High-performance non-resin-based bamboo rib and application thereof
By recombining bamboo through a stranding process to form resin-free high-performance bamboo reinforcement, the problems of poor bonding performance and unstable mechanical properties of bamboo in marine environments are solved, resulting in a high-strength, low-cost concrete reinforcement material that meets the requirements of green building.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA RAILWAY 18TH BUREAU GRP CO LTD
- Filing Date
- 2026-03-20
- Publication Date
- 2026-05-12
AI Technical Summary
Existing bamboo materials used as concrete reinforcement have problems such as irregular cross-sections, poor bonding performance with concrete, large dispersion of mechanical properties, easy moisture absorption and unstable dimensions, and resin aging, making it difficult to use stably in marine environments for a long time.
The high-strength vascular bundles in natural bamboo are reorganized using a purely physical stranding process to form resin-free, high-performance bamboo fibers. By optimizing the twist pitch and diameter control, structural reorganization and standardization of specifications are achieved. Combined with steel strand stranding technology, tensile strength and elastic modulus are improved.
It achieves high durability, excellent mechanical properties and good bonding performance of bamboo in marine environments, meets the requirements of green and sustainable development, and has low production costs.
Smart Images
Figure CN122013575A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of civil engineering materials, and more specifically, to a high-performance non-resin-based bamboo reinforcement and its applications. Background Technology
[0002] In coastal and marine engineering, reinforced concrete structures are widely used due to their excellent mechanical properties and plasticity. However, the high chloride ion content in the marine environment can penetrate the concrete cover, corroding the internal steel reinforcement, leading to steel corrosion, volume expansion, and ultimately causing the concrete cover to crack and peel off, resulting in a sharp decline in the structure's load-bearing capacity and durability. This is a major durability problem facing coastal infrastructure worldwide, causing enormous maintenance and reconstruction costs.
[0003] To address the problem of steel reinforcement corrosion, fiber-reinforced polymer (FRP) rebar has gradually become a research hotspot. FRP rebar boasts advantages such as high strength, lightweight, and resistance to chloride ion corrosion. However, FRP rebar also has significant limitations: firstly, its matrix resin (such as epoxy, unsaturated polyester, etc.) is prone to hydrolysis and degradation in the highly alkaline environment inside concrete, leading to fiber debonding from the matrix and severe long-term performance degradation; secondly, FRP rebar production is energy-intensive, relies on non-renewable petroleum resources, and is difficult to degrade after disposal, which contradicts the concept of green and sustainable development. Therefore, there is an urgent need to develop a new type of rebar that is both corrosion-resistant and environmentally friendly, and can operate stably in alkaline environments for extended periods.
[0004] Bamboo, as a natural biomass material, possesses advantages such as rapid growth, renewability, high strength, good toughness, and a unique microstructure. More importantly, bamboo itself exhibits excellent resistance to salt and alkali corrosion, and its chemical components (mainly cellulose, hemicellulose, and lignin) are relatively stable in alkaline environments. If it can be processed into a reinforcing steel structure that meets engineering requirements, it holds promise for fundamentally solving the dual challenges of steel corrosion and FRP resin degradation in marine environments, achieving a balance between structural durability and environmental sustainability.
[0005] Current technologies for bamboo applications mostly involve direct application in concrete or processing before use. However, existing bamboo applications all have certain drawbacks. The specific existing bamboo products and their associated defects are as follows: (1) Ordinary bamboo strips / bamboo chips reinforced concrete: bamboo is simply split into strips or chips and then directly embedded in concrete. This method does not perform in-depth homogenization of bamboo, the properties of the reinforcement are extremely unstable, the bond strength with concrete is weak, and it is prone to brittle failure and pull-out. It cannot meet the requirements of modern structural engineering for predictable and designable reinforcement material properties.
[0006] (2) Resin impregnation / coating of bamboo strips: In order to improve the performance of bamboo, some studies have used resin to impregnate or coat the surface of bamboo strips. Although it improves waterproofness and adhesion to concrete to a certain extent, it introduces the same resin matrix as FRP reinforcement, which fails to solve the fundamental problem of resin aging and degradation in the alkaline environment of concrete, and increases cost and production complexity, which deviates from the original intention of "all-natural" corrosion resistance.
[0007] (3) Bamboo fiber reinforced composite materials: Bamboo is crushed into short fibers or powder and then compounded with resin and molded. These materials belong to the category of composite materials. Their performance depends on the resin matrix. The short fibers have low reinforcement efficiency and it is difficult to obtain the high-strength, high-modulus continuous long fiber reinforcement effect. They are not suitable as the main load-bearing reinforcement material.
