SMAF-ECC assembly with reinforcing bars and concrete structural member of SMAF-ECC assembly
By burying rib materials in the SMAF-ECC matrix, the SMAF-ECC combination with reinforcement is formed, which solves the problem of performance degradation of existing reinforced concrete structures after long-term service, and achieves high load-bearing, good deformation coordination and self-restoration capabilities of the structure, improving the overall performance.
Patent Information
- Application Number
- CN202510091206.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-21
- Publication Date
- 2025-04-11
AI Technical Summary
The existing reinforced concrete structures are prone to aging, cracking, deformation and steel bar corrosion after long-term service, resulting in degradation of structural performance, and a system that relies on reinforced materials alone cannot meet the overall performance improvement needs of the structure.
Using the SMAF-ECC combination with reinforcement, the reinforcement material is buried in the SMAF-ECC matrix, and the high strength of the reinforcement material and the high ductility and self-recovery performance of the SMAF-ECC are used to form high-performance structural components, which are suitable for key parts such as the tension area, node core area, and shaping hinge area of the structure.
It significantly improves the load-bearing, deformation, durability and self-recovery capabilities of the structure, reduces the residual deformation of the ribs after being subjected to stress, provides better crack protection and self-closing characteristics, and has comprehensive performance advantages over traditional combinations.
Smart Images
Figure CN119801125A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of construction engineering, and in particular relates to a SMAF-ECC assembly with reinforcement and a concrete structural member thereof. Background Art
[0002] Reinforced concrete (RC) structures are one of the most widely used building structures. As the service life of the structure increases, RC structures are prone to problems such as aging, cracking, deformation, and steel corrosion, which lead to the degradation of structural performance.
[0003] Engineered cementitious composites (ECC) are fiber-reinforced cementitious composites with high ductility. They have been widely studied at home and abroad due to their significant strain hardening and multi-crack cracking characteristics. However, the high ductility and high energy dissipation of ECC are at the expense of significant residual deformation and a large number of crack damage, which is not conducive to post-earthquake repair and functional recovery of the structure.
[0004] The composite material of SMAF and ECC is a new type of composite material (SMAF-ECC) formed by shape memory alloy fiber (SMAF) reinforced engineering cement-based composite material. In the prior art, the bonding and anchoring strength between SMA fiber and ECC matrix are effectively improved by setting ends and surface polishing on SMA fiber, thereby ensuring that SMAF and ECC matrix can work together. Therefore, the obtained SMAF-ECC composite material not only has the excellent performance of ECC material, but also can effectively improve the crack closure, deformation recovery and energy dissipation capacity of the composite material by utilizing the superelastic properties of SMAF. Studies have shown that the strain recovery rate and crack recovery rate of SMAF-ECC specimens under tension can reach 69% and 77% respectively, which are significantly better than ECC specimens; the residual crack width under compression can be reduced by more than 75% compared with ECC specimens.
[0005] Steel bars, FRP bars and other reinforcement materials are important reinforcement materials in traditional concrete and are usually used to improve the strength of the structure. However, with the continuous improvement of the performance requirements of building materials, the system that relies solely on reinforcement materials can no longer meet the needs of improving the comprehensive performance of structural load-bearing, deformation, durability and self-recovery. Summary of the invention
[0006] In order to solve the deficiencies of the prior art, the present invention provides a SMAF-ECC assembly with reinforcement and a concrete structural member thereof. The present invention combines reinforcement materials with SMAF-ECC composite materials to form a high-performance SMAF-ECC assembly with reinforcement. The SMAF-ECC assembly with reinforcement can be used in key stress-bearing parts such as the tension zone, node core zone, and shaping hinge zone of structural members; it can be used for both new structures and reinforcement of existing structures, and is helpful for achieving post-earthquake repair and functional restoration of the structure.
[0007] The technical solution provided by the present invention is as follows:
[0008] A SMAF-ECC assembly with reinforcement, comprising:
[0009] SMAF-ECC matrix;
[0010] and a plurality of reinforcing bars embedded in the SMAF-ECC matrix.
