Spraying concrete construction method

Abstract

A concrete spraying construction method comprises the following steps that a spraying face is purified, and reinforcing steel bars are exposed; steel bar binding is conducted on the exposed steel bars; spraying concrete, and performing concrete spraying operation to obtain a spraying surface; and the spraying face is leveled and maintained, and construction operation is completed. According to the construction method, the spraying face is cleaned, then the exposed reinforcing steel bars are bound with the external reinforcing steel bars, then the external concrete is sprayed, the reinforced concrete structure can be obtained, the internal structure and the external structure are arranged into a whole, and the repairing effect on the original structure is guaranteed.

Description

Technical Field

[0001] The present application relates to a sprayed concrete construction method. Background Art

[0002] Whether it is a new building or a building renovation, in order to improve the strength of the building walls and other external components and the strength of the connection with the outside, the walls themselves need to be repaired and strengthened. Today's shotcrete is formed by loading pre-mixed cement, sand, gravel, water and a certain amount of admixtures into a sprayer, using high-pressure air to send it to the nozzle and mix it with the accelerator, and then spraying it at a high speed onto the surface of rock or concrete.

[0003] Existing shotcrete is generally used for auxiliary support and protection of new buildings, but it is not completely suitable for building renovation and repair scenarios because it is easy to separate from the foundation wall due to the relatively loose contact surface during use. Summary of the invention

[0004] In order to solve the above problems, the present application proposes a spraying concrete construction method, comprising the following steps:

[0005] The spraying surface is cleaned and the steel bars are exposed;

[0006] Tie the exposed steel bars;

[0007] Shotcrete is sprayed and a shotcrete operation is performed to obtain a sprayed surface;

[0008] The sprayed surface is leveled and maintained to complete the construction work. The present application cleans the sprayed surface and then ties the exposed steel bars with the external steel bars, and then sprays the external concrete, which can not only obtain a reinforced concrete structure, but also integrate the internal and external structures, ensuring the repair effect of the original structure.

[0009] Preferably, during the purification process, the following steps are performed:

[0010] For the sprayed surface with finishing layer, remove the exposed structural surface and perform roughening treatment, with the roughening depth not less than 5mm;

[0011] For the spraying surface of the clean water surface, roughening treatment is carried out, and the roughening depth is not less than 5mm;

[0012] After roughening, clean with high-pressure air at least twice; then clean with high-pressure water at least twice.

[0013] Preferably, the steel bar binding is performed in the following manner:

[0014] Lay out and position according to design requirements, determine the position of anchor reinforcement, the position of the holes through which reinforcement passes through the wall and the plate, and the position of the reinforcement of the inner and outer walls;

[0015] According to the layout position, holes are drilled at the anchor bars, wall penetration and structure penetration positions;

[0016] After confirming that the location and depth of the inspection hole meet the design requirements, anchor the reinforcement;

[0017] According to the layout position, the reinforcement is laid on the inner and outer wall surfaces and tied firmly with the anchor bars. The beam and column concrete components are chiseled out according to the design requirements to expose the main reinforcement of the original components without damaging the main reinforcement of the original components; the main reinforcement added according to the design requirements is welded to the main reinforcement of the original components through short steel bars; the U-shaped stirrups are welded to the stirrups of the original components. The present application uses different fixing and external connection methods for the main reinforcement and stirrups of the original components, and adopts different connection methods with the external main reinforcement and stirrups, which are more convenient to connect when in use and have high stability.

[0018] Preferably, the shotcrete operation is carried out in the following manner:

[0019] For the parts that need formwork, such as door and window openings, and the sides of the edges of beams and columns, formwork shall be provided according to the designed dimensions, and supports and tie rods shall be added;

[0020] The shotcrete shall be sprayed according to the following requirements:

[0021] The nozzle is set vertically to the sprayed surface, with a distance of 0.8-1.2m. The working air pressure at the nozzle is 0.15-0.2Mpa; the air pressure is controlled at 0.3-0.4Mpa;

[0022] When spraying, the nozzle moves along a spiral trajectory (R=300mm) in a circle and a half circle, spraying the depressions first and then filling them up; the thickness of one spray is 2-3cm; the interval time between spraying layers is 10-15 minutes;

[0023] The temperature in the working area shall not be lower than 5℃;

[0024] The temperature of the dry mix entering the sprayer and the water temperature shall not be less than 5°C.

