膨润土对3D打印砂浆可打印性能的影响  

Effects of Bentonite on Printability of 3D Printing Mortar

作　　者：张翼 朱艳梅 任强 蒋正武[1] ZHANG Yi;ZHU Yanmei;REN Qiang;JIANG Zhengwu(Key Laboratory of Advanced Civil Engineering Materials of Ministry of Education,School of Materials Science and Engineering,Tongji University,Shanghai 201804,China)

机构地区：[1]先进土木工程材料教育部重点实验室,同济大学材料科学与工程学院,上海201804

出　　处：《硅酸盐学报》2022年第2期420-428,共9页Journal of The Chinese Ceramic Society

基　　金：国家重点研发计划项目(2018YFC0705404);国家自然科学基金资助项目(51878480,52078369);中央高校基本科研业务费专项资金资助。

摘　　要：为探明膨润土及其掺量对3D打印砂浆可打印性能的影响规律,采用流动度评价砂浆的可挤出性,并以高度保留率和贯入阻力评价其可堆叠性。此外,采用动态、静态剪切测试浆体的流变行为,从流变学角度分析膨润土对砂浆可打印性能的影响。结果表明:可打印砂浆流动度与净浆的塑性黏度存在良好的线性关系,与动态屈服应力存在良好的对数关系;高度保留率则与静态屈服应力存在良好的指数关系。一方面,膨润土增大了浆体的塑性黏度与动态屈服应力,从而导致砂浆的可挤出性能降低。另一方面,膨润土提高了浆体静态屈服应力和结构重建速率,从而提高砂浆的可堆叠性能。因此,适宜掺量的膨润土可使砂浆保持良好可挤出性,且改善砂浆的可堆叠性。当膨润土掺量2%时,打印试件顶底宽度比为0.96。To ascertain the influences of bentonite and its content on the printability of 3D printing mortar,the extrudability of mortar was evaluated via fluidity,and its buildability was evaluated by height retention rate and penetration resistance.Also,the rheological behavior of cement pastes with bentonite was characterized via dynamic and static shear tests.Effects of bentonite and its content on the printability of mortars were analyzed via rheology.The results show that the fluidity of printable mortars is linearly correlated to the plastic viscosity of cement pastes and logarithmically to the dynamic yield stress of cement pastes.Besides,there is an exponential relationship between the height retention rate of printable mortars and the static yield stress of cement pastes.The addition of bentonite in the mortar increases the plastic viscosity and dynamic yield stress of cement pastes,resulting in a decrease in the extrudability of mortar.Also,the addition of bentonite improves the static yield stress and structural rebuilding rate of cement pastes,thereby improving the buildability of mortar.Therefore,appropriate amount of bentonite can make the mortar maintain good extrudability while improving its buildability.A width ratio between the top and bottom layers of the printed sample with 2%bentonite is 0.96.

关 键 词：膨润土 3D打印 砂浆 流变性能 可挤出性能 可堆叠性能 

分 类 号：TU528.041[建筑科学—建筑技术科学]