KR101763297B1 - Prevent cracks and repair method of construction structure - Google Patents

Abstract

Disclosed is a crack prevention and repair method of a construction structure, which can prevent a crack that may be generated in a concrete structure in advance by sequentially constructing a waterproof agent and a repair sheet, and improve waterproof performance. The present invention provides the crack prevention and repair method of a construction structure, which comprises the following steps of: (a) applying primer to a concrete structure; (b) primarily applying a water-soluble acrylic elastic coating film to concrete on which the primer is applied; (c) attaching the repair sheet to the concrete on which the water-soluble acrylic elastic coating film is applied; and (d) secondarily applying and drying a water-soluble acrylic elastic coating film to the concrete to which the repair sheet is attached.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of preventing cracks in a concrete structure,

The present invention relates to a method for preventing and repairing cracks in a concrete structure, and more particularly, to a method for preventing and repairing cracks in a concrete structure by sequentially applying a waterproofing agent and a repairing sheet, And more particularly, to a method for preventing and repairing cracks in a concrete structure that can be increased.

If leaks occur due to defects in waterproofing performance of concrete structures, compressive strength, freeze-thaw resistance, resistance to chemical erosion, etc. are reduced and the life of concrete structures is shortened. This results in a loss of aesthetics of the building and inconvenience to residence as a living space. As a result, deterioration due to physical and chemical environmental conditions is inevitable for large-scale maintenance and rework of concrete structures, which causes great economic losses. For the cracked concrete structure, it is necessary to repair the concrete structure in order to restore its waterproofness and durability, or to take into consideration the stability of the structure and the inertia. In order to repair the cracked part, a permeable waterproofing material generally applied by injection technique is used.

So far, penetration type waterproofing materials commonly used at home and abroad are composed of alkali silicate. These alkaline silicates rapidly react with calcium ions, which are the main constituents of concrete, to form calcium silicate even though the surface tension is low. This calcium silicate is a insoluble and chemically stable oxide that protects the surface of the concrete but has a problem that it can not penetrate into the concrete due to its penetration strength of only a few millimeters and thus it is difficult to restore the performance of the concrete structure.

Korean Patent No. 1645510 discloses an organic-inorganic hybrid composition for waterproofing concrete structures and a waterproofing method for concrete structures using the same. The present invention describes a waterproofing material capable of repairing concrete radiation cracks by using an inorganic binder and an organic waterproofing performance improving material. However, since the surface permeability is low and a new and old adhesive must be applied before using a waterproofing agent, I have.

Also, the concrete water repellent material, which is widely used in domestic and overseas, is applied to the concrete structure and reacts after the water repellent material penetrates into the concrete, thereby generating the hydraulic force, thereby blocking the penetration of water. When the water pressure is greatly affected as in the case of an exponential underground structure, it is difficult to apply due to the limit of the hydraulic force, and it is decomposed by heat and ultraviolet rays, so that it can not exhibit long-term performance. Particularly, in the case of the existing penetrating type water repellent material, since the concrete surface forms a strong lipophilic layer, there is a disadvantage in that when the secondary coating is applied to the concrete surface, the adhesiveness is lowered, the water pressure is weak, have. In addition, it has disadvantages such as degradation of chemical resistance and decomposition when it is exposed to sulfuric acid, hydrochloric acid, etc. and failing to exhibit its function.

Korean Patent Registration No. 1407360 discloses a method for reinforcing concrete section restoration using a concrete durability reinforcing composition. In the present invention, a method of repairing a cross section of a concrete using a resin compound and a phenylethyl water repellent agent is described. However, when a large amount of an organic solvent is used, contamination by an organic solvent may occur during operation, and the effect of the water- If it falls, there is a possibility that the recovered section will be damaged again.

Disclosure of the Invention The present invention has been conceived to solve the problems described above, and it is an object of the present invention to minimize the cracks due to vibration or shrinkage of concrete by laminating an acrylic elastic film agent and sheet having excellent permeability, And to provide a method for preventing and repairing cracks in a concrete structure having greatly improved waterproof performance.

