KR101265701B1 - Concrete repair method using microcapsule admixture - Google Patents

Abstract

PURPOSE: A repairing method of a concrete structure using a microcapsule additive admixture is provided to improve economical efficiency and workability in repairing work of a damaged concrete structure and to rapidly construct a cross-section including high possibility of damage. CONSTITUTION: Foreign substances on the surface of a damaged unit are removed, and the surface is treated. A reinforcing agent is coated on a surface treatment unit of a concrete structure. Repairing mortar including a microcapsule additive is coated. The damaged concrete structure is restored and is finished with an inorganic paint.

Description

CONCRETE REPAIR METHOD USING MICROCAPSULE ADMIXTURE}

The present invention relates to a method for repairing damaged concrete sections for cross-sectional recovery of deteriorated concrete structures, repairing damaged sections of concrete structures using a repair mortar containing microcapsule admixtures, and removing damaged concrete. In order to reinforce the spheres of carbonated concrete, the penetrating sphere reinforcement is applied and the microcapsule admixture is used to recover the cross-section removed by the repair mortar, which can significantly reduce the casting time. It relates to a repair method for a concrete structure consisting of the order of applying the surface treatment material.

The present invention is an effective technique in the case of rapid construction where the damage area of the concrete is relatively deep or wide and the repair area is large, and the construction period should be significantly shortened due to external construction conditions.

In addition, the present invention can pour the thickness of the repair section as deep as possible, it is possible to rapid construction by the fastening rate of the mortar under the influence of the microcapsule quickener.

Therefore, the present invention is an excellent technique for the renovation of concrete structures, such as subway and railway tunnels, the construction of a relatively wide port cross section, the construction time is relatively short by the passage of the train.

In general, concrete is composed of cement, coarse aggregate, fine aggregate, and admixture, and thus, unlike other construction materials (rebar), the composition of the material varies, and different heterogeneous materials are combined. Therefore, the quality of concrete is closely related to the quality of constituent materials, and varies according to the mixing ratio, the pouring method, and the curing method.

High-quality concrete has long been used in construction materials because it is economical and semi-permanent. However, concrete is rapidly broken when producing poor quality concrete or when the concrete structure is exposed to poor environmental conditions. For example, concrete exposed to the shore causes corrosion when seawater's chlorine ions penetrate into the concrete, eliminating the passivation film in the reinforcing bars, and concrete exposed to the polluted atmosphere invades carbon dioxide from the outside. It acts as a cement hydrate to neutralize the concrete surface, eventually leading to corrosion of the rebar. In addition, sulfuric acid gas, bacteria, and the like penetrate into the concrete by wastewater and domestic sewage of the plant, which accelerates the corrosion of the steel.

In addition, when the steel reinforcing the inside of the concrete, the volume is expanded to crack the concrete structure, the cross-sectional drop phenomenon occurs.

In addition, concrete may expand due to various deterioration factors invading from the outside and eventually cause the collapse of the cross section. In particular, as the damage of large concrete structures, such as port facilities, has increased, the wide and deep sections have to be repaired more often, and the traffic congestion has necessitated the need for shortening of the repair work. .

In order to be able to rapidly repair a large area of the damaged concrete structure in a short time to look at the prior art related to the cross-sectional recovery method to improve the workability by adding a fastener to the shotcrete as follows.

Patent registration No. 1005720350000 (2006.04.11) is a construction method for repairing damaged concrete, the structure of the mortar spraying device is a mixer for mixing mortar with water, cement and sand and mortar for spraying the mortar mixed in the mixer A mortar injector having a spray nozzle and an air compressor for injecting compressed air into the mortar spray nozzle, and in particular, a fastener injector capable of mixing a fastener with a mortar sprayed from a nozzle of the mortar injector Since it is additionally provided, the construction is reduced due to additional facilities and additional devices for the spraying of the quickener has been pointed out as a problem.