[0025] Preferably, the leveling is performed in the following manner: using a large bar and a wooden trowel to smooth the surface, the surface flatness does not exceed 5mm / 1m;

[0026] The maintenance is carried out in the following manner:

[0027] Within 2-4 hours after leveling, start water spraying and curing. The number of water spraying should be sufficient to keep the concrete in a sufficiently moist state.

[0028] The curing time shall not be less than 10 days and the curing temperature shall not be lower than 5°C.

[0029] Preferably, the shotcrete comprises the following raw materials in parts by mass:

[0030] Portland cement: 400-500 parts;

[0031] Fine aggregate: 900-1000 parts;

[0032] Coarse aggregate: 650-750 parts;

[0033] Polypropylene fiber: 1-2 parts;

[0034] Accelerator: 50-60 parts;

[0035] Water: 180-220 parts.

[0036] Preferably, the quick-setting agent comprises the following components in parts by weight:

[0037] Aluminum sulfate: 45-55 parts;

[0038] Citric acid: 2-3 parts;

[0039] Acetic acid: 2-3 parts. The present application adopts aluminum sulfate, citric acid and acetic acid to form a composite accelerating agent, which has good effect and stability and is suitable for the operation of shotcrete.

[0040] Preferably, the fine aggregate comprises fine sand with a particle size of less than 0.35 mm and small high-temperature asphalt particles with a particle size of less than 0.35, wherein the mass ratio of the fine sand to the small high-temperature asphalt particles is 1-1.2;

[0041] The coarse aggregate includes crushed stone with a particle size of less than 5 mm and large high-temperature asphalt particles with a particle size greater than 0.35 and less than 5 mm, wherein the mass ratio of crushed stone to large high-temperature asphalt particles is 4-5. The present application uses a combined batching method for fine skeleton and coarse aggregate, one part of which is fine sand and crushed stone, and the other part is high-temperature asphalt particles. The high-temperature asphalt particles need to be combined with the accelerator first to form a quick-setting center, ensure its quick-setting effect, and also contribute to the stability of the accelerator.

[0042] Preferably, the shotcrete is synthesized in the following manner:

[0043] Put citric acid and acetic acid into water, then add aluminum sulfate and keep stirring until it is completely dissolved;

[0044] The small high-temperature asphalt particles in the fine aggregate and the large high-temperature asphalt particles in the coarse aggregate are introduced into an aqueous solution containing citric acid, acetic acid and aluminum sulfate, and are fully stirred;

[0045] Then, polypropylene fibers are added to obtain a dissolving solution;

[0046] The fine sand in the fine aggregate, the crushed stone in the coarse aggregate and the silicate cement are dry-mixed uniformly to obtain mixed cement;

[0047] The mixed cement is introduced into the dissolving liquid and mixed evenly to obtain the sprayed concrete.

[0048] Preferably, the polypropylene fiber has a diameter of 0.4-0.7 mm and a length of 20-40 mm.

[0049] This application can bring the following beneficial effects:

[0050] 1. This application cleans the spraying surface and then ties the exposed steel bars with the external steel bars, and then sprays the external concrete, which can not only obtain a reinforced concrete structure, but also integrate the internal and external structures, ensuring the repair effect of the original structure.

[0051] 2. The present application adopts different fixing and external connection methods for the main reinforcement and stirrups of the original component, and adopts different connection methods with the external main reinforcement and stirrups respectively. When in use, the connection is more convenient and the connection stability is also high.

[0052] 3. The present application adopts aluminum sulfate, citric acid and acetic acid to form a composite accelerating agent, which has good effect and stability and is suitable for the operation of shotcrete.

