KR101936670B1 - Binder Composition for Repair Mortar with Water Permeability Resistance, Dry Mortar Composition Comprising the Binder and Concrete Repair Method Using the Mortar - Google Patents

Abstract

The present invention relates to an anti-permeable binder composition for mortar for repairing a cross section, a dry mortar composition preferably comprising the same, and a method for repairing a concrete cross section by using the dry mortar composition, wherein the anti-permeable binder composition for mortar has improved resistance to drying shrinkage and water repellency, thereby providing excellent anti-permeability. The anti-permeable binder composition for mortar for repairing a cross section comprises: 40-80 wt% of Portland cement; 5-15 wt% of fast-hardening cement; 3-8 wt% of a water-repelling and shrinkage-reducing admixture; 3-8 wt% of an expanding agent; 5-15 wt% of anhydrous gypsum; and 5-20 wt% of blast furnace slag. The water-repelling and shrinkage-reducing admixture is produced by grinding and mixing a composition including an inorganic filler for dispersion, an anti-aggregation agent, a water repellent, and a shrinkage reducing agent in a grinder, and has specific gravity of 2.20 or less and fineness of 5,500-9,000 cm2/g. According to the present invention, the anti-permeable dry mortar composition for repairing a cross section is composed of 50-200 parts by weight of aggregates based on 100 parts by weight of the anti-permeable dry mortar composition for repairing a cross section. According to the present invention, the method for repairing a concrete cross section comprises the steps of: producing wet mortar by adding 20-50 parts by weight of water based on 100 parts by weight of the binder composition to the anti-permeable dry mortar composition for repairing a cross section; and removing degraded portions from a concrete structure to fill the removed portions with the wet mortar.

Description

Technical Field [0001] The present invention relates to a binder composition for a water-repellent single-walled repair mortar, a dry mortar composition containing the same, and a concrete mortar composition using the dry mortar Mortar}

More particularly, the present invention relates to a concrete repairing method for repairing and repairing damage caused by cracks and deterioration of a concrete structure, and more particularly, Repair mortar composition, a dry mortar composition preferably comprising the same, and a concrete section maintenance method using the dry mortar.

Various types of cracks occur in concrete structures due to the natural or anthropogenic action of materials, formulations, construction, structure and load, and environmental conditions. Cracks in these concrete structures cause deterioration in the performance of the concrete structures, which causes the concrete structures to fall short of the design use years. Also, even if artificial actions such as materials, formulations, construction, structure and load are excluded, the concrete deteriorates with time depending on the ambient conditions and the environment, and the performance is deteriorated. Therefore, concrete structures always need to maintain maintenance activities. In particular, when the problems of materials, construction, and structure are mixed with natural environmental factors, the demand for maintenance of concrete structures increases more.

In order to increase the service life of concrete structures, artificial defects should be minimized, but aggressive coping with degradation due to natural environment should be possible. Natural factors that cause deterioration of concrete structures are penetration of deteriorating factors such as temperature changes outside concrete, carbon dioxide, chlorine ion, sulfate ion, acid ion through the atmosphere and soil moisture. When deterioration occurs in concrete due to penetration of these deteriorating factors, a concrete section repair method is performed to remove the deteriorated portion and recover the removed concrete section.

For the concrete section repair method, section repair mortar is used. Sectional maintenance mortar is important for water repellency to prevent penetration of water, which helps natural deterioration factors penetrate into the concrete. As a method for imparting water repellency, it is common to incorporate a water repellent agent into the cross-section repair mortar.

However, since mortar generally uses more binder than concrete, it causes severe shrinkage and frequent cracking. If cracks are generated in the section repair mortar, the durability of the section repair mortar is lowered, and also the durability of the concrete to be restored is lowered. Moisture penetrates through the cracks. Moisture becomes a means for moving various harmful components, which causes freezing and thawing, resulting in a decrease in durability. Accordingly, it is also important to have a property that a single-sided repair mortar is not sufficient to have a simple water-repellent property and can form a dense cured body by suppressing cracks due to drying shrinkage.

Korean Patent No. 10-0913255 Korean Patent No. 10-1466823

The present invention has been developed in order to provide a new section repair mortar exhibiting excellent water permeability, and it is an object of the present invention to provide a binder composition for waterproofing cross-section repair mortar having water repellency and exhibiting excellent water- There is a technical problem to provide a water-permeable cross-section repair-dried mortar composition which preferably comprises a binder composition, and a concrete cross-section repairing method which preferably uses the dry mortar.

