KR101654182B1 - Cement mortar composition for reinforcing concrete structure and reinforce method concrete structure therewith - Google Patents

Abstract

The present invention relates to a cement mortar composition for repairing a cross-sectional surface of a concrete structure, and to a method for repairing a concrete structure by using the same. The cement mortar composition comprises 10-60 wt% of a mineral binder, 20-70 wt% of a fine aggregate, 0.01-15 wt% of a powder function improver, and 1-20 wt% of water. The powder function improver comprises 35-98 wt% of styrene-p-methoxystyrene, 1-45 wt% of vinyl acetate, 0.1-35 wt% of methylmethacrylate-butadiene-styrene, 0.1-25 wt% of polyvinyl acetate-vinyl versatate, and 0.01-25 wt% of polyvinylpyrrolidone. According to the present invention, fluidity, flexural strength, tensile strength, adhesive strength, and durability are excellent, and flexural toughness, acid resistance, salt damage resistance, neutralization resistance, freezing and thawing resistance, and water tightness are improved. Thus, concrete corrosion caused by chemical erosion can be prevented, so maintenance costs used therefor can be remarkably reduced.

Description

TECHNICAL FIELD [0001] The present invention relates to a cement mortar composition for repairing a section of a concrete structure, and a concrete structure repairing method using the same. BACKGROUND ART [0002]

The present invention relates to a cement mortar composition for repairing a section of a concrete structure and a concrete structure repair method using the same. More particularly, the present invention relates to a cement mortar composition for repairing a section of a concrete structure, It is possible to prevent corrosion of concrete due to chemical erosion of concrete structures and sewage pipes, sewage culverts, sewage boxes and underground structures under harsh environments, and to prevent maintenance of concrete structures The present invention relates to a cement mortar composition for maintenance of a section of a concrete structure and a method of repairing a concrete structure using the same.

When the concrete structure is cracked due to deterioration or the like, the compressive strength of the concrete and the tensile strength of the reinforcing bar gradually decrease after a lapse of time, and the concrete exposed through the cracks is neutralized and corrosion of the reinforcing steel occurs. If these rebar corrosion phenomena become severe, the concrete structure may eventually collapse. Therefore, if the concrete structure deteriorates and cracks are generated, it is necessary to repair the deteriorated part quickly. The deterioration of the performance of the concrete is a crack, and when cracks occur, harmful outside air, moisture and chemical components permeate inside the concrete, thereby further deteriorating the performance of the concrete. In addition, due to the corrosion of the reinforcing bars inside the concrete structure due to moisture and chloride ions penetrating into the concrete, additional cracks occur or concrete falls off, and at the same time, the reinforcing steel section is reduced by the corrosion of the reinforcing bars, The structure may be damaged.

On the other hand, when cracks occur in concrete due to deterioration of concrete structures, especially in the case of stormwater and sewage-related structures, water treatment plant drainage roads, road side walls, concrete slabs of roads, roadsides, bridges, etc., The tensile strength of the concrete is gradually decreased, and the concrete exposed through the cracks is subjected to chlorine ion penetration, freezing and thawing, and neutralization phenomenon, resulting in corrosion of reinforcing steel. If these rebar corrosion phenomena become severe, the concrete structure may eventually collapse. In repairing such a concrete structure, a maintenance material excellent in strength and durability as that of a concrete-polymer composite is used because it can not secure required quality only by cementitious materials.

The problems to be solved by the present invention are to improve flowability, bending strength, tensile strength, adhesion strength and durability and to improve flexural toughness, acid resistance, chemical resistance, flame retardancy, neutralization resistance, The present invention provides a method of manufacturing a cement mortar composition for repairing a section of a concrete structure, a method of manufacturing the same, and a method of repairing a concrete structure using the same.

The present invention relates to a process for the production of granules comprising 10 to 60% by weight of a mineral binder, 20 to 70% by weight of fine aggregate, 0.01 to 15% by weight of a powder performance improving agent and 1 to 20% 35 to 98% by weight of vinyl acetate, 1 to 45% by weight of vinyl acetate, 0.1 to 35% by weight of methyl methacrylate-butadiene-styrene, 0.1 to 25% by weight of polyvinyl acetate- vinyl versatate and 0.01 to 25% by weight of polyvinylpyrrolidone % Of the cement mortar composition for repairing a section of a concrete structure.

The powder performance improving agent may further include 0.01 to 10 wt% of polyethersulfone to improve heat resistance and water resistance.

In addition, the powder performance improving agent may further include 0.01 to 10 wt% of a smoothing agent for improving self-leveling property.

The powder performance improving agent may further comprise 0.01 to 10% by weight of carboxyroloxazole calcium.

The mineral binder is usually 25 to 75 wt% of Portland cement, 5 to 45 wt% of calcium aluminate cement, 1 to 30 wt% of blast furnace slag, 0.1 to 20 wt% of wood ash, 0.1 to 15 wt% of anhydrous gypsum, To 15 wt%, sepiolite 0.01 to 10 wt%, alumina silicate based senospare 0.01 to 10 wt%, and retarder 0.01 to 8 wt%.

