KR101590951B1 - Mortar composition for cross-section restoration of reinforced concrete structures and restoring method for cross-section of reinforced concrete structures using the same - Google Patents

Abstract

The present invention relates to a mortar composition for restoring cross-section of reinforced concrete structures and a method for restoring cross-section of reinforced concrete structures using the same. According to the present invention, the mortar composition for restoring cross-section of reinforced concrete structures can effectively fixate chlorine ions being penetrated from the outside after restoring the cross-section of failed reinforced concrete structures. The mortar composition for restoring cross-section of reinforced concrete structures comprises materials for fixating chlorine ions as described, and the composition can be effectively applied for restoring cross-section of reinforced concrete structures by having excellent properties such as adhesion strength, flexural strength, compression strength, neutralization resistance, resistance against corrosion of reinforcing bars, chemical resistance, etc. The mortar composition for restoring cross-section of reinforced concrete structures comprises: 22.41 to 23.28 wt% of common Portland cement; 55.27 to 56.93 wt% of dry silica sand; 3.74 to 4.21 wt% of anorthite powder; 14.73 to 16.28 wt% of gypsum fibrosum powder; 0.31 to 0.42 wt% of redispersible acrylic powder; 0.56 to 0.70 wt% of high-performance water reducing agent; and 0.82 to 0.97 wt% of polyvinyl alcohol fiber.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mortar composition for repairing a section of a reinforced concrete structure and a method for repairing a section of the reinforced concrete structure using the same.

The present invention relates to a mortar composition for recovering a section of a reinforced concrete structure and a method for recovering a section of a reinforced concrete structure using the same.

Concrete can be manufactured in any shape, and it is not only easy to purchase materials but also is widely used as a construction material because it is structurally stable because of its high compressive strength. However, since the tensile strength of concrete is as small as 1 / 13-1 / 10 of the compressive strength, it is widely used as a reinforced concrete which is used by introducing a reinforcing bar having a large tensile strength in a portion where tensile stress of concrete acts.

These reinforced concrete structures have been recognized as being semi-permanently available because they have high durability. In addition, since the coefficient of thermal expansion of reinforcing bars and concrete is almost the same, the adhesion of reinforcing bars and concrete is good, and since the pH of concrete is about 12-13, a passive impermeable film is formed on the surface of reinforcing bars to protect the reinforcing bars from corrosion.

However, recent research results and investigation of existing structures have revealed that aged deterioration phenomenon can not be avoided in reinforced concrete structures. Especially, cases where the original function is lost after not more than several decades after the construction of the structure are often reported. The reason for this is that the carbon dioxide penetrates into the concrete from the outside, the pH of the concrete is lowered, and the impervious film of the passive surface formed on the surface of the reinforcing bar is destroyed, so oxygen and moisture come into contact with the surface of the reinforcing bar, If the tensile strength of the concrete is smaller than the expansion pressure of the reinforcing bar, cracks will occur in the concrete, and if it is severe, the concrete will be dropped.

In addition, corrosion of reinforcing bars becomes worse when chlorine ions penetrate into the concrete. When chloride ions penetrate into the concrete, soluble calcium chloride (CaCl ₂ ) formed by reaction with calcium ions (Ca ²⁺ ) As the concrete becomes porous, chlorine ions penetrate into the concrete more easily. The chlorine ions penetrate not only lower the pH of the concrete but also destroy the passive impermeable coating on the surface of the reinforcing steel, so that corrosion of the reinforcing steel due to oxygen- .

In the past, to repair the section of the concrete that was lost due to the corrosion of the reinforcing bar, the damaged concrete was removed and the section of the concrete was filled with the repair mortar. In order to suppress the penetration of the chloride ion, , The voids of the repair mortar were filled. However, such a physical method has a problem that the infiltration inhibition performance of the chlorine ion is not sufficient and the infiltration of the chlorine ion can not be suppressed when the fine cracks occur in the repair mortar.

In order to solve this problem, a method of fixing a chloride ion in a mortar by adding a resin capable of exchanging an anion to a repair mortar to a repair mortar has been developed. However, since the bonding force between a resin and a chloride ion is weak, And the resin is gradually decomposed at room temperature to be aminated and the ion exchange function as a whole can not be performed well.

As a prior art related to the present invention, Korean Patent No. 10-1104812 (Patent Document 1) as a prior art relates to a method of repairing and repairing a section of a reinforced concrete structure, The contents of repairing and repairing the cross section of the concrete structure by using the permeable diffusive caustic removers and the high strength corrosion resistant repair materials are disclosed and there is no disclosure or suggestion of effective fixing of the chloride ion.

