Experimental Study On Mechanical Properties Of 3D Printed Concrete Beams Reinforced With Steel Wire Ropes

As a new type of digital construction technology,3D printing technology integrates computer,digital modeling,materials science and electromechanical control technologies.Compared with the traditional construction technology,it has obvious advantages such as faster construction speed,moldless mechanized construction,saving manpower and construction costs,and completing arbitrary modeling structure in space.Since 3D printing is difficult to be compatible with the traditional layout process of steel bar,the bearing and deformation capacities of 3D printed concrete structure are limited.To overcome this problem,the integration of reinforcing materials into printed concrete must be studied.Due to the high tensile strength and a certain degree of flexibility,the steel wire rope can be installed on the 3D printing nozzle,and it can be laid on the concrete to form a reinforced member.Since the steel wire rope has a good compatibility with the 3D printing production system,it is expected to combine with the 3D printed concrete to form a new structure.As the research goal of steel wire rope reinforced 3D printed concrete beams,this paper exhibits the bonding properties between steel wire rope and 3D printed cement-based composite materials,and clarify the flexural and shear behaviours of 3D printed concrete beams reinforced with steel wire ropes.The specific contents are displayed as follows:(1)Based on a central pull-out experiment,the effects of printing direction and wire rope diameter on the bonding performance between the steel wire rope and the 3D printed cement-based composite material were studied,and the difference of bond slip curve between steel wire rope and ordinary steel bar was compared.In addition,the bond strength prediction model considering the printing directions was put forward.(2)Through the mechanical test of 3D printed flexural beams reinforced with steel wire ropes,the effects of reinforcement ratio and printing direction on the flexural bearing capacity of printed concrete beams were studied,and the calculated formula of flexural capacity of 3D printed concrete beams were given,which provided a reference for the bending design of 3D printed beam.The results show that the steel wire rope can effectively improve the bearing capacity of 3D printed concrete beams,and the bearing capacity of beams printed with the surround method is higher than that of the beams printed with the parallel method.(3)The failure process of steel wire reinforced 3D printed concrete beam was simulated using the finite element method,and the influence of the reinforcement ratio on the bending capacity of the 3D printed concrete beam was analyzed.The results show that the simulated values are in good agreement with the experimental values,which verifies the applicability of the 3D printed concrete constitutive model and the simulation method.(4)Through the shear test of 3D printed concretebeam reinforced with steel wire ropes,the effects of the hoop method and the hoop ratio on the shear bearing capacity of the printed concrete beam were clarified.The results show that the concrete in the shear zone effectively participates in the shearing resistance during the entire loading process.However,the stirrups only play a part role on the shearing resistance,resulting in the test value is far lower than the theoretical value.As the hoop ratio increases,the shear capacity of the test beam increases.