Combined core column plate and one-step forming construction method thereof

Abstract

The application discloses a combined core column plate and a one-time forming construction method thereof. The core column plate comprises, from bottom to top, a tension UHPC lower panel and a compression ordinary concrete or light-weight high-strength concrete upper panel, and the two panels are connected through a plurality of vertical combined core columns, and a shear key or a rough interface is arranged at the joint of the core column and the panel to ensure the cooperative stress. A polyurethane heat preservation inner mold is arranged between adjacent core columns, and the inner mold serves as a one-time permanent formwork and reserves a pipeline channel. The construction method is as follows: the UHPC lower panel and the lower section of the core column are poured in the same mold first, and then the upper ordinary concrete panel and the upper section of the core column are poured within a limited time interval, so that the wet joint is integrally formed. The application reduces the material cost on the premise of maintaining the high performance of the tension UHPC, and has the advantages of light weight, high heat preservation and being suitable for modular prefabrication.

Description

Technical Field

[0001] This invention relates to the field of building structure and prefabricated building technology, specifically to a composite core column panel suitable for floors, roofs and prefabricated modular buildings and its one-time molding construction method. Background Technology

[0002] Ultra-high performance concrete (UHPC) has ultra-high compressive strength, high tensile and crack resistance and excellent durability. It has been widely studied and applied in bridge and building structures. However, its raw material cost is high. Using UHPC as floor slabs or wall panels in a large area will significantly increase the cost and limit its promotion.

[0003] To balance mechanical and thermal insulation performance, existing technologies have proposed precast insulated sandwich panels based on UHPC (Ultra-High Performance Concrete). Examples include precast concrete insulation panels with prestressed UHPC slabs on both sides and an insulation layer in the middle. However, these panels use UHPC for both upper and lower flanges, resulting in high material costs and heavy weight. Other literature discloses ultra-high performance concrete ribbed sandwich slabs, where the upper and lower slabs and ribs are all made of UHPC, with insulation material or pipes filled between the ribs. While this improves both thermal insulation and load-bearing performance, it still falls under the category of "all-UHPC" components, making large-scale adoption in ordinary buildings difficult.

[0004] Regarding composite structures, existing studies have employed composite beams or reinforcing slabs with UHPC in the tension zone and ordinary or high-strength concrete in the compression zone. Test results show that this can significantly improve the flexural and shear bearing capacity of the components while achieving optimized material configuration. However, these composite components are mostly solid-section beams or composite slabs, failing to form a high-voidity core-column-slab system, and also failing to systematically consider the integrated design of insulation, weight reduction, and pipeline relocation.

[0005] On the other hand, in response to the problems of easy cracking of ordinary concrete formwork and the need for a large number of temporary supports in the construction of cast-in-place or composite floor slabs, there are already technologies such as support-free UHPC formwork and UHPC lightweight composite floor slabs. By using a thin UHPC layer in the tension zone, the early bearing capacity and durability are improved. However, a thicker ordinary concrete cast-in-place layer is still required on top, and the slab is mostly solid or low-hollowness solid ribs, with insufficient attention paid to thermal insulation and self-weight optimization.

[0006] Based on existing technologies, it is evident that: sandwich panels using double-sided UHPC with an intermediate insulation layer have high material costs and weight, hindering their widespread adoption in ordinary building construction projects; composite components that only partially introduce UHPC into the tension zone of beams or slabs are mostly solid or low-hollow-ratio structures, failing to fully utilize the advantages of high-hollow-ratio core columns in terms of weight reduction and insulation; existing UHPC formwork or lightweight composite floor slab technologies primarily focus on ease of construction and early load-bearing performance, and have not yet formed an integrated structural system of "tension-bearing UHPC panels + compression-bearing ordinary concrete panels + high-hollow-ratio composite core columns + permanent insulation inner formwork," nor have they achieved integral forming of the wet joints between UHPC, ordinary concrete core columns, and panels through two pours within the same mold; existing insulation inner formwork mostly uses detachable formwork or general insulation blocks, lacking a systematic solution that integrates the insulation layer, permanent formwork, and pipeline channels within the high-hollow-ratio core area.

