The Applications Of Recycled Fine Aggregate Concrete In Building 3D Printing

In construction industry in China,the level of automation is relatively low compared with those of others',and the basic ideas of sustainable development are not apparently applied as well.As concepts in Building Construction are changing worldwide especially in developed countries,to realize automatic and green construction with high efficiency and sustainability has been a common trend.Building 3D printing is a high-tech automatic construction technology in recent years,and on the other hand recycled aggregate concrete is a critical approach to fulfill such sustainable development.So the author combined both of them and conducted systematic study to prospective ?automatic & green construction?.At first,research status of building 3D printing and recycled aggregate concrete were summarized both in China and abroad,and the methodology and technical route used in this thesis was introduced.In the following part,a brief introduction to principles and printing system of building 3D printing were presented,at the same time,the difference between Extrusion Printing and Fused Deposition Modeling(FDM)was compared.The development direction of building 3D printing material is put forwardNext,based on orthogonal experimental theory,experiments were designed and conducted which tested recycled fine aggregate concrete with different mix proportions used for 3D printing.Through a series of experiments,the effects of w/c ratio,replacement ratio and fiber usage on workability,strength and durability were explored,and the optimal mix proportion of recycled fine aggregate concrete used for 3D printing was obtained,which was verified by the microstructure test and durability test.Last but not least,the author accomplished experiments on the Extrusion Printing 3D printing machine verifying feasibility of the optimal mix proportion.The whole processes were displayed in the thesis including devices and material preparations,modelling and printing,and then the printed flowerpots and specimens were shown.At the same time,the results were compared and analyzed with the FDM printing process.In this thesis,critical technical problems of building 3D printing were clarified,and optimal mix proportion designed.The main problems existing in the building 3D printing was also pointed out.For further study on related areas,it has some reference significance.