[0053] 4. This application uses a combination of ingredients for fine skeleton and coarse aggregate, one part of which is fine sand and crushed stone, and the other part is high-temperature asphalt particles. The high-temperature asphalt particles need to be combined with the accelerator first to form a quick-setting center, ensure its quick-setting effect, and also help stabilize the accelerator. DETAILED DESCRIPTION

[0054] In order to clearly illustrate the technical features of this solution, this application is elaborated in detail below through specific implementation methods.

[0055] A spraying concrete construction method comprises the following steps:

[0056] S1. The spray surface is cleaned and the steel bars are exposed;

[0057] During the purification process, proceed as follows:

[0058] For the sprayed surface with finishing layer, remove the exposed structural surface and perform roughening treatment, with the roughening depth not less than 5mm;

[0059] For the spraying surface of the clean water surface, roughening treatment is carried out, and the roughening depth is not less than 5mm;

[0060] After roughening, clean with high-pressure air at least twice; then clean with high-pressure water at least twice.

[0061] S2. Tie the exposed steel bars;

[0062] The steel bar binding is carried out in the following manner:

[0063] Lay out and position according to design requirements, determine the position of anchor reinforcement, the position of the holes through which reinforcement passes through the wall and the plate, and the position of the reinforcement of the inner and outer walls;

[0064] According to the layout position, holes are drilled at the anchor bars, wall penetration and structure penetration positions;

[0065] After confirming that the location and depth of the inspection hole meet the design requirements, anchor the reinforcement;

[0066] According to the layout position, the reinforcement is arranged on the inner and outer wall surfaces and firmly tied with the anchor bars. For the concrete components of beams and columns, the main reinforcement of the original components is chiseled out according to the design requirements, and the main reinforcement of the original components must not be damaged; the main reinforcement added according to the design requirements is welded to the main reinforcement of the original components through short steel bars; U-shaped stirrups are welded to the stirrups of the original components.

[0067] S3. Shotcrete is sprayed and the sprayed concrete operation is performed to obtain a sprayed surface;

[0068] The sprayed concrete operation is carried out as follows:

[0069] For the parts that need formwork, such as door and window openings, and the sides of the edges of beams and columns, formwork shall be provided according to the designed dimensions, and supports and tie rods shall be added;

[0070] The shotcrete shall be sprayed according to the following requirements:

[0071] The nozzle is set vertically to the sprayed surface, with a distance of 0.8-1.2m. The working air pressure at the nozzle is 0.15-0.2Mpa; the air pressure is controlled at 0.3-0.4Mpa;

[0072] When spraying, the nozzle moves along a spiral trajectory (R=300mm) in a circle and a half circle, spraying the depressions first and then filling them up; the thickness of one spray is 2-3cm; the interval time between spraying layers is 10-15 minutes;

[0073] The temperature in the working area shall not be lower than 5℃;

[0074] The temperature of the dry mix entering the sprayer and the water temperature shall not be less than 5°C.

[0075] The sprayed concrete comprises the following raw materials in parts by mass:

[0076] Portland cement: 400-500 parts;

[0077] Fine aggregate: 900-1000 parts;

[0078] Coarse aggregate: 650-750 parts;

[0079] Polypropylene fiber: 1-2 parts;

[0080] Accelerator: 50-60 parts;

[0081] Water: 180-220 parts.

[0082] The quick-setting agent comprises the following components in parts by mass:

[0083] Aluminum sulfate: 45-55 parts;

[0084] Citric acid: 2-3 parts;

[0085] Acetic acid: 2-3 parts.

[0086] The fine aggregate includes fine sand with a particle size of less than 0.35 mm and small high-temperature asphalt particles with a particle size of less than 0.35, wherein the mass ratio of the fine sand to the small high-temperature asphalt particles is 1-1.2;

[0087] The coarse aggregate includes crushed stone with a particle size of less than 5 mm and high-temperature asphalt particles with a particle size greater than 0.35 and less than 5 mm, wherein the mass ratio of the crushed stone to the high-temperature asphalt particles is 4-5.

