yield stress of the mortar increase exponentially.As the content of lithium carbonate reaches 2‰,3.5‰,and 5‰,the initial setting time is 94,62,39 min.The static yield stress of the mortar with a lithium carbonate content of 5‰is 2.5 times that of no lithium carbonate when the age is 10 minutes.The number of printed layers with a lithium carbonate content of 0,2‰,3.5‰,and 5‰is 26 layers,22 layers,28 layers,32 layers.When the static yield stress reaches 3544 Pa,the deterioration of the mortar′s extrudability has a negative impact on the buildability,and the rapid development of the strength of the underlying mortar can improve the buildability.