KR20210000924A - Structural reinforcement method using insulating carbon fiber sheet - Google Patents

Abstract

The present invention relates to a method for reinforcing a concrete structure and, more specifically, to a method for reinforcing a structure using a carbon fiber sheet with insulating properties. According to the present invention, the method for reinforcing a structure using the insulating carbon fiber sheet includes: a concrete surface treating step; a first primer applying step; an insulating carbon fiber sheet attaching step; a second primer applying step; and a finishing paint applying and curing step.

Description

Structure reinforcement method using insulating carbon fiber sheet {STRUCTURAL REINFORCEMENT METHOD USING INSULATING CARBON FIBER SHEET}

The present invention relates to a method for reinforcing a concrete structure, and more particularly, to a method for reinforcing a structure using a carbon fiber sheet having insulating properties.

In general, concrete structures are widely used in civil engineering and construction fields such as bridges, tunnels, houses, buildings, and roads. Concrete structures have excellent durability, fire resistance, workability, dimensional shape, and high rigidity, so they have high resistance to horizontal loads and deformation, and are recognized as a structure with high economical efficiency due to low maintenance costs. Nevertheless, concrete structures weaken durability due to errors during construction, changes in the use of the building, repeated loads, changes in material properties over time, changes in the environment, etc., causing cracks, strength reduction, and deformation. There is a problem that the safety and aesthetics of the structure may be damaged.

In general, 　 reinforcement construction methods of concrete structures include a section increase construction method, a post tension construction method and a steel plate attachment construction method, and recently 　 a bonding 　 reinforcement method using a fiber sheet. Among these 　 reinforcement methods, the section increase method increases the stiffness of the member, but there is a disadvantage in that the self-weight increases according to the increase in the section, and the securing of the work space and the space used are limited. The steel plate attaching method has the disadvantage that there is little change in the cross-sectional size of the member and the construction is simple, but the handling is inconvenient, corrosion and fire resistance are weak, and brittle 　 reinforcement plate dropping occurs. Although the concrete 　 reinforcement method using fiber sheet is lightweight, has no fear of corrosion, and has excellent workability and durability, it is not easy to control stiffness, repairs cracks and is weak against fire, and has problems with adhesive adhesion over time. There is a problem that the durability of the structure is lowered. Among the concrete reinforcement methods using fiber sheets, there is also a carbon fiber sheet reinforcement method, which has a problem that it is lightweight and high strength but has no insulation.

An object of the present invention is to provide a method for reinforcing structures capable of exerting a high reinforcing effect by using a carbon fiber sheet having insulation properties.

A method for reinforcing a structure using an insulating carbon fiber sheet according to an embodiment of the present invention includes a concrete surface treatment step; Applying a first primer; Attaching an insulating carbon fiber sheet; Applying a second primer; It includes; finishing paint application and curing step.

In addition, according to an embodiment of the present invention, the concrete surface treatment step includes repairing cracks and repairing sections.

In addition, according to an embodiment of the present invention, the crack repair and cross-section repair operation includes applying mortar.

In addition, according to an embodiment of the present invention, the mortar is characterized in that it is an SM moisture barrier type mortar.

In addition, according to an embodiment of the present invention, in the crack repair and cross-section repair work, exposed reinforcing bars are subjected to rust prevention treatment, and irregularities and/or protruding portions are surface treated and smoothed, so that the surface step is less than 1 mm and the width is 0.2 mm. The above cracked or damaged cross section is characterized by being repaired and/or repaired by injecting an epoxy resin.

Further, according to an embodiment of the present invention, the concrete surface treatment step includes a grinding operation.

In addition, according to an embodiment of the present invention, it further includes a step of applying a resin for impregnation after the step of applying the first primer.

In addition, according to an embodiment of the present invention, it further includes an uneven adjustment step after the first primer application step.

In addition, according to an embodiment of the present invention, the uneven adjustment step includes an epoxy putty operation.

In addition, according to an embodiment of the present invention, it further includes a step of applying a resin for impregnation after the uneven adjustment step.

