Fiber concrete for reinforcing and repairing tunnel and manufacturing method thereof

Abstract

The invention discloses fiber concrete for reinforcing and repairing a tunnel, which belongs to the technical field of fiber concrete and comprises the following components in parts by weight: 300-400 parts of silicate water; 20-50 parts of a fiber material; 500 to 800 parts of aggregate; 100 to 150 parts of water; and 5-15 parts of an additive. The Portland cement, the long fibers, the aggregate and the mineral admixture are uniformly mixed, then the short fibers are added for secondary mixing, finally the carbon nanofibers are added for tertiary mixing, uniform distribution of the fibers is ensured, then the admixture and the water are added into a stirrer, stirring is continued until the concrete is uniform, and the concrete is prepared. And finally, the concrete is poured to the to-be-reinforced and repaired part of the tunnel, the concrete is cured to the design strength according to a conventional method after vibration, the tensile strength and shear strength of the fiber concrete prepared through the technical scheme are remarkably improved, and meanwhile the crack resistance and toughness of the concrete are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of fiber concrete, and in particular relates to fiber concrete for tunnel reinforcement and repair and a manufacturing method thereof. Background Art

[0002] As an indispensable and main component of tunnel structures, concrete occupies a pivotal position in the field of modern engineering due to its many significant advantages. The abundance of its raw materials provides a solid foundation for large-scale application. From sand, cement to water, these basic ingredients are widely available around the world, ensuring the stability and sustainability of concrete supply. Low price is another major driving force for the widespread application of concrete. Compared with other high-performance materials, it is cost-effective and particularly suitable for infrastructure construction projects with limited funds but huge demand. The preparation process is simple and direct, whether it is on-site mixing or prefabricated components, it can flexibly adapt to various construction conditions, greatly shortening the construction period and improving work efficiency.

[0003] The plasticity and ease of shaping of concrete have added infinite possibilities to its application in tunnel structures. Through formwork casting, complex and changeable structural forms can be accurately shaped to meet the strict requirements of tunnel design for shape, size and precision. In addition, the durability and fire resistance of concrete are also important reasons for its popularity. In harsh natural environments, such as humidity, corrosion, high temperature and other conditions, concrete can still maintain structural stability and safety, effectively extending the service life of the tunnel. Its good fire resistance provides a solid guarantee for the safety of tunnels in emergencies such as fires.

[0004] However, everything has its two sides, and concrete is no exception. Although it performs well in terms of compressive strength and can withstand huge pressure without deformation or damage, it has obvious shortcomings in terms of tensile strength. Generally speaking, the tensile strength of concrete is only about 10% of its compressive strength, which means that concrete is very prone to cracks when subjected to tensile stress. This feature limits the performance of concrete in certain specific application scenarios, especially in structures that need to withstand large tensile or shear forces, where pure concrete materials cannot meet the design requirements. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that concrete is prone to cracks. This characteristic limits the performance of concrete in certain specific application scenarios, especially in structures that need to withstand large tensile or shear forces. Pure concrete materials cannot meet the design requirements. Therefore, a fiber concrete for tunnel reinforcement and repair and its manufacturing method are proposed.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: A fiber concrete for tunnel reinforcement and repair, comprising the following components in parts by weight:

[0007]

[0008] As a further description of the above technical solution:

[0009] The fiber material comprises long fibers, short fibers and carbon nanofibers, wherein the weight portion of the long fibers is 10-30 parts, the weight portion of the short fibers is 5-15 parts, and the weight portion of the carbon nanofibers is 1-5 parts.

[0010] As a further description of the above technical solution:

[0011] The long fibers are glass fibers or steel fibers, and have a length of 20-60 mm and a diameter of 0.1-0.12 mm.

[0012] As a further description of the above technical solution:

[0013] The short fibers have a length of 25-38 mm and a diameter of less than 0.05 mm.

[0014] As a further description of the above technical solution:

[0015] The aggregate is sand, crushed stone or a mixture of the two.

[0016] As a further description of the above technical solution:

[0017] The admixtures include an early strength agent, a water reducing agent, an anti-cracking agent and a waterproofing agent.

[0018] As a further description of the above technical solution:

[0019] It also includes 5-20 parts of mineral admixture, wherein the mineral admixture is at least one of fly ash, silica fume or slag.