The mineral binder may further contain 0.01 to 5% by weight of a high-performance water reducing agent to ensure a water-cement ratio lowering and workability.

The fine aggregate may comprise 60 to 99% by weight of silica silica and 1 to 40% by weight of dolomite.

The present invention also relates to a method of manufacturing a concrete slab, comprising the steps of: chipping and cleaning a concrete slab surface and a concrete slab surface with a planer, a shot blaster or a hand water jet; Applying a primer to improve the adhesion of the cement mortar composition for a concrete structure, and applying a cement mortar composition for repairing the section of the concrete structure to the upper surface to which the primer is applied, followed by surface finishing; And curing the concrete structure by surface finishing.

The primer may include at least one material selected from styrene-butadiene, polyethylene vinyl acetate, polyacrylic ester, and acrylic emulsion.

At this time, the surface finishing may further include a step of applying a surface protective material to improve chloride ion penetration inhibition, decrease in neutralization reactivity, chemical resistance, and freeze-thaw resistance.

The surface protecting material may be at least one selected from the group consisting of styrene-butadiene, polyethylene vinyl acetate, acrylic polymers, epoxy-free resins, urethane-acrylic polymers and silane compounds.

According to the cement mortar composition for repairing a section of a concrete structure of the present invention, the use of a mineral binder improves fluidity, bending strength, tensile strength and durability. Further, by using the powder performance improving agent, it is possible to improve the flexural toughness, salt resistance, neutralization resistance, freeze-thaw resistance and surface hardness. Also, by using the powder performance improving agent, the field workability of the cement mortar composition for repairing the section of the concrete structure can be improved, the early strength can be developed, and the construction time can be shortened and the traffic opening time can be shortened.

Further, according to the cement mortar composition for repairing a section of a concrete structure of the present invention, the use of a mineral binder improves flame retardancy, exhibits long-term strength, increases durability, suppresses temperature rise, Can be obtained.

Hereinafter, preferred embodiments according to the present invention will be described in detail. However, it should be understood that the following embodiments are provided so that those skilled in the art will be able to fully understand the present invention, and that various modifications may be made without departing from the scope of the present invention. It is not.

The cement mortar composition for repairing a section of a concrete structure according to a preferred embodiment of the present invention comprises 10 to 60 wt% of a mineral binder, 20 to 70 wt% of a fine aggregate, 0.01 to 15 wt% of a powder performance improver, and 1 to 20 wt% of water .

The powder performance improving agent is used to improve pot life, workability, flowability, bending strength, tensile strength, durability, flexural toughness, salt resistance, neutralization resistance, freeze-thaw resistance and surface hardness. The powder performance improver includes 35 to 98% by weight of styrene-p-methoxystyrene to induce bonding between minerals and improve strength and durability, 1 to 45% by weight of vinyl acetate for improving adhesion and toughness, strength and durability 0.1 to 35% by weight of methyl methacrylate-butadiene-styrene for improving adhesion, and 0.1 to 25% by weight of polyvinyl acetate-vinyl versatate for improving ductility and adhesion and polyvinylpyrrolidone 0.01 to 25% by weight of money.

The powder performance improving agent is preferably contained in the cement mortar composition for repairing the section of the concrete structure in an amount of 0.01 to 15% by weight. If the content of the powder performance improver exceeds 15% by weight, the viscosity is lowered and the material is easily separated, and the price competitiveness may be lowered. If the content of the powder performance improver is less than 0.01% by weight, the effect of improving the flow performance, strength, durability, toughness, flame retardancy, neutralization resistance, freezing and thawing resistance and surface hardness may be small.

The styrene-p-methoxystyrene is used to induce a bond between minerals and to improve strength and durability. The styrene-p-methoxystyrene is preferably contained in the powder performance improving agent in an amount of 35 to 98% by weight. When the content is less than 35% by weight, the styrene- And if it is more than 98% by weight, it is difficult to expect the effect of inducing further inter-inorganic-inorganic bond and improving the strength and durability, and it is not economical.

The vinyl acetate serves to improve adhesion and toughness. When the content of vinyl acetate is less than 1% by weight, the effect of improving adhesion and toughness may be insignificant. When the content of vinyl acetate is less than 1% by weight, When it exceeds 45% by weight, further adherence and toughness improving effect are hardly expected and economical.

The methyl methacrylate-butadiene-styrene is used to improve the elasticity and durability of the cement mortar composition for repairing the section of the concrete structure. It is preferable that the methylmethacrylate-butadiene-styrene is contained in the powder performance improver in an amount of 0.1 to 35% by weight. When the content of the methylmethacrylate-butadiene-styrene exceeds 35% by weight, The performance of the cement mortar composition may be improved but the workability and price competitiveness may be deteriorated. If the content of methyl methacrylate-butadiene-styrene is less than 0.1 wt%, the workability of the cement mortar composition for repairing the section of the concrete structure is improved, The effect of improving elasticity and durability may be weak.

