Method for reinforcing an existing concrete structure and reinforcing member
Patent Information
- Application Number
- CN202611320802.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-28
- Publication Date
- 2026-10-27
AI Technical Summary
[0023]本发明提出一种高强钢筋复合超高强高延性混凝土（UHP-ECC，抗压强度60～150MPa）增大截面加固结构及方法，区别于传统普通混凝土增大截面、常规ECC加固、UHPC加固等现有技术，本发明通过高强钢筋受力骨架与高强高延性UHP-ECC基体协同工作，并兼容传统现浇施工与喷射施工两种成型方式，实现了加固承载力、结构自重、抗震延性、耐久性能及施工适应性的全方位突破，整体技术方案具备显著创新性与综合技术优势，具体总结如下：
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Figure CN122980705A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of building structure technology, specifically to a method and reinforcement components for strengthening existing concrete structures. Background Technology
[0002] As a large number of reinforced concrete buildings, bridges, and municipal engineering projects enter the middle and later stages of their service life, major load-bearing components such as beams, slabs, and columns are prone to crack propagation, stiffness degradation, reduced load-bearing capacity, and decreased durability under the combined effects of long-term loads, environmental erosion, concrete carbonation, steel corrosion, freeze-thaw cycles, and earthquakes. These issues severely impact the safety and normal functionality of the structures. When the performance of components fails to meet current specifications or actual engineering requirements, reasonable reinforcement measures are needed to restore or improve their load-bearing capacity, ductility, and durability to extend the structural service life. Therefore, reinforcement technology for existing reinforced concrete structures has become an important research direction in the field of civil engineering and is widely used in projects such as existing building renovation, bridge repair and reinforcement, and post-earthquake structural restoration.
[0003] Currently, existing reinforced concrete beams, slabs, columns, and other structural members are mainly strengthened using traditional methods such as increasing the cross-section, FRP reinforcement (slab), high-strength steel reinforcement, ECC reinforcement, and UHPC reinforcement. While these methods can improve the structural performance, they still have certain shortcomings.
[0004] Traditional cross-section enlargement reinforcement method: The traditional cross-section enlargement method improves the load-bearing capacity of the component by adding steel bars and ordinary concrete. However, the newly added cross-section is thicker, the self-weight of the structure increases, and it occupies usable space. Ordinary concrete has poor crack resistance, and cracking and slippage are prone to occur at the interface between the old and new concrete, which affects the overall coordinated stress and durability performance.
[0005] FRP reinforcement (plate) method: FRP reinforcement (plate) has the advantages of being lightweight and corrosion resistant, but it has a low elastic modulus and limited ability to control cracks and deflection; at the same time, it mainly relies on adhesive bonding, and is prone to interface peeling under long-term load and high temperature environment, and the component failure has brittle characteristics, and the improvement of seismic performance is limited.
[0006] High-strength steel reinforcement method: High-strength steel can improve the load-bearing capacity of beams, slabs and columns, but the development of cracks in ordinary concrete still limits the performance of high-strength steel. After the cracks expand, they are prone to corrosion of steel, reducing the durability of the structure. At the same time, the requirements for anchorage connection and stress coordination are high.
[0007] ECC reinforcement method: ECC has good ductility and crack control capabilities, which can improve the crack resistance of the structure, but the load-bearing capacity is limited and the reinforcement effect on heavy-load components is insufficient; at the same time, the material cost is relatively high, which limits its application in large-scale projects.
[0008] UHPC reinforcement method: UHPC has high strength and excellent durability, but the material has high stiffness, which can easily lead to stress concentration at the interface with ordinary concrete; its resistance to time delay is limited, and the cracks generated under stress are relatively concentrated; in addition, the construction process requires high standards and the cost is high, which limits its promotion and application.
[0009] In summary, existing reinforcement technologies generally suffer from problems such as increased self-weight of the newly added cross-section, insufficient crack control capabilities, limited interfacial synergistic performance, and difficulty in simultaneously improving load-bearing capacity, ductility, and durability. Summary of the Invention
[0010] To address the problems of traditional reinforcement methods, this invention provides a method for reinforcing existing concrete structures and a reinforcement component.