In addition, Patent Registration No. 1010762170000 (October 18, 2011) is a wet shotcrete construction equipment system equipped with a powder supply device, which supplies dry compressed air and prevents backflow of moisture to prevent the rapid settlement of the quickener tank and the quickener delivery pipe by moisture. Condensation can be prevented, and the front and rear injectors and Y-tubes with steel wires can be used to increase the mixing efficiency of concrete and fasteners, and the amount of fastener inputs can be precisely adjusted to reduce the rebound amount. By changing the distance between the Y-pipe and the Y-pipe and the shear injector, there is an advantage that quick action can be taken when the concrete pressure pipe is blocked during construction, thus reducing the construction time and input material. However, since the installation property of the fastener transporting device installed additionally varies depending on the type of material, Siege deterioration has been pointed out as a problem in the field, and additional facility costs are increased due to additional installations of a fastener tank, a transfer pipe, a rear end injector, a shear injector, and a Y-pipe for the use of a fastener. Has the disadvantage of being delayed.

In addition, Korean Patent Registration No. 1006475310000 (Nov. 13, 2006) relates to a wet shotcrete placing equipment system using cement mineral fillers, wherein a pumping pump is formed to pump concrete into a pumping pipe by forming a pumping pressure for spraying concrete. And a transport pipe for transporting concrete through a supply pipe formed to supply concrete to be conveyed to the transport pipe, and a fastener mixing pipe formed to supply and mix a fastener to the concrete transported from the transport pipe. The present invention relates to a wet shotcrete placing equipment system equipment using a cement mineral quickener, characterized in that it consists of a concrete conveying unit formed to be sprayed from the spray nozzle.

In this patent, it is pointed out that the problem that clogging of the tube occurs when the fastener passes through the mixing plate and that the workability is remarkably inferior.

In view of the above-mentioned problems, the present invention provides a concrete structure capable of rapid construction in a short period of time by placing a repair mortar containing a microcapsule admixture in a deep and wide area of damaged concrete structures. The purpose of this is to provide damage repair method.

The present invention is different from the method of adding a fastener mixing device to the pouring equipment or adding a fastener by changing the pouring equipment, as in the prior art, by directly incorporating the microcapsule admixture into the repair mortar without any additional equipment. It is also an object of the present invention to provide a repair method for a concrete structure that can be used easily without changing.

Repairing method of the concrete structure of the present invention for achieving the above object comprises the steps of removing and surface treatment of foreign matter on the surface of the damaged portion of the concrete structure; Applying a concrete reinforcement to the surface treatment of the concrete structure; Applying a repair mortar containing a microcapsule admixture; It characterized in that it comprises the step of applying an inorganic paint.

Surface treatment of the concrete structure includes removing any one of peeling, lifting or neutralization of the deteriorated concrete structure.

Application of the inorganic paint is preferably to be carried out after the pre-coated maintenance mortar is cured.

The microcapsule admixture of the present invention includes a core material and a wall material coated on an outer circumferential surface of the core material, and the core material includes aluminum oxide as a fastener.

In addition, the concrete reinforcing material is preferably made to have a function of alkalizing the carbonated concrete structure to prevent corrosion of the reinforcement and to deteriorate the concrete.

The repair mortar containing the microcapsule admixture of the present invention has 30.0 to 50.0 parts by weight of binder, 3.0 to 5.0 parts by weight of inorganic additive, 1.0 to 9.0 parts by weight of adjuvant and admixture, and 36.0 to 66.0 of aggregate. It should be made of a formulation containing parts by weight.

In the blending, the inorganic additive includes an expander and anhydrous gypsum, and the admixture contains a fluidizing agent and a powdered resin. The binder is 30.0 to 50.0 parts by weight of cement, the inorganic additive is to be made of 2.0 to 3.0 parts by weight of the expansion material and 1.0 to 2.0 parts by weight of anhydrous gypsum.