Patent Document 1. Korean Patent No. 10-1104812

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method of recovering a section of a reinforced concrete structure, which can fix chlorine ions penetrated from the outside, Mortar composition and a method of recovering a section of a reinforced concrete structure using the mortar composition.

The present invention also provides a mortar composition for reinforced concrete structure having excellent adhesion strength, bending strength, compressive strength, neutralization resistance, corrosion resistance and chemical resistance while fixing chloride ion effectively in mortar, and a cross section of a reinforced concrete structure using the mortar composition The goal is to provide a recovery method.

According to one aspect of the present invention, there is provided a mortar composition for recovering a section of a reinforced concrete structure,

The present invention relates to a method for producing a high-performance water-reducing agent, comprising the steps of: (1) preparing a cement composition comprising 22.41-23.28% by weight of Portland cement, 55.27-56.93% by weight of dried silica, 3.74-4.21% by weight of anorthite powder, 14.73-16.28% by weight of fumed silica powder, 0.31-0.42% 0.70 wt% and polyvinyl alcohol fibers 0.82-0.97 wt%.

According to another aspect of the present invention, there is provided a method of recovering a section of a first reinforced concrete structure,

As a method for repairing a section of a reinforced concrete structure in which a reinforcing bar is corroded,

1) removing the damaged concrete;

2) removing the rust from the exposed surface of the reinforcing bar;

3) cleaning the surface of the removed reinforced concrete after the removed concrete surface and the concrete are removed;

4) applying a rebar anti-corrosive material to the surface of the cleaned reinforcing bar;

5) applying a primer to the surface of the cleaned concrete surface and the surface of the reinforcing bar coated with the anticorrosive material;

6) repairing the concrete portion removed with the mortar composition for reinforcing concrete section after applying the primer; And

7) coating the exposed surface of the structure with the surface protection material among the repaired areas;

/ RTI >

The above-mentioned mortar composition for recovering reinforced concrete section is usually composed of 22.41-23.28% by weight of Portland cement, 55.27-56.93% by weight of dried silica sand, 3.74-4.21% by weight of anorthite powder, 14.73-16.28% by weight of fumed powder, -0.42% by weight, high performance water reducing agent 0.56-0.70% by weight and polyvinyl alcohol fiber 0.82-0.97% by weight.

According to another aspect of the present invention, there is provided a method of recovering a section of a second reinforced concrete structure,

As a method for recovering a section of a reinforced concrete structure in which the concrete is peeled off,

1) removing the damaged concrete;

2) cleaning the surface of the removed concrete;

3) applying a primer to the cleaned concrete surface;

4) repairing the concrete part removed with the mortar composition for reinforcing concrete cross-section after applying the primer; And

5) coating the exposed surface of the structure with the surface protecting material among the repaired areas;

/ RTI >

The above-mentioned mortar composition for recovering reinforced concrete section is usually composed of 22.41-23.28% by weight of Portland cement, 55.27-56.93% by weight of dried silica sand, 3.74-4.21% by weight of anorthite powder, 14.73-16.28% by weight of fumed powder, -0.42% by weight, high performance water reducing agent 0.56-0.70% by weight, and polyvinyl alcohol fiber 0.82-0.97% by weight.

The mortar composition for repairing a section of a reinforced concrete structure according to the present invention is a mortar composition for repairing a section of a reinforced concrete structure capable of effectively fixing chlorine ions intruding into mortar from outside after restoration of a section of a dropped reinforced concrete structure, It is a method to recover the section of a reinforced concrete structure. When the chloride ions are fixed in the mortar, it is possible to prevent additional penetration of chlorine ions into the concrete, thereby preventing corrosion of the steel in the concrete.

In addition, although it contains a substance for fixing the chloride ions in the mortar, it has excellent adhesion strength, bending strength, compressive strength, neutralization resistance, corrosion resistance of reinforcing steel and chemical resistance, and can be effectively used for repairing the section of a reinforced concrete structure have.

FIG. 1 is a sectional view showing a state in which a reinforced concrete exposed section is restored by using a mortar composition for restoration of a reinforced concrete structure according to an embodiment. FIG.
FIG. 2 is a cross-sectional view showing a state in which a section of a concrete without a reinforcing bar exposed using a mortar composition for repairing a section of a reinforced concrete structure according to an embodiment is recovered. FIG.
FIG. 3 is a graph showing the results of measurement of the adhesion strength of a mortar composition for repairing a section of a reinforced concrete structure according to an embodiment. FIG.
FIG. 4 is a graph showing a measurement result of the flexural strength of a mortar composition for repairing an end face of a reinforced concrete structure according to an embodiment.
5 is a graph showing compressive strength measurement results of a mortar composition for recovering a section of a reinforced concrete structure according to an embodiment.
FIG. 6 is a graph showing the results of measurement of the neutralization depth of a mortar composition for recovering a section of a reinforced concrete structure according to an embodiment. FIG.
FIG. 7 is a graph showing a result of measurement of spontaneous potential of a mortar composition for repairing an end face of a reinforced concrete structure according to an embodiment. FIG.
FIG. 8 is a graph showing a measurement result of a weight change rate of a mortar composition for repairing a section of a reinforced concrete structure according to an embodiment. FIG.