In addition, according to an embodiment of the present invention, in the step of attaching the insulating carbon fiber sheet, the insulating carbon fiber sheet is coated with an airgel paint containing airgel.

In addition, according to an embodiment of the present invention, the second primer application step is a step of applying a resin.

In addition, according to an embodiment of the present invention, it includes applying a mortar prior to the primer application step.

In the method for reinforcing a structure using an insulating carbon fiber sheet according to the present invention, insulation may be secured by using a carbon fiber sheet coated with an airgel paint containing airgel.

The method of reinforcing a structure using an insulating carbon fiber sheet according to the present invention is excellent in heat insulation and waterproofing effects by using a carbon fiber sheet coated with an airgel paint containing airgel.

The method for reinforcing a structure using an insulating carbon fiber sheet according to the present invention can produce a high reinforcing effect even with a small amount.

In the method of reinforcing a structure using an insulating carbon fiber sheet according to the present invention, since the specific gravity of the carbon fiber sheet is light, it is possible to reduce the burden of increasing dead weight due to the reinforcement.

The method for reinforcing a structure using an insulating carbon fiber sheet according to the present invention exhibits high durability after reinforcement because carbon fibers do not undergo natural deterioration unlike steels subjected to natural corrosion.

The method for reinforcing a structure using an insulating carbon fiber sheet according to the present invention is suitable for reinforcing structures having a curved shape or a complex shape because the carbon fiber sheet retains flexibility.

1 is a flowchart illustrating a method of reinforcing a structure using an insulating carbon fiber sheet according to an embodiment of the present invention.
2 is a view for explaining a concrete structure reinforcement process to which a structure reinforcement method using an insulating carbon fiber sheet according to an embodiment of the present invention is applied.
3 is a view for explaining a concrete surface treatment step.
4 is a view for explaining an uneven adjustment step.
5 is a view for explaining the step of attaching the insulating carbon fiber sheet.
6 is a material table for applying a method of reinforcing a structure using an insulating carbon fiber sheet according to an embodiment of the present invention.
7 is a view for explaining a cross-section of a concrete structure to which a structure reinforcement method using an insulating carbon fiber sheet according to an embodiment of the present invention is applied.

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 is a flowchart illustrating a method of reinforcing a structure using an insulating carbon fiber sheet according to an embodiment of the present invention.

2 is a view for explaining a concrete structure reinforcement process to which a structure reinforcement method using an insulating carbon fiber sheet according to an embodiment of the present invention is applied.

3 is a view for explaining a concrete surface treatment step.

4 is a view for explaining an uneven adjustment step.

1 or 2, a method for reinforcing a structure using an insulating carbon fiber sheet according to an embodiment of the present invention includes a concrete surface treatment step (A), a first primer application step (B), and an insulating carbon fiber sheet attachment step ( It includes C) and the secondary primer application step (D), and the finishing paint application and curing step (E).

