Combined accessory of in-situ concrete 3-D printed horizontal load-bearing member and preparation method

A preparation method of an in-situ concrete 3-D printed horizontal load-bearing member, wherein 3-D printed concrete and a bottom mesh are adopted, wherein the 3-D printed concrete contains fine aggregate having a particle size of 0.08 mm-4.75 mm, and a fluidity of the 3-D printed concrete is larger than or equal to 110 mm and smaller than or equal to 190 mm;

• the bottom mesh is a reinforcing mesh or expanded metal, a diameter of a reinforcing bar of the bottom mesh is larger than or equal to 0.5 mm, and a mesh aperture of the reinforcing mesh is smaller than or equal to 7.5 times of an upper limit of the particle size of the fine aggregate and is larger than or equal to 7.5 times of a lower limit of the particle size of the fine aggregate, and the method comprises:
• (1) providing the bottom mesh according to a structure and span of the horizontal load-bearing member;
• (2) when the bottom mesh bears a weight of a first layer of 3-D printed concrete alone:
• fixing two or four sides of the bottom mesh to connection embedded parts reserved on support walls on two sides or four sides in a welding or binding mode, then directly printing the first layer of 3-D printed concrete on the bottom mesh, and enabling the first layer of 3-D printed concrete to flow out through meshes of the bottom mesh to wrap the bottom mesh;
• or paving a reinforcing cage on the first layer of 3-D printed concrete after a setting of the first layer of 3-D printed concrete;
• when the bottom mesh and the reinforcing cage bear the weight of the first layer of 3-D printed concrete together:
• binding the bottom mesh at a lower part of the reinforcing cage, and placing a spacer block between the reinforcing cage and the bottom mesh to control a distance between the reinforcing cage and the bottom mesh, and then directly printing the first layer of 3-D printed concrete on the bottom mesh;
• and
• (3) after the setting of the first layer of 3-D printed concrete, continuing the printing of the 3-D printed concrete on the first layer of 3-D printed concrete until a predetermined thickness of the horizontal load-bearing member is reached.