[0088] The sprayed concrete is synthesized as follows:

[0089] Put citric acid and acetic acid into water, then add aluminum sulfate and keep stirring until it is completely dissolved;

[0090] The small high-temperature asphalt particles in the fine aggregate and the large high-temperature asphalt particles in the coarse aggregate are introduced into an aqueous solution containing citric acid, acetic acid and aluminum sulfate, and are fully stirred;

[0091] Then, polypropylene fibers are added to obtain a dissolving solution;

[0092] The fine sand in the fine aggregate, the crushed stone in the coarse aggregate and the silicate cement are dry-mixed uniformly to obtain mixed cement;

[0093] The mixed cement is introduced into the dissolving liquid and mixed evenly to obtain the sprayed concrete.

[0094] The diameter of the polypropylene fiber is 0.4-0.7 mm, and the length is 20-40 mm.

[0095] S4. Level and maintain the sprayed surface to complete the construction work.

[0096] Use a large bar and wooden trowel to smooth the surface, and the surface flatness should not exceed 5mm / 1m;

[0097] The maintenance is carried out in the following manner:

[0098] Within 2-4 hours after leveling, start water spraying and curing. The number of water spraying should be sufficient to keep the concrete in a sufficiently moist state.

[0099] The curing time shall not be less than 10 days and the curing temperature shall not be lower than 5°C.

[0100] In order to characterize the strength of shotcrete, the following experiment was conducted on the shotcrete. A concrete base surface was set up. The concrete base surface was a concrete block with a thickness of 20mm and a size of 500mm*500mm obtained by pouring C30 concrete. The surface was roughened with a depth of not less than 5mm. The 500mm*500mm surface after roughening was used as the position of the shotcrete.

[0101] Embodiment 1:

[0102] S101. Add 2 parts of citric acid and 3 parts of acetic acid to 180 parts of water, then add 45 parts of aluminum sulfate and stir until all dissolved;

[0103] S102. The 900 parts of small high-temperature asphalt particles in the fine aggregate and the 650 parts of large high-temperature asphalt particles in the coarse aggregate are introduced into an aqueous solution of citric acid, acetic acid, and aluminum sulfate, and stirred thoroughly;

[0104] Then, 1 part of polypropylene fiber is added to obtain a dissolving solution; the diameter of the polypropylene fiber is 0.4-0.7 and the length is 20-40 mm.

[0105] The fine aggregate includes fine sand with a particle size of less than 0.35 mm and small high-temperature asphalt particles with a particle size of less than 0.35, wherein the mass ratio of the fine sand to the small high-temperature asphalt particles is 1;

[0106] The coarse aggregate includes crushed stone with a particle size less than 5 mm and high-temperature asphalt particles with a particle size greater than 0.35 and less than 5 mm, wherein the mass ratio of the crushed stone to the high-temperature asphalt particles is 4.

[0107] S103. The fine sand in the fine aggregate and the crushed stone in the coarse aggregate and 400 parts of Portland cement are dry-mixed to obtain a mixed cement;

[0108] The mixed cement is introduced into the dissolving liquid and mixed evenly to obtain the shotcrete, and the shotcrete is set as follows: the nozzle is set vertically to the sprayed surface, the distance is 0.8m, the working wind pressure at the nozzle is 0.15Mpa; the wind pressure is controlled at 0.3Mpa; the spraying thickness is 2cm; the temperature in the working area shall not be lower than 5℃;

[0109] S104. Use a large bar and wooden trowel to smooth the surface, and the surface flatness shall not exceed 5mm / 1m;

[0110] S105. The maintenance is carried out as follows:

[0111] Within 2 hours after leveling, start water spraying and curing. The number of water spraying times should be sufficient to keep the concrete in a sufficiently moist state.

[0112] The curing time is 10 days and the curing temperature is not lower than 5°C.

[0113] No obvious gap was found when observing the appearance. Hammering was performed on the side and the damaged position was observed. No separation of the sprayed cement layer from the original concrete was found at the damaged position.

