CN117303941A - Concrete structure maintenance coatings and concrete structure maintenance methods - Google Patents

Abstract

The invention relates to a concrete structure curing coating and a concrete structure curing method. The maintenance coating comprises the following main components in parts by mass: 0.5-2 parts of sodium hydroxide, 10-30 parts of flour and 500-1000 parts of water. The maintenance method comprises the following steps: (1) The concrete structure curing coating is coated on the surface of the concrete structure after the demolding; (2) Sticking a plastic film on the outer side of the concrete structure curing coating for curing; and (3) after curing is completed, the plastic film is detached. The curing coating disclosed by the invention is simple in components, is prepared from materials and resources which are commonly used in daily life, is environment-friendly, low in cost and convenient to prepare, and can be effectively used for preventing and controlling concrete carbonization by being coated on the surface of a concrete structure, so that the structural strength of the concrete is ensured; compared with the traditional method, the maintenance method has the advantages of fewer steps, simple and convenient operation, low construction operation strength and short engineering period.

Description

Concrete structure maintenance coatings and concrete structure maintenance methods

Technical field

The invention relates to a concrete structure maintenance coating and a concrete structure maintenance method, belonging to the technical field of concrete maintenance.

Background technique

During the construction process of construction projects, in order to improve the turnover and utilization of building formwork and improve work efficiency, the formwork removal time for concrete structures (walls, columns, equipment foundations, etc.) is generally about 12 hours after the completion of concrete pouring. If the concrete is not properly maintained after the formwork is removed, it will lose water, dry out, crack, and react with CO ₂ in the air to carbonize, affecting the strength and structural stability of the concrete.

Traditional concrete structure maintenance methods mostly use watering or film application. The invention patent with publication number CN103978547A discloses a long wall structure concrete maintenance device and its maintenance method. In the maintenance method, in order to avoid dry shrinkage caused by water loss on the concrete surface Cracks require watering and curing after the concrete formwork is removed. However, although watering and curing can avoid concrete cracking to a certain extent, it wastes water resources, is time-consuming and labor-intensive, and due to the flow of water, water remains on the surface of the concrete structure. The time is too short, and the curing effect is limited, especially in dry weather, which requires high-frequency watering; the invention patent with the publication number CN110194678A discloses a concrete curing agent and a curing method using the curing agent. In the curing method, Maintain the moisture of the concrete after pouring, and cover the surface of the concrete with a polymer film after sprinkling and curing. However, although the film curing method can reduce the water loss of the concrete to a certain extent, it cannot effectively prevent the carbonization of the concrete. preventive or inhibitory effect.

Contents of the invention

In order to overcome the above-mentioned defects of the prior art, the present invention provides a concrete structure maintenance coating and a concrete structure maintenance method using this maintenance coating, which can not only reduce water evaporation after the concrete structure is removed from the formwork, ensure its molding quality, but also prevent and cure concrete. Carbonization ensures its structural strength.

The technical solution of the present invention to achieve the above object is: concrete structure maintenance coating, the main components and proportions of which are: 0.5-2 parts of sodium hydroxide (parts by mass, the same below), 10-30 parts of flour (or white flour), water Appropriate amount to achieve the required thickness (or viscosity) for use, usually 500-1000 parts.

As a further preferred ratio, the main components of the concrete structure maintenance coating and the mass parts of each component are: 1 part of sodium hydroxide, 20 parts of flour, and 700 parts of water.

In addition to the above main ingredients, other ingredients can be added or not added according to actual needs. For example, a water-retaining agent may or may not be added. The amount of the water-retaining agent is based on actual needs and is mixed evenly with the above-mentioned main ingredients during preparation.

The sodium hydroxide in the concrete structure maintenance coating component can be commercially available caustic soda or caustic soda.

The concrete structure maintenance method uses any of the concrete structure maintenance coatings disclosed in the present invention and includes the following steps:

(1) Apply the concrete structure maintenance paint on the surface of the concrete structure after the formwork is removed;

(2) Paste a plastic film on the outside of the concrete structure curing paint for maintenance;

(3) After the maintenance is completed, remove the plastic film.