[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0012] The first aspect of this invention provides a method for strengthening existing concrete structures, the method comprising the following steps:
[0013] Erect supports and unload, and lay out the positioning lines; pre-treat the existing concrete structure; roughen the joint surface; install rebar; set up formwork and reserve pouring and vibration ports; pour UHP-ECC; moisturize and cure, and remove the formwork after reaching the design strength.
[0014] The rebar installation may use high-strength steel bars in some or all of its components.
[0015] Preferably, the pretreatment step includes treating the loose concrete of the existing structure and removing rust from the reinforcing steel.
[0016] Preferably, the rebar installation includes newly added longitudinal bars and U-shaped stirrups.
[0017] More preferably, the U-shaped stirrups are reliably welded to the original stirrups of the existing concrete structure, and the reinforcing bars are concealed.
[0018] Preferably, before pouring the UHP-ECC, an interface agent is applied to the bonding surface with the existing concrete structure.
[0019] Preferably, the raw materials for preparing the UHP-ECC include cement, mineral powder, microsphere fly ash, silica fume, quartz sand, water-reducing agent, and PE fiber.
[0020] More preferably, per 1m 3 The raw materials for preparing the UHP-ECC include: 600-700kg cement, 140-170kg mineral powder, 400-500kg microsphere fly ash, 100-200kg silica fume, 500-600kg quartz sand, 26-30kg water-reducing agent, and 15-20kg PE fiber.
[0021] A second aspect of the present invention provides a reinforcing member, which is prepared by the aforementioned method for reinforcing existing concrete structures.
[0022] Compared with the prior art, the beneficial effects of the present invention are:
[0023] This invention proposes a high-strength reinforced concrete composite ultra-high-strength high-ductility concrete (UHP-ECC, compressive strength 60-150MPa) cross-section enlargement reinforcement structure and method. Unlike existing technologies such as traditional ordinary concrete cross-section enlargement, conventional ECC reinforcement, and UHPC reinforcement, this invention achieves a comprehensive breakthrough in strengthening load-bearing capacity, structural self-weight, seismic ductility, durability, and construction adaptability by working synergistically between a high-strength reinforced steel framework and a high-strength high-ductility UHP-ECC matrix, and is compatible with both traditional cast-in-place and shotcrete construction methods. The overall technical solution possesses significant innovation and comprehensive technical advantages, summarized as follows:
[0024] 1. Ultra-high strength significantly improves the load-bearing capacity of the reinforcement while greatly reducing the thickness of the reinforcement layer.
[0025] Compared to conventional ECC (compressive strength generally ≤60MPa) and ordinary concrete, this invention uses 60-150MPa grade UHP-ECC material, significantly improving the matrix compressive strength (60-150MPa) and tensile strength (10-20MPa). Under the same load-bearing capacity improvement requirements, the thickness of the reinforcement layer section can be significantly reduced, overcoming the shortcomings of conventional methods that increase the cross-section thickness, resulting in large reinforcement thickness and limited load-bearing capacity improvement. This achieves thin-layer high-load-bearing-capacity reinforcement, greatly improving the efficiency of bending, compressive, and shear reinforcement of structural members.
[0026] 2. Significantly reduces the self-weight of the reinforcement, effectively alleviating the additional load on the original structure and foundation.
[0027] Relying on the ultra-high strength characteristics of UHP-ECC, the thickness of the reinforcement layer is significantly reduced. Compared with the traditional concrete, the increased cross-section can significantly reduce the added self-weight, avoiding the problems of large self-weight increase, insufficient foundation bearing capacity, and significant increase in additional internal forces caused by the thickening of the cross-section in traditional reinforcement methods. It is especially suitable for existing building renovation scenarios with limited load margin and where it is not advisable to increase the weight significantly.
[0028] 3. Retaining the high ductility and multi-slit energy dissipation characteristics, solving the problem of brittle fracture in high-strength materials.
[0029] Unlike ultra-high strength UHPC, which is inherently brittle, has poor deformation capacity, and is prone to breakage and detachment under earthquakes, UHP-ECC possesses both ultra-high strength and high tensile strain ductility. Under stress, it exhibits a multi-microcrack propagation pattern without penetrating brittle cracks. The reinforcement layer maintains good deformation coordination with the original concrete structure and high-strength steel reinforcement, preventing spalling, cracking, and delamination under seismic loading, significantly improving the seismic energy dissipation capacity and overall stability of the reinforced component. Furthermore, the multi-crack characteristic allows more sections of the steel reinforcement to yield under tension, further enhancing seismic energy dissipation capacity.