The polyvinyl acetate-vinyl versatate is used to prepare a cement mortar composition for maintenance of the concrete structure having ductility and adhesive strength. It is preferable that the polyvinyl acetate-vinyl versatate is contained in the powder performance improving agent in an amount of 0.1 to 25 wt%, and when the content of the polyvinyl acetate-vinyl versatate exceeds 25 wt%, the ductility becomes strong, If the content of the polyvinyl acetate-vinyl versatate is less than 0.1% by weight, the effect of improving the ductility and adhesive strength is weak and the brittleness is intensified, so that the impact strength may be lowered.

The polyvinylpyrrolidone is used to improve the durability of the cement mortar composition for maintenance of the section of the concrete structure. The polyvinylpyrrolidone is preferably contained in the powder performance improving agent in an amount of 0.01 to 25% by weight. When the content of the polyvinylpyrrolidone is more than 25% by weight, workability and price competitiveness may be deteriorated, If the content of vinylpyrrolidone is less than 0.01% by weight, the durability improving effect is weak and the binding force of the powder performance improving agent may be lowered.

The polyethersulfone is used for improving heat resistance and water resistance. It is preferable that the polyether sulfone is contained in the powder performance improving agent in an amount of 0.01 to 10% by weight. If the content of the polyether sulfone exceeds 10% by weight, the heat resistance and water resistance may be improved but the price competitiveness may be deteriorated. If the content of sulfone is less than 0.01% by weight, the workability is improved but the effect of improving heat resistance and water resistance may be weak.

In addition, the powder performance improving agent may further include 0.01 to 10 wt% of a smoothing agent for improving self-leveling property. The smoothing agent may be used to improve the fluidity and self-leveling property of the powder performance improving agent. As the smoothing agent, a polycarboxylic acid-based smoothing agent may be used. It is preferable that the smoothing agent is contained in the powder performance improving agent in an amount of 0.01 to 10 wt%. When the content of the smoothing agent exceeds 10 wt%, the reaction between the organic materials is delayed, If the content of the smoothing agent is less than 0.01% by weight, there is no material separation phenomenon, but the effect of improving the self-leveling property may be weak.

The powder performance improving agent may further include 0.01 to 10% by weight of carboxyroloxazole calcium to prevent material separation and improve workability. The carboxyroloxazole calcium is used for preventing the powder performance improving agent from separating and improving workability. It is preferable that the carboxyroloxazole calcium is contained in the powder performance improving agent in an amount of 0.01 to 10 wt%. If the content of the carboxyroloxazole calcium is less than 0.01% by weight, separation of the material tends to occur. If the content of the carboxyroloxazole calcium exceeds 10% by weight, the material is not separated, but the viscosity is increased, have.

In addition, the powder performance improving agent may further include a defoaming agent. The antifoaming agent is used to remove bubbles in the powder performance improving agent to increase strength and durability. When the antifoaming agent is added to the powder performance improving agent, the air entraining effect is imparted to improve the workability and the pot life. The antifoaming agent is preferably contained in the powder performance improving agent in an amount of 0.01 to 5% by weight. Examples of the defoaming agent include alcohol defoaming agents, silicone defoaming agents, fatty acid defoaming agents, oil defoaming agents, ester defoaming agents and oxyalkylene defoaming agents. Examples of the silicone defoaming agent include dimethyl silicone oil, polyorganosiloxane, and fluorosilicone oil. Examples of the fatty acid defoaming agent include stearic acid and oleic acid. Examples of the oil-based antifoaming agents include kerosene, animal and plant oil, and castor oil. Examples of the ester type antifoaming agents include solitol trioleate, glycerol monoricinolate, and the like. Examples of the oxyalkylene antifoaming agents include polyoxyalkylene, acetylene ethers, polyoxyalkylene diisocyanate esters, and polyoxyalkylene alkylamines. Examples of the alcohol-based defoaming agent include glycol.

In addition, the powder performance improving agent may further include a water reducing agent. The water reducing agent is used to reduce the water-cement ratio to improve the strength and durability and ensure the fluidity of the powder performance improving agent. When the water reducing agent is added to the powder performance improving agent, the water-cement ratio is reduced. The water reducing agent is preferably contained in the powder performance improving agent in an amount of 0.01 to 5% by weight. The water reducing agent may be a polycarbonate-based, melamine-based or naphthalene-based water reducing agent, but the strength of the cement mortar composition for repairing the cross-section of the concrete structure may be lowered compared to the polycarbonate-based naphthalene- and melamine- Therefore, it is preferable to use a polycarboxylic acid-based water reducing agent which does not lower the strength, workability and pot life of the concrete structure surface protective composition.

 The mineral binders are used to develop initial strength, to improve durability, to suppress temperature rise, to improve flame retardancy, to improve abrasion resistance, and the like. The cement mortar composition for repairing a section of a concrete structure If the content of the mineral binder is more than 60% by weight, the strength and durability are improved but cracks easily occur due to the expansion and contraction effect. If the content of the mineral binder is less than 10% by weight, And the occurrence of cracks are reduced, but the effect of improving strength and durability may be weak.

The mineral binder is usually 25 to 75 wt% of Portland cement, 5 to 45 wt% of calcium aluminate cement, 1 to 30 wt% of blast furnace slag, 0.1 to 20 wt% of wood ash, 0.1 to 15 wt% of anhydrous gypsum, To 15 wt%, sepiolite 0.01 to 10 wt%, alumina silicate based senospare 0.01 to 10 wt%, and retarder 0.01 to 8 wt%.