[0011] Based on the above technical solution, the reinforcement and the SMAF-ECC matrix have good bonding properties. On the one hand, the combination can greatly improve the bearing capacity of SMAF-ECC by utilizing the high strength of the reinforcement; on the other hand, it can also utilize the high ductility of SMAF-ECC to achieve deformation coordination with the reinforcement, and utilize fine cracks and crack self-closing characteristics to achieve better protection of the reinforcement; in addition, the self-recovery properties of SMAF-ECC can be used to reduce the residual deformation of the reinforcement after stress; compared with the existing reinforced concrete, reinforced ECC and other combinations, it has significant comprehensive performance advantages. The composite matrix of SMAF and ECC has high ductility, its ultimate tensile strain is greater than 3%, and its strength is not less than the equivalent strength of the concrete C30 standard.
[0012] Specifically, in the SMAF-ECC matrix, the volume ratio of SMAF to ECC material is (0.002-0.01):1.
[0013] SMAF surface treatments include but are not limited to no treatment, sandpaper grinding, gravel grinding, mechanical torsion, mechanical abrasion, chemical oxidation surface or surface coating.
[0014] Preferably, in the SMAF-ECC matrix, the water-binder ratio is in the range of 0.2 to 0.3, and the sand-binder ratio is in the range of 0.2 to 0.25.
[0015] Preferably, in the SMAF-ECC matrix: the diameter range of SMAF is 0.2 mm to 1 mm.
[0016] Specifically: the SMAF-ECC matrix includes the following components in parts by weight: cementitious material, fine sand, water, water reducing agent, fiber and SMAF.
[0017] Preferably, the mass ratio of each raw material to the cementitious material is: water is (0.2-0.3):1, fine sand is (0.2-0.25):1, and water reducing agent is (0.0016-0.0080):1.
[0018] Preferably, the volume ratio of the fiber to the entire SMAF-ECC matrix is (0.015-0.02):1.
[0019] Preferably, the cementitious material comprises cement and fly ash in a weight ratio of (0.25-3):1.
[0020] Specifically: the fiber is selected from any one or more of polyvinyl alcohol fiber (PVA), polypropylene fiber (PP), nylon fiber or polyethylene fiber (PE).
[0021] Specifically: the longitudinal cross-section of the SMAF-ECC matrix includes but is not limited to a rectangle, a circle, an annular shape or a trapezoid.
[0022] For rectangles or trapezoids, reinforcement can be provided in multiple layers.
[0023] For a circle or annular shape, they can be arranged around the circumference.
[0024] Specifically: in the SMAF-ECC matrix, the end shape of the SMAF includes but is not limited to straight, knotted, N-shaped, hooked, L-shaped or curled.
[0025] Specifically: the reinforcement is selected from any one of steel bars or FRP bars or a combination of the two.
[0026] The present invention also provides a concrete structural member, comprising a concrete beam, and a SMAF-ECC assembly with reinforcement combined on the bottom surface of the concrete beam.
[0027] The present invention also provides a concrete structural member, comprising a concrete column and the SMAF-ECC assembly with reinforcement combined on the peripheral wall of the concrete column.
[0028] The present invention also provides a concrete structural member, comprising a concrete wall, and the SMAF-ECC assembly with reinforcement combined on the peripheral wall of the concrete wall.
[0029] The present invention also provides a concrete structural member, comprising a concrete slab and the SMAF-ECC assembly with reinforcement combined on the peripheral wall of the concrete slab.
[0030] Based on the above technical solution, the combination is applied to building structures to effectively enhance the comprehensive performance of the structure, such as bearing, deformation, durability and self-recovery. Specifically, the applicable areas include but are not limited to the tensile areas of structural beams or columns, the core areas of nodes, the shaping hinge areas and other key stress-bearing parts.
[0031] The present invention also provides a method for manufacturing a concrete structural member, which specifically comprises the following steps:
[0032] 1) Determine the mechanical properties, cross-sectional form and geometric dimensions of the SMAF-ECC assembly with reinforcement;
[0033] 2) Determine the reinforcement type, mechanical performance index and cross-sectional area, and determine the diameter, number of reinforcements and layout according to the structural requirements;
[0034] 3) Roughen and clean the bottom surface of the concrete beam, or roughen and clean the surrounding wall surface of the concrete column;
[0035] 4) Set up formwork, arrange reinforcement, and pour SMAF-ECC materials;
[0036] 5) After the SMAF-ECC material solidifies, the formwork is removed and then watered for curing.