In the concrete surface treatment step (A), as a preliminary work for first applying the primer 30, referring to FIG. 3, the concrete surface 10 is remarkable in repairing cracks on the surface of the concrete 10 and performing cross-section restoration. Fill the defective area with high-strength mortar, epoxy mortar, etc. that have the strength higher than concrete. At this time, the mortar surface is smoothly finished within 1mm of a step, and if the reinforcing bar is exposed, anti-rust treatment is performed, and if there is leakage on the construction surface, water and water treatment are performed. For example, exposed reinforcing bars are subjected to rust prevention treatment, and uneven and/or protruding parts are surface treated and smoothed, so that the surface level difference is less than 1 mm, and cracks or damaged sections with a width of 0.2 mm or more are repaired by injecting epoxy resin. And/or recover. Grinding and filling the corners of the concrete 10 is made to be curved to R=10mm or more. For example, when using a high elastic carbon fiber sheet, R = 20mm or more. In addition, by grinding, impurities and contaminated layers (aging, deteriorated layers, etc.) on the surface of the concrete 10 are removed and treated cleanly, and foreign substances such as protrusions and latencies of the concrete 10 are removed. Dust is removed with compressed air or a rag, and if it is washed with water, dry it sufficiently. The operation of repairing cracks on the surface of the concrete 10 and retrieving the cross section may include applying the mortar 20 to the surface of the concrete 10 according to the condition of the surface of the concrete 10. According to the embodiment, the mortar 20 may be applied with an SM moisture barrier type mortar. SM moisture barrier mortar uses admixture and re-emulsified powder resin, which increases initial strength and improves water resistance. It blocks chlorine ions and at the same time retains crack recovery performance, thus extending the life of concrete and preventing paints on the top. It is a mortar that can prevent swelling. When the concrete surface treatment step (A) is finished, the primer 30 is applied, for example, 2-3 times on the surface of the concrete surface treated concrete 10 in the first primer application step (B). Moisture), select an appropriate primer in consideration of temperature, and determine the amount of primer 30 to be mixed at one time in consideration of the work area, pot life, available personnel, and skill level of the operator. Put the base material and the hardener of the primer 30 in a mixing container at a weight ratio of 2:1, mix with an electric mixer for about 2 to 5 minutes until the color becomes uniform, and then transfer the mixed primer 30 to a suitable distribution container and then apply it. Apply evenly to the surface with an application roller. The primer 30 is applied so as to penetrate into the pores of the concrete 10 surface. The standard of the application amount of the primer 30 is 300 g/m², but when the quantity is indicated in the specification, it is based on the specification. Generally, it is 200g/m²~ 300g/m². The areas where the amount of penetration of the primer 30 is large is additionally applied after the primer 30 is completely dried. When applying the primer 30, do not apply at a temperature of 5°C or less and a relative humidity of 85% or more. Mixing of the primer 30 main material and the hardener is very important, and in particular, much attention should be paid to the mixing of the wall and the bottom of the mixing container. The primer 30 whose pot life has exceeded is discarded. The pot life becomes shorter as the amount of the primer 30 to be mixed increases, the higher the ambient temperature. Therefore, the working hours may vary depending on the site situation. If the temperature of the mixed primer 30 increases or the viscosity increases and requires a lot of force during application, the pot life has been exceeded and the use should be stopped. Mixing container and dispensing container should be reused after checking their cleanliness by using disposable or washing with a solvent (acetone) after use. The coating roller cannot be reused after cleaning with a solvent. Therefore, it is important to sufficiently prepare the coating roller. When the application amount of the primer 30 is large, droplet formation may occur on the surface. If there is a condensation phenomenon, remove it using an application roller or the like before curing the primer. Complete drying of the primer 30 is a state in which stickiness is not felt by touching it with hands. In addition, according to an embodiment, it may further include an uneven adjustment step after the first primer application step (B). Referring to Figure 4, in the uneven adjustment step, the epoxy putty work is performed on the protrusion of the concrete surface or the step of 1 mm or more. In the case of performing after the first primer application step (B), the epoxy putty work is performed after the primer is completely dried. Select an appropriate epoxy putty material in consideration of adhesive strength, viscosity, and curing speed, and referring to Fig. 4(a), after the primer 30 is completely dried, use a rubber or plastic spatula to remove holes and irregularities on the surface. Finish smoothly with putty and, referring to (b) of FIG. 4, the corners are treated with rounding. The purpose of the Epoxy putty treatment is to correct the final irregularities for attaching the insulating carbon fiber sheet 40. After drying of the primer 30, the coated surface is carefully observed to determine the part requiring the epoxy putty treatment. Do not apply at temperatures below 5℃ and relative humidity above 85%. The finish of the putty should be as smooth as possible (for example, within 1mm of a step). If the concrete surface is good, the step of adjusting the irregularities can be omitted. Depending on the embodiment, after the first primer application step (B) is finished, the impregnation resin application step may be preceded before the insulating carbon fiber sheet attaching step (C). After the primer 30 is dried, the impregnation resin (resin) Apply evenly with a brush or paint roller. The resin applied at this time is called Hado resin. Put the resin (resin) main material and hardener in a mixing container at a weight ratio of 2:1 and mix with an electric mixer for about 2-3 minutes until the color becomes uniform.

5 is a view for explaining the step of attaching the insulating carbon fiber sheet.