The ordinary portland cement is preferably the one specified in KS, and the cement distributed in the general market can be used. The ordinary Portland cement is preferably contained in the mineral binder in an amount of 25 to 75 wt%.

The calcium aluminate cement is an inorganic fast hard mineral material added to increase hydration reactivity and to suppress cracking. It reacts with water in an instant when it comes into contact with water to produce an ettringite hydrate, It is possible to obtain an excellent compressive strength in a short time. The calcium aluminate cement is preferably contained in an amount of 5 to 45% by weight based on the mineral binder. When the weight ratio of the calcium aluminate cement is increased, rapid curing properties are exhibited. When the content of the calcium aluminate cement is less than 5% by weight, the strength improving effect and the crack generation inhibiting effect may be insufficient. If it is more than 45% by weight, good physical properties can be obtained due to fast curing properties, but it is not economical because the manufacturing cost is high.

The blast furnace slag is used for improving latent hydraulic characteristics, long-term strength development and durability. When the weight ratio of the blast furnace slag is increased, the early strength is lowered, but the long-term strength development and durability are increased. The blast furnace slag is preferably contained in an amount of 1 to 30% by weight based on the mineral binder. If the content of the blast furnace slag exceeds 30% by weight, the initial strength is lowered. If the blast furnace slag content is less than 1% by weight, the effect of improving the long-term strength and improving the durability may be insignificant.

The wood ash is used for potential hydraulic properties, long-term strength development and durability enhancement. When the weight ratio of the wood ash is increased, the early strength is lowered, but the long-term strength development and durability are increased. The wood ash is preferably contained in an amount of 0.1 to 20% by weight based on the mineral binder. If the content of the wood ash exceeds 200% by weight, the initial strength is lowered. If the content of the wood ash is less than 0.1% by weight, the effect of improving long-term strength and improving durability may be weak.

The anhydrous gypsum (CaSO ₄ ) reacts with the components in the cement, in particular C ₃ A ( ₃ CaO.Al ₂ O ₃ ), to produce etrinite (AFt phase, C _{3 A 3} .CaSO ₄ .32 H ₂ O) The produced etrinzate decreases in its amount as the hydration proceeds, or a part thereof is transferred to monosulfate (AFm phase, C ₃ A · CaSO ₄ · 12H ₂ O). When a large amount of anhydrous gypsum is added as in the present invention, etrinzite is sufficiently generated from the beginning to densify the structure of the cement, thereby increasing penetration resistance to chloride ions in the early age. In the case of general cement, etrinzite is mainly present at the initial stage. However, since the amount of anhydrous gypsum is sufficiently added in the case of the composition of the present invention, Zites are also generated continuously. The nitrite produced in this way increases the penetration resistance to chlorides even in the long term by densely filling the pores in the concrete structure. The anhydrous gypsum is preferably contained in an amount of 0.1 to 15% by weight based on the mineral binder. If the content of the gypsum anhydrite is higher than 15% by weight, rapid curing can be attained. If the content of the gypsum anhydrite is less than 0.1% by weight, the strength and workability may be lowered. Good properties can be obtained due to the characteristics, but the production cost is not high and it is not economical.

Magnesium sulfate (MgSO ₄ ) is an inorganic flame retardant material. The magnesium sulfate has a formula of MgSO ₄ and a chemical formula of 120.3, which is also referred to as jute. The magnesium sulfate has a melting point of 1185 ° C, a specific gravity of 2.66, and a solubility of 26.9 g / 100 g. The magnesium sulfate is preferably contained in the mineral binder in an amount of 0.1 to 15% by weight. If the content of the magnesium sulfate is less than 0.1 wt%, the workability and strength are increased but the flame retardant effect may be lowered. If the content of the magnesium sulfate exceeds 15 wt%, the flame retardancy is improved but the workability and strength have.

The sepiolite is used as a hygroscopic agent to prevent material separation and control viscosity. The amount of the sepiolite is preferably 0.01 to 10% by weight in the mineral binder. If the content of the sepiolite is less than 0.01% by weight, the workability is good but the effect of preventing material separation may be weak. If the content of the sepiolite exceeds 10% by weight, the material separation phenomenon does not occur, Can be lowered.

The alumina silicate based SenoSpare powder is obtained by collecting coal in a coal-fired power plant by a wet or dry method in fly ash generated after combustion. The alumina silicate-based spherical powder is filled with gas (CO ₂ or N ₂ ) Hollow Microsphere is a hollow microsphere, which is characterized by ultra-light weight, sound insulation, insulation and fluidity compared to other mineral fillers, thereby improving the workability and smoothness of the inorganic binder and increasing the adhesion strength and durability have. The aluminosilicate-based senespare powder is preferably contained in an amount of 0.01 to 10 wt% based on the mineral binder. When the weight ratio of the alumina silicate based senso spear powder is increased, it exhibits fast curing property. When the content of the alumina silicate based senso spear powder is less than 0.01 wt%, the effect of improving workability, smoothness, adhesion strength and durability may be insignificant, If the content of the alumina silicate based SenoSpare powder is more than 10% by weight, good physical properties can be obtained due to rapid curing properties, but the production cost is high and it is not economical.