Accordingly, the present inventors have made extensive efforts to develop a mortar composition which can effectively fix chlorine ions penetrating into mortar and have an effect necessary for restoration of a section of a reinforced concrete structure. As a result, Mortar composition and a method for recovering a section of a reinforced concrete structure using the same.

In order to simplify the premise of completing the present invention, in general, the tensile strength of concrete is much smaller than the compressive strength. Therefore, in order to compensate the above, reinforcing bars are introduced into the portions where tensile stress acts to construct structures in the form of reinforced concrete do. On the surface of such reinforcing bars, a passive film is formed as an impermeable film to protect the reinforcing bars from corrosion. However, when the carbon dioxide penetrates into the concrete, the pH of the concrete is lowered, and the impervious coating is broken, so that the reinforcing steel is corroded. Also, the corrosion of these reinforcing bars becomes worse when the chloride ions penetrate into the concrete. This is because when the chloride ion penetrates into the concrete a little, it reacts with the calcium ion (Ca ²⁺ ) existing in the concrete pore, and the soluble calcium chloride (CaCl ₂ ) formed therefrom is eluted and the concrete becomes porous. As the concrete changes in porosity, the chloride ions penetrate into the concrete more easily. The chlorine ions penetrate not only lower the pH of the concrete but also destroy the passive impervious coating on the surface of the reinforcing steel, (See Reaction Scheme 1 below). Accordingly, the present inventors have completed the present invention for the purpose of providing a composition for effectively preventing the corrosion of reinforcing bars and effectively recovering the cross-section, by effectively fixing the chloride ion to the mortar so as not to penetrate into the concrete after repairing. .

[Reaction Scheme 1]

Specifically, the mortar composition for recovering a section of a reinforced concrete structure according to the present invention contains 22.41-23.28% by weight of Portland cement, 55.27-56.93% by weight of dried silica sand, 3.74-4.21% by weight of anorthite powder, 14.73-16.28% by weight of fumed powder %, Redispersible acrylic powder 0.31-0.42 wt%, high performance water reducing agent 0.56-0.70 wt%, and polyvinyl alcohol fiber 0.82-0.97 wt%.

The ordinary Portland cement is used for expressing the strength of the mortar composition for restoration of the reinforced concrete structure. When high initial strength of the mortar is required, the rapid hardening Portland cement can be used at the same weight. If the ordinary Portland cement is less than 22.41% by weight, the strength of the reinforced concrete sectional restoration mortar may be lowered, which is not preferable. When the ordinary Portland cement is 23.28% If the amount exceeds the above-mentioned range, the mortar composition for an endless restoration of an unreinforced reinforced concrete structure is produced, which limits the content of the remaining material contributing to lowering the penetration of chlorine ions.

The dried silica sand is used for suppressing expansion of cracks in the reinforced concrete section recovery mortar composition and is used as an extender. It does not limit the size and the granulation ratio of the particles. Usually, the amount of the Portland cement is reduced to obtain an economical reinforced concrete structure Dried mortars having an average particle size of 0.03-1.1 mm and a granulation ratio of 2.3-3.1 are preferred in order to obtain a mortar composition for restoration of the mortar and to obtain good workability. When the dried silica sand is less than 55.27% by weight, the ratio of the Portland cement is usually increased, so that the mortar composition for repairing an endless reinforcing concrete structure due to an increase in cost, However, when the dried silica sand is more than 56.93% by weight, the amount of air is increased and the strength is decreased, so that usually the Portland cement paste is separated from the dried silica sand, which is not preferable. In addition, when the dried silica sand content exceeds 56.93% by weight, there is a problem of limiting the content of the remaining substances contributing to lowering the penetration of chlorine ions.