In order to solve the above-mentioned technical problem, the present invention relates to a cement paste composition comprising 54 to 84% by weight of ordinary portland cement; 5 to 15% by weight of quick-setting cement; 3 to 8% by weight of water repellent shrinkage reducing admixture; 3 to 8% by weight of a swelling agent; And 5 to 15% by weight of anhydrous gypsum; wherein the water-repellent shrinkage reducing admixture comprises an inorganic filler for dispersion, an aggregation inhibitor, a water repellent, and a shrinkage reducing agent, which is pulverized and mixed in a pulverizer, And a powdery degree of 5,500 to 9,000 cm < 2 > / g.

The present invention also provides a mortar-resistant, moisture permeable mortar composition, wherein 50 to 200 parts by weight of an aggregate is mixed with 100 parts by weight of a binder composition for a water-resistant single-walled repair mortar.

Further, the present invention relates to a mortar composition having a water-permeable cross-section, wherein 20 to 50 parts by weight of water is further blended with 100 parts by weight of the binder composition to form a wet mortar, then the deteriorated portion is removed from the concrete structure, And a method for repairing a concrete section is provided.

According to the present invention, the following effects can be expected.

First, it is possible to provide a new concrete section repair mortar which further improves water repellency and shrinkage resistance.

Secondly, the section repair mortar according to the present invention exhibits excellent water repellency and at the same time exhibits crack suppression performance due to reduction in shrinkage of drying, thereby effectively preventing penetration of harmful components, carbon dioxide, moisture and the like, and is also advantageous in terms of compressive strength and freeze- Performance. Therefore, when the concrete section repair method is performed by using the section repair mortar according to the present invention, the durability of the repair part can be improved.

Third, since the section repair mortar according to the present invention exerts excellent water permeability, it can be advantageously used for repairing and reinforcing concrete structures requiring repairing of cross-section of an underground structure or other water permeability.

The present invention is characterized in that it comprises a water-repellent shrinkage reduction admixture exhibiting water repellency and dry shrink resistance in forming a binder for a moisture-permeable cross-section repair mortar. Specifically, the binder composition for waterproofing cross-section repair mortar according to the present invention usually comprises 54 to 84% by weight of Portland cement; 5 to 15% by weight of quick-setting cement; 3 to 8% by weight of water repellent shrinkage reducing admixture; 3 to 8% by weight of a swelling agent; And 5 to 15% by weight of anhydrous gypsum. Such composition materials and composition range are results in consideration of water repellency, shrinkage reduction, strength, economy and the like.

Usually, Portland cement becomes a basic binder, and quick-speed cement accelerates curing speed, contributes to shrinkage compensation due to ettringite formation and densification of hardened structure, swelling agent contributes to shrinkage compensation, and anhydrite- This contributes to shrinkage compensation due to generation and densification of the cured body structure. CSA-based ultrafast cement containing a specific gravity of 2.7 to 3.0, a powder of 3400 to 6000 cm2 / g and Al2O3 of 36 weight% or more is preferable, and a swelling agent is CaO having a specific gravity of 2.8 to 3.1 and a powder of 2500 to 4000 cm & Based anhydrous gypsum, and the anhydrous gypsum preferably has a specific gravity of 2.8 to 3.0 and a powdery size of 3500 to 5000 cm 2 / g.

The water-repellent shrinkage reducing admixture, which is a characteristic constitution of the present invention, is a composition comprising an inorganic filler for dispersion, an aggregation inhibitor, a water repellent, and a shrinkage reducing agent in a pulverizer. Preferably 45 to 85% by weight of an inorganic filler for dispersion in consideration of grinding efficiency, performance development, usability and the like; 1 to 10% by weight of an anti-aggregation agent; 2 to 20% by weight of a water repellent agent; And 5 to 30% by weight of a shrinkage reducing agent, and the mixture is pulverized to have a specific gravity of 2.20 or less and a powder content of 5,500 to 9,000 cm 2 / g. In particular, when the shrinkage reducing agent is excessively dispersed, it is difficult to be stored for a long time by agglomeration due to deliquescence, so that it is preferably 5 to 30% by weight.

Conventional shrinkage reducing agents are in the form of flakes having deliquescent properties and are difficult to be independently pulverized, and even if pulverized, they are agglomerated within a few hours, making them difficult to use in dry mortar products. In the present invention, the shrinkage reducing agent is pulverized and mixed with an inorganic filler for dispersion, an anti-aggregation agent and a water-repellent agent to prevent the agglomeration phenomenon due to the deliquescence of the shrinkage reducing agent and to be smoothly dispersed in the dry mortar product. Here, pulverization and mixing may be carried out in a disk type mill for about 30 minutes. Ball mills, vibration mills and the like are susceptible to agglomerating of the deliquescent material by the continuous friction grinding action. The disc mill is instantaneous (relatively much less persistent) and is continuously pulverized to facilitate the pulverization of the deliquescent material. In the pulverized mixed water-repellent shrinkage reducing admixture, the dispersion inorganic filler, the cohesion preventing agent, the water repellent agent and the shrinkage reducing agent are dispersed and mixed well.

