KR100515948B1 - The composition of repair mortar containing nitrite based hydrotalcite(or hydrocalumite) and corrosion inhibitive repair method of reinforced concrete structure using repair mortar described above - Google Patents

Abstract

The present invention relates to a mortar composition for sectional recovery containing nitrite-based hydrotalcite or nitrite-based hydrocalumite, and to a method for restoring reinforcing corrosion of reinforced concrete structures using the same. By incorporating and preparing hydrochlorumite, it is possible to extend the period of reinforcement corrosion by forming a multi-step function to block the reinforcement corrosion factor (chlorine ion), which is the main performance deterioration source of reinforced concrete structures, and to block it by ion exchange. This increases the service life of reinforced concrete structures, and it can omit a separate rust preventive process, so that the economic effect of reduction in manpower can be realized, and the mortar for sectional recovery containing nitrite-based hydrotalcite or nitrite-based hydrocalumite Furtherance And it is to provide a corrosion inhibiting repair method of the reinforced concrete structure using the same.

The present invention is a base treatment step to remove the deteriorated area and remove foreign substances on the concrete structure, 20 to 40 wt% cement, 1 to 5 wt% alumina cement, 5 to 20 wt% high powder filler in the ground concrete structure , 1-5 wt% of powdered polymer, 0.05-0.2 wt% of water reducing agent, 0.01-0.1 wt% of reinforcing fiber, 1-2 wt% of nitrite-based hydrotalcite or nitrite-based hydrochalumite, and the remainder made of silica sand It is a cross-sectional recovery step that is continuously sprayed or polished by mixing with water to form a multi-level barrier that can block and delay salts.

Description

Mortar composition for sectional recovery containing nitrite-based hydrotalcite or hydrocalumite and reinforcement corrosion inhibiting method of reinforced concrete structure using the same {the composition of repair mortar containing nitrite based hydrotalcite (or hydrocalumite) and corrosion inhibitive repair method of reinforced concrete structure using repair mortar described above}

The present invention relates to a mortar composition for sectional recovery containing nitrite-based hydrotalcite or nitrite-based hydrocalumite, and to a method for repairing reinforcing corrosion protection of reinforced concrete structures using the same, which provides chlorine ion Ion exchange, chemically fix chlorine ion in mortar, and form passive layer of reinforcement by ion exchange material to block (or delay) the penetration of harmful substances in multiple stages, The present invention relates to a mortar composition for sectional recovery containing nitrite-based hydrotalcite or nitrite-based hydrocalumite, which can be formed to improve resistance to reinforcing corrosion, and to a method for repairing and restoring reinforcing corrosion of reinforced concrete structures using the same.

In general, concrete structures have been recognized to be semi-permanent because they have high durability. However, in recent years, concrete deterioration of concrete structures cannot be avoided, and the number of years has passed. It is often seen that no more than a decade has passed and the original function has been lost.

As mentioned above, the deterioration phenomenon of shortening the life of concrete has been variously shown, but the effect of reinforcing corrosion by chlorides invading from the outside such as melting concrete or snow removal material used in winter or manufacturing concrete using sea sand without salt removal in particular As a result, damage to concrete structures has been seriously investigated.

Conventionally, in order to repair a structure in which degradation occurs due to chlorine ions, an anticorrosive method using an acrylic or epoxy surface coating material, a steel corrosion method using a nitrite-based corrosion inhibitor, and a corrosion inhibitor and a silicate impregnation agent Reinforcement corrosion prevention method was mainly used. However, the anticorrosive method using the acrylic or epoxy surface coating material has the effect of blocking chlorine ions and carbon dioxide, which penetrates from the outside, by coating a coating material on the surface of concrete or mortar, but having physical and physical heterogeneity with the mother. Due to this, the degradation of performance such as peeling and dropping over time cannot be avoided, and thereafter, there was a problem in that the corrosion rate increased when the chlorine ion was invaded.