The anorthite powder is intended to prevent chlorine ions from reaching the reinforcing bars inside the concrete by reacting with chlorine ions penetrating from the outside to fix the chlorine ions. The chlorine ions penetrated from the outside are present in the mortar pores calcium salt of (Ca ²⁺⁾ and the reaction was formed availability (CaCl ₂₎ and coupled to _{3CaO · Al 2 O 3 · CaCl} 2 · nH 2 O or _{3CaO · SiO 2 · CaCl 2 ·} nH ₂ O to the reaction product of Thereby maintaining a stable state while fixing the chloride ion. In addition, the Oh Nord site powder is preferably 10-50 ㎛ to the fast reaction of the calcium chloride (CaCl ₂₎ in the pores of the mortar composition is, but are some restrictions on the particle size. It is preferable that the anorthite powder is 3.74-4.21% by weight. When the anorthite powder is less than 3.74% by weight, the performance of fixing the chloride ion is lowered, , The workability is deteriorated. Therefore, it is not preferable to use an admixture for improving fluidity.

In addition to the anorthite powder, the fused gypsum powder is reacted with a compound of chlorine ion to fix the chlorine ion to inhibit the arrival of the chlorine ion to the reinforcing bar in the concrete. The fired powder is usually reacted with the Portland cement To produce 3CaO · Al ₂ O ₃ · 3CaSO ₄ · 32H ₂ O and the reaction product is combined with soluble calcium chloride (CaCl ₂ ) in the pores of the mortar composition for the cross-section recovery mortar of the reinforced concrete structure to form an insoluble 3CaO · Al ₂ O ₃ .CaCl ₂ .nH ₂ O is formed to fix the chloride ion. It is preferable that the density is 2.30 g / cm 3 or more and the specific surface area is 3000 cm 2 / g or more in order to prevent cracking and improve workability in a mortar composition for repairing an endless reinforced concrete structure by abrupt reaction of the above flour powder Do. The frit powder is preferably 14.73-16.28 wt%. If the frit powder is less than 14.73 wt%, the performance of fixing the chloride ion is deteriorated, and the frit powder is 16.28 wt% %, It is not preferable because the mortar composition for repairing the cross-section of the reinforced concrete structure is rapidly condensed and cracks are generated due to high heat of reaction.

The redispersible acrylic powder is chemically bonded with the reaction product of Portland cement, anorthite powder and flour powder to reduce the crack width of the mortar composition for the cross-sectional restoration of the reinforced concrete structure. The mortar composition of the reinforced concrete structure And to improve watertightness and airtightness. The particle size is not limited, but it is preferably 0.2-0.5 [micro] m to disperse the acrylic powder uniformly. When the redispersible acrylic powder is less than 0.31% by weight, the adhesion force of the mortar composition for repairing a section of a reinforced concrete structure is lowered, and the water tightness and airtightness are lowered. There is a problem and it is not preferable. When the above-mentioned redispersible acrylic powder is more than 0.42% by weight, the reaction of the ordinary Portland cement, anorthite powder and fumed powder, which contribute to the chloride ion fixation, in the mortar composition for restoration of the reinforced concrete structure is hindered Which is undesirable.

The above-mentioned high-performance water reducing agent is intended to improve the strength of the mortar of the section-restoring concrete of the reinforced concrete structure by reducing the amount of water mixed in the mortar composition for the section-restoring of the reinforced concrete structure. Although there is no limitation on the components of the high- Or a lignin-based high-performance water reducing agent is preferable. If the high-performance water reducing agent is less than 0.56% by weight, the amount of water to be mixed with the mortar composition for restoring the reinforced concrete section is reduced, which is not preferable. If the high-performance water reducing agent is more than 0.70% by weight, the mortar composition of the reinforced concrete structure is not preferable because the mortar composition of the mortar composition is delayed.

The polyvinyl alcohol fiber is intended to suppress cracking of the reinforced concrete structure and to improve the flexural strength of the reinforced concrete mortar. However, the polyvinyl alcohol fiber does not limit the length and diameter of the reinforced concrete structure. However, It is preferable that the aspect ratio of the diameter to the length is 50-100. It is preferable that the polyvinyl alcohol fiber is 0.82-0.97% by weight. If the polyvinyl alcohol fiber is less than 0.82% by weight, crack resistance and bending strength improvement performance of the mortar composition for reinforced concrete structure can be deteriorated If the amount of the polyvinyl alcohol fiber is more than 0.97% by weight, the fibers are aggregated at the time of mixing the water with the mortar composition for repairing the cross-section of the reinforced concrete structure, and the surface of the hardened mortar is not smooth Which is undesirable.

Thus, the mortar composition for restoration of the reinforced concrete structure according to the present invention can achieve the chloride ion fixing effect in the mortar to be achieved in the present invention only when the content of the composition falls within the above-mentioned numerical range as a whole, Corrosion can be prevented. In addition, it is possible to effectively utilize for the repair of the section of the reinforced concrete structure because of the excellent adhesion strength, bending strength, compressive strength, neutralization resistance, corrosion resistance and chemical resistance.

