Study On Optimization Method Of Volume Stability Performance Of 3D Printing Components Of Cement-based Materials

3D printing construction technology,which combines 3D printing technology with traditional construction industry,has become the key technology to promote the transformation and upgrading of traditional construction industry and realize intelligent construction.Cement-based materials are the most commonly used materials in construction industry.Using cement-based materials for 3D printing is the main research direction in the industry,and researchers have made large quantities of breakthroughs in recent years.However,in the research of 3D printing components of cement-based materials,it is always a difficult problem to control the volume stability performance of components.Control to the volume stability performance of cement-based 3D printing components includes control to deformation during printing and stacking,and shrinkage regulation after setting and hardening.Meanwhile,the influence factors of components deformation were analyzed,and the theoretical model of deformation control was put forward.After analyzing material mixture ratio to control the shrinkage,the regulation scheme of shrinkage was proposed.Finally,the material experiments and printing experiments were designed to control and optimize the volume stability performance of components.In this thesis,the theoretical model of deformation control in the 3D printing stacking process was proposed and verified.The mathematical expression of components deformation by compressive stress was derived,and it shows that the deformation by compressive stress was related to factors such as inter-layer printing interval time,number of layers of components and weight of single-layer components.The deformation by compressive stress of components was controlled by improving the time-varying bearing capacity of cement-based materials and adjusting inter-layer printing interval time.The self-deformation performance of components was regulated by adjusting material mixture ratio.In order to regulation the printing components shrinkage,this thesis draws a conclusion that the amount and proportion of accelerator,cementitious material system and fibers should be given priority in selecting cement-based materials through a large number of experimental data analysis.The regulation scheme of shrinkage for 3D printing components of cement-based materials was put forward.According to theoretical model of deformation control in 3D printing stacking process,and regulate scheme of shrinkage after setting and hardening of 3D printing components of cement-based materials,the material performance selection and technical parameters design before printing could be guided.The deformation and shrinkage of components could be controlled and regulated within a reasonable range to achieve the goal of improving the quality of 3D printing components.