[0008] (4) Traditional bamboo rope / cable: It is made of multiple strands of bamboo strips or bamboo filaments twisted together, and is mainly used for non-structural or temporary purposes such as ropes and hoisting. Its manufacturing process is crude, resulting in low tensile strength and elastic modulus, large creep, and poor dimensional stability, which cannot meet the long-term service requirements of prestressed or high-performance concrete structures.
[0009] It is known that existing bamboo materials used as concrete reinforcement have significant drawbacks: 1) Irregular cross-sections and poor bonding performance with concrete; 2) Large dispersion in mechanical properties, especially tensile strength and elastic modulus, which are difficult to meet the requirements for structural reinforcement (e.g., tensile strength > 300 MPa, elastic modulus > 20 GPa); 3) Easily absorbs moisture and has unstable dimensions, making it prone to drying shrinkage and wetting expansion inside the concrete, leading to interfacial failure; 4) Adding resin to improve the bonding performance with concrete presents problems such as resin aging and degradation.
[0010] Therefore, how to overcome the inherent variability and defects of bamboo through innovative physical processing methods to manufacture high-performance bamboo fibers with stable performance and controllable specifications is a technical bottleneck in this field. Summary of the Invention
[0011] This application provides a high-performance non-resin-based bamboo reinforcement and its application. This application abandons the composite approach of adding resin, and creatively restructures the high-strength vascular bundles in natural bamboo through a purely physical twisting and molding process, forming a high-performance reinforcement material that is entirely bamboo and resin-free. It retains the natural salt and alkali corrosion resistance of bamboo, and achieves a significant improvement in mechanical properties and standardization of specifications through structural restructuring, fundamentally avoiding the durability problems of steel reinforcement corrosion and FRP reinforcement resin degradation.
[0012] In a first aspect, this application provides a method for preparing high-performance non-resin-based bamboo fiber, employing the following technical solution: A high-performance non-resin-based bamboo reinforcement, wherein the bamboo reinforcement is formed by twisting bamboo filament bundles together using a steel strand twisting process, wherein the bamboo filament bundles are composed of joined bamboo monofilaments, the twist pitch of the bamboo reinforcement is 10-15 mm in diameter, the diameter of the bamboo monofilaments is 0.3-0.8 mm, and the diameter of the bamboo filament bundles is 3-8 mm.
[0013] By adopting the above technical solutions, bamboo monofilaments are bundled into bamboo strands after being joined and initially bundled, which can initially improve the homogeneity and mechanical property stability of the material. Simultaneously, by optimizing the twist pitch of the bamboo rope, the mechanical properties and dimensional stability of the bamboo rope can be improved. For this application, the twist angle is obtained through the steel strand formula and twist pitch calculation.
[0014] Meanwhile, for bamboo reinforcing bars with a steel strand structure, slight sliding and adjustment occur between the bamboo filament bundles under stress and tension. This ensures that each bamboo filament bundle distributes the load as evenly as possible, preventing stress concentration at any point that could lead to overall breakage. The diameter of the bamboo filaments and bundles affects the stress area and surface roughness during this slight sliding process, thus influencing the stress on the bamboo material at each location and consequently its performance. This application controls the diameter of the bamboo filaments to 0.3-0.8 mm and the diameter of the bamboo bundles to 3-8 mm. Appropriate twist pitch combined with the specified diameters of the bamboo filaments and bundles not only facilitates the stranding of the material but also maximizes the various properties of the bamboo reinforcing bar. Finally, bamboo ropes stranded using the steel strand stranding process meet the following core performance requirements: tensile strength ≥ 300 MPa and tensile modulus of elasticity ≥ 20000 MPa.
[0015] Furthermore, the bamboo monofilament is a portion taken from the middle section of the bamboo, which is 1 / 3 to 1 / 2 of the total length of the bamboo after removing the yellow and green parts of the bamboo.
[0016] By adopting the above technical solutions, the bamboo material in this part has high strength and regular dimensions, which is conducive to improving the strength of the bamboo fibers and facilitating processing.
[0017] Furthermore, the twisting pitch of the bamboo rope is 60-80mm.