In addition, the rebar corrosion method by the nitrite-based corrosion inhibitor is clear, but the effect on the reinforcement corrosion inhibition is clear, but the amount of addition to obtain the reinforcement corrosion inhibitory effect is too high, there is a great influence on the mortar initial characteristics such as quenching, nitrite-based corrosion Inhibitors were added to mortar or applied directly to rebar, but did not directly fix chlorine ions, but were involved only in the formation of the passive film of the rebar, thus limiting corrosion.

In addition, the reinforcement corrosion inhibiting method by the corrosion inhibitor and silicate-based impregnating agent increases the alkalinity around the reinforcement corrosion suppression technology to reduce the corrosion rate by increasing the alkalinity around the reinforcement corrosion inhibitory technology, but more effective reinforcement corrosion inhibition effect can be obtained, When silicate-based inorganic penetrant is applied to concrete surface, it is practically difficult to penetrate along the capillary in concrete, and it is practically very unclear whether the alkalinity in the concrete is increased by applying penetrant only on the surface. Since construction property depends on distribution, it had a construction problem.

The present invention is to solve such a problem, the purpose of the incorporation of nitrite-based hydrotalcite or nitrite-based hydrocalumite in the cross-sectional recovery mortar by the reinforcement corrosion factor (chlorine ion) which is the main performance deterioration source of reinforced concrete structure By immobilizing and ion-exchanging, the function to block this is formed in multiple stages to extend the period of reinforcement corrosion as much as possible, thereby increasing the service life of reinforced concrete structures, and eliminating a separate rust prevention process. The present invention provides a mortar composition for sectional recovery containing nitrite-based hydrotalcite or nitrite-based hydrocalumite and a reinforcing corrosion inhibiting repair method for reinforced concrete structures using the same.

Mortar composition for the cross-sectional recovery of the present invention is composed of cement, alumina cement, high powder filler, powder polymer, water reducing agent, reinforcing fiber, nitrite-based hydrotalcite or nitrite-based hydrocalumite and the rest of the silica sand.

The cement is used as the main binder for the strength of the mortar, using one kind of Portland cement, is added about 20 to 40wt%.

The alumina cement is added as a coagulation accelerator of the cross-sectional recovery mortar for a subsequent subsequent process, and is added in an amount of about 1 to 5 wt%.

The high-powder filler is a slag-based high-powder filler in the range of 6,000 to 10,000 cm 2 / g of gypsum and slag as a main component, and densifies the tissue by filling micropores between the cement particles and the particles, about 5 to 20 wt% % Is added, improves durability and protects concrete structures from chemical erosion by sulfates or chloride ions.

The powdered polymer is a polymer material, and in the case of a member having a large area ratio compared to the construction thickness, such as the cross-sectional recovery mortar, the plastic shrinkage phenomenon caused by the rapid evaporation of water in the cross-sectional recovery mortar to the surface is suppressed to prevent water evaporation. After curing, it improves durability by blocking harmful substances such as moisture or carbon dioxide from outside, and is selected from the group consisting of polyvinyl alcohol (vinyl acetate) and vinyl versatate polymer (vinyllacetate and vinyl versatate polymer). It is a compound having a bulk density of 460 to 560 g / L, a pH of 6.5 to 7.5 and a physical property of 1% or less of moisture content, and is added in an amount of about 1 to 5 wt%. In addition, when the powder polymer is used in excess, that is, when it exceeds 5wt%, it will interfere with the hardening of the cross-sectional recovery mortar causing adverse effects.

The water reducing agent is to prevent the degradation of durability caused by excess mixing water to secure the required kneading, using a naphthalene sulfonic acid-based water reducing agent such as naphthalene sulfonate sodium salt is added about 0.05 ~ 0.2wt%.