[0007] Therefore, there is a need for a composite core column panel and its construction method that fully utilizes the high tensile strength, crack resistance, and ductility of UHPC in the tension zone, uses ordinary or lightweight high-strength concrete to reduce costs in the compression zone, forms a high-hollow-ratio insulation core column system within the panel, and achieves reliable combined stress distribution between UHPC and ordinary concrete through reasonable construction techniques. This composite core column panel is suitable for factory prefabrication and on-site assembly, and aims to solve problems such as uneconomical material utilization, excessive self-weight, low integration of insulation and pipelines, and complex construction procedures in existing technologies. These requirements are precisely the technical problems that this invention aims to solve. Summary of the Invention

[0008] The purpose of this invention is to address the problems of high material cost, heavy weight, insufficient integration of insulation and pipelines, and complex construction procedures of existing all-UHPC sandwich panels by providing a composite core column panel and its one-time molding construction method. By using UHPC in the tension zone and ordinary concrete or lightweight high-strength concrete in the compression zone, and configuring a high-voidity polyurethane insulation inner mold within the panel, the wet joint is integrally formed through two pours within the same mold. This significantly reduces material costs and structural weight while ensuring load-bearing capacity and durability, and improves the integration level of insulation and electromechanical pipelines. It is suitable for factory prefabrication and on-site overall assembly.

[0009] To achieve the above objectives, the present invention adopts the following technical solution.

[0010] (1) Composite core plate structure

[0011] This invention provides a composite core plate, as shown in the attached figure. Figure 1 Appendix Figure 2 As shown, it includes:

[0012] UHPC lower panel (1): The tension zone is located at the bottom of the plate. It is an integral plate structure, preferably a thin plate section, used to bear bending tensile stress and control cracks. The UHPC lower panel (1) is provided with a lower steel mesh (5) and optional prestressed steel bars to give full play to the tensile, crack-resistant and ductile advantages of UHPC.

[0013] Upper ordinary / lightweight high-strength concrete panel (2): Set in the compression zone at the top of the panel. The thickness of the upper panel (2) is greater than that of the lower panel (1) of the UHPC. The material is ordinary concrete or lightweight high-strength concrete. It is mainly used to bear bending compressive stress and distribute surface load. The upper panel (2) is equipped with an upper steel mesh (6) and together with the composite core column (3) forms an integral stress section.

[0014] Vertical composite core columns (3): Arranged between the lower panel (1) and the upper panel (2) of the UHPC, they are arranged at intervals along the panel surface to form a regular or irregular array, used to transfer shear force and axial force between the upper and lower panels. Each composite core column (3) includes, in sequence along the height direction: a lower UHPC core column section (31), which is integrally formed with the lower panel (1) of the UHPC in the first pour; and an upper ordinary concrete core column section (32), which is integrally formed with the upper ordinary / lightweight high-strength concrete panel (2) in the second pour. Vertical steel bars (7) are set inside the composite core column (3), and the two ends of the vertical steel bars (7) are anchored to the lower steel mesh (5) and the upper steel mesh (6) respectively, forming a spatial frame stress system.

[0015] Polyurethane insulation inner mold (4): Arranged between adjacent combined core columns (3), preferably in the form of strips, boxes, or grids, and continuously or quasi-continuously arranged along the length and width of the board. The polyurethane insulation inner mold (4), together with the lower panel (1), upper panel (2), and combined core columns (3) of the UHPC, forms multiple cavities, thereby controlling the overall void ratio of the core column board within a certain range. Within the scope. The polyurethane insulation inner mold (4) is retained in the board as a one-time permanent template during the construction process, while providing insulation function, and forming pipeline channels (12) inside or on the side for the reservation and laying of mechanical and electrical equipment pipelines.

[0016] Connection and interface construction: at the junction of the lower UHPC core column section (31) and the upper ordinary concrete core column section (32) of the composite core column (3), and at the junction of the composite core column (3) and the upper and lower panels (1, 2), shear keys (8) and / or interface roughening treatment surfaces (9) are set to improve the interface shear resistance and bonding performance; at the contact area between the lower UHPC panel (1) and the upper ordinary / lightweight high-strength concrete panel (2), a wet joint interface agent layer (10) is set to enhance the bonding and collaborative working ability between the new and old concrete; embedded connectors or anchor steel bars (14) can be set at the edge of the core column plate to achieve reliable connection with the supporting beam or wall (13), which facilitates prefabricated assembly and overall stress.