[0030] 4. Excellent matrix density significantly improves structural durability and corrosion resistance.
[0031] The porosity of the UHP-ECC matrix is much lower than that of ordinary concrete and conventional ECC. Its internal structure is dense and stable, which can significantly slow down the penetration rate of chloride ions, water vapor and other harmful ions, effectively delay the corrosion of internal high-strength steel bars, avoid long-term aging and performance degradation of the reinforcement system, and greatly improve the service life and long-term durability and safety of the reinforced structure. It is suitable for structural reinforcement and renovation in humid, coastal and corrosive environments.
[0032] 5. High-strength steel bars and UHP-ECC form an excellent synergistic stress-bearing system, maximizing performance utilization.
[0033] Traditional ordinary concrete has low strength and is easily crushed, failing to fully utilize the high-strength mechanical properties of high-strength steel reinforcement; conventional ECC has insufficient strength, limiting the improvement of load-bearing capacity after reinforcement. This invention employs ultra-high-strength UHP-ECC to match the load-bearing skeleton of high-strength steel reinforcement. The matrix strength can match the yield strength level of high-strength steel reinforcement, preventing the matrix from failing before the reinforcement. This fully utilizes the tensile and compressive properties of high-strength steel reinforcement, forming a highly efficient synergistic stress-bearing mechanism of high-strength matrix + high-strength reinforcement, resulting in reinforcement efficiency far exceeding that of traditional reinforcement systems.
[0034] 6. Compatible with dual construction techniques, highly adaptable to construction, and widely applicable to various projects.
[0035] This invention's technical solution is not limited to a single construction method; it allows for flexible selection of either traditional cast-in-place or sprayed construction techniques depending on site conditions. Cast-in-place construction offers good overall integrity and is suitable for regular components; sprayed construction eliminates the need for formwork, offers rapid forming, and is suitable for irregularly shaped components, confined spaces, the bottom of beams and slabs, complex nodes, and other challenging construction areas. This dual-mode compatibility significantly improves project adaptability and solves the pain points of traditional methods such as cumbersome formwork for enlarging cross-sections and strengthening, construction limitations, and long construction periods.
[0036] 7. Comprehensively resolve the technical contradictions that existing technologies have long been unable to address simultaneously.
[0037] Existing reinforcement technologies all have inherent shortcomings and cannot achieve unified performance: traditional concrete reinforcement is heavy, prone to cracking, and has poor durability; conventional ECC has good ductility but insufficient strength, limiting its load-bearing capacity improvement; UHPC has high strength but is brittle and has poor seismic performance; various thin-layer reinforcements lack a complete load-bearing steel skeleton and cannot achieve significant load increases. This invention simultaneously solves five core contradictions: load-bearing capacity, self-weight, ductility and seismic resistance, durability and corrosion resistance, and ease of construction. It achieves a comprehensive technological breakthrough integrating high strength, lightweight, high ductility, high durability, and ease of construction, possessing unexpected technical effects that existing technologies cannot achieve.
[0038] This invention overcomes the technical bottlenecks of traditional cross-section enlargement reinforcement, which suffers from low strength, heavy self-weight, poor ductility, insufficient durability, and limited construction, by combining a high-strength steel reinforcement skeleton with an ultra-high-strength, high-ductility UHP-ECC composite enlargement system and a dual construction mode of cast-in-place and shotcrete. It achieves multiple synergistic improvements in reinforced structures, including high load-bearing capacity, thin cross-section, low self-weight, high seismic resistance, high durability, and strong adaptability to various working conditions. It possesses outstanding substantive characteristics and significant technological progress. Attached Figure Description
[0039] Figure 1 The diagram shows three types of reinforcement for the beam in Example 1; 101 Ordinary concrete structure, 102 UHP-ECC layer, 103 High-strength steel reinforcement.