When the first primer application step (B) is finished, in the insulating carbon fiber sheet attaching step (C), referring to Fig. 5 (a), the insulating carbon fiber sheet 40 is reinforced with concrete (10) according to the site standard, scissors, cutter, etc. Cut it into an appropriate length (usually 3-4m) in advance using. If the resin for impregnation is applied in advance, impregnation and defoaming are performed with a defoaming roller or rubber roller until the resin oozes over the insulating carbon fiber sheet 40 in the fiber direction. The general impregnation and defoaming operation direction is as shown in FIG. 5(b). Referring to FIG. 5C, when connecting the carbon fiber sheet 40, the insulating carbon fiber sheet 40 is attached while securing an overlap length of 10 cm or more in the fiber length direction. After attachment, impregnation and defoaming are performed in the same way, and overlap in the width direction is not required. The cut insulating carbon fiber sheet 40 should be handled carefully so as not to disturb the arrangement of fibers, and should not be rolled or folded too small to be transported or stored. After attaching the insulating carbon fiber sheet 40, the defective part must be corrected. Referring to Fig. 5(d), if the surface treatment is defective, an epoxy resin is injected with a syringe, and referring to Fig. 5(e), the insulating carbon fiber When the sheet 40 is lifted, the insulating carbon fiber sheet 40 is reattached after cutting and removing the defective part. The overlap length in the fiber length direction is 10 cm or more. In the case of very small lifts, make a cut in the fiber direction and replenish the resin. According to the embodiment, in the step (C) of attaching the insulating carbon fiber sheet, the insulating carbon fiber sheet 40 coated with an airgel paint containing airgel is applied. Aerogel is an ultra-porous nanostructured material that has excellent insulation, high surface area, porosity, and low density. It is a new material that is attracting attention as a future insulation material and waterproofing agent. Airgel paint containing Aerogel is an ultra-insulating coating that prevents heat transfer through construction inside and outside buildings, reducing energy loss in places requiring cooling and heating. It is harmless to the human body and is ideal. It exhibits insulation and water repellency to block moisture penetration and heat loss in buildings. In addition, as a paint with elasticity and fatigue resistance, it has excellent resistance to micro-cracks that occur on the wall, and the superhydrophobicity of aerogel exhibits waterproof and leak control functions, so it has high resistance to mold and heat rays during painting. Not only does it reflect light, but its thermal conductivity is very low, making it difficult for external heat to be transferred to the inside and internal heat to go out at the same time, so that it is possible to expect a remarkable cooling and heating cost reduction effect. Table 1 below shows the physical properties of the airgel paint.

Deadline Matte color White Drying time Very dry Within 60 minutes Repainting interval More than 2 hours Softness 3 or more Volume solids 73% Number of paintings 2~4 times Recommended dry film thickness 300㎛ or more Theoretical application area 2m² (when dry film thickness is 300㎛) Viscosity 98~102KU (adjustable according to working conditions) storage duration 1 year (stored at room temperature at 5~38℃)

As an embodiment according to the present invention, the insulating carbon fiber sheet 40 coated with an airgel paint containing airgel has excellent thermal insulation properties and waterproof properties, and can secure insulation. After the insulating carbon fiber sheet attachment step (C) is finished, the primer 30 is applied in the secondary primer application step (D). According to the embodiment, the resin 50 is applied as a primer in the secondary primer application step (D). do. The resin 50 to be applied at this time is referred to as top coat resin. The resin 50 is uniformly applied to the carbon fiber sheet 40. In the case of constructing two or more layers of insulating carbon fiber sheet 40, the first layer of the top coat resin is completely dried, and then the top coat resin is performed in the same manner. Before construction on the second floor, construction must be performed after correcting the defective area on the first floor.

After the second primer application step (D) is finished, the concrete (10) surface that is reinforced by applying the finish paint (60) in the finishing paint application and curing step (E) is finished and reinforced at a predetermined temperature and humidity ( 10) Maintain the structure. Finish coating should be performed after the initial hardening of the impregnating resin. Initial hardening varies greatly depending on the type of resin and the ambient temperature, but it usually takes about 2 to 3 days. After the construction of the carbon fiber sheet, until the design strength is expressed, for example, a curing period as shown in Table 2 below is required.

