Interface agent for reducing rebound rate of shotcrete and construction method

Abstract

The application discloses an interface agent for reducing rebound rate of sprayed concrete, which comprises the following raw materials: sandstone, a quickening agent, mineral powder, aluminate, a water reducing agent, a defoaming agent and water, wherein the sandstone is 20-30 parts, the quickening agent is 30 parts, the mineral powder is 20-30 parts, the aluminate is 20-25 parts, the water reducing agent is 5-15 parts, the defoaming agent is 3-5 parts, and the water is 20-30 parts; the interface agent for reducing rebound rate of sprayed concrete and the construction method can effectively reduce the rebound rate of the sprayed concrete, save cost, and make the concrete easy to be bonded with the interface agent in the later period, so that the overall strength is large, and the anti-seepage and waterproof performance is increased to a certain extent.

Description

Technical Field

[0001] This invention relates to the field of concrete spraying technology, and in particular to an interface agent and construction method for reducing the rebound rate of sprayed concrete. Background Technology

[0002] The rebound rate of shotcrete refers to the proportion of the weight of the concrete that falls off after being shot onto the surrounding rock to the total weight of the shotcrete. Due to various factors such as the inability of the shotcrete particles to solidify in time and their interaction, a large amount of concrete will rebound and fall off during shotcreting.

[0003] Currently, in order to reduce the rebound rate of shotcrete during construction, the following measures are usually taken: controlling raw materials, optimizing mix proportions, selecting additives, adding admixtures, optimizing construction process parameters, and standardizing construction methods.

[0004] Currently, the main construction methods for shotcrete include dry spraying, wet spraying, semi-damp spraying, and mixed spraying. Dry spraying is widely used in tunnel construction in China due to its convenience, mobility, ease of operation, and low machine investment costs; however, its development is limited by the high rebound rate and dust levels. Wet spraying, semi-damp spraying, and mixed spraying methods require high-performance spraying machinery, and machinery cleaning and troubleshooting are more complicated. Relevant construction specifications require that the rebound rate of shotcrete on sidewalls should not exceed 15%, and on the arch, it should not exceed 25%. An excessively high rebound rate of shotcrete will result in significant material waste and increased construction costs; therefore, reducing the rebound rate of shotcrete is a crucial task. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned problems by providing an interface agent and construction method that can effectively reduce the rebound rate of shotcrete, save costs, and make the concrete easy to bond with the interface agent in the later stage, resulting in high overall strength and significantly improving the anti-seepage and waterproof performance.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: an interface agent for reducing the rebound rate of shotcrete, comprising the following raw materials: sand and gravel, quick-setting agent, mineral powder, aluminate, water-reducing agent and defoamer, wherein the sand and gravel are 20-30 parts, the quick-setting agent is 30 parts, the mineral powder is 20-30 parts, the aluminate is 20-25 parts, the water-reducing agent is 5-15 parts, and the defoamer is 3-5 parts.

[0007] Preferably, the mixture comprises 25 parts sand and gravel, 30 parts quick-setting agent, 25 parts mineral powder, 23 parts aluminate, 10 parts water-reducing agent, and 4 parts defoamer.

[0008] Preferably, the interface agent also includes a pH buffer, wherein the pH buffer is 0.5-1.5 parts.

[0009] Preferably, the aluminate is a thioaluminate.

[0010] Preferably, the particle size of the mineral powder is not less than 600 mesh.

[0011] Preferably, the pH buffer is one or a combination of potassium hydrogen phthalate, mixed phosphate and sodium tetraborate.

[0012] A construction method for an interface agent to reduce the rebound rate of shotcrete includes the following steps: (1) Bedrock surface excavation construction: excavate the bedrock surface according to the construction drawings, measure the excavation dimensions, and check for areas that need to be treated, such as areas with encroachment lines; (2) Hazard investigation: remove loose and dangerous stones, and take measures such as drainage and plugging for areas with serious water seepage; (3) Interface agent construction; (4) Quality inspection: check whether the interface agent is sprayed evenly and whether the thickness meets the relevant requirements; (5) Shotcrete construction: after the interface agent has been sprayed and solidified, shotcrete construction can be carried out.

[0013] Preferably, step (3) includes the following steps: (31) preparing the interface agent according to the proportion and injecting it into the concrete spraying machine; (32) spraying once, spraying the interface agent onto the inner wall of the tunnel, with a thickness of 1-3cm; (33) solidification, spraying a second time after 5-10 minutes of the first spraying; (34) the thickness of the second spraying is 2-4cm; (35) the quality of the second spraying is tested after solidification for 5-10 minutes.