According to the present invention, the workability and economical efficiency are improved when repairing the damaged concrete structure in cross section, and the time required to perform repair work such as subway or railway tunnel is relatively short compared to other structures on the ground, so that the construction is conventionally performed. It is difficult and has the effect of rapidly constructing a cross section where defects are likely to occur.

In addition, the thickness of the mortar that can be poured in one time can be 200mm or more has the effect of solving the existing construction difficulties.

In addition, by using a microcapsule admixture, it can be used as an existing equipment without additional auxiliary equipment, and construction is easy.

1 to 3 are micrographs and SEM observation results of the fasteners (I, II, III) contained in the microcapsule admixture of the present invention.

Prior to the description of the present invention, for convenience of description, the general state of the quickener injector mounted on the shotcrete pouring apparatus will be described first.

Currently, the fastener feeder used at the shotcrete construction site is largely divided into a silicate quickener feeder and an aluminate quickener feeder.

 Since the silicate-based fasteners have a very fast reaction rate, the fasteners are injected in a mixing chamber located at the nozzle portion.

The present invention recognizes the necessity of using a fastener in order to pour mortar on a concrete section with a large damage area and does not add the fastener through a shotcrete pouring device for mortar, and inserts the fastener into a microcapsule to form a microcapsule admixture. It is possible to pour without additional equipment because it is manufactured, and mixed with the mortar and using the existing shotcrete equipment as it is.

In addition, in the present invention, since the fastening agent is used by microcapsule unlike the existing method, it is possible to prevent the strong alkali component or the strong acidic component contained in the fastening agent from being exposed to the outside.

In the present invention, when the microcapsule is encapsulated, the microcapsule admixture containing the quickener is mixed with conservative mortar, and the microcapsule admixture is released in the conservative mortar after being poured, and absorbed into the conservative mortar, thus being a strong alkali or harmful to the human body. Strongly acidic components are not released from the rapidener to the outside. Therefore, it is possible to protect the skilled workers, to produce environmentally friendly repair mortar, and unlike the existing technology, the construction can be performed without the device for storing and transporting the quick payment, and thus the construction property is remarkably improved compared to the existing technology.

On the other hand, the microcapsule admixture used in the present invention has been previously developed by the present applicant (see Patent Application No. 10-2010-0112226), briefly described the configuration and performance as follows.

The microcapsule admixture is a microcapsule admixture comprising a core material and a wall material coated on the outer circumferential surface of the core material, wherein the core material is aluminum hydroxide as a quickener, and the wall material is an acrylic emulsion or sodium which is a water-soluble polymer. It is characterized in that the silica (Sodium silicate).

The microcapsule admixture used in the present invention includes a quickener as a core material, but may include only lithium carbonate, which is an accelerator, in place of the quickener, and may be included together with the quickener and the accelerator.

Accordingly, the microcapsule admixture of the present invention may contain 30-70% of lithium carbonate as the core material, 20-50% of the acrylic emulsion and 20-50% of the sodium silicate as the wall material, respectively. Can be.

In addition, the microcapsule admixture applied in the present invention contains lithium carbonate 30-50% as a core material, 10-30% aluminum oxide as a fastener, respectively 5-30% acrylic emulsion, sodium silicone as the wall material May contain 5-30% of sodium silicate, respectively.

Formulation of the repair mortar using the microcapsule admixture developed by the above formulation is based on 100 parts by weight of the total composition, 30.0 to 50.0 parts by weight of the binder, 3.0 to 5.0 parts by weight of the inorganic additive, 1.0 to 9.0 parts by weight of the adjuvant and admixture, and 36.0 to the aggregate. Including 66.0 parts by weight, the inorganic additive includes an expanding material, anhydrous gypsum, the admixture contains a fluidizing agent, a powdered resin.

In the above configuration, the binder may include 30.0 to 50.0 parts by weight of cement, the inorganic additive may include 2.0 to 3.0 parts by weight of the expandable material, and 1.0 to 2.0 parts by weight of anhydrous gypsum.