[0037] In step 1), the method of roughening and cleaning the surface of the structure includes but is not limited to sandblasting, drilling, steel brushing, high-pressure water jet spraying or surface chiseling (electronic circuit breaker) method.
[0038] In step 5), the assembly can be demoulded after 24 hours and then watered and cured for 28 days.
[0039] The present invention also provides another method for manufacturing a concrete structural member, which specifically comprises the following steps:
[0040] 1) Tie the steel cage, set up the formwork, and pour the SMAF-ECC material to the designed height;
[0041] 2) pouring concrete;
[0042] 3) After the specimen solidifies, remove the mold and then sprinkle water for curing.
[0043] In step 3), the assembly can be demoulded after 24 hours and then watered and cured for 28 days.
[0044] The beneficial effects of the present invention are as follows:
[0045] 1) The assembly provided by the present invention has mechanical properties such as high strength, high ductility, high energy consumption, self-recovery of deformation, self-closing of cracks, etc., which can significantly improve the bearing, deformation and self-recovery capabilities of structural components such as reinforced concrete and steel-concrete;
[0046] 2) The cross-sectional form and geometric dimensions of the assembly provided by the present invention can be adjusted according to actual engineering requirements;
[0047] 3) The present invention can be used for key stress-bearing locations such as tension zones, node core zones, and shaping hinge zones of structural members; it can be used for both new structures and reinforcement of existing structures. BRIEF DESCRIPTION OF THE DRAWINGS
[0048] Figure 1 It is a schematic diagram of the overall structure of a reinforced concrete beam strengthened by a SMAF-ECC assembly with reinforcement.
[0049] Figure 2 Longitudinal section of a composite column reinforced in the lateral bending tension zone by a SMAF-ECC assembly with reinforcement.
[0050] Figure 3 yes Figure 2 BB cross-section diagram in.
[0051] Figure 4 is a longitudinal section of a composite beam reinforced in the tension zone by a SMAF-ECC assembly with reinforcement.
[0052] Figure 5 yes Figure 4 AA cross-section diagram.
[0053] Figure 6 is a longitudinal section of another reinforced concrete beam strengthened by a SMAF-ECC combination with reinforcement.
[0054] Figure 7 yes Figure 6 CC cross-section diagram in .
[0055] Attached Figures 1 to 7 The structures represented by the labels are listed below:
[0056] 1. Concrete beam; 2. Reinforcement; 3. SMAF-ECC matrix; 4. SMAF-ECC assembly with reinforcement. DETAILED DESCRIPTION
[0057] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.
[0058] Unless otherwise specified, the test methods used in the examples are conventional methods; the materials and reagents used are commercially available reagents and materials unless otherwise specified.
[0059] Example 1
[0060] like Figure 1 As shown, the reinforced concrete beam reinforced by the SMAF-ECC assembly with reinforcement comprises: a concrete beam 1, and a SMAF-ECC assembly with reinforcement 4 combined on the bottom surface of the concrete beam 1. The SMAF-ECC assembly with reinforcement 4 is composed of a SMAF-ECC matrix 3 and at least one layer of reinforcement 2 horizontally cast therein, and the number of reinforcements 2 in each layer can be one or more.
[0061] Example 2
[0062] like Figure 2 , 3As shown, in a composite column in which the lateral bending tension area is reinforced by a SMAF-ECC assembly with reinforcement, the middle part is a concrete column, and a SMAF-ECC assembly 4 with reinforcement is set in its lateral bending tension area.
[0063] In this example, the reinforcement used in the assembly is rebar.
[0064] Example 3
[0065] like Figure 4 , 5 As shown, in the composite beam in which the tension region is reinforced by the SMAF-ECC assembly with reinforcement, the upper layer is a concrete beam and the lower layer is a SMAF-ECC assembly 4 with reinforcement.
[0066] In this example, the reinforcement used in the assembly is rebar.