[0017] (2) One-time molding construction method

[0018] This invention also provides a one-time molding construction method for the above-mentioned composite core column plate, as shown in the attached figure. Figure 3 Appendix Figure 4 As shown, it includes the following steps:

[0019] Template and reinforcement preparation: Erect bottom and side formwork on the production line or on site to form template (11). Tie the lower reinforcement mesh (5) of the UHPC lower panel (1) and the vertical reinforcement (7) of the composite core column (3) to the bottom formwork, and reserve the anchorage length for connection with the upper reinforcement mesh (6). Install the polyurethane insulation inner formwork (4) between the two panels according to the design spacing. It can be fixed by plugging, snapping or spot welding with the reinforcement to form a stable spatial position between the polyurethane insulation inner formwork (4) and the vertical reinforcement (7) and template (11) to ensure that the overall hollowness of the cavity reaches the required level. And form a continuous or quasi-continuous pipeline channel (12).

[0020] First pouring of UHPC: The UHPC mixture is poured into the template (11) to form the lower panel (1) of the UHPC and the lower UHPC core column section (31) of the composite core column. The slump expansion of the UHPC mixture is preferably not less than 220 mm to ensure that it can fill the bottom space and the lower area of ​​the core column. During the pouring process, moderate vibration is used to avoid the formation of honeycomb holes. At the same time, the vibration energy and time are controlled to prevent the polyurethane insulation inner mold (4) from floating or shifting. After the pouring is completed, initial curing is carried out to make the UHPC reach the early strength required by the design.

[0021] Interface treatment and wet joint preparation: When the compressive strength of the lower panel (1) and the core column section (31) of the UHPC reaches 20% to 60% of the design strength, and the time interval since the first pour is no more than 48 hours, the necessary temporary side formwork is removed, and the upper surface of the UHPC is roughened to form a roughened interface surface (9), with the roughness controlled at 2 to 6 mm. After roughening, the laitance and debris are cleaned until the interface exposes the fresh, solid UHPC matrix and the working surface of the pre-embedded shear key (8). Then, a wet joint interface agent layer (10) is evenly applied to the roughened interface. The interface agent is preferably at least one of epoxy resin, acrylic or cement-based interface adhesive, and the coating thickness is controlled at 0.3 to 1.0 mm to enhance the bond between the newly poured ordinary / lightweight high-strength concrete and the UHPC.

[0022] Second pour of ordinary / lightweight high-strength concrete: Without removing the polyurethane insulation inner mold (4) and bottom mold, tie the upper steel mesh (6) in the same mold and reliably anchor it to the vertical steel bars (7). Then pour ordinary concrete or lightweight high-strength concrete to form the upper ordinary / lightweight high-strength concrete panel (2) and the upper ordinary concrete core column section (32) of the composite core column. The slump of the concrete poured in this second pour is preferably 120-200 mm, and moderate vibration is used to ensure that the concrete fully wraps the steel bars and makes complete contact with the roughened interface of UHPC, ensuring the formation of a continuous wet joint interface agent layer (10) and reliable interface bonding.

[0023] Curing and demolding: After the second pouring is completed, the entire core column panel is uniformly cured. Covering and moisturizing, steam curing or other suitable methods can be used. After the upper ordinary / lightweight high-strength concrete panel (2) and the upper ordinary concrete core column section (32) of the composite core column reach the specified demolding strength, the outer formwork (11) is removed, and the polyurethane insulation inner mold (4) is retained in the panel, forming a composite structure in which the lower UHPC panel (1), the upper ordinary / lightweight high-strength concrete panel (2) and the composite core column (3) are integrally formed through wet joints.

[0024] Assembly and Application: The finished composite core column panel can be transported to the construction site as a prefabricated component and connected to the supporting beam / wall (13) through pre-embedded connectors or anchor steel bars (14) to achieve rapid assembly of the floor or roof system. Using the pipeline channel (12) formed inside or on the side of the polyurethane insulation inner mold (4), water, electricity, HVAC and other equipment pipelines can be pre-installed in the factory or on site to achieve integrated construction of structure and electromechanical systems.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] Material optimization and cost reduction: UHPC is used only in the tension areas of the lower panel and core column, while ordinary or lightweight high-strength concrete is used in the upper panel and core column areas under compression. This achieves graded utilization of materials, namely "UHPC for tension and ordinary / lightweight concrete for compression", thereby reducing the amount of UHPC used and the total cost while maintaining the structural bearing capacity and crack control capabilities.

[0027] High void ratio and reduced weight: By arranging polyurethane insulation inner molds between the core columns, the overall void ratio is controlled within a certain range. This significantly reduces the slab's self-weight, improves span utilization efficiency, reduces the design load on the foundation and main structure, while retaining the necessary core column force transmission path and overall stiffness.