[0114] Embodiment 2:

[0115] S201. Add 3 parts of citric acid and 2 parts of acetic acid to 220 parts of water, then add 55 parts of aluminum sulfate, and stir until all dissolved (50-60 parts of citric acid, acetic acid, and aluminum sulfate in total);

[0116] S202. The small high-temperature asphalt particles in 1000 parts of fine aggregate and the large high-temperature asphalt particles in 750 parts of coarse aggregate are introduced into an aqueous solution of citric acid, acetic acid and aluminum sulfate, and stirred thoroughly;

[0117] Then, 2 portions of polypropylene fibers are added to obtain a dissolving solution; the diameter of the polypropylene fibers is 0.4-0.7 mm and the length is 20-40 mm.

[0118] The fine aggregate includes fine sand with a particle size of less than 0.35 mm and small high-temperature asphalt particles with a particle size of less than 0.35, wherein the mass ratio of the fine sand to the small high-temperature asphalt particles is 1.2;

[0119] The coarse aggregate includes crushed stone with a particle size of less than 5 mm and high-temperature asphalt particles with a particle size greater than 0.35 and less than 5 mm, wherein the mass ratio of the crushed stone to the high-temperature asphalt particles is 5.

[0120] S203. The fine sand in the fine aggregate and the crushed stone in the coarse aggregate and 500 parts of Portland cement are dry-mixed to obtain a mixed cement;

[0121] The mixed cement is introduced into the dissolving liquid and mixed evenly to obtain the shotcrete, and the shotcrete is set as follows: the nozzle is set vertically to the sprayed surface, the distance is 1.2m, the working wind pressure at the nozzle is 0.2Mpa; the wind pressure is controlled at 0.4Mpa; the spraying thickness is 2cm; the temperature in the working area shall not be lower than 5℃;

[0122] S204. Use a large bar and wooden trowel to smooth the surface, and the surface flatness shall not exceed 5mm / 1m;

[0123] S205. The maintenance is carried out as follows:

[0124] Within 4 hours after leveling, start water spraying and curing. The number of water spraying times should be sufficient to keep the concrete in a sufficiently moist state.

[0125] The curing time is 10 days and the curing temperature is not lower than 5°C.

[0126] No obvious gap was found when observing the appearance. Hammering was performed on the side and the damaged position was observed. No separation of the sprayed cement layer from the original concrete was found at the damaged position.

[0127] Comparative Example 1:

[0128] S301. Put 2 parts of citric acid and 3 parts of acetic acid into 180 parts of water, then add 45 parts of aluminum sulfate and keep stirring until all dissolved;

[0129] S302. Add 1 part of polypropylene fiber to obtain a dissolving solution; the diameter of the polypropylene fiber is 0.4-0.7 and the length is 20-40 mm.

[0130] The fine aggregate is fine sand with a particle size less than 0.35 mm;

[0131] The coarse aggregate is crushed stone with a particle size less than 5 mm.

[0132] S303. The fine aggregate and the coarse aggregate and 400 parts of Portland cement are dry-mixed to obtain a mixed cement;

[0133] The mixed cement is introduced into the dissolving liquid and mixed evenly to obtain the shotcrete, and the shotcrete is set as follows: the nozzle is set vertically to the sprayed surface, the distance is 0.8m, the working wind pressure at the nozzle is 0.15Mpa; the wind pressure is controlled at 0.3Mpa; the spraying thickness is 2cm; the temperature in the working area shall not be lower than 5℃;

[0134] S304. Use a large bar and wooden trowel to smooth the surface, and the surface flatness shall not exceed 5mm / 1m;

[0135] S305. The maintenance is carried out as follows:

[0136] Within 2 hours after leveling, start water spraying and curing. The number of water spraying times should be sufficient to keep the concrete in a sufficiently moist state.

[0137] The curing time is 10 days and the curing temperature is not lower than 5°C.