According to another aspect of the present invention, there is provided a method of recovering a section of a first reinforced concrete structure,

As a method for repairing a section of a reinforced concrete structure in which a reinforcing bar is corroded,

1) removing the damaged concrete;

2) removing the rust from the exposed surface of the reinforcing bar;

3) cleaning the surface of the removed reinforced concrete after the removed concrete surface and the concrete are removed;

4) applying a rebar anti-corrosive material to the surface of the cleaned reinforcing bar;

5) applying a primer to the surface of the cleaned concrete surface and the surface of the reinforcing bar coated with the anticorrosive material;

6) repairing the concrete portion removed with the mortar composition for reinforcing concrete section after applying the primer; And

7) coating the exposed surface of the structure with the surface protection material among the repaired areas;

/ RTI >

The above-mentioned mortar composition for recovering reinforced concrete section is usually composed of 22.41-23.28% by weight of Portland cement, 55.27-56.93% by weight of dried silica sand, 3.74-4.21% by weight of anorthite powder, 14.73-16.28% by weight of fumed powder, -0.42% by weight, high performance water reducing agent 0.56-0.70% by weight and polyvinyl alcohol fiber 0.82-0.97% by weight.

The method of removing the damaged concrete is not particularly limited as long as the damaged concrete can be removed. The method of step 1) may be applied to all of the concrete, , Water jets, rock drills and other suitable methods.

The rust removal step in step 2) removes rust by wire brush, water jet, water sand jet and other suitable methods. In addition, if it is necessary to remove the rust from the exposed reinforcing bar after the removal of concrete and find out that the reinforcing bar is corroded strongly due to the lack of tensile strength or to increase the bearing capacity by changing the use of the reinforced concrete structure, The reinforcement can be installed to reinforce the reinforced concrete structure.

In the step 3), the surface of the concrete and the surface of the reinforcing bar are completely removed by a suitable method such as water jet or vacuum inhaler to remove foreign matter such as dust or oil which lowers the adhesion of the surface of the concrete and the surface of the reinforced concrete, When water jet is applied, it is preferable that the water film is not formed on the surface to interfere with the adhesion.

The step of applying the rustproofing material of the step 4) is preferably carried out by using a brush, a roller or a spray to prevent corrosion of the exposed reinforcing steel, and it is preferable to apply the rustproofing material evenly to the back of the reinforcing steel .

The step of applying the primer in the step 5) is intended to further enhance the adhesion of the concrete and the mortar to be used for repairing the section, and it is applied by a suitable method such as spraying, roller or brush, In order to reduce the dropout rate, it is desirable to make the angle of the injection nozzle at right angles to the possible installation surface, and keep the distance between the injection nozzle and the installation surface at 0.2-0.3 m.

The step 6) is a step of repairing a concrete part removed by using the mortar composition for repairing a section of the reinforced concrete structure or removed by the step 1). That is, the mortar composition for restoration of the reinforced concrete structure is installed in the reinforced concrete structure while replacing the removed concrete. In this way, it is possible to restore the damaged section of reinforced concrete, to fix the chloride ion penetrating from the outside and to improve the watertightness of the concrete, and the reinforced concrete section recovery mortar can be made of the whole mortar composition in consideration of temperature, humidity and workability 16-19 parts by weight based on 100 parts by weight of the mixture is preferably mixed with the spraying equipment, trowel and hera by a suitable method. In the case of spraying equipment, in order to reduce the dropout rate and the dust amount of the material, The angle between the spray nozzle and the sprayed surface should be 0.5-1.0 m.

The above-mentioned mortar composition for recovering reinforced concrete section is usually composed of 22.41-23.28% by weight of Portland cement, 55.27-56.93% by weight of dried silica sand, 3.74-4.21% by weight of anorthite powder, 14.73-16.28% by weight of fumed powder, -0.42% by weight, high performance water reducing agent 0.56-0.70% by weight, and polyvinyl alcohol fiber 0.82-0.97% by weight. Also, the mortar composition for recovering a section of the reinforced concrete structure can achieve the chloride ion fixing effect in the mortar to be achieved in the present invention only when the content of the composition falls within the above-mentioned numerical range as a whole, , Bending strength, compressive strength, neutralization resistance, corrosion resistance of reinforcing steel, and chemical resistance, it is possible to effectively utilize for restoring the section of a reinforced concrete structure.