[0028] Thermal insulation and electromechanical integration: The polyurethane insulation inner mold serves as both an insulation layer and a permanent formwork, forming continuous or quasi-continuous pipeline channels within the board. This achieves an integrated design that combines insulation functionality with the pre-installation of electromechanical pipelines. Compared to traditional sandwich panels or solid floor slabs, it reduces the need for secondary grooving and on-site splicing of the insulation layer.

[0029] Reliable integral molding and co-stressing of wet joints: By implementing a two-stage casting process of "UHPC first casting + ordinary / lightweight high-strength concrete subsequent casting" in the same mold, combined with roughening, shear key and interface agent treatment, an integral molding interface is formed between the lower panel of UHPC and the upper ordinary / lightweight high-strength concrete panel, which improves the shear bearing capacity of the interface and the overall co-stressing performance, and avoids the interface slippage problem common in simple composite slabs.

[0030] Suitable for industrialized prefabrication and assembly construction: The combined core column panel of this invention can complete the two-stage pouring of UHPC and ordinary / lightweight high-strength concrete and the placement of the insulation inner mold in the factory, forming an integrated prefabricated component that integrates structure, insulation and pipeline channels. This facilitates standardized production, modular design and rapid on-site assembly, which is conducive to the promotion and application of prefabricated buildings. Attached Figure Description

[0031] To more clearly illustrate the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and do not constitute a limitation of the present invention.

[0032] Figure 1 This is a schematic diagram (partial cross-sectional view) of the overall structure of the composite core plate of the present invention.

[0033] Figure 2 For along Figure 1 A schematic diagram of the cross-sectional structure of the core column plate in the AA direction.

[0034] Figure 3This is an enlarged structural diagram of the shear key and rough interface at the junction of the combined core column and the upper and lower panels in this invention.

[0035] Figure 4 This is a schematic diagram of the process flow of the one-time molding construction method of the present invention.

[0036] Figure 5 This is a schematic diagram illustrating the application of the composite core column panel of the present invention as a prefabricated component in a floor system.

[0037] Wherein: 1—UHPC lower panel; 2—Upper ordinary / lightweight high-strength concrete panel; 3—Composite core column; 31—Lower UHPC core column segment; 32—Upper ordinary concrete core column segment; 4—Polyurethane insulation inner formwork; 5—Lower steel mesh; 6—Upper steel mesh; 7—Vertical reinforcement; 8—Shear key; 9—Roughened interface surface; 10—Wet joint interface agent layer; 11—Formwork; 12—Pipeline channel; 13—Supporting beam / wall; 14—Embedded connectors or anchoring reinforcement. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the described embodiments are for illustrative purposes only and are not intended to limit the invention. Various equivalent substitutions or modifications made by those skilled in the art to specific structural forms, dimensional parameters, and construction processes without departing from the concept of the present invention should fall within the protection scope of the present invention.

[0039] Example 1: Composite core column slab for ordinary floor slabs

[0040] 1.1 Basic Parameters of Components

[0041] like Figure 1 , Figure 2 As shown, the combined core column plate in this embodiment is a rectangular flat plate, suitable for standard floor slabs in residential or office buildings.

[0042] Board dimensions: Length ,width Panel thickness arrangement: UHPC lower panel 1 thickness Upper ordinary concrete panel, thickness 2 Total height of the core column .

[0043] Material properties (example): UHPC: cubic compressive strength axial compressive strength ,tensile strength Upper ordinary concrete: strength grade C40, standard value of cube compressive strength. Reinforcing steel: HRB400 grade steel, yield strength .

[0044] Hollowness design: By arranging the polyurethane insulation inner mold 4, the overall volumetric hollowness of the core column plate is reduced. Controlled To balance weight reduction and overall component stiffness.

[0045] 1.2 Arrangement of Combined Core Columns and Cavities

[0046] like Figure 2 As shown, a row of combined core columns 3 is arranged at 400 mm intervals along the width of the plate, and a column of combined core columns 3 is arranged at 600 mm intervals along the length of the plate, forming a regular rectangular grid array. The combined core columns 3 have a square cross-section with dimensions of [dimensions missing]. A box-shaped polyurethane insulation inner mold 4 is arranged between adjacent composite core columns 3. The outer contour of the inner mold 4 is matched with the net distance between the center lines of the composite core columns, for example, in the longitudinal dimension. Width dimension ;high (The thickness is basically the same as that of the upper panel 2, and the bottom of the inner mold is slightly embedded in the upper surface of the lower panel 1 of the UHPC).