[0067] Example 4
[0068] like Figure 6 , 7 As shown, in another reinforced concrete beam reinforced by a SMAF-ECC assembly with reinforcement, the upper layer is a concrete beam, and the bottom concrete protective layer is chiseled off; the lower layer is a SMAF-ECC assembly 4 with reinforcement.
[0069] In this example, the reinforcement used in the assembly is rebar.
[0070] In Examples 1 and 4, the SMAF-ECC assembly with reinforcement is used to reinforce a concrete beam, and the reinforcement in the SMAF-ECC assembly with reinforcement is separately provided and does not need to be connected to the reinforcement of the reinforced concrete beam. In Examples 2 and 3, the SMAF-ECC assembly with reinforcement forms a composite structure with a concrete beam or column, and the reinforcement in the SMAF-ECC assembly with reinforcement shares reinforcement with the concrete beam or column.
[0071] Effect Example 1
[0072] The steps of making concrete structural components include:
[0073] 1) Roughen and clean the bottom surface of the concrete beam;
[0074] 2) Set up formwork, arrange various reinforcement materials (steel bars or CFRP bars), and cast SMAF-ECC;
[0075] 3) After 24 hours, the assembly is demoulded and then watered and cured for 28 days.
[0076] In this effect example, the constituent materials of SMAF-ECC include cementitious materials, fine sand, water, water reducing agent, fiber and SMAF;
[0077] The mass ratio of each raw material to the cementitious material is: water (0.22):1, fine sand (0.2):1, water reducing agent (0.0016):1;
[0078] The volume ratio of the fiber to the SMAF-ECC matrix as a whole is 0.02:1;
[0079] Among them, the cementitious material includes cement and fly ash with a weight ratio of 0.25:1.
[0080] The water-to-binder ratio in ECC material is 0.22, and the sand-to-binder ratio is 0.2.
[0081] In this effect example, the fiber used is polyvinyl alcohol fiber (PVA); SMAF is a shape memory alloy fiber with a diameter of 0.5 mm and a knotted end shape, and its volume ratio to ECC material is 0.006:1.
[0082] In this effect example, the cement is ordinary Portland cement with a market grade of 52.5; the fly ash is Class F high-quality fly ash; the fine sand is white crystalline quartz sand with a fineness of 100 to 200 meshes; and the chemical additive is a polycarboxylic acid high-performance water-reducing agent.
[0083] The main indicators of various types of SMAF-ECC assemblies with reinforcement obtained through quasi-static tests are shown in Table 1:
[0084] Table 1
[0085]
[0086] As can be seen from Table 1, the SMAF-ECC matrix in the present invention has better bonding performance at the material level compared to the traditional ECC matrix, showing good synergistic working ability between the reinforcement material and the SMAF-ECC matrix.
[0087] The main indicators of the concrete structural components of the structure shown in Example 2 obtained through the quasi-static test are shown in Table 2:
[0088] Table 2
[0089]
[0090] Effect Example 2
[0091] The steps of making a reinforced SMAF-ECC assembly combined with a concrete structural member include:
[0092] 1) Tie the steel cage, set up the formwork, and pour the SMAF-ECC material to the designed height;
[0093] 2) pouring concrete;
[0094] 3) After 24 hours, the assembly is demoulded and then watered and cured for 28 days.
[0095] In this effect example, the constituent materials of SMAF-ECC include cementitious materials, fine sand, water, water reducing agent, fiber and SMAF;
[0096] The mass ratio of each raw material to the cementitious material is: water (0.22):1, fine sand (0.2):1, water reducing agent (0.0016):1;
[0097] The volume ratio of the fiber to the SMAF-ECC matrix as a whole is 0.02:1;
[0098] Among them, the cementitious material includes cement and fly ash with a weight ratio of 0.25:1.
[0099] The water-to-binder ratio in ECC material is 0.22, and the sand-to-binder ratio is 0.2.
[0100] In this effect example, the fiber used is polyvinyl alcohol fiber (PVA); SMAF is a shape memory alloy fiber with a diameter of 0.5 mm and a knotted end shape, and its volume ratio to ECC material is 0.006:1.