Resin type Standard type Summer type Winter Application temperature (℃) 15-25 25 to 35 5 to 15 Curing period (days) 7 7 14

In the case of outdoor construction, a protective cover should be covered during the curing period to prevent contamination by rain or wind dust. At this time, make sure that the protective cover does not touch the construction surface.

6 is a material table for applying a method of reinforcing a structure using an insulating carbon fiber sheet according to an embodiment of the present invention. In FIG. 6, the amount of material generally required for the insulating carbon fiber sheet 1.5T is shown, and when the thickness (T) of the insulating carbon fiber sheet 40 is increased, the amount of material required increases at the same ratio. The application of the finishing paint 60 can be selected according to the condition of the concrete 10 structure or the surrounding environment.

7 is a view for explaining a cross-section of a concrete structure to which a structure reinforcing method using an insulating carbon fiber sheet according to an embodiment of the present invention is applied. Referring to FIG. 7, the concrete 10 structure to which the structure reinforcement method using an insulating carbon fiber sheet according to an embodiment of the present invention is applied is a mortar 20 and a primer 30 and a photo-curing insulating carbon fiber in the concrete 10. The sheet 40, the resin 50, and the finishing paint 60 are sequentially stacked, including a reinforcing structure of the concrete 10 structure, and the effect thereof is as described above.

The present invention is not limited to the specific preferred embodiments described above, and any person of ordinary skill in the technical field to which the present invention pertains without departing from the gist of the present invention claimed in the claims can implement various modifications. Of course, such changes are within the scope of the claims.

10: concrete 20: mortar
30: primer 40: insulating carbon fiber sheet
50: resin 60: finishing paint

Claims (12)

A concrete surface treatment step;
Applying a first primer;
Attaching an insulating carbon fiber sheet;
Applying a second primer;
A method for reinforcing a structure using an insulating carbon fiber sheet comprising: applying and curing a finish paint.
The method of claim 1,
The concrete surface treatment step is a method for reinforcing a structure using an insulating carbon fiber sheet, characterized in that it includes repairing cracks and repairing sections.
The method of claim 2,
Crack repair and cross-section repair work is a structure reinforcement method using an insulating carbon fiber sheet, characterized in that it includes the work of applying a mortar.
The method of claim 3,
The mortar is a method for reinforcing a structure using an insulating carbon fiber sheet, characterized in that it is an SM moisture barrier type mortar.
The method of claim 2,
For crack repair and cross-section repair work, exposed reinforcing bars are treated with rust prevention, and uneven and/or protruding parts are surface treated and smoothed, so that the surface level is less than 1 mm, and cracks or damaged cross sections with a width of 0.2 mm or more are treated with epoxy resin Structure reinforcement method using an insulating carbon fiber sheet, characterized in that to repair and / or repair by injection.
The method of claim 1,
The concrete surface treatment step is a method for reinforcing a structure using an insulating carbon fiber sheet, characterized in that it includes a grinding operation.
The method of claim 1,
Structure reinforcement method using an insulating carbon fiber sheet, characterized in that it further comprises a step of applying a resin for impregnation after the first primer application step.
The method of claim 1,
Structure reinforcement method using an insulating carbon fiber sheet, characterized in that it further comprises an uneven adjustment step after the first primer application step.
The method of claim 8,
The uneven adjustment step is a method for reinforcing a structure using an insulating carbon fiber sheet, characterized in that it includes an epoxy putty operation.
The method of claim 8,
Structure reinforcement method using an insulating carbon fiber sheet, characterized in that it further comprises the step of applying a resin for impregnation after the uneven adjustment step.
The method according to any one of claims 1 to 10,
In the step of attaching the insulating carbon fiber sheet, the insulating carbon fiber sheet is a method of reinforcing a structure using an insulating carbon fiber sheet, characterized in that an airgel paint containing airgel is coated.
The method according to any one of claims 1 to 10,
The second primer application step is a method of reinforcing a structure using an insulating carbon fiber sheet, characterized in that the step of applying a resin.

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