In the step 7), the step of applying the surface protective material may include a step of improving the appearance of the structure restored by the cross-sectional restoration mortar composition of the reinforced concrete structure and a method of improving the appearance of the reinforced concrete structure from the factors damaging the reinforced concrete such as carbon dioxide, chlorine ion, The surface protection material is not particularly limited as long as it can finish the exposed surface of the reinforced concrete structure. However, the surface protection material is selected from acrylic, epoxy, urethane, polyurea, and mixtures thereof It is preferable that any one of them is used. Also, the application of the surface protection material is carried out by a brush, a roller or a spray. In order to reduce the dropout rate of the material when spraying is carried out and to obtain a good appearance, the angle of the spray nozzle is made to be perpendicular to the spray surface, It is desirable that the spacing of the construction surface is maintained at 0.2-0.3 m.

In the case of repairing the section of the reinforced concrete structure using the method of recovering the section of the reinforced concrete structure according to the present invention, the reinforcing steel in the concrete is prevented from being corroded by the chloride ion even if the penetration of the chloride ion is fixed in the mortar. Also, it has excellent restoration effect of reinforced concrete structure because of excellent adhesion strength, bending strength, compressive strength, neutralization resistance, corrosion resistance of reinforcing steel and chemical resistance.

According to another aspect of the present invention, there is provided a method of recovering a section of a second reinforced concrete structure,

As a method for recovering a section of a reinforced concrete structure in which the concrete is peeled off,

1) removing the damaged concrete;

2) cleaning the surface of the removed concrete;

3) applying a primer to the cleaned concrete surface;

4) repairing the concrete part removed with the mortar composition for reinforcing concrete cross-section after applying the primer; And

5) coating the exposed surface of the structure with the surface protecting material among the repaired areas;

/ RTI >

The above-mentioned mortar composition for recovering reinforced concrete section is usually composed of 22.41-23.28% by weight of Portland cement, 55.27-56.93% by weight of dried silica sand, 3.74-4.21% by weight of anorthite powder, 14.73-16.28% by weight of fumed powder, -0.42% by weight, high performance water reducing agent 0.56-0.70% by weight and polyvinyl alcohol fiber 0.82-0.97% by weight.

The method for repairing a section of a reinforced concrete structure in which the concrete is detached and peeled according to the present invention is effective not only for repairing concrete in a peeled reinforced concrete structure but also for preventing corrosion in a reinforcing steel existing in the concrete. Do.

Also, since the method of repairing the section of the reinforced concrete structure in which the concrete is detached and peeled according to the present invention is to repair the damaged concrete section so that the reinforcing steel is not corroded and the reinforcing steel is not exposed, Unlike the method, there is no need to clean the rebar and remove the rust from the rebar and apply the rustproofing material. Other processes, compositions, and composition ratios are the same as those described above in the method for repairing a section of a reinforced concrete structure in which the reinforcing steel is corroded according to another aspect of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Example

The water-soluble acrylic resin composition of the present invention was prepared by mixing 22.93% by weight of ordinary Portland cement, 56.06% by weight of dried silica sand, 3.83% by weight of anorthite powder, 15.28% by weight of fumed silica powder, 0.38% by weight of redispersible acrylic powder, To prepare a mortar composition for restoration of a reinforced concrete structure. At that time, 17 parts by weight of water was added to 100 parts by weight of the mortar composition for restoration of the above-mentioned reinforced concrete structure, and these were mixed.

Example  One

The section of the reinforced concrete structure with the exposed section of the reinforced concrete structure was recovered with the mortar composition of the reinforced concrete structure manufactured by the above example by using chloride ion and carbon dioxide or the like. In the concrete procedure, first, the damaged concrete around the corroded rebar was removed by attraction chipping. Also, the melted wire brushes in the exposed reinforcing bars were removed by the removal of the concrete, and the surfaces of the removed concrete and the rusted reinforcing bars were cleaned with a vacuum inhaler. After that, a water - based acrylic rebar was applied to the surface of the reinforced steel exposed by the removal of concrete. The mortar composition of the reinforced concrete structure was coated on the exposed concrete surface of the concrete and the surface of the reinforcing bars coated with the reinforcing bars. After the concrete was removed, the outer surface of the reinforced concrete was coated with a surface protective material, and then the concrete was closed with the mortar composition of the reinforced concrete structure. 1 is a cross-sectional view showing a state in which a section of a concrete in which a reinforcing bar is exposed is restored.

Example  2

The reinforced concrete specimen was repaired in the same manner as in Example 1, except that the damaged concrete was removed, but the concrete was removed so that the reinforcing steel did not corrode and the reinforcing steel was not exposed. That is, since the reinforcing bars are not corroded and exposed, the damaged concrete section is repaired within the coating thickness of the reinforcing bars. Therefore, the step of removing the rust of the reinforcing bars is not necessary and the concrete surface is cleaned . FIG. 2 is a cross-sectional view showing a state in which a section of the concrete in which the reinforcing bars are not exposed is restored.