In the water-shrinkage-reducing admixture, the inorganic filler for dispersion uses fly ash, which can be expected to have a strength-enhancing effect by the pozzolanic reaction, magnesium hydroxide as the coagulation inhibitor, and stearic acid and wax, , And the shrinkage reducing agent is preferably glycol-based.

The above-mentioned binder for the water-permeable cross-section repair mortar may be prepared by mixing the aggregate further with a premix-type dry mortar. The dried mortar may be blended with 100 to 20 parts by weight of the binder and 50 to 200 parts by weight of the fine aggregate (silica). Further, 0.1 to 2 parts by weight of the re-firing powder resin and / or 0.1 to 2 parts by weight of the fluidizing agent may be further blended. The re-oil type powder resin contributes to the improvement of adhesion, water resistance and elasticity, and the fluidizing agent contributes to improvement of fluidity. Further, various functional additives such as a dispersant, a thickener, and a retarder can be further mixed into the dry mortar composition.

The mortar composition and the mortar composition for repairing the cross-section of the water-repellent single-walled mortar are in the form of a dry powder, so they can be packaged for commercialization. Particularly when water is added to the surface-repair mortar composition, wet mortar is formed. In this case, 20 to 50 parts by weight of water is suitable for 100 parts by weight of the binder composition when considering the workability. Since such wet mortar exhibits excellent performance in terms of strength, water repellency, change in length, freeze-thaw resistance and the like, it can be advantageously applied to a section repair method of a concrete structure requiring water permeability.

The concrete section repair method is carried out by removing the deteriorated part from the concrete structure and filling the removed part with wet mortar. Prior to filling the wet mortar, it is preferable to apply the concrete performance remover and the primer to improve the performance of the concrete matrix and to improve the adhesion of the absorption control type mortar. The concrete performance remediation agent is suitable for the alkali recovery agent of concrete, and the acrylic primer and the EVA primer are suitable as the primers. In addition, it is preferable for the concrete section protection to be repaired to apply the protective coating after filling the wet mortar, and the protective coating is applied as usual.

Hereinafter, the present invention will be described in detail based on a test example. However, the following test examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

[ Test Example ] Mortar properties of permeable cross-section

One. Foot type Shrinkage reduction Mixed material  Produce

The materials shown in Table 1 below were prepared, and these materials were pulverized and mixed in a disk mill for 30 minutes to prepare a water-shrinkage reduction admixture. The water repellent shrinkage reducing admixture thus produced had a specific gravity of 2.11 and a powder density of 7800 cm 2 / g.

Water-shrinkage reduction Admixture composition (% by weight) material Furtherance characteristic Dispersing inorganic filler Fly ash 68 Specific gravity 2.21, powder degree 3600 Anti-aggregation agent Magnesium hydroxide 4 Weight 2.4 Water repellent agent Stearic acid 12 White solid, with formula C ₁₇ H ₃₅ COOH, specific gravity 0.87,
Melting point (℃) 69 ~ 72 Shrinkage abatement agent Neopental glycol 16 C ₅ H ₁₂ O ₂ , specific gravity 1.06, purity 99.2 or higher
Solubility 520g / H2O100g (20 ℃), water content 0.3% or less

2. Mortar formulation

The dry mortar was mixed with the composition shown in Table 2 below while using the water-shrinkage reduction admixture according to the above [Production Example], and the water-binding ratio (W / C) was adjusted to 42 wt% Respectively.

Dry mortar composition (parts by weight) division Comparative Example 1 Comparative Example 2 Comparative Example 3 Example Binders Voto Portland Cement 100 93 72 65 CSA based fast curing cement - - 12 12 CaO-based expander - - 6 6 Anhydrous plaster - - 10 10 Shrinkage reducing agent - 7 - 7 sub Total 100 100 100 100 Resuspended Powder Resin Acrylic 0.2 0.2 0.2 0.2 aggregate Standard yarn 135 135 135 135 Fluidizing agent Naphthalene series 0.7 0.7 0.7 0.7

3. Mortar characteristics test method

Fluidity, compressive strength, water repellency, length change and freezing and thawing test were applied to the wet mortar mixed above.

The flow test was carried out in accordance with the flow test of KS L 5105 and the circle diameter was expressed in mm. The compressive strength test was carried out according to KS F 2405 at 3 days, 7 days and 28 days. The specimens were prepared in accordance with KS F 2403.