[0047] After installation, the polyurethane insulation inner mold 4, together with the lower UHPC panel 1, the upper ordinary concrete panel 2, and the composite core column 3, forms multiple closed or semi-closed cavities. No more concrete is poured into the cavities; only the polyurethane material is retained, ensuring that the overall void ratio meets the aforementioned range.

[0048] To facilitate the passage of electromechanical pipelines, a through-flow pipeline channel 12 is provided inside the insulation inner mold 4. This can be achieved by: pre-forming hollow channels during the molding of the insulation inner mold 4; or pre-forming semi-circular grooves on the edge of the module, so that adjacent grooves form a circular or near-circular channel 12 after installation.

[0049] 1.3 Reinforcement Structure

[0050] UHPC lower panel 1 internal reinforcement

[0051] The lower steel mesh 5 adopts (Longitudinal and transverse directions), the concrete protective layer thickness is 15 mm; for floor slabs with large spans or large loads, prestressing tendons can be set in the main span direction (not shown in the attached drawings). The prestressing tendons are arranged in the lower protective layer of the lower panel 1 of the UHPC to further enhance the high tensile strength of the UHPC.

[0052] Upper ordinary concrete panel 2 internal reinforcement

[0053] Upper steel mesh 6 adopts (Vertical and horizontal bidirectional), the concrete protective layer is 15 mm thick; the upper steel mesh 6 and the vertical steel bars 7 in the composite core column 3 are reliably connected by binding or welding to ensure integrity.

[0054] Composite core column 3 internal reinforcement

[0055] Each composite core column 3 contains 4 vertical reinforcing bars 7, with a diameter of... or Anchorage lengths of not less than 10d (d is the diameter of the vertical reinforcement) are respectively anchored in the lower panel 1 and upper panel 2 of the UHPC; stirrups (not shown in the attached drawings) are set in the composite core column 3 with a spacing of 100-150 mm to improve the shear resistance and restraint capacity of the core column.

[0056] 1.4 Interface and Shear Key Construction

[0057] like Figure 3 As shown: At the junction of the composite core column 3 and the lower panel 1 and upper panel 2 of the UHPC, prefabricated toothed shear keys 8 are installed, with a tooth height of 5-8 mm and a tooth pitch of 30-60 mm, to improve the shear bearing capacity between the core column and the panel. At the junction of the lower UHPC core column section 31 and the upper ordinary concrete core column section 32, a roughened interface surface 9 is formed by roughening after the first pour, with a roughness of 2-6 mm.

[0058] Before the second pour, apply a wet joint interface agent layer 10 evenly to the roughened surface 9, with a coating thickness of 0.3 to 1.0 mm. Cement-based interface agents or epoxy interface agents can be used to form a wet joint with high bonding strength between the newly poured ordinary concrete and the hardened UHPC.

[0059] II. Construction Process of Example 1

[0060] Combination Figure 3 and Figure 4 The construction method in this embodiment is as follows.

[0061] 2.1 Installation of formwork and reinforcing steel

[0062] The bottom formwork is laid on the prefabrication plant production line, and templates 11, including side and end forms, are set according to the slab dimensions and edge beam support form. Spacers are placed on the bottom formwork to ensure the protective layer thickness of the lower UHPC panel 1 meets design requirements. The lower reinforcing mesh 5 is tied, and any prestressing tendons that may be present are arranged according to the design; the prestressing tendons are either pre-installed in ducts or unbonded, and tensioning can be carried out after the UHPC reaches the specified strength. Vertical reinforcing bars 7 pass through the predetermined core column positions from bottom to top, with their lower ends tied or welded to the lower reinforcing mesh 5, and a certain length reserved at the upper end for subsequent connection to the upper reinforcing mesh 6.

[0063] 2.2 Installation of polyurethane insulation inner mold

[0064] Place the box-shaped polyurethane insulation inner mold 4 between the vertical reinforcing bars 7 according to the designed grid dimensions, and fix it to the vertical reinforcing bars 7 using slots, buckles, or plastic straps to ensure its planar position and elevation. Check the relative position of the inner molds 4 to ensure that continuous or quasi-continuous pipeline channels 12 can be formed in both the length and width directions of the slab. If necessary, set a limiting block between the inner mold 4 and the formwork 11 to prevent the inner mold from floating or shifting during the pouring and vibration of concrete.