[0020] As a further description of the above technical solution:

[0021] The present invention also provides a method for manufacturing fiber concrete for tunnel reinforcement and repair, comprising the following steps:

[0022] a) preparing raw materials: preparing the silicate cement, the fiber material, the aggregate, the water and the admixture according to parts by weight;

[0023] b) Mixing dry materials: The silicate cement, the long fibers, the aggregates and the mineral admixtures are mixed uniformly in a mixer for the first time; the short fibers are then added for the second mixing; and finally the carbon nanofibers are added for the third mixing to ensure that all the fiber materials are evenly distributed in the concrete;

[0024] c) adding the admixture and the water: adding the admixture and the water into a mixer, and continuing to stir until the concrete is uniform and the fiber material is uniformly dispersed in the concrete;

[0025] d) Pouring and curing: Pour the mixed concrete into the tunnel to be reinforced and repaired, vibrate it appropriately, and then cure it according to conventional methods until the concrete reaches the designed strength.

[0026] As a further description of the above technical solution:

[0027] In step d), the curing temperature is 20-30° C. and the curing time is 7-28 days.

[0028] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0029] 1. In the present invention, the skeleton of concrete is formed by aggregate, silicate cement is used as the main cementitious material of concrete; fiber materials (long fibers, short fibers, carbon nanofibers) enhance the crack resistance, shear resistance and tensile strength of concrete, wherein long fibers provide macroscopic reinforcement effect, short fibers and carbon nanofibers provide reinforcement and toughening effect at the micro level, water is used as solvent and reaction medium to participate in the hydration reaction of cement, admixtures improve the performance of concrete, wherein early strength agent accelerates cement hydration, water reducer improves workability, anti-cracking agent and waterproofing agent enhance durability, mineral admixtures: improve the durability, strength and To reduce the heat of hydration, when preparation is needed, only the above materials need to be prepared according to the component ratio. First, the silicate cement, long fiber, aggregate and mineral admixture are evenly mixed, and then the short fiber is added for secondary mixing. Finally, the carbon nanofiber is added for tertiary mixing to ensure the uniform distribution of the fiber. Then, the admixture and water are added to the mixer, and stirring is continued until the concrete is uniform. Finally, the concrete is poured into the part of the tunnel to be reinforced and repaired, and after vibration, it is cured to the designed strength according to the conventional method. The fiber concrete prepared by this technical solution significantly improves the tensile strength and shear strength of the concrete, while also improving the crack resistance and toughness of the concrete.

[0030] 2. In the present invention, by reasonably controlling the component ratio in the fiber material, short fibers and long fibers are added to the concrete at the same time. The short fibers (such as polypropylene fibers) are mainly responsible for enhancing the initial crack toughness and impact resistance of the concrete and preventing crack expansion; the long fibers (such as steel fibers and glass fibers) improve the compressive strength and flexural strength of the concrete, and cooperate with the carbon nanotube fibers, which can not only enhance the strength and flexibility, but also send out signals when the concrete is damaged, realize the self-monitoring function, and facilitate timely maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 This is a component diagram of fiber concrete used for tunnel reinforcement and repair.

[0033] Figure 2 A step diagram of a method for making fiber concrete for tunnel reinforcement and repair DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0038] In the description of the embodiments of the present invention, it should be noted that the terms "upper", "inner", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0039] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] See also Figure 1 The present invention provides a technical solution: a fiber concrete for tunnel reinforcement and repair, comprising the following components in parts by weight:

[0041]

[0042] The fiber material comprises long fibers, short fibers and carbon nanofibers, wherein the weight portion of the long fibers is 10-30 parts, the weight portion of the short fibers is 5-15 parts, and the weight portion of the carbon nanofibers is 1-5 parts.

[0043] The long fibers are glass fibers or steel fibers, and have a length of 20-60 mm and a diameter of 0.1-0.12 mm.

[0044] The length of the short fiber is 25-38 mm, and the diameter is less than 0.05 mm. The length and diameter of the long fiber are greater than the short fiber. During the preparation process, the short fiber is wrapped inside the long fiber, which improves the strength and tensile resistance and avoids cracks.

[0045] The aggregate is sand, crushed stone or a mixture of the two.

[0046] The admixtures include an early strength agent, a water reducing agent, an anti-cracking agent and a waterproofing agent.

[0047] It also includes 5-20 parts of mineral admixture, wherein the mineral admixture is at least one of fly ash, silica fume or slag.