[0040] Figure 2 This is a schematic diagram of the slab reinforcement in Example 2; as shown in the figure: 201 ordinary concrete structure, 202 UHP-ECC layer, 203 high-strength steel reinforcement;
[0041] Figure 3 This is a schematic diagram of column reinforcement in Example 3; as shown in the figure: 301 ordinary concrete structure, 302 UHP-ECC layer, 303 high-strength steel reinforcement. Detailed Implementation
[0042] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
[0043] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.
[0044] The UHP-ECC layer of this invention is prepared by the following method:
[0045] The raw materials for UHP-ECC preparation consist of cement, mineral powder, microsphere fly ash, silica fume, quartz sand, water-reducing agent, PE fiber, and water. The design mix of UHP-ECC is shown in Table 1 below. The preparation process of UHP-ECC is as follows: Accurately weigh the required cement, water, and other materials. Wet the mixing pot, then pour the weighed materials into the mixing pot and begin mixing. During the mixing process, gradually add the water-reducing agent to control the slurry to achieve good fluidity. This process should be completed within 5 minutes. Subsequently, uniformly add the PE fiber and continue mixing for 2 minutes to allow the fiber to integrate with the slurry.
[0046] Table 1. Design mix proportions for UHP-ECC
[0047]
[0048] Note: The mass of cement, mineral powder, silica fume, quartz sand, microsphere fly ash, water-reducing agent, water and PE fiber refers to the amount used per 1m³ of UHP-ECC.
[0049] The present invention uses UHP-ECC instead of traditional ordinary concrete as the material for the new section of the concrete and configures high-strength steel bars to form a composite reinforcement layer. This fully leverages the advantages of UHP-ECC's high strength, high toughness, and high crack resistance, as well as the high load-bearing capacity of high-strength steel bars, thereby improving the material utilization rate of the new section and the synergistic working performance of the new and old structures.
[0050] This method is applicable to the enlargement and strengthening of existing reinforced concrete beams, slabs, columns, and other components. It can effectively solve the problems of traditional enlargement and strengthening methods, such as the large self-weight of the newly added section, insufficient crack control, poor interface synergy, and limited improvement in durability. At the same time, it overcomes the shortcomings of existing technologies, such as brittle failure of FRP reinforcement, insufficient crack control of high-strength steel reinforcement, limited improvement of bearing capacity of ECC reinforcement, and insufficient ductility of UHPC reinforcement. It achieves a synergistic improvement in bearing capacity, stiffness, ductility, energy dissipation capacity, and durability, providing a safe, reliable, efficient, and promising composite reinforcement technology for existing reinforced concrete structures.
[0051] Example 1
[0052] This invention provides three methods for strengthening beams, such as... Figure 1 As shown, the specific reinforcement process includes the following steps:
[0053] 1. Erect temporary supports to relieve the load, and lay out the positioning lines; treat cracks and loose concrete in the original beams, and remove rust from the reinforcing bars;
[0054] 2. Roughen the surface of the ordinary concrete structure 101 to expose the coarse aggregate and clean off the loose dust.
[0055] 3. For the treated beam, the ordinary concrete structure 101 surface is as follows: Figure 1 The three methods shown are for laying high-strength steel bars 103, adding U-shaped stirrups (ordinary steel bars) at certain intervals, binding the new steel bars, reliably welding the U-shaped stirrups to the original stirrups, and conducting concealed acceptance of the steel bars;
[0056] 4. Set up the formwork, reserve the pouring and vibration opening, pour the UHP-ECC layer 102, and vibrate to compact it;
[0057] 5. Moisturize and maintain the material; remove the mold and temporary supports after the material has reached the designed strength.
[0058] In step 4, before pouring the UHP-ECC layer 102, an interface agent can be selectively applied to the bonding surface according to the actual situation to enhance the adhesion between the UHP-ECC layer 102 and the ordinary concrete structure 101.
[0059] Figure 1 (c) Reinforcement methods used when there is no floor slab around the beam.
[0060] Example 2
[0061] This invention provides a method for reinforcing a plate, such as... Figure 2 As shown, the specific reinforcement process includes the following steps:
[0062] 1. Erect temporary supports to unload the load and lay out the positioning lines; remove plaster and loose concrete from the slab surface and remove rust from the steel reinforcement on the slab surface;
[0063] 2. Roughen the surface of the ordinary concrete structure 201 on the slab to expose the coarse aggregate, and clean and rinse it thoroughly.