[0065] 2.3 First UHPC Pouring and Initial Curing

[0066] Prepare a UHPC mixture that meets the requirements for fluidity and early strength, with a slump expansion of not less than 220 mm to ensure good flow between the dense reinforcement and the inner formwork. Pour the UHPC mixture into formwork 11 and pour it sequentially from one end to the other. Use an immersion vibrator and moderate surface vibration to fully compact the UHPC, ensuring that the area of ​​the lower panel 1 of the UHPC and the area of ​​the lower UHPC core column section 31 of the composite core column 3 are filled. Control the vibration time to 5-15 s / point to prevent the polyurethane insulation inner formwork 4 from floating due to excessive vibration; at the same time, avoid direct contact between the vibrator head and the inner formwork 4 to avoid damage. After pouring, perform preliminary leveling on the surface and cover it with plastic film or use steam curing to allow the UHPC to reach 20%-60% of its design strength within 24-48 hours.

[0067] 2.4 Interface roughening and interface agent application

[0068] When the compressive strength of the lower UHPC panel 1 and the lower UHPC core column section 31 reaches the above-mentioned range, and the time between the first pour and the first pour does not exceed 48 hours, remove part of the side formwork to expose the upper surface of the UHPC that requires interface treatment. Roughen the upper surface of the UHPC using mechanical or manual chiseling to form an interface roughening surface 9 with a roughness of 2–6 mm, giving it an irregular, uneven shape. Remove the laitance and loose particles from the interface, rinse the interface with compressed air or water, and if necessary, allow it to dry until there is no visible water but it remains slightly damp. Apply a wet joint interface agent layer 10 evenly to the roughened interface. The interface agent can be a cement-based interface agent or an epoxy interface agent, with a coating thickness controlled between 0.3 and 1.0 mm. Control the open time according to the product instructions to ensure that the interface agent remains in a suitable bonding state before the second pour begins.

[0069] 2.5 Second pouring of ordinary / lightweight high-strength concrete

[0070] After the interface agent layer 10 is applied, install and tie the upper steel mesh 6, ensuring reliable anchorage to the upper end of the vertical steel bars 7. The spacing between the upper steel mesh 6 and the lower panel 1 of the UHPC is determined according to the design. Prepare a mixture of ordinary concrete or lightweight high-strength concrete, with a slump controlled at 120–200 mm to ensure both fluidity and prevent excessive segregation. Pour the concrete mixture into the formwork 11, fully covering the upper steel mesh 6 and the vertical steel bars 7, reaching the designed thickness of the upper ordinary concrete panel 2, and filling the area of ​​the upper ordinary concrete core column section 32 of the composite core column 3. Use an immersion vibrator for light vibration at 5–20 s / point to prevent the polyurethane insulation inner mold 4 from floating or shifting; if necessary, apply appropriate weight to the top of the inner mold to further stabilize its position. After pouring and vibration, smooth and finish the concrete surface to provide a good base layer for subsequent surface layer or finishing material construction.

[0071] 2.6 Overall curing and demolding

[0072] After the second pour, the entire core column slab is uniformly cured, preferably using a combination of steam heating and covering for moisture retention to ensure a temperature and humidity environment conducive to hydration of the UHPC and ordinary concrete. When the strength of the ordinary concrete panel 2 and the upper ordinary concrete core column segment 32 of the composite core column reaches the design demolding strength (e.g., When removing the formwork 11, only the polyurethane insulation inner formwork 4 remains inside the panel. Interfacial shear and bending tests on representative specimens are used to verify the cooperative performance of the wet joint between the lower UHPC panel 1 and the upper ordinary concrete panel 2. After confirming that the geometric dimensions, reinforcement cover thickness, and appearance quality of the core column panel meet the requirements through dimensional and visual inspections, it can be transported to the construction site as a finished product.

[0073] 2.7 On-site assembly and use

[0074] like Figure 5 As shown, on-site, the composite core column slab is placed on the supporting beam / wall 13. It is then welded or tied to the supporting member 13 using pre-embedded connectors or anchoring steel bars 14 at the slab ends. An overlay layer or wet joint concrete can be poured in place at the slab joints to form an integrated floor system. Utilizing the pre-set pipeline channels 12 within the polyurethane insulation inner mold 4 inside the slab, water supply and drainage pipes, electrical conduits, and HVAC pipes can be installed during the prefabrication or on-site stages, achieving integrated layout of the structure and electromechanical systems and reducing secondary grooving and insulation layer application processes.