[0014] Preferably, the total thickness of the interface agent sprayed twice in step (35) does not exceed 6 cm.

[0015] Compared with the prior art, the interface agent and construction method for reducing the rebound rate of shotcrete disclosed in this invention have the following beneficial effects: (1) It reduces the rebound rate of shotcrete, reduces the damage to construction materials, and saves construction costs; (2) It ensures the quality of the project entity. The added interface agent has the effect of reducing rebound and increasing adhesion, and ensures the quality of the joint surface; (3) It increases structural stability: By spraying a special interface agent for shotcrete of the invention, the excavated bedrock surface is pretreated once. By utilizing the covering and surface penetration effect of the interface agent, the excavated bedrock surface forms an integral structure, which plays a temporary reinforcement role, increases the overall stability of the structure, and at the same time plays a certain role in preventing seepage and waterproofing; (4) It reduces dust and improves the construction environment: By spraying a special interface agent for shotcrete of the invention, the adhesion between the bedrock surface and shotcrete is increased, and the adsorption capacity of dust and fine particles during construction is enhanced; at the same time, due to the reduction of the rebound rate of concrete, the dust and fine particles generated by concrete rebound can also be reduced. Detailed Implementation

[0016] An interface agent for reducing the rebound rate of shotcrete comprises the following raw materials: sand and gravel, quick-setting agent, mineral powder, aluminate, water-reducing agent and defoamer, wherein the sand and gravel are 20-30 parts, the quick-setting agent is 30 parts, the mineral powder is 20-30 parts, the aluminate is 20-25 parts, the water-reducing agent is 5-15 parts, the defoamer is 3-5 parts, the pH buffer is 0.5-1.5 parts and water.

[0017] Example 1: The interface agent contains 20 parts sand and gravel, 30 parts quick-setting agent, 20 parts mineral powder, 20 parts aluminate, 5 parts water-reducing agent, 3 parts defoamer, 0.5 parts pH buffer, and water. The aluminate is sulfoaluminate, the mineral powder has a particle size of not less than 600 mesh, and the pH buffer is one or a combination of potassium hydrogen phthalate, mixed phosphate, and sodium tetraborate.

[0018] Example 2: The interface agent contains 25 parts sand and gravel, 30 parts quick-setting agent, 25 parts mineral powder, 23 parts aluminate, 10 parts water-reducing agent, 4 parts defoamer, 1 part pH buffer, and water. The aluminate is sulfoaluminate, the mineral powder has a particle size of not less than 600 mesh, and the pH buffer is one or a combination of potassium hydrogen phthalate, mixed phosphate, and sodium tetraborate.

[0019] Example 3: The interface agent contains 30 parts sand and gravel, 30 parts quick-setting agent, 30 parts mineral powder, 25 parts aluminate, 15 parts water-reducing agent, 5 parts defoamer, 1.5 parts pH buffer, and water. The aluminate is sulfoaluminate, the mineral powder has a particle size of not less than 600 mesh, and the pH buffer is one or a combination of potassium hydrogen phthalate, mixed phosphate, and sodium tetraborate.

[0020] Example 4: The interface agent consists of 30 parts sand and gravel, 30 parts quick-setting agent, 30 parts mineral powder, 25 parts aluminate, 15 parts water-reducing agent, 5 parts defoamer, and water. The aluminate is sulfoaluminate, the mineral powder has a particle size of not less than 600 mesh, and the pH buffer is one or a combination of potassium hydrogen phthalate, mixed phosphate, and sodium tetraborate.

[0021] Example 5: The interface agent contains 30 parts sand and gravel, 30 parts quick-setting agent, 30 parts mineral powder, 25 parts aluminate, 15 parts water-reducing agent, 5 parts defoamer, and a mixture of water and pH buffer with a mass concentration of 5-10%. The aluminate is sulfoaluminate, the mineral powder has a particle size of not less than 600 mesh, and the pH buffer is one or a combination of potassium hydrogen phthalate, mixed phosphate, and sodium tetraborate.