[0018] By adopting the above technical solution, due to the limitations of bamboo growth and the need to cut the middle section of bamboo to make bamboo monofilaments, the bamboo monofilaments and bamboo bundles cannot be infinitely long. Therefore, during the twisting process, it is necessary to add new bamboo bundles at intervals. This interval is the twisting pitch. The starting point for calculating the length of the twisting pitch is the end point of the last group of bamboo bundles before the addition, which is furthest from the addition side.
[0019] Furthermore, the bamboo reinforcement includes a single-layer strand structure or a multi-layer twisted structure.
[0020] Furthermore, the structure of the bamboo reinforcement includes 1×7 and 1×19.
[0021] By adopting the above technical solutions, the 1×7 stranded structure refers to 1 central steel wire + 6 outer steel wires; the 1×19 stranded structure refers to 1 central steel wire + inner steel wire + outer steel wire, a total of 19 wires. The common arrangement is 1+6+12 or 1+9+9. For example, 1+6+12 means 1 central steel wire + 6 inner steel wires + 12 outer steel wires.
[0022] Furthermore, the diameter of the bamboo monofilament is 0.5-0.8 mm, and the diameter of the bamboo bundle is 5-6 mm.
[0023] By adopting the above technical solutions and further optimizing the diameter of bamboo monofilaments and bamboo bundles, the overall performance of bamboo fibers can be further improved.
[0024] Secondly, this application provides an application of high-performance non-resin-based bamboo reinforcement, employing the following technical solution: An application of a high-performance non-resin-based bamboo reinforcement, wherein the bamboo reinforcement is used as a reinforcing material for concrete components in environments including seawater, marine salt spray, or saline-alkali geological environments.
[0025] By adopting the above technical solutions, the bamboo rope of this application not only retains the salt and alkali corrosion resistance of bamboo, but also achieves a leapfrog improvement in mechanical properties and standardization of specifications through structural reorganization. In addition, the surface of the bamboo reinforcement of this application has natural texture and micropores, and the twisted structure provides a good mechanical interlocking surface. The bonding strength between the bamboo reinforcement and concrete is better than that of smooth FRP reinforcement and ordinary bamboo strips.
[0026] In summary, this application has the following beneficial effects: (1) Excellent durability: This bamboo reinforcement is made of pure bamboo and contains no metal or synthetic resin. Therefore, it is naturally resistant to chloride salt corrosion and concrete alkaline environment corrosion, which fundamentally solves the bottleneck problem of the durability of reinforcement materials in marine and saline-alkali environments.
[0027] (2) Excellent mechanical properties: By combining “selecting the best bamboo fibers”, “stretching and strengthening” and “specific structural parameters”, the high strength characteristics of bamboo in the axial direction are maximized. The principle of synergistic force of steel strands is also referenced, so that the tensile strength and elastic modulus of the final product meet the requirements of structural reinforcement materials, and the performance is stable and reliable.
[0028] (3) Good bonding performance: The surface of bamboo reinforcement has natural texture and micropores, and the twisted structure provides a good mechanical interlocking surface. Its bonding strength with concrete is better than that of smooth FRP reinforcement and ordinary bamboo strips.
[0029] (4) Green and sustainable: The raw materials are renewable, the production process has low energy consumption, the products are biodegradable, and the carbon footprint throughout the entire life cycle is extremely low, which is in line with the green building and sustainable development strategy.
[0030] (5) High designability: By adjusting the process parameters, bamboo strips of different diameters and mechanical grades can be produced in series to meet the design requirements of different engineering structures.
[0031] (6) Economic potential: The raw material cost is low, the production process is relatively simple, and the long-term maintenance cost is far lower than that of reinforced concrete structures that require frequent repairs. Attached Figure Description
[0032] Figure 1 This is a schematic diagram of the bamboo reinforcement structure in an embodiment of this application.
[0033] Explanation of the attached diagram: 1. Bamboo fiber bundle. Detailed Implementation
[0034] The present application will be further described in detail below with reference to the accompanying drawings and embodiments.
[0035] Example This embodiment provides a high-performance non-resin-based bamboo fiber, such as... Figure 1 As shown, the bamboo fiber bundle 1 is made by twisting bamboo filament bundle 1 together using the steel strand twisting process. The twisting process can be completed using a commonly used stranding machine.
[0036] Bamboo filament bundle 1 consists of joined bamboo monofilaments, which are made by arranging a certain number of bamboo monofilaments in parallel and joining them together, ensuring that the bundle 1 does not unravel. The bamboo monofilaments are taken from the middle section of the bamboo, representing 1 / 3 to 1 / 2 of the total length of the bamboo after removing the outer and inner bamboo fibers. The extraction of bamboo monofilaments can be accomplished using common bamboo splitting machines, filament opening machines, and filament drawing machines.
