摘要
混凝土3D打印具有灵活、低碳、快速等建造优势。无模堆叠的增材建造过程对材料超早期力学性质具有严格的要求,3D打印的稳定建造需满足材料、工艺、结构三者间的优化协调。3D打印结构常因材料刚度发展与建造速率的不协调而发生坍塌失稳的现象。本文测试了3D打印水泥基材料的水分蒸发速率、凝结时间以及流变特性等参数,明确了基于流变静态屈服应力的3D打印建造失稳判别条件,并试验验证了所提方法的可行性和有效性。本文的所述方法和思路,可有效地提高3D打印的可控性和可预测性。
3D concrete printing is featured by the advantages of flexibility,low carbon and fast etc.in construction activities.Mouldless stable stacking processes has strict requirements on the workability of fresh concrete materials at early ages,meanwhile,the optimization and coordination among materials,processes and structures are required to ensure the stable construction.3D printed structures often collapse and lose stability due to the inconsistent between the development of material stiffness and the construction climbing rate.Currently,there is still lack of reasonable prediction and evaluation method on this issue.It proposes an instability prediction criterion for 3D printing by taking the dynamic yield stress into account.The feasibility and effectiveness of the proposed method are verified by experimentally testing the relevant physical and mechanical parameters of 3D printing materials,such as water evaporation rate,early stiffness evolution law and rheological characteristics,etc.The described methods and ideas contribute to improving the controllability and predictability of 3D printing.
作者
张心颖
王里
冯舵
马国伟
ZHANG Xinying;WANG Li;FENG Duo;MA Guowei(School of Civil and Transportation Engineering,Hebei University of Technology,Tianjin 300401,China;Tianjin Key Laboratory of Prefabricated Building and Intelligent Construction,Tianjin 300401,China)
出处
《混凝土》
CAS
北大核心
2021年第7期38-42,共5页
Concrete
基金
国家自然科学基金(51808183)
河北省引进留学人员项目资助(C20190327)。
关键词
混凝土3D打印
建造失稳
早期刚度
流变性
3D printing of concrete
construction instability
early stiffness
rheology