In order to solve the above-mentioned problems, the present invention provides a method of manufacturing a concrete structure, comprising: (a) applying a primer to a concrete structure; (b) first coating a water-soluble acrylic elastic film agent on the primer-coated concrete; (c) attaching a repairing sheet to the concrete to which the water-soluble acrylic elastic coating agent is applied; And (d) secondly coating a water-soluble acrylic elastic coating agent on the concrete to which the repair sheet is attached and drying the same.

Also, the water-soluble acrylic elastic film agent may include a resin, calcium carbonate, a thickener, and titanium dioxide.

The water-soluble acrylic elastic coating agent is a coating agent of a paste cream type at a temperature of 5 to 35 ° C for 30 to 120 minutes for a tack-free curing time of less than 72 hours and a complete curing time of 72 hours or less. ≪ / RTI >

The water-soluble acrylic elastic coating agent is applied at a rate of 0.5 to 2 kg per 1 m < 2 > of the concrete structure and a thickness of 0.5 mm or more twice.

And the repairing sheet is a mesh glass fiber sheet or a composite waterproof sheet.

According to the present invention, it is possible to improve the durability of concrete by laminating an acrylic elastic film agent and sheet having excellent permeability, and to prevent re-cracking due to vibration or shrinkage of concrete, It can be used for surface improvement, and unlike existing repair methods using organic waterproofing agent, it is possible to install it safely by using water-soluble coating agent.

Hereinafter, preferred embodiments of the present invention will be described in detail. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Throughout the specification, when an element is referred to as "including " an element, it means that it can include other elements, not excluding other elements, unless specifically stated otherwise.

The present inventors paid attention to the fact that the existing waterproofing or repairing method of concrete is weak in the concrete penetration ability and the effect of improving the physical properties of concrete is inferior and the use of the organic solvent may adversely affect the health of the workers at the time of construction. As a result, it was confirmed that when the acrylic elastic film agent and the sheet having excellent permeability are laminated and installed, the penetration of the concrete into the concrete is increased and the use of the organic solvent can be minimized.

Accordingly, the present invention provides a method of making a concrete structure comprising: (a) applying a primer to a concrete structure; (b) first coating a water-soluble acrylic elastic film agent on the primer-coated concrete; (c) attaching a repairing sheet to the concrete to which the water-soluble acrylic elastic coating agent is applied; And (d) secondly coating a water-soluble acrylic elastic coating agent on the concrete with the water-repellent sheet and drying the water-repellent acrylic elastic coating agent.

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

(a) applying a primer to a concrete structure

After removing the foreign matter (oil, latens, dust, etc.) using a wire brush, a brush, a sand grinder or the like, the water-soluble acrylic elastic coating agent, cement, gravel, Repair and reinforce. This step is performed when there is damage to the target concrete, and it is not necessary to perform it if the concrete is not damaged and the surface is clean.

The primer is applied to the concrete having the surface arranged through the above process. The primer used herein is not limited as long as it is a primer generally used in concrete, and the primer is used for the purpose of enhancing the bonding force between the concrete and the coating agent.

(b) a step of first coating a water-soluble acrylic elastic film agent

And is densely applied in one direction using a hand tool such as a rubber hera, a brush, a roller, or an air tool such as an air brush or a spray gun. At this time, when the coating is applied in both directions, the adhesive force to the primer is weakened, and the waterproofing ability may be lowered.

The water-soluble acrylic elastic coating agent applied has a tack-free time of 30 to 120 minutes, preferably 40 to 80 minutes, more preferably 50 to 70 minutes, and a complete curing time of 72 hours or less, 60 hours or less, more preferably 48 hours or less, and a paste cream type paste can be used. If the tack-free time is less than 30 minutes, it is hard to apply a uniform coating film during the operation, and if it exceeds 120 minutes, it takes a long time to complete the next operation after curing. Also, even if the full curing time exceeds 72 hours, the working time is excessively consumed and the working efficiency may be lowered.