[0037] The diameter of the bamboo monofilament is 0.3-0.8 mm, and the diameter of the bamboo bundle 1 is 3-8 mm. Preferably, the diameter of the bamboo monofilament is 0.5-0.8 mm, and the diameter of the bamboo bundle is 5-6 mm.
[0038] The twist pitch of bamboo fibers is 10-15 mm in diameter. Bamboo fibers can be single-layer strands or multi-layer twisted structures. For example, bamboo fibers can have a 1×7 or 1×19 twist structure.
[0039] The aforementioned bamboo reinforcement can be used as a reinforcing material for concrete components in environments including seawater, marine salt spray, or saline-alkali geological environments.
[0040] The following explanation is provided through specific examples.
[0041] Example 1 This embodiment provides a 1×7 structural bamboo rib with a diameter of 12mm. The bamboo material is selected from 4-5 year old moso bamboo. After cutting and splitting the bamboo, continuous bamboo filaments are extracted longitudinally along the bamboo strips, controlling the diameter of each filament to be within 0.5±0.05mm. Approximately 150 bamboo filaments are bundled together and initially joined to form a bamboo filament bundle with a diameter of approximately 5mm.
[0042] The aforementioned bamboo filament bundles are formed using a steel stranding process, which involves twisting seven bamboo filament bundles around a central bamboo filament bundle on a stranding machine at a specified twist pitch of 60mm, forming a 1×7 bamboo rope, or bamboo rib. The twist pitch of the bamboo rib is 12mm in diameter.
[0043] Example 2 This embodiment provides a 1×19 structural bamboo rib with a diameter of 16mm. The bamboo material is selected from 4-5 year old moso bamboo. After cutting and splitting the bamboo, continuous bamboo filaments are extracted longitudinally along the bamboo strips, controlling the diameter of each filament to be 0.6±0.05mm. Approximately 200 bamboo filaments are bundled together and initially joined to form a bamboo filament bundle with a diameter of 6mm.
[0044] The aforementioned bamboo filament bundles are twisted together using a steel stranding process. They are then twisted on a stranding machine with a specified twist pitch of 80mm to form a 1×19 bamboo rope, or bamboo rib. The twist pitch of the bamboo rib is 12mm in diameter.
[0045] Example 3 This embodiment provides a 1×7 structural bamboo rib with a diameter of 12mm. The bamboo used is 4-5 year old moso bamboo. After cutting and splitting the bamboo, continuous bamboo filaments are extracted longitudinally along the bamboo strips, with the diameter of each filament controlled at 0.8±0.05mm. Approximately 120 bamboo filaments are bundled together and initially joined to form a bamboo filament bundle with a diameter of approximately 5mm.
[0046] The aforementioned bamboo filament bundles are formed using a steel stranding process, which involves twisting seven bamboo filament bundles around a central bamboo filament bundle on a stranding machine at a specified twist pitch of 60mm to form a 1×7 bamboo rope, or bamboo rib. The twist pitch of the bamboo rib is 15mm in diameter.
[0047] Example 4 This embodiment provides a 1×7 structural bamboo rib with a diameter of 12mm. The bamboo used is 5-year-old Giant Dragon Bamboo. After cutting and splitting the bamboo, continuous bamboo filaments are extracted longitudinally along the bamboo strips, with the diameter of each filament controlled at 0.5±0.05mm. Approximately 150 bamboo filaments are bundled together and initially joined to form a bamboo filament bundle with a diameter of approximately 5mm.
[0048] The aforementioned bamboo filament bundles are formed using a steel stranding process, which involves twisting seven bamboo filament bundles around a central bamboo filament bundle at a twist pitch of 60mm on a stranding machine to form a 1×7 bamboo rope, or bamboo rib. The twist pitch of the bamboo rib is 10mm in diameter.
[0049] Comparative Example The difference between Comparative Example 1 and Example 1 is that the twist pitch is 20 mm in diameter.
[0050] The difference between Comparative Example 2 and Example 1 is that the twist pitch is 5 mm in diameter.
[0051] The difference between Comparative Example 3 and Example 1 is that 450 bamboo monofilaments are bundled together and initially joined to form a bamboo filament bundle with a diameter of about 15 mm.
[0052] The difference between Comparative Example 4 and Example 3 is that approximately 240 bamboo monofilaments are bundled together and initially joined to form a bamboo filament bundle with a diameter of approximately 10 mm.