Comparative Example

Comparative Example  One

The concrete mortar of the domestic F company was regarded as Comparative Example 1.

Comparative Example  2

The concrete mortar of the domestic S company was regarded as Comparative Example 2.

Experimental Example

< Experimental Example  1: Bond strength test>

In order to measure the adhesion strength of the mortar composition of the reinforced concrete structure according to the present invention, the mortar composition for repairing the cross-section of the reinforced concrete structure according to the present invention (Example) according to KS F 4042 polymer concrete mortar for repairing the concrete structure , Concrete mortar of domestic F company (comparative example 1) and mortar of concrete repair mortar of comparative example 2 (comparative example 2), and cured for 28 days in the atmosphere, and then the bond strength was measured under standard conditions.

Results of Evaluation of Bond Strength As shown in Fig. 3, the test specimens (Example A) prepared from the mortar composition for restoring reinforcing concrete structures according to the above examples were F (Comparative Example 1, B) and S (Comparative Example 2, C), the adhesion strength of the mortar composition of the reinforced concrete structure according to the present invention was superior to that of Comparative Example 1 and Comparative Example 2.

< Experimental Example  2: Flexural strength test>

In order to measure the flexural strength of the mortar composition of the reinforced concrete structure according to the above example, a test agent was prepared according to KS F 4042 polymer concrete mortar for repairing the concrete structure, and the flexural strength was measured after curing for 28 days in the atmosphere.

As shown in FIG. 4, the bending strength of the test specimen (Example A) of the mortar composition for the section restoration of the reinforced concrete structure according to the above Example was F (Comparative Examples 1 and 2) and S (Comparative Examples 2 and 3 ), The flexural strength of the mortar composition for the section-restoring mortar of the reinforced concrete structure according to the present invention was superior to that of the comparative example 1 and the comparative example 2.

< Experimental Example  3: Compressive strength test>

In order to measure the compressive strength of the mortar composition of the reinforced concrete structure according to the above example, the test material was prepared according to the compressive strength test method of KS L 5105 hydraulic mortar and the test materials were prepared for 3 days, 28 days and 91 days After curing, the compressive strength was measured.

As a result of the compressive strength evaluation, as shown in Fig. 5, the compressive strengths of the specimen (Example, A) of the mortar composition for the section-restoring reinforcing concrete structure according to the above Example were F (Comparative Examples 1 and 2) and S , C). Thus, it was found that the compressive strength of the mortar composition for the section-restoring mortar of the reinforced concrete structure according to the above-mentioned example is superior to that of the comparative example 1 and the comparative example 2. [

< Experimental Example  4: Neutralization resistance test>

In order to measure the depth of neutralization by carbon dioxide in the mortar composition of the reinforced concrete structure according to the above example, a specimen was prepared according to KS F 4042 polymer concrete mortar for repairing concrete structures, cured for 28 days in the atmosphere, The depth of neutralization was measured by placing it in the tester for 28 days.

As shown in FIG. 6, the neutralization depth of the specimen (Example, A) of the mortar composition for restoration of the reinforced concrete structure according to the above Example was F yarn (Comparative Example 1, B) and S yarn (Comparative Example 2 , C). It was found that the mortar composition of the mortar composition of the reinforced concrete structure according to the above example was superior to that of Comparative Example 1 and Comparative Example 2.

< Experimental Example  5: Reinforcing Corrosion Resistance Test>

In order to measure the corrosion resistance of the reinforcing steel mortar composition of the reinforced concrete structure according to the above example, a steel bar having a diameter of 10 mm was placed in a concrete of 100 x 100 x 400 mm in the same manner as in Table 1 (concrete formulation table) The surface of the concrete was embedded in the longitudinal direction of the concrete with a distance of 20 mm so that it was cured for 48 hours in the atmosphere and both sides in the longitudinal direction of the concrete were coated with epoxy. Mortar composition of reinforced concrete structure, repair mortar of Domestic F Co., and repair mortar of Domestic S Company were coated with 30 mm thickness and cured for 7 days in air to prepare a specimen. Both sides of the mortar were coated with epoxy (OPC) having no mortar applied thereto was also prepared. Thereafter, the natural potential was measured by immersing the surface of the steel rod in a 3.5% NaCl solution for 3 months with the surface of the steel rod and the surface of the concrete facing a small distance downward. ASTM C 876-1991 Standard Test Method for Corrosion Potentials of Uncoated Reinforcing Steel in Concrete (ASTM C 876-91).