The retarder is used for delaying rapid curing to ensure workability for a certain period of time, and it is preferable that the retarder is contained in the mineral binder in an amount of 0.01 to 8 wt%. As the delaying agent, generally well known substances can be used. Examples thereof include saccharides such as glucose, glucose, texturin and dextran, acids or salts thereof such as gluconic acid, malic acid, citric acid and citric acid, Or a salt thereof, a phosphonic acid or a derivative thereof, and a polyhydric alcohol such as glycerin.

The high-performance water reducing agent may further include 0.01 to 5% by weight of the mineral binder in order to ensure a reduction in water-cement ratio and workability.

The fine aggregate may include silica silica and dolomite. Preferably, the fine aggregate comprises 60 to 99% by weight of silica silica and 1 to 40% by weight of dolomite.

In general, aggregate is classified into fine aggregate and coarse aggregate. Coarse aggregate means aggregate exceeding 5 mm in diameter. Hereinafter, fine aggregate refers to aggregate having particle size of 5 mm or less in comparison with coarse aggregate. The use of the fine aggregate containing dolomite excellent in the far-infrared ray effect has an advantage of excellent heat insulation and strength, and excellent durability against acidity, saltiness and the like.

It is preferable that the silica silica has a particle size of from 4 to 6 (0.05 to 2.0 mm). If the particle size of the silica silica is larger than the above range, the fluidity of the cement mortar composition for repairing the section of the concrete structure may be lowered. If the particle size is smaller than the above range, the workability of the cement mortar composition for repairing the cross- have. The silica silica is preferably contained in an amount of 60 to 99% by weight based on the fine aggregate.

The dolomite has a specific gravity of 2.9 and a hardness of about 4. The dolomite is excellent in strength, abrasion resistance and fire resistance and is used for improving the strength, abrasion resistance and fire resistance in the cement mortar composition for maintenance of the section of the concrete structure. The dolomite is preferably contained in an amount of 1 to 40% by weight based on the fine aggregate.

The cement mortar composition for surface finishing a concrete structure according to the preferred embodiment of the present invention comprises 10 to 60 wt% of a mineral binder, 20 to 70 wt% of a fine aggregate, and 0.01 to 15 wt% of a powder performance improver in a forced mixer or a vacuum type mixer. After mixing, 1 to 20% by weight of water is added and mixed with a forced mixer or a continuous mixer for a predetermined time (for example, 1 to 5 minutes).

The present invention proposes a method of repairing a concrete structure using the above-described cement mortar composition for repairing a section of a concrete structure. Hereinafter, the term "concrete structure" is used to mean all structures made of concrete, such as road sections, road surfaces, bridge bridges, concrete slabs of bridges, bridge bridges,

The method of repairing concrete structures according to a preferred embodiment of the present invention is also characterized in that the present invention is a method for repairing concrete structures, comprising the steps of: chipping and cleaning a concrete slab surface of a concrete slab surface with a planer, a short blaster or a hand water jet, Applying a primer to improve the adhesion of the concrete concrete and the cement mortar composition for maintenance of the section of the concrete structure after confirming the moisture content of the cement mortar composition for repairing the water content of the concrete structure, Followed by surface finishing; And curing the concrete structure by surface finishing. In this case, the cleaning step may further include a step of using the vacuum suction vehicle as a cleaner when cleaning the area where the repair area is large. At this time, the surface finishing may further include a step of applying a surface protective material to improve chloride ion penetration inhibition, decrease in neutralization reactivity, and freeze-thaw resistance.

The primer may include at least one material selected from styrene-butadiene, polyethylene vinyl acetate, polyacrylic ester, and acrylic emulsion. The surface protecting material may be at least one selected from the group consisting of styrene-butadiene, polyethylene vinyl acetate, acrylic polymers, epoxy-free resins, urethane-acrylic polymers and silane compounds.

Hereinafter, embodiments of the cement mortar composition for repairing a section of a concrete structure according to the present invention will be more specifically shown and the present invention is not limited by the following embodiments.

≪ Example 1 >

40% by weight of mineral binder, 50% by weight of fine aggregate and 4% by weight of powder performance improver were premixed in a forced mixer, and then 6% by weight of water was added and stirred for 2 minutes to prepare a cement mortar composition for repairing a section of a concrete structure . The fine aggregate was mixed with 70% by weight of silica silica and 30% by weight of dolomite.

The powder performance enhancer was prepared by mixing 90 wt% styrene-p-methoxystyrene, 3 wt% vinyl acetate, 2 wt% methyl methacrylate-butadiene-styrene, 1 wt% polyvinyl acetate- 1% by weight of polyether sulfone, 0.5% by weight of a smoothing agent, 0.5% by weight of carboxycellulose calcium, 0.5% by weight of an antifoaming agent and 0.5% by weight of a water reducing agent. The smoothing agent used was a polycarboxylic acid-based smoothing agent, the defoaming agent used was a silicone-based defoaming agent, and the reducing agent used was a polycarboxylic acid-based reducing agent.