Preferably, in the step (1), before applying the concrete structure curing paint, the components of the concrete structure curing paint are mixed, stirred evenly, and mixed for immediate use. Preferably, the concrete structure maintenance paint is applied evenly on the surface of the concrete structure.

Preferably, the entire surface of the concrete structure is coated with the concrete structure curing paint.

Preferably, the thickness of the concrete structure curing paint applied to the surface of the concrete structure is 5-15 mm.

The concrete curing paint can be applied with a roller brush.

Preferably, the concrete curing coating is applied immediately after the concrete structure is removed from the formwork.

Preferably, in the step (2), the plastic film is pasted before the concrete structure curing paint dries. The plastic film can be bonded to the surface of the concrete structure curing paint by relying on the bonding ability of the concrete structure curing paint itself.

The plastic film can be pasted by pressing with a roller brush.

Preferably, the plastic film covers the entire surface of the concrete structure.

Preferably, the film curing time is 5-7 days.

The plastic film can be a resin film such as polyvinyl chloride, polyethylene or polypropylene.

Preferably, during the film curing period, the surface humidity and temperature of the concrete structure are detected. For example, corresponding humidity and temperature sensors (sensing elements or probes of the sensor) are set between the plastic film and the surface of the concrete structure to detect temperature and humidity.

During film maintenance, the concrete structure surface (plastic film surface) can be sprinkled with water or not sprinkled with water according to actual needs.

The surface temperature and humidity detection data can be used to determine whether to spray water, as well as the time and/or amount of water spraying.

Depending on actual needs (e.g., ambient temperature, humidity, light conditions, etc.), a moist covering (e.g., damp cloth) may or may not be covered during film curing.

Further, after the film curing is completed, cover curing is performed, and the surface (especially the upper surface) of the concrete structure is covered with a moist covering (for example, wet cloth).

The covering, covering method, covering position, area, etc. can be based on existing technology.

The wetted mulch can be kept moist by sprinkling water onto the wetted mulch, or alternatively, by keeping the wetted mulch wet.

The beneficial effects of the present invention are:

(1) After the concrete curing paint is painted on the surface of the concrete structure, a protective layer will be formed on the surface of the concrete structure. The sodium hydroxide in its component reacts with the CO ₂ that penetrates into the air to generate sodium bicarbonate (white crystalline powder). ), sodium bicarbonate covers the surface of the concrete structure and fills the gaps on the concrete surface, which can effectively prevent CO ₂ in the air from contacting the concrete and prevent CO ₂ from reacting with the calcium hydroxide in the concrete components, thereby preventing concrete carbonization. It can not only ensure the structural strength of concrete, but also prevent the steel bars in the concrete from coming into contact with air and water, causing rust;

(2) Applying concrete structure maintenance paint on the surface of the concrete structure and then pasting a plastic film on it can effectively block wind blowing, thereby reducing the evaporation of water in the concrete, allowing the concrete to complete strength improvement in an environment with high relative humidity, ensuring that the concrete The molding quality is good, and it can also play a certain role in thermal insulation and maintenance of the concrete after pouring;

(3) Since the concrete structure maintenance coating contains flour, sodium hydroxide and water, it will become a viscous fluid after being stirred evenly. It can be applied according to the actual conditions (for example, concrete characteristics, environmental conditions, painting methods and thickness, etc. ) Select the amount of water (proportion), which will not only help it to cover (paste) the entire surface of the concrete structure after being painted on the surface of the concrete structure, without gaps and not easy to fall off, but also help the plastic film to adhere In which the main components such as starch/carbohydrates and proteins in flour react with sodium hydroxide in water and synergize with each other. It can rely on starch to obtain good adhesion, film-forming properties and moderate film-forming under the synergistic reaction of the response. Thickness, and can rely on the protein to obtain good mixing uniformity, permeability to concrete pores, and spreadability and compactness on the surface under the corresponding synergistic reaction;