[0064] 3. For the treated surface of the ordinary concrete structure 201, according to... Figure 2 High-strength steel 203 is laid out in the manner shown, short anchor bars (tie bars) are installed, and a pull-out test is performed after curing; new reinforcement is laid and tied, and the concealed acceptance of the steel reinforcement is carried out.
[0065] 4. Set up the formwork, reserve the pouring and vibration opening, pour the UHP-ECC layer 202, and vibrate to compact it;
[0066] 5. Moisturize and maintain the material; remove the mold and temporary supports after the material has reached the designed strength.
[0067] In step 4, before pouring the UHP-ECC layer 202, an interface agent can be selectively brushed onto the bonding surface according to the actual situation to enhance the adhesion between the UHP-ECC layer 202 and the ordinary concrete structure 201.
[0068] Example 3
[0069] This invention provides a method for reinforcing columns, such as... Figure 3As shown, the specific reinforcement process includes the following steps:
[0070] 1. Erect temporary supports to relieve the load, and lay out the positioning lines; remove the loose concrete from the original column and remove rust from the reinforcing steel;
[0071] 2. Roughen the surface of the ordinary concrete structure 301 on the column surface to expose the coarse aggregate, and clean and rinse it thoroughly.
[0072] 3. For the treated beams, the ordinary concrete structure 301 surface is treated according to... Figure 3 The high-strength 303 steel bars are laid out as shown. The lower end of the newly added longitudinal steel bars is anchored into the foundation / floor slab, and the upper end is anchored into the beam. Tie stirrups are installed, and a pull-out test is performed after the steel bars are installed.
[0073] 4. Tie the newly added longitudinal bars and stirrups, and complete the concealed inspection of the reinforcing steel bars;
[0074] 5. Erect reinforced formwork, reserve pouring and vibration ports, pour UHP-ECC layer 302, and ensure sealing to prevent grout leakage;
[0075] 6. Moisturize and maintain the material until the design strength is achieved, then remove the mold and temporary supports.
[0076] In step 5, before pouring the UHP-ECC layer 302, an interface agent can be selectively brushed onto the bonding surface according to the actual situation to enhance the adhesion between the UHP-ECC layer 302 and the ordinary concrete structure 301.
[0077] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.
Claims
1. A method for reinforcing existing concrete structures, characterized in that, The reinforcement method includes the following steps: Erect supports and unload, and lay out the positioning lines; pre-treat the existing concrete structure; roughen the joint surface; install rebar; set up formwork and reserve pouring and vibration ports; pour UHP-ECC; moisturize and cure, and remove the formwork after reaching the design strength. The rebar installation may use high-strength steel bars in some or all of its components.
2. The method for strengthening existing concrete structures according to claim 1, characterized in that, The pretreatment steps include treating the loose concrete of the existing structure and removing rust from the reinforcing steel.
3. The method for strengthening existing concrete structures according to claim 1, characterized in that, The rebar installation includes newly added longitudinal bars and U-shaped stirrups.
4. The method for strengthening existing concrete structures according to claim 3, characterized in that, The U-shaped stirrups are reliably welded to the original stirrups of the existing concrete structure, and the reinforcing bars are concealed.
5. The method for strengthening existing concrete structures according to claim 1, characterized in that, Before pouring the UHP-ECC, an interface agent is applied to the interface surface with the existing concrete structure.
6. The method for strengthening existing concrete structures according to claim 1, characterized in that, The raw materials for preparing UHP-ECC include cement, mineral powder, microsphere fly ash, silica fume, quartz sand, water-reducing agent, and PE fiber.
7. The method for strengthening existing concrete structures according to claim 6, characterized in that, per 1m 3 The raw materials for preparing the UHP-ECC include: 600-700kg cement, 140-170kg mineral powder, 400-500kg microsphere fly ash, 100-200kg silica fume, 500-600kg quartz sand, 26-30kg water-reducing agent, and 15-20kg PE fiber.
8. A reinforcing component, characterized in that, The reinforcing member is prepared by the method for reinforcing existing concrete structures as described in any one of claims 1-7.