As shown in FIG. 7, the specimen (Example A) to which the mortar composition for restoration of the reinforced concrete structure according to the above Example was applied was F Firms (Comparative Example 1, B) and S Samples (Comparative Example 2, and C), it was found that the natural potential was higher than that of the specimen coated with the maintenance mortar, and it was within -100 to -200 mV spontaneous potential when the reinforcing bar was protected by the passive film due to the alkalinity of the concrete. It was found that the reinforcing effect of the reinforcing concrete mortar of reinforcing concrete was superior to that of Comparative Example 1 and Comparative Example 2.

< Experimental Example  6: Chemical resistance test>

In order to measure the chemical resistance performance of the mortar composition for restoration of the reinforced concrete structure according to the above example, the mortar composition for the section-restoring mortar composition of the reinforced concrete structure according to the present invention (Example, A) The mortar test specimens (comparative examples 1 and 2) and the repair mortar specimens (comparative examples 2 and 3) of the domestic S company were made into cubes having a size of 50 mm and cured for 7 days in the air. Then, the weight was measured and 10% solution (a in Fig. 8), a 10% magnesium chloride (MgCl ₂₎ solution (Fig. 8 b) and 5% sulfuric acid (H ₂ SO ₄₎ solution (Fig. 8 c) was immersed for 28 days in weight And the weight after immersion relative to the weight before immersion was calculated to be the weight change rate.

Results of chemical resistance evaluation As shown in FIG. 8, the weight change of the mortar composition of the reinforced concrete structure according to the present invention was the smallest, and the weight of the mortar composition of the reinforced concrete structure according to the present invention was the smallest. It was found that the fixing and penetration suppression performance was excellent.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. It is natural.

10. Concrete
20. Reinforcement
30. Reinforcement
40. Primer
50. Sectional restoration mortar for reinforced concrete structures
60. Surfactant

Claims (6)

The present invention relates to a method for producing a high-performance water-reducing agent, comprising the steps of: (1) preparing a cement composition comprising 22.41-23.28% by weight of Portland cement, 55.27-56.93% by weight of dried silica, 3.74-4.21% by weight of anorthite powder, 14.73-16.28% by weight of fumed silica powder, 0.31-0.42% 0.70 wt.% Of polyvinyl alcohol fiber and 0.82-0.97 wt.% Of polyvinyl alcohol fiber.
The method according to claim 1,
Wherein the high-performance water reducing agent is a polycarbonate-based or lignin-based mortar composition for repairing a section of a reinforced concrete structure.
A method of recovering a section of a reinforced concrete structure with a reinforced reinforced concrete
1) removing the damaged concrete;
2) removing the rust from the exposed surface of the reinforcing bar;
3) cleaning the surface of the removed reinforced concrete after the removed concrete surface and the concrete are removed;
4) applying a rebar anti-corrosive material to the surface of the cleaned reinforcing bar;
5) applying a primer to the surface of the cleaned concrete surface and the surface of the reinforcing bar coated with the anticorrosive material;
6) repairing the concrete portion removed with the mortar composition for reinforcing concrete section after applying the primer; And
7) coating the exposed surface of the structure with the surface protection material among the repaired areas;
/ RTI &gt;
The above-mentioned mortar composition for recovering reinforced concrete section is usually composed of 22.41-23.28% by weight of Portland cement, 55.27-56.93% by weight of dried silica sand, 3.74-4.21% by weight of anorthite powder, 14.73-16.28% by weight of fumed powder, -0.42 wt% of a high-performance water reducing agent, 0.56-0.70 wt% of a high-performance water reducing agent, and 0.82-0.97 wt% of polyvinyl alcohol fiber.
A method of recovering a section of a reinforced concrete structure with a concrete peeled off,
1) removing the damaged concrete;
2) cleaning the surface of the removed concrete;
3) applying a primer to the cleaned concrete surface;
4) repairing the concrete part removed with the mortar composition for reinforcing concrete cross-section after applying the primer; And
5) coating the exposed surface of the structure with the surface protecting material among the repaired areas;
/ RTI &gt;
The above-mentioned mortar composition for recovering reinforced concrete section is usually composed of 22.41-23.28% by weight of Portland cement, 55.27-56.93% by weight of dried silica sand, 3.74-4.21% by weight of anorthite powder, 14.73-16.28% by weight of fumed powder, -0.42 wt% of a high-performance water reducing agent, 0.56-0.70 wt% of a high-performance water reducing agent, and 0.82-0.97 wt% of polyvinyl alcohol fiber.
The method according to claim 3 or 4,
Wherein the high-performance water reducing agent is a polycarbonate-based or lignin-based reinforced concrete structure.
The method according to claim 3 or 4,
Wherein the surface protection material is any one selected from the group consisting of acrylic, epoxy, urethane, urea, and mixtures thereof.

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