[0138] Upon observation of the exterior, slight gaps were found. Hammering was performed on the side to damage the structure. The damaged locations were observed and nine locations were found where the sprayed cement layer had separated from the original concrete (separation length exceeding 5 mm was recorded as concrete separation).

[0139] Comparative Example 2:

[0140] S401. Add 5 parts of citric acid to 180 parts of water, then add 45 parts of aluminum sulfate, and keep stirring until all dissolved;

[0141] S402. The 900 parts of small high temperature asphalt particles in the fine aggregate and the 650 parts of large high temperature asphalt particles in the coarse aggregate are introduced into an aqueous solution of citric acid and aluminum sulfate, and are fully stirred;

[0142] Then, 1 part of polypropylene fiber is added to obtain a dissolving solution; the diameter of the polypropylene fiber is 0.4-0.7 and the length is 20-40 mm.

[0143] The fine aggregate includes fine sand with a particle size of less than 0.35 mm and small high-temperature asphalt particles with a particle size of less than 0.35, wherein the mass ratio of the fine sand to the small high-temperature asphalt particles is 1;

[0144] The coarse aggregate includes crushed stone with a particle size less than 5 mm and high-temperature asphalt particles with a particle size greater than 0.35 and less than 5 mm, wherein the mass ratio of the crushed stone to the high-temperature asphalt particles is 4.

[0145] S403. The fine sand in the fine aggregate and the crushed stone in the coarse aggregate and 400 parts of Portland cement are dry-mixed to obtain a mixed cement;

[0146] The mixed cement is introduced into the dissolving liquid and mixed evenly to obtain the shotcrete, and the shotcrete is set as follows: the nozzle is set vertically to the sprayed surface, the distance is 0.8m, the working wind pressure at the nozzle is 0.15Mpa; the wind pressure is controlled at 0.3Mpa; the spraying thickness is 2cm; the temperature in the working area shall not be lower than 5℃;

[0147] S404. Use a large bar and wooden trowel to smooth the surface, and the surface flatness shall not exceed 5mm / 1m;

[0148] S405. The maintenance is carried out as follows:

[0149] Within 2 hours after leveling, start water spraying and curing. The number of water spraying times should be sufficient to keep the concrete in a sufficiently moist state.

[0150] The curing time is 10 days and the curing temperature is not lower than 5°C.

[0151] Upon observation of the appearance, no obvious gap was found. Hammering was performed on the side and the damaged position was observed. Two places were found where the sprayed cement layer was detached from the original concrete (detachment length exceeding 5 mm was recorded as concrete detachment).

[0152] Comparative Example 3:

[0153] S501. Add 5 parts of acetic acid to 180 parts of water, then add 45 parts of aluminum sulfate, and keep stirring until all dissolved;

[0154] S502. The 900 parts of small high temperature asphalt particles in the fine aggregate and the 650 parts of large high temperature asphalt particles in the coarse aggregate are introduced into an aqueous solution of acetic acid and aluminum sulfate, and are fully stirred;

[0155] Then, 1 part of polypropylene fiber is added to obtain a dissolving solution; the diameter of the polypropylene fiber is 0.4-0.7 and the length is 20-40 mm.

[0156] The fine aggregate includes fine sand with a particle size of less than 0.35 mm and small high-temperature asphalt particles with a particle size of less than 0.35, wherein the mass ratio of the fine sand to the small high-temperature asphalt particles is 1;

[0157] The coarse aggregate includes crushed stone with a particle size less than 5 mm and high-temperature asphalt particles with a particle size greater than 0.35 and less than 5 mm, wherein the mass ratio of the crushed stone to the high-temperature asphalt particles is 4.