In the water repellency test, a 40 × 40 × 60 mm specimen was prepared, and after curing in water for 14 days at a certain age, a specimen was set up in a water tank of 30 mm in height. The height of the absorbed water was measured based on the upper part of the water tank height of 30 mm. For the accuracy of the measurement, the dark blue ink was dissolved in the water tank to check the height of the water.

For the length change test, the buried strain gauge was buried before the 40 × 40 × 160mm specimen was manufactured, and the length change was measured using a data logger immediately after the test piece was formed. The measurement conditions were 20 ± 2 ℃ and relative humidity of 60 ± 5%.

The freezing and thawing test was carried out in accordance with the water-melting test method after rapid freezing in air of KS F 2456. The temperature range of the freezing and thawing test was determined by measuring the primary resonance frequency and specimen mass up to 300 cycles every 36 cycles with the specimen center temperature of -18 ~ 4 ℃ and the cycle time of 3 hours and 30 minutes. Respectively.

Here, P _c: sangdaedong modulus after freezing and thawing cycles C (%), n _0: the primary resonance frequency (Hz) after freezing and thawing cycles C: beginning of the first resonance frequency (Hz), n _c.

4. Test results of mortar characteristics

The properties of the mortar were tested according to the test method described above, and the results are shown in Table 3 below.

Mortar characteristic test result division Comparative Example 1 Comparative Example 2 Comparative Example 3 Example Flow (mm) 220 215 210 215 Compressive strength
(MPa) 3 days 26.4 23.6 36.4 35.3 7 days 45.3 41.4 49.7 51.9 28th 58.7 55.5 63.2 66.3 Water repellency
(Water absorption height, mm) 68 22 44 18 Length change (10 ^-6 ) -1800 -1250 -873 -355 Freeze-thaw resistance
(300 cycles, relative modulus of elasticity (%)) NA NA 89 92

Comparative Example 1 is an example in which a Portland cement and blast furnace slag are combined with each other, and Comparative Example 2 is an example in which the water-based shrinkage reduction admixture is further mixed by replacing cement and blast furnace slag in Comparative Example 1. As shown in Table 3 It was confirmed that the water absorption height and length change were improved by the mixing of the water shrinkage reduction admixture, but the compressive strength was slightly lowered. Comparative Example 3 is an example in which a binder is composed of ordinary portland cement, CSA-based ultrafast cement, swelling agent, anhydrous gypsum and blast furnace slag. In Example 3, cement and blast furnace slag are substituted in Comparative Example 3 to further incorporate a water- As a result, the water absorption height and length change were remarkably improved and the compressive strength and freeze - thaw resistance were somewhat improved by the incorporation of water - type shrinkage reducing admixture. As a result, the mortar containing the water-shrinkage-reducing admixture improves the water repellency and the shrinkage resistance as well as the compressive strength and the freeze-thaw resistance, which is advantageous for the maintenance of the concrete which requires the permeability It is expected to be able to do.

Claims (6)

delete Usually Portland cement 54-84 wt%; 5 to 15% by weight of quick-setting cement; 3 to 8% by weight of water repellent shrinkage reducing admixture; 3 to 8% by weight of a swelling agent; 5 to 15% by weight of anhydrous gypsum,
The water-repellent shrinkage reduction admixture is characterized in that,
45 to 85 wt% of fly ash; 1 to 10% by weight of magnesium hydroxide; 2 to 20% by weight of a water repellent agent based on at least one of stearic acid and wax in a melt; And 5 to 30 wt% of a glycol-based shrinkage reducing agent is pulverized and mixed in a pulverizer and has a specific gravity of 2.20 or less and a powder viscosity of 5,500 to 9,000 cm 2 / g. Binder composition. A mortar composition with moisture permeable cross-section repair mortar characterized in that 50 to 200 parts by weight of an aggregate are mixed with 100 parts by weight of a binder composition for a waterproofing cross-section repair mortar according to claim 2. 4. The method of claim 3,
0.1 to 2 parts by weight of a fluidizing agent, and 0.1 to 2 parts by weight of a re-oiling type powder resin. According to the concrete maintenance method of the concrete using the moisture-permeable section repair mortar composition according to claim 4,
The mortar composition of the present invention is characterized in that 20 to 50 parts by weight of water is further blended with 100 parts by weight of the binder composition of the dry mortar composition to form a wet mortar and then the deteriorated portion is removed from the concrete structure and the removed portion is filled with wet mortar Method. In claim 5,
Wherein a concrete performance restorer and a primer are applied before filling the wet mortar, or a protective coating agent is applied after the wet mortar is filled.