The water-soluble acrylic elastic film agent preferably comprises a resin, calcium carbonate, a thickening agent, and titanium dioxide. The resin may contain 20 to 60% of acrylic resin, 10 to 30% of limestone, preferably 15 to 25% % Can be included. The incremental zero acrylic emulsion may comprise 10 to 40%, preferably 20 to 25%. The coating agent may further contain 5 to 10% of water, 1 to 5% of 2-butoxyethanol and 1 to 5% of 1,2-ethanol as a solvent, and the titanium dioxide may be added in an amount of 5 to 20% May comprise 8 to 12%.

The water-soluble acrylic elastic coating agent is applied at a rate of 0.5 to 2 kg, preferably 0.7 to 1.7 kg, and more preferably 1.0 to 1.4 kg per 1 m 2 of the concrete structure, and the thickness of the coating film is 0.1 to 1 mm, Is preferably 0.3 to 0.8 mm. When the amount of the coating agent used is less than 0.5 kg per 1 m 2 of the concrete structure, the thickness of the coating film is thinned to deteriorate the waterproofing performance and durability, and if it exceeds 2 kg, the thickness of the coating film becomes excessively thick, and the physical properties may be deteriorated due to internal incomplete solidification.

(c) attaching the repair sheet

After the application of the water-soluble acrylic elastic coating agent, a repair sheet is attached. At this time, the water-soluble acrylic elastic coating agent may be adhered to the water-retaining sheet prior to curing, and may be adhered after curing. In the case of adhering the coating film and the repairing sheet to each other, the physical properties of the repaired portion can be improved. However, when the repairing sheet is erroneously removed, the coating film is damaged and the workability is deteriorated. When it is attached after curing, the workability is improved, but the property improvement value may be small. Therefore, it is preferable to attach the repair sheet after proper curing in consideration of the skill level of the operator, the desired durability improvement value, and the like.

The repairing sheet may be a mesh glass fiber sheet or a composite waterproof sheet. It is preferable to use a highly durable mesh glass fiber sheet in order to prevent cracking due to shrinkage or the like of concrete, and it is preferable to use a composite waterproof sheet to improve waterproofness. It is also possible to construct two sheets at the same time, and it is also possible to use one sheet stacked several times.

(d) a step of applying a water-soluble acrylic elastic coating agent secondarily and drying

It is more preferable to further coat the water-soluble acrylic elastic film agent to protect the water-repellent sheet after the water-repellent sheet is applied and further improve durability and waterproofness. At this time, it is preferable to apply the second coating after the first coating surface is dried (after 3-4 hours at 20 ° C) to evenly apply the coating surface.

In the case of the second coating, pinholes are prevented from being applied when the coating is applied in the first coating direction and the crosswise direction, so that a more durable elastic coating film can be obtained.

Hereinafter, a specific embodiment of the present invention will be described.

Example  One

The surface of 1 m 2 of concrete was washed and then thoroughly dried and primer applied. After the primer was cured, 1.2 kg of acrylic elastic coating agent was applied uniformly to a thickness of 0.5 mm or more uniformly. The coating was cured for 1 hour after application, and after 1 hour, a mesh glass fiber sheet was attached. After the glass fiber sheet was attached, additional curing was performed for 3 hours. After the curing was completed, 1.2 kg of acrylic elastic coating agent was uniformly applied to a thickness of 0.5 mm or more uniformly and then completely cured for 48 hours.

Example  2

The experiment was carried out in the same manner as in Example 1 except that a composite waterproof sheet was used in place of the mesh glass fiber sheet.

Example  3

Experiments were carried out in the same manner as in Example 1, except that 0.5 kg per 1 m 2 concrete was used as the acrylic elastic coating agent applied in primary and secondary coatings.

Example  4

Experiments were carried out in the same manner as in Example 1, except that 2 kg of acrylic elastic coating agent applied on the first and second sides was used per 1 m2 of concrete.

Comparative Example  One

The same experiment as in Example 1 was conducted using a urethane waterproof coating agent instead of the acrylic elastic coating agent applied in primary and secondary coatings. The product name "Urethane Elastic Waterproof 100" was first applied and cured by Samhwa Paint, and the product name "Water Tan" was applied secondarily and cured.