In addition, the admixture is 1.0 to 2.0 parts by weight of the fluidizing agent, 0 to 7.0% of the microcapsule admixture, aggregate No. 4 (size 0.85-1.18mm), No. 5 (size 0.60-0.85mm), No. 6 (size 0.21-0.60 mm) and 36.0 to 66.0 parts by weight.

Hereinafter, as shown in Table 1 below, a repair including 30.0 parts by weight of a binder, 4.0 parts by weight of an inorganic additive, 1.0 parts by weight of an auxiliary and admixture, and 48.0 parts by weight of an aggregate, and mixing three types of microcapsule admixtures In order to examine the characteristics of mortar, conservative mortar containing microcapsule admixtures through carbonation and freeze-thawing tests in terms of condensation time, compressive strength, length change rate and durability of condensation mortar containing microcapsule admixtures and microcapsule admixtures The characteristics of were investigated.

cement
(Holy Church)
aggregate
(Standard yarn)
Inflating material
(Hyeonam)
Anhydrous gypsum
(Hyeonam) High Performance Fluidizer
(Power tag)
Powdered resin
(From Germany)
Microcapsule Admixtures
Sum Example  One 40% 48% 2.5% 1.5% 0.5% 0.5% 7% - - 100% Example  2 40% 48% 2.5% 1.5% 0.5% 0.5% - 7% - 100% Example  3 40% 48% 2.5% 1.5% 0.5% 0.5% - - 7% 100%

Next, microscopic and SEM photographs were taken to understand the shape of the microcapsule admixture of the present invention, and the photographing results are shown in FIG. 1.

That is, Figure 1 is a view showing the micrographs and SEM observation results for the rapid setting agent.

As shown in FIG. 1, the shape of the microcapsule admixture forms the shape of each shape, and the size was observed to be a particle size of several tens of tens. In general, the fasteners produced by the chemical manufacturing process show a complete spherical shape, whereas the fasteners produced in large quantities using a fluidized bed process machine for the application to conservative mortar show a more aggregated form than the complete spherical shape.

Next, the condensation time of the repair mortar containing three kinds of microcapsule admixtures was carried out, and the results are shown in the following [Table 2].

In general, when the mixing amount of the fastener is less than 5%, the effect of reducing the setting time is insignificant. Therefore, the effect of the setting of the fastener was changed to 5%, 7%, and 9%, and the effect on the setting time was observed. The initial grain was reduced from 10 minutes to 15 minutes depending on the amount of incorporation.

Setting time according to the amount of microcapsules division First minute Termination (minutes) Remarks No additives 125 minutes 325 minutes Microcapsule Admixture () 5% 15 58 7% 13 49 9% 10 50 Microcapsule Admixture () 5% 43 120 7% 39 105 9% 35 104 Microcapsule Admixture () 5% 26 81 7% 22 70 9% 19 72

1. Compressive strength

Referring to the conservative mortar compressive strength test applying the microcapsules admixture of the present invention is as follows.

Compressive strength was tested by changing the mixing ratio from 5% to 9% to see the change in compressive strength according to the amount of the microcapsule admixture, and the test results are shown in Table 3 below.

Concrete compressive strength test results using microcapsule admixture division 1 day 3 days 7 days 28 days Plain 10.0 18.4 23.2 36.2 10.1 19.2 25.4 34.7 20.4 24.7 36.3 Average 10.1 19.3 24.4 35.7 Microcapsule Admixture () 11.2 18.1 21.5 29.4 11.5 18.4 21.6 28.4 18.3 20.5 28.9 Average 11.3 18.3 21.2 28.9 Microcapsule Admixture () 12.6 16.3 18.4 27.5 12.3 16.5 17.8 26.7 16.4 18.3 26.9 Average 12.5 16.4 18.2 27.0 Microcapsule Admixture () 8.3 14.9 17.4 27.5 8.5 15.3 16.7 27.8 15.4 18.0 28.2 Average 8.4 15.2 17.4 27.8

As can be seen in Table 3, the test results indicate that the strength decreases as the amount of admixture increases, and the initial strength decreases as the admixture increases. As a result of the strength measurement, the daily strength shows the compressive strength of 11.3 and 12.5 of the microcapsule admixture (1) and 12.5 of the microcapsule admixture, respectively.