[0158] S503. The fine sand in the fine aggregate and the crushed stone in the coarse aggregate and 400 parts of Portland cement are dry-mixed to obtain a mixed cement;

[0159] The mixed cement is introduced into the dissolving liquid and mixed evenly to obtain the shotcrete, and the shotcrete is set as follows: the nozzle is set vertically to the sprayed surface, the distance is 0.8m, the working wind pressure at the nozzle is 0.15Mpa; the wind pressure is controlled at 0.3Mpa; the spraying thickness is 2cm; the temperature in the working area shall not be lower than 5℃;

[0160] S504. Use a large bar and wooden trowel to smooth the surface, and the surface flatness shall not exceed 5mm / 1m;

[0161] S505. The maintenance is carried out as follows:

[0162] Within 2 hours after leveling, start water spraying and curing. The number of water spraying times should be sufficient to keep the concrete in a sufficiently moist state.

[0163] The curing time is 10 days and the curing temperature is not lower than 5°C.

[0164] Upon observation of the appearance, no obvious gap was found. Hammering was performed on the side and the damaged position was observed. Four places were found where the sprayed cement layer had detached from the original concrete (detachment length exceeding 5 mm was recorded as concrete detachment).

[0165] Comparative Example 4:

[0166] S601. Put 2 parts of citric acid and 3 parts of acetic acid into 180 parts of water, then add 45 parts of aluminum sulfate and keep stirring until all dissolved;

[0167] S602. The 900 parts of small high-temperature asphalt particles in the fine aggregate and the 650 parts of large high-temperature asphalt particles in the coarse aggregate are introduced into an aqueous solution of citric acid, acetic acid, and aluminum sulfate, and stirred thoroughly;

[0168] The fine aggregate includes fine sand with a particle size of less than 0.35 mm and small high-temperature asphalt particles with a particle size of less than 0.35, wherein the mass ratio of the fine sand to the small high-temperature asphalt particles is 1;

[0169] The coarse aggregate includes crushed stone with a particle size less than 5 mm and high-temperature asphalt particles with a particle size greater than 0.35 and less than 5 mm, wherein the mass ratio of the crushed stone to the high-temperature asphalt particles is 4.

[0170] S603. The fine sand in the fine aggregate and the crushed stone in the coarse aggregate and 400 parts of Portland cement are dry-mixed to obtain a mixed cement;

[0171] The mixed cement is introduced into the dissolving liquid and mixed evenly to obtain the shotcrete, and the shotcrete is set as follows: the nozzle is set vertically to the sprayed surface, the distance is 0.8m, the working wind pressure at the nozzle is 0.15Mpa; the wind pressure is controlled at 0.3Mpa; the spraying thickness is 2cm; the temperature in the working area shall not be lower than 5℃;

[0172] S604. Use a large bar and wooden trowel to smooth the surface, and the surface flatness shall not exceed 5mm / 1m;

[0173] S605. The maintenance is carried out as follows:

[0174] Within 2 hours after leveling, start water spraying and curing. The number of water spraying times should be sufficient to keep the concrete in a sufficiently moist state.

[0175] The curing time is 10 days and the curing temperature is not lower than 5°C.

[0176] Upon observation of the appearance, no obvious gap was found. Hammering was performed on the side and the damaged position was observed. Five locations were found where the sprayed cement layer was detached from the original concrete (detachment length exceeding 5 mm was recorded as concrete detachment).

[0177] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A spraying concrete construction method, characterized in that: The steps include: The spraying surface is cleaned and the steel bars are exposed; Tie the exposed steel bars; Shotcrete is sprayed and a shotcrete operation is performed to obtain a sprayed surface; The construction work is completed by leveling and maintaining the spraying surface.

2. A sprayed concrete construction method as claimed in claim 1, characterized in that: During the purification process, proceed as follows: For the sprayed surface with finishing layer, remove the exposed structural surface and perform roughening treatment, with the roughening depth not less than 5mm; For the spraying surface of the clean water surface, roughening treatment is carried out, and the roughening depth is not less than 5mm; After roughening, clean with high-pressure air at least twice; then clean with high-pressure water at least twice.

