Study On Preparation Technology Of Cement-Based 3D Printing Permanent Template And Mechanical Properties Of Composite Components

With the development of China's society and economy,under the guidance of relevant national policies,building industrialization has gradually developed in China.The main signs of building industrialization are the standardization of architectural design,the production of components and components,the mechanization of construction and the scientific management of organization.For the production and construction process of complex modeling components in buildings,it is difficult to achieve large-volume on-demand customization and personalized customization.The popular 3D printing technology provides a kind of standardized and personalized production for complex modeling building parts and structural components.Solution ideas,3D printing based on digital model files,using computer automatic control technology,through the layer-by-layer printing method to quickly construct 3D entities,the application of 3D printing technology in the construction industry,can achieve complex customization of complex shapes in the building,complex The styling members are formed by direct printing or printing a permanent template of complex shapes combined with a post-cast combination.This article will use this as a starting point to construct a permanent template of a cylinder using 3D printing technology,and study the mechanical properties of its composite components.The main research work is as follows:1.In order to explore the mix ratio of cement-based materials for 3D printing,27 groups of different mix ratios of cement-based materials were obtained by full-cross variable method with sand-cement ratio,silica fume content and calcium carbonate whisker content as variables.Through the fluidity and rheological tests,the fluidity and rheological indexes of each group of cement-based materials are obtained,and the optimum fluidity index is determined according to the actual 3D printing.The material groups closest to the index are obtained,and the rheological properties are compared to get the best material mix ratio.2.Explore the technology of 3D printing and the preparation of permanent template.The technology of 3D printing consists of three aspects: printing process,code optimization and time parameters.According to the structure and basic operation process of 3D printer,the printing process is obtained.According to the basic composition of 3D printing code,the satisfactory printable effect is obtained by optimizing the height parameters and extrusion parameters through actual printing.By using sulphoaluminate cement instead of Portland cement in material mix ratio,the working time and setting time of cement-based materials are adjusted,and the time parameters in printing process are obtained.By choosing suitable printing materials and 3D printing process based on code and feeding plan,two kinds of permanent cylinder templates are printed according to different rising positions between layers.3.The interlaminar bonding properties of 3D printing products were investigated by tensile,shear and compressive tests,and the integrity of 3D printing products under the "stacking" manufacturing method was evaluated,reflecting the integrity of permanent templates produced by 3D printing.4.The permanent formwork made by 3D printing is filled with traditional building materials to form a composite cylinder.Cast-in-situ cylinders with the same size and reinforcement ratio are set up.The effects of different formwork forming methods and reinforcement ratio on the axial compression performance of the composite cylinder are analyzed through the axial compression test.By comparing cast-in-situ cylindrical members,the difference of axial compression performance between composite cylindrical members and castin-situ cylindrical members is discussed,and the practicability of composite cylindrical members is evaluated.Based on the criterion,the formulas for calculating the bearing capacity of composite columns under axial compression and eccentric normal section are deduced and calculated,and the finite element modeling and analysis of the axial compression and eccentric compression of composite columns are carried out..Based on the above research,the innovation and harvest of this paper are as follows:1.Design and fabrication of 3D printing cement-based materials;2.Detailed the process of 3D printing and the specific parameters of code compilation,and combined with the working time and setting time of materials,developed a 3D printing process with the cooperation of printing materials and printing equipment.Based on this printing process,two permanent templates of cylinders were successfully printed.3.Experiments verify that the 3D printing products have good interlaminar bonding performance,which guarantees the integrity of the permanent template for 3D printing.4.Permanent formwork composite columns have better mechanical properties,which provides experimental basis for the popularization and application of this new type of composite members.