[0022] In this interface agent, the sand and gravel have a mesh size between 16 and 24. The quick-setting agent slows down the various raw materials and increases their adhesion to the tunnel. Furthermore, the presence of sand and gravel in the interface agent creates a rough and uneven surface after spraying, further facilitating contact with concrete and reducing the rebound rate of shotcrete, thus lowering costs. Simultaneously, the interface agent easily bonds to concrete, providing some degree of seepage prevention and rodent control. The defoamer eliminates air bubbles in the interface agent, preventing internal blistering after spraying. Mineral powder and aluminates increase overall strength, while the water-reducing agent reduces the fluidity of the interface agent, preventing rebound. The pH buffer is liquid or solid calcium hydroxide; its addition makes the overall interface agent weakly alkaline (pH value not less than 7), preventing the embedded reinforcing steel from rusting.

[0023] The present invention also discloses a construction method for an interface agent to reduce the rebound rate of shotcrete, including the following steps: (1) Bedrock surface excavation construction, bedrock surface excavation construction according to the construction drawings, measuring the excavation dimensions, checking for any areas that need to be treated such as encroachment lines; (2) Hidden danger investigation, removing loose and dangerous stones, and taking measures such as drainage and plugging for areas with serious water seepage; (3) Interface agent construction, specifically the following steps: (31) Prepare the interface agent according to the proportion and inject it into the concrete spraying machine; (32) First spraying, spray the interface agent onto the inner wall of the tunnel, with a first spray thickness of 1-3cm; (33) Solidification, perform a second spraying 5-10 minutes after the first spraying; (34) Second spray thickness of 2-4cm; (35) Perform quality inspection after the second spray solidifies for 5-10 minutes; the total thickness of the interface agent in the two sprays shall not exceed 6cm; (4) Quality inspection, checking whether the interface agent spraying is uniform and whether the thickness meets the relevant requirements; (5) Shotcrete construction, after the interface agent spraying is completed and solidified, shotcrete construction can be carried out.

[0024] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An interface agent for reducing the rebound rate of shotcrete, characterized in that, The raw materials include sand and gravel, quick-setting agent, mineral powder, aluminate, water-reducing agent and defoamer, wherein sand and gravel are 20-30 parts, quick-setting agent is 30 parts, mineral powder is 20-30 parts, aluminate is 20-25 parts, water-reducing agent is 5-15 parts and defoamer is 3-5 parts.

2. The interface agent for reducing the rebound rate of shotcrete according to claim 1, characterized in that, The mixture consists of 25 parts sand and gravel, 30 parts quick-setting agent, 25 parts mineral powder, 23 parts aluminate, 10 parts water-reducing agent, and 4 parts defoamer.

3. The interface agent for reducing the rebound rate of shotcrete according to claim 1 or 2, characterized in that, The interface agent also includes a pH buffer, of which 0.5-1.5 parts are pH buffer.

4. The interface agent for reducing the rebound rate of shotcrete according to claim 1, characterized in that, The aluminate is a thioaluminate.

5. The interface agent for reducing the rebound rate of shotcrete according to claim 3, characterized in that, The particle size of the mineral powder is not less than 600 mesh.

6. The interface agent for reducing the rebound rate of shotcrete according to claim 3, characterized in that, The pH buffer is one or a combination of potassium hydrogen phthalate, mixed phosphate and sodium tetraborate.

7. A construction method for an interface agent for reducing the rebound rate of shotcrete as described in any one of claims 1-6, characterized in that, The process includes the following steps: (1) Bedrock surface excavation: excavate the bedrock surface according to the construction drawings, measure the excavation dimensions, and check for any areas that need to be treated, such as areas with encroachment lines; (2) Hazard investigation: remove loose and dangerous rocks, and take measures to drain and plug leaks in areas with severe water seepage; (3) Interface agent application; (4) Quality inspection: check whether the interface agent is sprayed evenly and whether the thickness meets the relevant requirements; (5) Shotcrete application: after the interface agent has been sprayed and solidified, shotcrete application can be carried out.

8. The construction method of the interface agent for reducing the rebound rate of shotcrete according to claim 7, characterized in that, Step (3) includes the following steps: (31) Prepare the interface agent according to the proportion and inject it into the concrete spraying machine; (32) Spray the interface agent onto the inner wall of the tunnel in one spraying, with a thickness of 1-3 cm in one spraying; (33) Solidify, spray a second time after 5-10 minutes of the first spraying; (34) The thickness of the second spraying is 2-4 cm; (35) Perform quality testing on the second spraying after solidification for 5-10 minutes.

9. The construction method of the interface agent for reducing the rebound rate of shotcrete according to claim 8, characterized in that, In step (35), the total thickness of the interface agent sprayed twice does not exceed 6 cm.