(4) Since the concrete structure curing paint contains a large amount of water and the amount of water added can be set according to actual needs, after it is painted on the surface of the concrete structure, it can keep the concrete moist and hydrate the concrete after the pouring is completed. Providing sufficient water can replace the watering and curing process in traditional maintenance methods, which can not only save water resources, but also shorten the curing time and reduce the intensity of construction operations;

(5) The components of concrete structure maintenance coatings are simple, and each component is a material and resource commonly used in daily life. It is environmentally friendly, low-cost and easy to prepare. Compared with traditional methods, the maintenance method has fewer steps, is easy to operate, and has low construction intensity. The project cycle is short, and it has good adhesion to many existing interior and exterior wall surface decorative layers and coatings, without hindering subsequent construction.

Description of drawings

Figure 1 is a flow chart of the concrete structure maintenance method of the present invention.

Detailed ways

The invention discloses a concrete structure maintenance coating. Its main components and the mass parts of each component are: 0.5-2 parts of sodium hydroxide, 10-30 parts of flour (or white flour), and 500-1000 parts of water.

The following are preferred ingredient ratio examples:

Example 1: 0.5 parts of sodium hydroxide, 20 parts of flour, and 1000 parts of water.

Example 2: 1 part of sodium hydroxide, 30 parts of flour, 500 parts of water.

Example 3: 1 part of sodium hydroxide, 20 parts of flour, 700 parts of water.

Example 4: 2 parts of sodium hydroxide, 10 parts of flour, 800 parts of water.

The sodium hydroxide in the concrete structure maintenance coating component can be caustic soda or caustic soda.

One of the main components of concrete is Portland cement. CaO, the main component in Portland cement, is hydrated to form Ca(OH) _2. Most of Ca(OH) ₂ exists in the concrete in a crystalline state, making the concrete maintain Highly alkaline. After the concrete structure building is completed, CO ₂ in the air continues to enter the concrete and neutralizes with Ca(OH) ₂ in the concrete (concrete carbonization), generating CaCO ₃ and H ₂ O. After the surface layer of concrete is carbonized, CO ₂ in the atmosphere continues to diffuse deep into the concrete along the capillary channels that are not completely filled with water, and the carbonization reaction proceeds more deeply, causing changes in the properties of the concrete. The carbonized concrete has a loose texture and reduced strength. When the carbonization depth exceeds the concrete protective layer, the steel bars in the concrete will come into contact with air and water, causing the steel bars to rust, thus affecting the structural safety of the building.

One of the main functions of the concrete structure maintenance coating is to prevent concrete carbonization. When it is used, it is painted on the surface of the concrete structure (such as walls, columns, equipment foundations, etc.) to form a protective layer and protect the components of the coating. Sodium hydroxide will react with CO ₂ in the air to generate sodium bicarbonate (white crystalline powder). Sodium bicarbonate covers the surface of the concrete structure and fills the gaps on the concrete surface, which can effectively block CO ₂ in the air from interacting with the concrete. Contact to prevent CO ₂ from reacting with calcium hydroxide (Ca(OH) ₂ ) in the concrete composition, thereby preventing carbonization of concrete. This can not only ensure the structural strength of the concrete, but also prevent the steel bars in the concrete from contacting air and water, which may cause rust. Since the curing paint contains flour and water, it becomes paste-like and sticky after being mixed evenly, which helps it to cover (paste) the entire surface of the concrete structure after being painted on the surface of the concrete structure, without gaps and It is not easy to fall off and ensures the prevention and control effect of concrete carbonization.

Referring to Figure 1, the present invention also discloses a concrete structure maintenance method using any of the concrete structure maintenance coatings disclosed in the present invention, which includes the following steps:

(1) Apply the concrete structure maintenance paint on the surface of the concrete structure after the formwork is removed;

(2) Paste a plastic film on the outside of the concrete structure curing paint for curing (film curing);

(3) After the maintenance is completed, remove the plastic film.

Subsequent maintenance without film can be carried out according to actual needs. Usually, you can cover it with a wet cloth and regularly sprinkle water on the wet cloth to keep the wet cloth wet and meet the required degree of moistening.