[0075] III. Example 2: Roof panel using lightweight high-strength concrete upper panel

[0076] Based on Embodiment 1, this embodiment changes the material of the upper panel 2 from ordinary concrete to lightweight high-strength concrete for use in long-span roofs or structures that are more sensitive to their own weight.

[0077] 3.1 Key Differences

[0078] The upper panel 2 is made of lightweight high-strength concrete with a dry density of Cube compressive strength To reduce the dead load. To compensate for the slight decrease in stiffness that may result from the reduced density, the thickness of the upper panel 2 can be appropriately increased, such as... Alternatively, the core column spacing can be slightly reduced to improve overall bending stiffness. The height of the polyurethane insulation inner mold 4 can be appropriately increased to enhance the effective thickness of the upper panel 2 while maintaining the hollowness. Still in Within this range, the properties of the lightweight high-strength concrete mixture, curing conditions, and type of interface agent can be adjusted appropriately according to the material characteristics, but the overall construction sequence is basically the same as in Example 1.

[0079] IV. Example 3: Variations in Shear Key Form and Interface Treatment

[0080] Without changing the core concept of the invention, the shear key 8 and the roughened surface 9 of the present invention can be adopted in the following variations.

[0081] 1. Shear key form variation

[0082] Depend on Figure 3 The toothed interface shown is transformed into a boss-type shear key, such as pre-embedding a perforated steel plate or a boss concrete block at the junction of the composite core column 3 and the panel, and transmitting force through its side shear; or using a perforated steel plate shear key, anchoring one end of the steel plate in the lower panel 1 of the UHPC, and extending the other end into the upper ordinary concrete panel 2, with several round or oblong holes on the steel plate to enhance mechanical interlocking.

[0083] 2. The rough interface processing method has been modified.

[0084] Roughening can be achieved through various processes such as sandblasting, sanding, and mechanical grooving, with the roughness controlled between 2 and 8 mm. When using high-performance interface agents (such as epoxy interface agents), the roughness can be appropriately reduced to balance construction efficiency and interface performance.

[0085] 3. Variations in interface agent types

[0086] For the wet joint interface agent layer 10, in addition to cement-based and epoxy materials, other materials with good adhesion and durability, such as acrylic emulsion modified cement-based interface agents, can also be used. The construction thickness should still be controlled within the range of 0.3 to 1.0 mm.

[0087] V. Example 4: Cast-in-place monolithic construction method

[0088] In addition to factory prefabrication, the composite core column slab of this invention can also be constructed on-site using a cast-in-place method, which is particularly suitable for non-standard sizes or locally irregularly shaped components. The steel mesh 5 and vertical steel bars 7 of the UHPC lower panel 1 are directly arranged on the cast-in-place floor slab formwork 11, and the polyurethane insulation inner mold 4 is installed on-site. Two pouring operations and interface treatments are completed according to steps 2.3 to 2.6 in Example 1, with the difference that the second pouring can be synchronized with the concrete of the surrounding beams and walls, forming an integral cast-in-place structure of the floor slab and supporting components 13; the embedded connectors 14 can be directly anchored to the surrounding beam reinforcement cage to achieve reliable integrity.

[0089] The on-site casting method is particularly suitable for renovation projects or situations where the geometric shape of the slab is required to be complex.

[0090] VI. Other optional features

[0091] Based on the above embodiments, the present invention may further include the following optional technical features: the surface of the UHPC lower panel 1 can be directly used as a structural exposed surface, or sound-absorbing panels, metal decorative panels, and other materials can be pasted on its lower surface to meet building physics and decoration requirements. The density and thermal conductivity of the polyurethane insulation inner mold 4 can be optimized according to building energy conservation standards to ensure that the overall heat transfer coefficient of the composite core column panel meets relevant specifications. The pipeline channel 12 can be prefabricated with standardized apertures to match the sizes of commonly used electrical conduits, water supply and drainage pipes, and air ducts, realizing modular electromechanical design. For large-span or high-load floor slabs, post-tensioned prestressed tendons can be used in the UHPC lower panel 1 to improve the stiffness of the component under cracking load and serviceability limit state through tensioning.