However, the strength tendency is reversed after 3 days, and the microcapsule admixture () is 18.3, the microcapsule admixture () is 16.4, and the microcapsule admixture () is 15.2, while the compressive strength of plain is 19.3. In all concretes to which is applied, it shows lower strength than plain. The same trend is observed on the 7th and 28th days.

2. Length change rate

In order to use the fastener in mortar, the compressive strength and the rate of change of length due to dry shrinkage are one of the important items among the mechanical properties reflected in the design of the structure. In order to determine the length change rate of the microcapsule admixture applied in the present invention, the length change rate of the conservative mortar containing the microcapsule admixture (), the microcapsule admixture (), and the microcapsule admixture () was measured. As shown in the conservative mortar formulation including the microcapsule admixture, the rate of change in length is somewhat higher than the formulation without the microcapsule admixture.

division Length change rate (%) Plain -0.021 Microcapsule Admixture () -0.035 Microcapsule Admixture () -0.032 Microcapsule Admixture () -0.033

3. Carbonation

Table 5 below shows the results of carbonation test that have a significant effect on the durability of concrete structures. The carbonation of the conservative mortar containing the microcapsule admixture was found to be about 0.3-0.4mm deeper than the plain, but it was negligible in consideration of the thickness of the concrete.

division Carbonation Penetration Depth (mm) Plain 4.288 Microcapsule Admixture () 4.6 Microcapsule Admixture () 4.706 Microcapsule Admixture () 4.578

4. Chloride Permeability Coefficient

One method of measuring mortar durability can be predicted by measuring the size and number of pores in the mortar and the interconnection of the pores. In particular, chlorine ion permeability tests are used to measure interconnected pores (capillary pores) that have the greatest impact on durability.

[Table 6] below shows the results of the test for the chlorine ion permeability coefficient of the conservative mortar containing the microcapsule admixture of the present invention. There are some more capillary voids in the mortar.

division Passing volume (coulombs) Plain 2344 Microcapsule Admixture () 3066 Microcapsule Admixture () 2911 Microcapsule Admixture () 2783

5. Freeze-thawing

As in Korea, the four seasons are distinct, and when the temperature of winter falls below freezing, water in the pores inside the mortar often freezes and expands. The results of freezing and thawing test to predict the damage of conservative mortar due to the East Sea are shown in [Table 7].

 Plain elastic modulus of elasticity was higher than that of conservative mortar containing microcapsule admixture, which showed a little better resistance to the East Sea.

division Relative dynamic modulus of elasticity (%) Plain 93.7 Microcapsule Admixture () 90.2 Microcapsule Admixture () 88.1 Microcapsule Admixture () 87.6

In the present invention, the construction sequence of the damaged section cross-sectional recovery method in the damaged concrete structure is made as follows.

First, the damaged surface of the deteriorated concrete structure is surface treated. In other words. The concrete reinforcement is applied after removing damaged parts such as peeling or lifting or neutralization at the surface part. After that, the repair mortar, which improves the workability due to shortening of air, is poured to further prevent deterioration of the concrete structure.

Next, coating and finishing the inorganic paint prevents further deterioration and improves durability.

The concrete reinforcing material applied preferentially to the deteriorated concrete structure of the present invention has a function to prevent additional reinforcement corrosion by alkalizing the carbonated existing structure, and to remove concrete degradation that may occur due to the penetration of chlorine ions.

In addition, conservative mortar, including microcapsules, has a function of preventing the ingress of deterioration factors from the outside and protecting the reinforcing bars from corrosion because it can express strength early and the tissue is dense.