[0053] Performance testing The tensile strength and modulus of elasticity of the bamboo fibers obtained in the examples and comparative examples were tested. The test methods were designed based on GB / T1927-2021 / 2022 "Test Methods for Physical and Mechanical Properties of Small Clear Specimens of Timber" and ASTM D143-14 "Standard Test Methods for Small Clear Specimens of Timber". Bamboo strips, with dimensions of 10mm × 10mm × 60mm, were used as a control group.
[0054] Table 1 Performance test results of the examples and comparative examples Firstly, the performance analysis of the embodiments and the control group revealed that the bamboo reinforcement of this application is far superior to the ordinary bamboo strips of the control group in both tensile strength and elastic modulus. This application not only retains the natural salt and alkali corrosion resistance of bamboo, but also achieves a leapfrog improvement in mechanical properties and standardization of specifications through structural reorganization. It not only fundamentally avoids the durability problems of steel reinforcement corrosion and FRP resin degradation, but also meets the requirements of structural reinforcement materials in terms of excellent tensile strength and elastic modulus, with stable and reliable performance.
[0055] Further analysis of the performance of Comparative Examples 1 and 2 revealed that the performance of the bamboo reinforcement decreased to varying degrees when the twist pitch of this application was relatively increased or decreased. This is because, for twisted structures, the twist pitch is a crucial parameter determining the performance of the steel cable. Simply put, the twist pitch determines the tightness of the steel cable and directly affects the mechanical properties of the bamboo cable.
[0056] In addition, analysis of the performance of Comparative Examples 3 and 4 revealed that, besides the twist pitch, the properties of the bamboo fibers also changed after adjusting the thickness of the bamboo filament bundles. Logically, as the diameter of the bamboo filament bundle increases, the diameter of its bamboo ribs should also increase relatively, thus increasing the tensile strength of the bamboo ribs. However, the performance of the bamboo ribs in Comparative Examples 3 and 4 decreased to varying degrees. This is because, based on the twisted structure, it is not an inseparable, relatively static whole during the stress process. There are slight sliding and adjustments between the bamboo filament bundles. Since the bamboo filament bundles are formed by the joining of bamboo monofilaments, the change in the diameter of the bamboo filament bundle means a change in the surface area and roughness of the bamboo filament bundle. Therefore, during the slight sliding and adjustment process of the bamboo filament bundles, the diameter of the bamboo filament bundles affects the stress and "damage" of the bamboo. Thus, for the bamboo ribs of this application, not only is the twist pitch a core influencing factor on the twisted structure, but the bamboo filament bundles and bamboo monofilaments of this application are also very important. The combination and balance of the three factors enable the bamboo ribs of this application to not only retain the salt and alkali corrosion resistance of bamboo, but also achieve a leapfrog improvement in mechanical properties and standardization of specifications through structural reorganization.
[0057] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A high-performance non-resin-based bamboo fiber, characterized in that, The bamboo reinforcement is made by twisting bamboo strands together using a steel strand twisting process. The bamboo strands are composed of joined bamboo monofilaments. The twist pitch of the bamboo reinforcement is 10-15 mm in diameter, the diameter of the bamboo monofilaments is 0.3-0.8 mm, and the diameter of the bamboo strands is 3-8 mm.
2. The high-performance non-resin-based bamboo fiber according to claim 1; characterized in that, The bamboo monofilaments are the portion taken from the middle section of the bamboo after removing the yellow and green parts of the bamboo. This portion is 1 / 3 to 1 / 2 of the total length of the bamboo.
3. The high-performance non-resin-based bamboo fiber according to claim 1, characterized in that, The twisting pitch of the bamboo rope is 60-80mm.
4. The high-performance non-resin-based bamboo reinforcement according to claim 1, characterized in that, The bamboo reinforcement includes a single-layer strand structure or a multi-layer twisted structure.
5. The high-performance non-resin-based bamboo fiber according to claim 4, characterized in that, The bamboo reinforcement has a structure of 1×7 and 1×19.
6. The high-performance non-resin-based bamboo reinforcement according to claim 1, characterized in that, The diameter of the bamboo monofilament is 0.5-0.8 mm, and the diameter of the bamboo bundle is 5-6 mm.
7. An application of the high-performance non-resin-based bamboo fiber as described in any one of claims 1-6, characterized in that, The bamboo reinforcement is used as a reinforcing material for concrete components in environments including seawater, marine salt spray, or saline-alkali geological environments.