The mineral binder usually comprises 50 wt% Portland cement, 20 wt% calcium aluminate cement, 10 wt% blast furnace slag, 5 wt% wood ash, 5 wt% anhydrous gypsum, 3 wt% magnesium sulfate, 3 wt% 3% by weight of alumina silicate based Senospear, 0.5% by weight of retarder 0.5 and 0.5% by weight of a high-performance water reducing agent. The high performance water reducing agent used was a polycarboxylic acid based high performance water reducing agent.

≪ Example 2 >

40% by weight of mineral binder, 50% by weight of fine aggregate and 4% by weight of powder performance improver were premixed in a forced mixer, and then 6% by weight of water was added and stirred for 2 minutes to prepare a cement mortar composition for repairing a section of a concrete structure . The fine aggregate was mixed with 70% by weight of silica silica and 30% by weight of dolomite.

The powder performance enhancer was prepared by mixing 80 wt% styrene-p-methoxystyrene, 6 wt% vinyl acetate, 4 wt% methyl methacrylate-butadiene-styrene, 4 wt% polyvinyl acetate- 3% by weight of polyethersulfone, 1% by weight of polyether sulfone, 0.5% by weight of a smoothing agent, 0.5% by weight of carboxycellulose calcium, 0.5% by weight of a defoaming agent and 0.5% by weight of a water reducing agent. The smoothing agent used was a polycarboxylic acid-based smoothing agent, the defoaming agent used was a silicone-based defoaming agent, and the reducing agent used was a polycarboxylic acid-based reducing agent.

The mineral binder usually comprises 50 wt% Portland cement, 20 wt% calcium aluminate cement, 10 wt% blast furnace slag, 5 wt% wood ash, 5 wt% anhydrous gypsum, 3 wt% magnesium sulfate, 3 wt% 3% by weight of alumina silicate based Senospear, 0.5% by weight of retarder 0.5 and 0.5% by weight of a high-performance water reducing agent. The high performance water reducing agent used was a polycarboxylic acid based high performance water reducing agent.

≪ Example 3 >

40% by weight of mineral binder, 50% by weight of fine aggregate and 4% by weight of powder performance improver were premixed in a forced mixer, and then 6% by weight of water was added and stirred for 2 minutes to prepare a cement mortar composition for repairing a section of a concrete structure . The fine aggregate was mixed with 70% by weight of silica silica and 30% by weight of dolomite.

The powder performance enhancer was prepared by mixing 70 wt% styrene-p-methoxystyrene, 10 wt% vinyl acetate, 7 wt% methyl methacrylate-butadiene-styrene, 5 wt% polyvinyl acetate- vinyl versatate, 5% by weight of polyethersulfone, 1% by weight of polyether sulfone, 0.5% by weight of a smoothing agent, 0.5% by weight of carboxycellulose calcium, 0.5% by weight of a defoaming agent and 0.5% by weight of a water reducing agent. The smoothing agent used was a polycarboxylic acid-based smoothing agent, the defoaming agent used was a silicone-based defoaming agent, and the reducing agent used was a polycarboxylic acid-based reducing agent.

The mineral binder usually comprises 50 wt% Portland cement, 20 wt% calcium aluminate cement, 10 wt% blast furnace slag, 5 wt% wood ash, 5 wt% anhydrous gypsum, 3 wt% magnesium sulfate, 3 wt% 3% by weight of alumina silicate based Senospear, 0.5% by weight of retarder 0.5 and 0.5% by weight of a high-performance water reducing agent. The high performance water reducing agent used was a polycarboxylic acid based high performance water reducing agent.

A comparative example which can be compared with the embodiments of the present invention is shown in order to more easily grasp the characteristics of the above-described first to third embodiments. It is to be noted that Comparative Example 1 described below is provided merely for comparison with the characteristics of the embodiments, and is not a prior art of the present invention.

≪ Comparative Example 1 &

40 wt% of ordinary Portland cement and 50 wt% of fine aggregate were stirred in a forced mixer for 2 minutes, and then 10 wt% of water was added and stirred for 2 minutes to prepare a cement mortar composition.

≪ Comparative Example 2 &

40% by weight of Portland cement, 50% by weight of fine aggregate and 4% by weight of styrene-p-methoxystyrene were premixed in a forced mixer, and then 6% by weight of water was added and stirred for 2 minutes to prepare a polymer cement mortar composition .

The following test examples show experimental results in which the characteristics according to the present invention are compared with the characteristics of Comparative Example 1 and Comparative Example 2 in order to more easily grasp the characteristics of Examples 1 to 3 according to the present invention .

≪ Test Example 1 >

The cement mortar composition for repairing the cross-section of the concrete structure prepared according to Examples 1 to 3 and the composition prepared according to Comparative Example 1 and Comparative Example 2 were subjected to a flow test (degree of kneading) according to the method defined in KS F 2476 Respectively. The flow test is to test the dough of the composition such as the flue and viscosity of the composition. The larger the value, the better the workability, that is, the workability at the time of pouring the composition.

Table 1 below shows the changes in the flow over time.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Flow (mm) 21 23 25 12 17

As shown in Table 1 above, it was found that the cement mortar composition for repairing the section of the concrete structure manufactured according to Examples 1 to 3 was superior in workability to the composition prepared according to Comparative Example 1 and Comparative Example 2 .