[0092] As can be seen from the above embodiments, this invention, through the rational configuration of UHPC and ordinary / lightweight high-strength concrete, functionally divides the materials in the tension and compression zones, and introduces a high-hollow polyurethane insulation inner mold and a composite core column system within the slab, thereby comprehensively optimizing the structural load-bearing capacity, self-weight, thermal insulation performance, and the degree of industrialization in construction. Technical features not detailed in the above embodiments can be implemented using conventional methods known in the art, and will not be elaborated further.

Claims

1. A composite core plate, characterized in that, include: A UHPC panel is installed at the bottom; an ordinary concrete or lightweight high-strength concrete panel is installed at the top, the thickness of the upper panel being greater than the thickness of the UHPC panel; several vertical composite core columns are arranged between the two panels, each composite core column consisting of a lower UHPC core column segment and an upper ordinary concrete core column segment along its height direction, the lower core column segment being integrally cast with the UHPC panel, and the upper core column segment being integrally cast with the upper panel; a polyurethane insulation inner mold is arranged between adjacent composite core columns, the inner mold, the two panels, and the composite core columns together forming a cavity, making the overall hollowness of the core column panel 65% to 70%, and the polyurethane insulation inner mold is a disposable permanent template that forms a reserved channel for equipment pipelines; wherein, shear keys and / or rough interfaces are provided at the interface between the lower UHPC segment and the upper ordinary concrete segment of the composite core column and at the junction area between the composite core column and the upper and lower panels to ensure reliable combined stress between the UHPC and the ordinary concrete.

2. The composite core plate according to claim 1, characterized in that, The polyurethane insulation inner mold is a strip-shaped, box-shaped, or grid-shaped module, which is positioned and connected to the steel reinforcement skeleton by plugging or snapping, so that the cavity forms a continuous or quasi-continuous pipeline channel in both the length and width directions of the plate.

3. The composite core plate according to claim 1 or 2, characterized in that, The shear key is at least one of the following: a boss, a groove, a perforated plate shear key, or a toothed interface located at the junction of the composite core column and the upper and lower panels, and / or a roughened surface with a roughness of 2 to 6 mm.

4. The composite core plate according to any one of claims 1 to 3, characterized in that, The UHPC panel is equipped with a distributed steel mesh and necessary prestressed steel bars, the upper panel is equipped with a regular steel mesh, and the composite core column is equipped with vertical steel bars that are anchored to the steel bars of the two panels to form a spatial stress system.

5. The composite core plate according to any one of claims 1 to 4, characterized in that, The upper panel is made of ordinary concrete or concrete with a density not exceeding 2000 kg / m³. The UHPC panel is made of lightweight, high-strength concrete, and its compressive strength is not less than 120 MPa and its tensile strength is not less than 6 MPa.

6. A one-time molding construction method for the composite core column plate according to any one of claims 1 to 5, characterized in that, The process includes the following steps: erecting a template and tying the vertical reinforcing bars of the lower panel and composite core column; installing a polyurethane insulation inner mold between the two panels to achieve an overall hollowness of 65%–70% in the cavity to be formed; casting the lower UHPC panel and the lower UHPC core column segment of the composite core column in the template and performing initial curing; when the compressive strength of the lower UHPC panel and the lower core column segment reaches 20%–60% of the design strength and the casting interval is no more than 48 hours, roughening and cleaning the upper surface and applying an interface agent; without removing the template and the polyurethane insulation inner mold, casting the upper ordinary concrete or lightweight high-strength concrete panel and the upper ordinary concrete core column segment of the composite core column in the same mold; curing the entire core column panel to form a composite structure of UHPC panel, ordinary concrete panel, and composite core column integrally formed through wet joints.

7. The construction method according to claim 6, characterized in that, The interface agent is at least one of epoxy resin, acrylic or cement-based interface adhesive, and the coating thickness of the interface agent is 0.3 to 1.0 mm.

8. The construction method according to claim 6 or 7, characterized in that, In step 2), shear keys are prefabricated or embedded at the junction of the composite core column and the two panels, and the working surface of the shear keys is exposed during the roughening process in step 3) to improve the shear bearing capacity of the wet joint interface.

9. The construction method according to any one of claims 6 to 8, characterized in that, The pouring and vibration process parameters for steps 2) and 4) include: the slump expansion of the UHPC mixture is not less than 220 mm, the slump of the upper ordinary concrete is 120-200 mm, and the vibration time is controlled at 5-20 s / point to prevent the polyurethane insulation inner mold from floating or shifting.

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