Comparative Example  2

The experiment was carried out in the same manner as in Example 1, except that the mesh glass fiber sheet was not used.

Comparative Example  3

The experiment was carried out in the same manner as in Comparative Example 1 except that the mesh glass fiber sheet was not used.

Experimental Example

The curing degree, durability and waterproofing properties of the waterproof surfaces of Examples 1 to 4 and Comparative Examples 1 to 3 were tested, and the results are shown in Table 1 below.

Surface hardening was performed by visual inspection and palpation test. In order to confirm the durability by cracking, 10kg of the object was dropped on the concrete surface of 1m2 which was completed, and crack formation was confirmed. Finally, to check the waterproof performance, the time until the lower concrete was wet was measured by supplying 100 atm of water to the top of the coating.

Surface hardening completion time durability Waterproof Toughening hardening Full cure concrete
crack Coat
crack Example 1 51 minutes 47 hours 15 times 21 times 542 minutes Example 2 52 minutes 47 hours 14 times 18 times 615 minutes Example 3 49 minutes 38 hours 15 times 20 times 486 minutes Example 4 58 minutes 56 hours 16 times 22 times 561 minutes Comparative Example 1 275 minutes 82 hours 14 times 16 times 315 minutes Comparative Example 2 65 minutes 68 hours 10 times 11 times 533 minutes Comparative Example 3 273 minutes 91 hours 9 times 9 times 322 minutes

As shown in Table 1, the curing time of commercially available urethane waterproofing agent was very long as compared with the embodiment of the present invention, and accordingly, it took much time to work. In addition, "Urethane Elastic Waterproof 100", which is a commercially available primary coating agent, uses an organic solvent, and therefore, there is a risk of ignition and it is considered that it is difficult to apply it to an indoor environment. It was also found that the durability of the concrete was improved in comparison with the case where the glass fiber sheet was used (Examples 1, 3 and 4) and the case where it was not used (Comparative Examples 2 and 3) I was able to confirm the delay. Particularly, in the case of the urethane waterproofing agent applied without using the repairing sheet, it was confirmed that the cracks of the coating film occurred simultaneously with the concrete cracking.

Finally, in the case of the waterproof property, it was confirmed that the waterproofing property of the waterproofing material of the present invention was the highest in the case of the second embodiment of the present invention, and that the waterproofing property of the urethane waterproofing agent was lower than that of the present invention.

The preferred embodiments of the present invention have been described in detail above. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning, range, and equivalence of the claims are included in the scope of the present invention Should be interpreted.

Claims (5)

A method for preventing and repairing cracks in a concrete structure comprising the steps of:
(a) applying a primer to a concrete structure;
(b) first coating a water-soluble acrylic elastic film agent on the primer-coated concrete;
(c) attaching a repairing sheet to the concrete to which the water-soluble acrylic elastic coating agent is applied; And
(d) Secondarily applying a water-soluble acrylic elastic coating agent to the concrete to which the repair sheet is attached and drying the same.
A method for preventing and repairing cracks in a concrete structure,
The water-soluble acrylic elastic film agent comprises 20 to 60% of acrylic resin, 10 to 30% of limestone as calcium carbonate, 10 to 40% of acrylic emulsion as an incremental agent, 5 to 10% of water as a solvent, 1 to 5% of 2-butoxyethanol, 1 to 5% of 1,2-ethanol and 5 to 20% of titanium dioxide,
The water-soluble acrylic elastic coating agent is a coating agent of a paste cream type at a temperature of 5 to 35 ° C., a curing time of 30 seconds to 120 minutes, and a complete curing time of 72 hours or less,
Wherein the water-soluble acrylic elastic coating agent is applied at a rate of 0.5 to 2 kg per 1 m < 2 > of the concrete structure, and the thickness of the coating film is 0.1 to 1 mm. delete delete delete The method according to claim 1,
Wherein the repairing sheet is a mesh glass fiber sheet or a composite waterproof sheet.