3. A sprayed concrete construction method as claimed in claim 1, characterized in that: The steel bar binding is carried out in the following manner: Lay out and position according to design requirements, determine the position of anchor reinforcement, the position of the holes through which reinforcement passes through the wall and the plate, and the position of the reinforcement of the inner and outer walls; According to the layout position, holes are drilled at the anchor bars, wall penetrations and structure penetrations; After confirming that the location and depth of the inspection hole meet the design requirements, anchor the reinforcement; According to the layout position, the reinforcement is arranged on the inner and outer wall surfaces and firmly tied with the anchor bars. For the concrete components of beams and columns, the main reinforcement of the original components is chiseled out according to the design requirements, and the main reinforcement of the original components must not be damaged; the main reinforcement added according to the design requirements is welded to the main reinforcement of the original components through short steel bars; U-shaped stirrups are welded to the stirrups of the original components.

4. A sprayed concrete construction method as claimed in claim 1, characterized in that: The sprayed concrete operation is carried out as follows: For the parts that need formwork, such as door and window openings, and the sides of the edges of beams and columns, formwork shall be provided according to the designed dimensions, and supports and tie rods shall be added; The shotcrete shall be sprayed according to the following requirements: The nozzle is set vertically to the sprayed surface, with a distance of 0.8-1.2m. The working air pressure at the nozzle is 0.15-0.2Mpa; the air pressure is controlled at 0.3-0.4Mpa; When spraying, the nozzle moves in a spiral trajectory, one circle and half a circle, spraying the depressions first and then filling them up; the thickness of one spray is 2-3cm; the interval time between spraying layers is 10-15 minutes; The temperature in the working area shall not be lower than 5℃; The temperature of the dry mix entering the sprayer and the water temperature shall not be less than 5°C.

5. A sprayed concrete construction method as claimed in claim 1, characterized in that: The leveling is performed as follows: using a large bar and a wooden trowel to smooth the surface, the surface flatness does not exceed 5mm / 1m; The maintenance is carried out in the following manner: Within 2-4 hours after leveling, start water spraying and curing. The number of water spraying should be sufficient to keep the concrete in a sufficiently moist state. The curing time shall not be less than 10 days and the curing temperature shall not be lower than 5°C.

6. A sprayed concrete construction method as claimed in claim 1, characterized in that: The sprayed concrete comprises the following raw materials in parts by mass: Portland cement: 400-500 parts; Fine aggregate: 900-1000 parts; Coarse aggregate: 650-750 parts; Polypropylene fiber: 1-2 parts; Accelerator: 50-60 parts; Water: 180-220 parts.

7. A sprayed concrete construction method as claimed in claim 6, characterized in that: The quick-setting agent comprises the following components in parts by mass: Aluminum sulfate: 45-55 parts; Citric acid: 2-3 parts; Acetic acid: 2-3 parts.

8. A sprayed concrete construction method as claimed in claim 7, characterized in that: The fine aggregate includes fine sand with a particle size of less than 0.35 mm and small high-temperature asphalt particles with a particle size of less than 0.35, wherein the mass ratio of the fine sand to the small high-temperature asphalt particles is 1-1.2; The coarse aggregate includes crushed stone with a particle size of less than 5 mm and high-temperature asphalt particles with a particle size greater than 0.35 and less than 5 mm, wherein the mass ratio of the crushed stone to the high-temperature asphalt particles is 4-5.

9. A sprayed concrete construction method as claimed in claim 8, characterized in that: The sprayed concrete is synthesized as follows: Put citric acid and acetic acid into water, then add aluminum sulfate and keep stirring until it is completely dissolved; The small high-temperature asphalt particles in the fine aggregate and the large high-temperature asphalt particles in the coarse aggregate are introduced into an aqueous solution containing citric acid, acetic acid and aluminum sulfate, and are fully stirred; Then, polypropylene fibers are added to obtain a dissolving solution; The fine sand in the fine aggregate, the crushed stone in the coarse aggregate and the silicate cement are dry-mixed uniformly to obtain mixed cement; The mixed cement is introduced into the dissolving liquid and mixed evenly to obtain the sprayed concrete.

10. A sprayed concrete construction method as claimed in claim 6, characterized in that: The diameter of the polypropylene fiber is 0.4-0.7 mm, and the length is 20-40 mm.