[0101] In this effect example, the cement is ordinary Portland cement with a market grade of 52.5; the fly ash is Class F high-quality fly ash; the fine sand is white crystalline quartz sand with a fineness of 100 to 200 meshes; and the chemical additive is a polycarboxylic acid high-performance water-reducing agent.
[0102] The main indicators of the concrete structural components of the structure shown in Example 3 obtained through the quasi-static test are shown in Table 3:
[0103] Table 3
[0104]
[0105] It can be seen from Tables 2 and 3 that the SMAF-ECC assembly with reinforcement provided by the present invention can significantly improve the structural performance, including but not limited to higher peak bearing capacity, better ductility, greater total energy consumption and higher deformation recovery rate.
[0106] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A SMAF-ECC assembly with reinforcement, characterized in that: include: SMAF-ECC matrix; and a plurality of reinforcing bars embedded in the SMAF-ECC matrix.
2. The SMAF-ECC assembly with reinforcement according to claim 1, characterized in that: In the SMAF-ECC matrix, the volume ratio of SMAF to ECC materials is (0.002-0.01):
1.
3. The SMAF-ECC assembly with reinforcement according to claim 1, characterized in that: In the SMAF-ECC matrix: The water-binder ratio is between 0.2 and 0.3, and the sand-binder ratio is between 0.2 and 0.25; The diameter range of SMAF is 0.2mm to 1mm.
4. The SMAF-ECC assembly with reinforcement according to claim 1, characterized in that: The SMAF-ECC matrix includes the following components in parts by weight: cementitious material, fine sand, water, water reducing agent, fiber and SMAF; The mass ratio of water to cementitious material is (0.2-0.3):1; The mass ratio of fine sand to cementitious material is: (0.2-0.25):1; The mass ratio of water reducing agent to cementitious material is: (0.0016~0.0080):1; The volume ratio of the fiber to the entire SMAF-ECC matrix is (0.015-0.02):1; The cementitious material includes cement and fly ash, and the weight ratio of the two is (0.25-3):
1.
5. The SMAF-ECC assembly with reinforcement according to claim 4, characterized in that: The fiber is selected from any one or more of polyvinyl alcohol fiber, polypropylene fiber, nylon fiber or polyethylene fiber.
6. The SMAF-ECC assembly with reinforcement according to claim 1, characterized in that: The longitudinal cross-section of the SMAF-ECC matrix includes, but is not limited to, a rectangle, a circle, an annular shape or a trapezoidal shape.
7. The SMAF-ECC assembly with reinforcement according to claim 1, characterized in that: In the SMAF-ECC matrix, the end shape of the SMAF includes but is not limited to straight, knotted, N-shaped, hooked, L-shaped or curled.
8. The SMAF-ECC assembly with reinforcement according to claim 1, characterized in that: The reinforcement is selected from any one of steel bars or FRP bars or a combination of the two.
9. A concrete structural member, characterized in that: A concrete beam, and a SMAF-ECC assembly with reinforcement as claimed in any one of claims 1 to 8 combined on the bottom surface of the concrete beam; Or comprising a concrete column, and the SMAF-ECC assembly with reinforcement according to any one of claims 1 to 8 combined on the peripheral wall of the concrete column; Or comprising a concrete wall, and the SMAF-ECC assembly with reinforcement according to any one of claims 1 to 8 combined on the peripheral wall of the concrete wall; Or it includes a concrete slab, and the SMAF-ECC assembly with reinforcement according to any one of claims 1 to 8 combined on the peripheral wall of the concrete slab.
10. A method for manufacturing a concrete structural member according to claim 9, characterized in that: At least the following steps are included: 1) Roughen and clean the bottom surface of the concrete beam, or roughen and clean the surrounding wall surface of the concrete column; 2) Set up formwork, arrange reinforcement, and pour SMAF-ECC materials; 3) After the SMAF-ECC material solidifies, the formwork is removed and then watered for curing; Or, at least the following steps: 1) Tie the steel cage, set up the formwork, and pour the SMAF-ECC material to the required height; 2) pouring concrete; 3) After the specimen solidifies, remove the mold and then sprinkle water for curing.