[0048] See also Figure 2 The present invention also provides a method for manufacturing fiber concrete for tunnel reinforcement and repair, comprising the following steps:

[0049] a) preparing raw materials: preparing the silicate cement, the fiber material, the aggregate, the water and the admixture according to parts by weight;

[0050] b) Mixing dry materials: The silicate cement, the long fibers, the aggregates and the mineral admixtures are mixed uniformly in a mixer for the first time; the short fibers are then added for the second mixing; and finally the carbon nanofibers are added for the third mixing to ensure that all the fiber materials are evenly distributed in the concrete;

[0051] c) adding the admixture and the water: adding the admixture and the water into a mixer, and continuing to stir until the concrete is uniform and the fiber material is uniformly dispersed in the concrete;

[0052] d) Pouring and curing: Pour the mixed concrete into the tunnel to be reinforced and repaired, vibrate it appropriately, and then cure it according to conventional methods until the concrete reaches the designed strength.

[0053] In step d), the curing temperature is 20-30° C. and the curing time is 7-28 days.

[0054] Working principle: Aggregates form the skeleton of concrete, and silicate cement is the main cementing material of concrete; fiber materials (long fibers, short fibers, carbon nanofibers) enhance the crack resistance, shear resistance and tensile strength of concrete, among which long fibers provide macroscopic reinforcement effects, short fibers and carbon nanofibers provide reinforcement and toughening effects at the micro level, and water, as a solvent and reaction medium, participates in the hydration reaction of cement. Admixtures improve the performance of concrete, among which early strength agents accelerate cement hydration, water reducers improve workability, anti-cracking agents and waterproofing agents enhance durability, and mineral admixtures improve the durability, strength and toughness of concrete. Low hydration heat. When preparation is needed, only the above materials need to be prepared in the composition ratio. First, mix the silicate cement, long fiber, aggregate and mineral admixture evenly, then add the short fiber for secondary mixing, and finally add the carbon nanofiber for tertiary mixing to ensure the uniform distribution of the fiber. Then, add the admixture and water into the mixer and continue to stir until the concrete is uniform. Finally, pour the concrete into the part of the tunnel to be reinforced and repaired, vibrate it and cure it to the designed strength according to the conventional method. The fiber concrete prepared by this technical solution significantly improves the tensile strength and shear strength of the concrete, while also improving the crack resistance and toughness of the concrete.

[0055] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A fiber concrete for tunnel reinforcement and repair, characterized in that: The composition comprises the following components in parts by weight:

2. The fiber concrete for tunnel reinforcement and repair according to claim 1, characterized in that: The fiber material comprises long fibers, short fibers and carbon nanofibers, wherein the weight portion of the long fibers is 10-30 parts, the weight portion of the short fibers is 5-15 parts, and the weight portion of the carbon nanofibers is 1-5 parts.

3. The fiber concrete for tunnel reinforcement and repair according to claim 2, characterized in that: The long fibers are glass fibers or steel fibers, and have a length of 20-60 mm and a diameter of 0.1-0.12 mm.

4. The fiber concrete for tunnel reinforcement and repair according to claim 2, characterized in that: The length of the short fibers is 25-38 mm and the diameter is less than 0.05 mm.

5. The fiber concrete for tunnel reinforcement and repair according to claim 1, characterized in that: The aggregate is sand, crushed stone or a mixture of the two.

6. The fiber concrete for tunnel reinforcement and repair according to claim 1, characterized in that: The admixtures include an early strength agent, a water reducing agent, an anti-cracking agent and a waterproofing agent.

7. The fiber concrete for tunnel reinforcement and repair according to claim 1, characterized in that: It also includes 5-20 parts of mineral admixture, wherein the mineral admixture is at least one of fly ash, silica fume or slag.

8. A method for manufacturing fiber concrete for tunnel reinforcement and repair according to claims 1-7, characterized in that: The following steps are involved: a) preparing raw materials: preparing the silicate cement, the fiber material, the aggregate, the water and the admixture according to parts by weight; b) Mixing dry materials: The silicate cement, the long fibers, the aggregates and the mineral admixtures are mixed uniformly in a mixer for the first time; the short fibers are then added for the second mixing; and finally the carbon nanofibers are added for the third mixing to ensure that all the fiber materials are evenly distributed in the concrete; c) adding the admixture and the water: adding the admixture and the water into a mixer, and continuing to stir until the concrete is uniform and the fiber material is uniformly dispersed in the concrete; d) Pouring and curing: Pour the mixed concrete into the tunnel to be reinforced and repaired, vibrate it appropriately, and then cure it according to conventional methods until the concrete reaches the designed strength.

9. The method for manufacturing fiber concrete for tunnel reinforcement and repair according to claim 8, characterized in that: In step d), the curing temperature is 20-30° C. and the curing time is 7-28 days.

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