≪ Test Example 2 &

The cement mortar composition for repairing the cross-section of the concrete structure prepared according to Examples 1 to 3 and the composition prepared according to Comparative Example 1 and Comparative Example 2 were measured according to the method specified in KS F 2476 (test method for polymer-cement mortar) Compression strength test was carried out.

Table 2 below shows the change in compressive strength with time.

division
Compressive strength (kgf / ㎠) After 3 hours After 1 day After 7 days After 28 days Example 1 170 276 388 510 Example 2 185 305 422 581 Example 3 205 356 458 611 Comparative Example 1 - 232 323 452 Comparative Example 2 - 256 359 493

As shown in Table 2 above, the cement mortar composition for repairing the section of the concrete structure produced according to Examples 1 to 3 was much higher in compressive strength than the composition prepared according to Comparative Example 1 and Comparative Example 2.

≪ Test Example 3 >

The cement mortar composition for repairing the cross-section of the concrete structure prepared according to Examples 1 to 3 and the composition prepared according to Comparative Example 1 and Comparative Example 2 were measured according to the method specified in KS F 2476 (test method for polymer-cement mortar) The bending strength was measured.

Table 3 below shows the changes in flexural strength with time.

division
Bending strength (kgf / ㎠) After 3 hours After 1 day After 7 days After 28 days Example 1 38 48 70 98 Example 2 41 52 78 105 Example 3 45 60 86 112 Comparative Example 1 - 35 45 68 Comparative Example 2 - 41 58 85

As shown in Table 3, the cement mortar composition for repairing the cross-section of the concrete structure prepared according to Examples 1 to 3 had significantly higher bending strength than the composition prepared according to Comparative Example 1 and Comparative Example 2.

<Test Example 4>

The cement mortar composition for repairing the cross-section of the concrete structure prepared according to Examples 1 to 3 and the composition prepared according to Comparative Example 1 and Comparative Example 2 were measured for KS F 2476 (Test Method of Polymer Cement Mortar) The results are shown in Table 4 below.

division
Adhesion strength (kgf / cm 2) After 3 hours After 1 day After 7 days After 28 days Example 1 11 14.8 20.0 21.8 Example 2 12 15.6 22 23.9 Example 3 12.6 16.7 23.5 25.1 Comparative Example 1 - 7 10.2 14.1 Comparative Example 2 - 10 16.8 20.9

As shown in Table 4 above, it was confirmed that the cement mortar composition for repairing the cross-section of the concrete structure prepared according to Examples 1 to 3 was much better than the composition prepared according to Comparative Example 1 and Comparative Example 2 I could.

&Lt; Test Example 5 >

The cement mortar composition for repairing the cross-section of the concrete structure prepared according to Examples 1 to 3 and the composition prepared according to Comparative Example 1 and Comparative Example 2 were measured by KS F 2476 (Test Method of Polymer Cement Mortar) The results are shown in Table 5 below.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Length change rate (%) 0.05 0.03 0.02 0.15 0.09

As shown in Table 5, the cement mortar composition for repairing a section of a concrete structure manufactured according to Examples 1 to 3 had a decreased rate of change in length compared with the composition prepared according to Comparative Example 1 and Comparative Example 2, .

&Lt; Test Example 6 >

The cement mortar composition for repairing the cross-section of the concrete structure prepared according to Examples 1 to 3 and the composition prepared according to Comparative Example 1 and Comparative Example 2 were measured according to the method specified in KS F 2476 (test method for polymer-cement mortar) The results of the measurement of the water absorption are shown in Table 6.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Absorption Rate (%) 0.8 0.6 0.4 1.8 1.0

As shown in Table 6 above, the cement mortar composition for repairing a section of a concrete structure manufactured according to Examples 1 to 3 is superior in water resistance due to its low water absorption rate as compared with the composition prepared according to Comparative Example 1 and Comparative Example 2 Could know.

&Lt; Test Example 7 >

The cement mortar composition for repairing the section of the concrete structure prepared according to Examples 1 to 3 and the composition prepared according to Comparative Example 1 and Comparative Example 2 were tested by KS F 2476 (Test Method of Polymer Cement Mortar) The results are shown in Table 7 below.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Neutralization depth (mm) 0.3 0.2 0.15 1.5 0.8

As shown in Table 7, the cement mortar composition for repairing a section of a concrete structure according to Examples 1 to 3 had a lower neutralization penetration depth than the composition prepared according to Comparative Example 1 and Comparative Example 2, And the resistance was high.

<Test Example 8>

The cement mortar composition for repairing the cross-section of the concrete structure prepared according to Examples 1 to 3 and the composition prepared according to Comparative Example 1 and Comparative Example 2 were subjected to the infiltration of chloride ion by KS F 2476 (Test Method of Polymer Cement Mortar) The depth test was performed, and the results are shown in Table 8.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Chloride ion penetration depth (mm) 0.62 0.5 0.38 2.3 1.0

As shown in Table 8 above, the cement mortar composition for repairing the section of the concrete structure prepared according to Examples 1 to 3 had a lower chloride ion penetration depth than the composition prepared according to Comparative Example 1 and Comparative Example 2 And it was confirmed that the resistance to salting was high.

