Abstract: The present disclosure relates to an rebar-free prestressed concrete and a forming method therefor. The unreinforced prestressed concrete includes: a base layer, which is a mortar, concrete or neat paste pouring piece, where the base layer has a deformation value S1; and a prestressed layer disposed on a surface of the base layer and completely covering the base layer. The prestressed layer is a mortar, concrete or neat paste pouring piece, and does not include a steel bar. The prestressed layer has a deformation value S2, where S1 is smaller than S2. The solved technical problem is how to achieve an unreinforced prestressed concrete having a prestressed surface layer without the use of steel bar tensionsing, allowing same to improve the crack resistance and durability of a building without increasing new investment, reducing construction costs without bringing about fire hazards, and thus improving suitability for practical use.

Abstract: The present application relates to the technical field of engineering construction and provides a rebar, a device and a construction method for 3D-printing a concrete interlayer structure. The rebar at least comprises: a body in the form of a chain structure, comprising a plurality of sub-parts mutually spliced, wherein the body is adapted for being sandwiched between two adjacent upper and lower cement-based slurry layers; a rotatable joint arranged between two adjacent sub-parts in such a way that the two adjacent sub-parts are rotatably connected to each other; insertion members, wherein both sides of each of the sub-parts are provided with the insertion members extending away from the center of each of the sub-parts, wherein the insertion member on one side of each of the sub-parts is adapted for being inserted in an upper cement-based slurry layer, and the insertion member on an opposite side of each of the sub-parts is adapted for being inserted in a lower cement-based slurry layer.

Abstract: Provided is an apparatus for preparing a building structure with 3D printing, comprising: a 3D printing device (1), having a storage chamber (11) and a printing head (12) connected to the storage chamber (11) and being movable relative to a base frame; and a reinforcing device, movably disposed relative to the base frame, and having a driving mechanism (3) for driving short rebars or short ribs to perform an insertion movement in a direction intersected with a stacking direction of a cement-based slurry layer; the driving mechanism inserts the short rebars or the short ribs into an interlayer interface spanning at least two adjacent cement-based slurry layers printed by the 3D printing device (1). Also provided a method for preparing a building structure with 3D printing.

Abstract: Provided is an apparatus for preparing a building structure with 3D printing, comprising: a 3D printing device (1), having a storage chamber (11) and a printing head (12) connected to the storage chamber (11) and being movable relative to a base frame; and a reinforcing device, movably disposed relative to the base frame, and having a driving mechanism (3) for driving short rebars or short ribs to perform an insertion movement in a direction intersected with a stacking direction of a cement-based slurry layer; the driving mechanism inserts the short rebars or the short ribs into an interlayer interface spanning at least two adjacent cement-based slurry layers printed by the 3D printing device (1). Also provided a method for preparing a building structure with 3D printing.

Abstract: There is disclosed a process for destroying halogenated hydrocarbons such as PCBs and PCBs in PCB containing fluids (e.g., Askarel) and oils (e.g., paraffin oil, transformer oil, etc.) at ambient temperature. The process comprises reacting halogenated hydrocarbons, such as PCB containing fluids or oils with a solid oxidant in the presence of a concentrated acid. Preferably, the solid oxidant is potassium permanganate and the concentrated acid is sulfuric acid. Destruction efficiency is as high as 99.95%.