In addition, the inorganic paint applied after the repair mortar casting functions to prevent intrusion of deterioration factors that degrade concrete, including carbon dioxide penetrating from the outside, and the construction sequence is as follows.

  Removal of damaged parts and surface treatment → Application of concrete reinforcement → Repair mortar casting → Application of inorganic paint

In the above-described construction procedure, it is preferable to apply the inorganic paint after the maintenance mortar is cured.

By repairing the damaged concrete structure by using the concrete reinforcement, repair mortar, and inorganic paint of the present invention, the corrosion and chemical deterioration of reinforcement in the concrete can be prevented by suppressing the cracks and cracks and the lifting phenomenon caused by the shrinkage and expansion of the concrete. You can prevent it.

Meanwhile, the concrete reinforcing material developed in the present invention is manufactured with distilled water, lithium, potassium silicate (RSChem), trimethylsilyl acrylate (TEA, Aldridge, Germany) at a ratio as shown in Table 8 below. It was.

(weight%) Distilled water lithium Potassium silicate TEA Remarks Mixing ratio 80.5-83.5 2.5 13.0-27.0 1.0-2.0 -

Concrete reinforcement developed in the present invention has a specific gravity of 1.056 and has a good penetration depth into concrete (up to 4.58mm from the concrete surface), and in the case of damaged structures, the concrete reinforcement has a merit of 5 mm or more. It will have a function to greatly improve the effect of alkalizing carbonated concrete by penetrating into the concrete. The test results of the concrete reinforcement are shown in [Table 9].

Test Event unit Test result pH - 12.5 importance - 1.056 Penetration depth mm 4.58 Permeability - 0.05

In the present invention, after repairing the damaged concrete structure to finish the inorganic coating to prevent carbonation and to prevent impurities from entering the outside, with respect to 100 parts by weight of the total composition of the inorganic coating, 30.0 to 50.0 parts by weight of the binder It includes cement, calcium carbonate and silica fume, and contains 3.0 to 5.0 parts by weight of a high performance fluidizing agent, 10.0-20.0 parts by weight of polymer, 30.0-52.0 parts by weight of sand (standard yarn).

According to the test results, the bond strength was 1.0-1.3MPa and the compressive strength was 30-40MPa.

Claims (7)

As a repair method for repairing damaged concrete structures,
Removing and surface treating foreign matter on the damaged surface of the concrete structure;
Applying a concrete reinforcement to the surface treatment of the concrete structure;
Applying a repair mortar containing a microcapsule admixture;
Applying an inorganic paint,
The repair mortar containing the microcapsule admixture includes 30.0 to 50.0 parts by weight of the binder, 3.0 to 5.0 parts by weight of the inorganic additive, 1.0 to 9.0 parts by weight of the auxiliary and admixtures, and 36.0 to 66.0 parts by weight of the aggregate. Is made up of
The inorganic additive includes an expander and anhydrous gypsum, the admixture contains a fluidizing agent and a powdered resin,
The binder is 30.0 to 50.0 parts by weight of cement,
Inorganic additives are 2.0 to 3.0 parts by weight of the expansion material and 1.0 to 2.0 parts by weight of anhydrous gypsum repair method of the concrete structure. The method according to claim 1,
Surface treatment of the concrete structure is a cross-sectional repair method of the concrete structure comprising removing any one of the peeling, lifting or neutralization of the deteriorated concrete structure. The method according to claim 1,
The coating of the inorganic paint is repairing method of the concrete structure, characterized in that is carried out after curing the pre-coated repair mortar. The method according to claim 1,
The microcapsule admixture includes a core material and a wall material coated on an outer circumferential surface of the core material, wherein the core material includes aluminum oxide as a fastener. The method according to claim 1,
The concrete reinforcing material is a repair method of a concrete structure having a function of preventing the corrosion of reinforcing steel and deterioration of concrete by alkalizing the carbonated concrete structure. delete delete

Images