In the step (1), before applying the concrete structure curing paint, stir the concrete structure curing paint evenly to avoid precipitation. The concrete structure curing paint is preferably applied to the entire surface of the concrete structure and applied evenly (usually using a roller brush) to ensure that the curing paint can cover (paste) the entire surface of the concrete structure without gaps, thereby ensuring the curing effect. .

Usually, the concrete curing coating is prepared after the concrete structure is removed from the formwork to avoid modification of the curing coating after being stored for a long time without being used. In practical applications, the components of the concrete curing coating can be stored separately and prepared according to the progress of demoulding the concrete structure. It can be prepared on demand, so that the prepared paint can be used up within one or two hours to ensure the effect of use.

The thickness of the concrete structure maintenance paint applied to the surface of the concrete structure is preferably 5-15mm, such as 5mm, 10mm or 15mm, which can effectively isolate the air and contribute to the adhesion of the plastic film (so The concrete structure curing coating described above is pasty and sticky).

In the step (2), the plastic film is usually pasted before the concrete structure maintenance coating dries to ensure the adhesion effect of the plastic film. When pasting the plastic film, a roller brush can be used to press it, so that The plastic film is firmly bonded to the concrete structure maintenance coating and is not easy to fall off.

The plastic film preferably covers the entire surface of the concrete structure, which can effectively block wind blowing, thereby reducing water evaporation in the concrete, allowing the concrete to complete strength improvement in an environment with high relative humidity, ensuring the molding quality of the concrete, and also It can play a role in thermal insulation and maintenance of concrete after pouring.

The plastic film can be a resin film such as polyvinyl chloride, polyethylene or polypropylene.

The film curing time in step (2) is preferably 5-7 days.

Since the concrete structure curing paint contains a large amount of water, after it is painted on the surface of the concrete structure, it can keep the concrete in a moist state, provide sufficient water for the hydration of the concrete after the pouring is completed, and can replace the traditional curing methods. The watering and maintenance process can not only save water resources, but also shorten the maintenance time and reduce the intensity of construction operations.

The composition of the concrete structure maintenance coating of the present invention is simple, and each component is a material and resource commonly used in daily life. It is environmentally friendly, has low cost and is easy to prepare. Compared with the traditional method, the maintenance method has fewer steps, is easy to operate, and has low construction operation intensity. The project cycle is short.

Claims (10)

1. The concrete structure curing coating is characterized by comprising the following main components in percentage by weight: 0.5-2 parts by mass of sodium hydroxide; 10-30 parts of flour; proper amount of water.

2. The concrete structure curing coating as claimed in claim 1, wherein the main components and proportions thereof are: 1 part by mass of sodium hydroxide; 20 parts of flour; 700 parts of water.

3. The concrete structure curing coating according to claim 1 or 2, wherein the preparation method is to add each component into a stirring container and stir the mixture uniformly to form the coating.

4. A method for curing a concrete structure, characterized in that the concrete structure curing paint according to any one of claims 1 or 2 is used, comprising the steps of:

(1) The concrete structure curing coating is coated on the surface of the concrete structure after the demolding;

(2) Sticking a plastic film on the outer side of the concrete structure curing coating for curing with a film;

(3) And after the maintenance of the film is completed, the plastic film is disassembled.

5. The method for curing a concrete structure according to claim 4, wherein the curing with a film is performed after the curing with a film is completed, and the surface of the concrete structure is covered with a wetting cover.

6. The method for curing a concrete structure according to claim 4, wherein the curing coating for a concrete structure is uniformly applied to the surface of the concrete structure.

7. The method of curing a concrete structure according to claim 4, wherein said plastic film covers the entire surface of the concrete structure.

8. A method of curing a concrete structure as claimed in any one of claims 4 to 7, wherein the curing time with film is from 5 to 7 days.

9. A method of curing a concrete structure according to any one of claims 4-7, characterized in that the surface humidity and temperature of the concrete structure are detected during curing with a film.

10. A method of curing a concrete structure as claimed in any one of claims 4 to 7, wherein the wet cover is covered or uncovered during curing with the film.