&Lt; Test Example 9 >

The cement mortar composition for repairing the section of the concrete structure prepared according to Examples 1 to 3 and the composition prepared according to Comparative Example 1 and Comparative Example 2 were subjected to the freeze-thaw resistance test according to the method defined in KS F 2456. Freezing and thawing means that the water absorbed in the concrete is frozen and melted. When freezing and thawing is repeated, fine cracks are generated in the concrete structure, and the durability is lowered.

Table 9 shows the durability indexes of the respective examples and the comparative example 1 and the comparative example 2 according to the freeze-thaw resistance test.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Durability index 92 93 93 68 89

As shown in Table 9, the durability index of the cement mortar composition for repairing a section of a concrete structure manufactured according to Examples 1 to 3 is much higher than that of the composition prepared according to Comparative Example 1 and Comparative Example 2, Is improved.

&Lt; Test Example 10 &

The cement mortar composition for repairing the section of the concrete structure prepared according to Examples 1 to 3 and the composition prepared according to Comparative Example 1 and Comparative Example 2 were tested according to the Japanese Industrial Standards [Test Method for Chemical Resistance by Solution Deposition of Concrete] The results of the chemical resistance test are shown in Table 10 below by immersing the 28 day specimen in an aqueous solution of 2% hydrochloric acid, 5% sulfuric acid and 45% sodium hydroxide in the test solution.

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Weight change rate
(%) Hydrochloric acid -1.1 -0.85 -0.68 -4.0 -2.2 Sulfuric acid -0.1 0 0.1 -2.5 -0.6 Sodium hydroxide +0.5 +1.1 +1.5 0 0.4

As shown in Table 10, the cement mortar composition for repairing a section of a concrete structure manufactured according to Examples 1 to 3 had less weight change rate with respect to chemical resistance than the composition prepared according to Comparative Example 1 and Comparative Example 2 And the resistance to chemical resistance was high.

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, This is possible.

Claims (11)

A cement mortar composition for repairing a section of a concrete structure,
10 to 60 wt% of a mineral binder, 20 to 70 wt% of a fine aggregate, 0.01 to 15 wt% of a powder performance improving agent, and 1 to 20 wt%
Wherein the powder performance improver is selected from the group consisting of 35-98 wt% styrene-p-methoxystyrene, 1-45 wt% vinyl acetate, 0.1-35 wt% methyl methacrylate-butadiene-styrene, 0.1-25 wt% polyvinyl acetate- 0.01 to 25% by weight of polyvinylpyrrolidone, and 0.01 to 10% by weight of carboxycellulose calcium.
Wherein the cement mortar composition is a cement mortar composition for repairing a section of a concrete structure.
The method according to claim 1,
Wherein the powder performance improving agent further comprises 0.01 to 10 wt% of polyethersulfone to improve heat resistance and water resistance.
The method according to claim 1,
Wherein the powder performance improving agent further comprises 0.01 to 10% by weight of a smoothing agent for improving the self-leveling property of the cement mortar composition.
delete The method according to claim 1,
The mineral binder is usually 25 to 75 wt% of Portland cement, 5 to 45 wt% of calcium aluminate cement, 1 to 30 wt% of blast furnace slag, 0.1 to 20 wt% of wood ash, 0.1 to 15 wt% of anhydrous gypsum, By weight of cerium oxide, 0.01 to 10% by weight of sepiolite, 0.01 to 10% by weight of alumina silicate based cenospheres and 0.01 to 8% by weight of retardant.
6. The method of claim 5,
Wherein the mineral binder further comprises 0.01 to 5% by weight of a high-performance water reducing agent to ensure a water-cement ratio lowering and workability.
6. The method of claim 5,
Wherein the fine aggregate comprises 60 to 99% by weight of silica silica and 1 to 40% by weight of dolomite.
A concrete structure repairing method using the cement mortar composition for repairing a section of a concrete structure according to any one of claims 1 to 3 and 5 to 7,
Removing and cleaning the laitance and impurities of the concrete slab surface by chipping by a planer, a short blaster, or a hand water jet,
Applying a primer for improving the adhesion of the concrete concrete and the cement mortar composition for repairing the section of the concrete structure after confirming the moisture content of the cleaned part,
Applying a cement mortar composition for repairing the section of the concrete structure to the upper surface to which the primer is applied, and then finishing the surface
And curing and curing the surface of the concrete structure.
9. The method of claim 8,
Wherein the primer comprises at least one material selected from styrene-butadiene, polyethylene vinyl acetate, polyacrylic ester, and acrylic emulsion.
9. The method of claim 8,
Further comprising the step of applying a surface protecting material to the surface finishing step to improve chloride ion penetration inhibition, decrease in neutralization reactivity, chemical resistance, and freezing and thawing resistance.
11. The method of claim 10,
Wherein the surface protection material of the step of applying the surface protective material comprises at least one material selected from the group consisting of styrene-butadiene, polyethylene vinyl acetate, acrylic polymer, epoxy-free resin, urethane-acrylic polymer and silane- Repair method.