The reinforcing fibers are dispersed in a cross-sectional recovery mortar in a three-dimensional network form to vaporize the tensile force in the mortar, and is added in about 0.01 ~ 0.1wt%, can increase the tensile stress during plastic shrinkage and dry shrinkage can occur in long-term age It provides a crack resistance and improves the construction thickness when spraying. At this time, the reinforcing fibers are reinforcing known in the Patent Publication No. 1996-0022343, Patent Publication No. 10-2004-0010423, Patent Publication No. 2001-007672, Patent Publication No. 2002-0065133, Patent Publication No. 1989-0008049 It is a known reinforcing fiber which is added in concrete or mortar to reinforce rigidity, such as fiber or alkali resistant glass fiber, carbon fiber, aramid fiber and high strength / high elastic polyethylene and the like.

The nitrite-based hydrotalcite or nitrite-based hydrocalumite is added to extend the period of reinforcing corrosion as much as possible and to give a multi-stage corrosion-blocking function. The passive film is formed by the NO ₂ ⁻ released by the exchange of chlorine ions.

The nitrite hydrotalcite is M _1-x ²⁺ M _x ³⁺ (OH ⁻ ) _{2 + xy} (A ⁿ⁻ ) _{y / n wherein} M ²⁺ is a divalent metal ion, and M ³⁺ is Trivalent metal ion is shown and A ^n- represents n-valent anion. Where x is 0.1 ≦ x ≦ 0.5, and y is in the range of 0.1 ≦ y ≦ 0.5 and n is 1 or 2.

The nitrite hydrotalcite of the present invention selected Mg as M ²⁺ , Al as M ³⁺ and NO ₂ ⁻ as A ^{n −} , and the molar ratio of Mg and Al was adjusted to be 2-3. After adjusting the composition ratio to the raw material containing the components as described above, the reaction was carried out in the autoclave through a reaction time of 85 ℃, 24 hours, and then prepared by drying and grinding. At this time, the nitrite hydrotalcite was prepared by selecting nitrite group instead of carbonate group in general composition Mg ₄ Al ₂ (OH) (CO ₃ ) .4H ₂ O.

Hydrotalcite prepared as described above is an ultrafine powder having an average particle diameter of 0.3 to 0.5㎛ as shown in FIG. In addition to the ion fixing effect, additional physical properties such as water tightness can be improved.

In addition, as shown in FIG. 2, it can be seen that the intrinsic diffraction lines of the hydrotalcite are present alone, so that a single-phase hydrotalcite is prepared, and the prepared hydrotalcite has a hexagonal plate shape having a positive charge as shown in FIG. 3. [M _1-x ²⁺ M _x ³⁺ (OH ⁻ )] ⁺ of the structure forms an existing layer, and (A ^{n −} ) _{y / n ·} nH ₂ O of a triclinic system having a negative charge is disposed between these layers. It forms a balanced bilayer structure, and when chlorine ions are present, the chlorine ions are fixed by ion exchange with anions in the negatively charged layer. In addition, the hydrocalumite is provided with Ca ₄ Al ₂ (NO ₂ ) ₂ · nh ₂ O.

Figure 4 shows the results of the thermal analysis of hydrotalcite, up to 100 ° C is reduced by crystal water and free moisture, and 250 ~ 450 ° C is a loss due to volatilization of NO ₂ ^- which corresponds to about 29 wt%. . Therefore, the theoretical amount to which chlorine ions can be fixed corresponds to a weight ratio of 29 wt% of NO ₂ ⁻ , and about 0.3 g per 1 g of hydrotalcite. If the total amount of chlorine ions added to concrete is limited to 0.3 kg / m 3, this is the theoretical amount that can be fixed to 1 kg of hydrotalcite, which is 0.35 of cement assuming the amount of cement in the concrete mixture is 350 kg. It is the same as adding hydrotalcite by%. Therefore, in consideration of the proper mixing ratio of hydrotalcite added to the mortar, it is possible to obtain a chlorine ion fixing effect that does not lead to reinforcing corrosion even in a very high concentration of chlorine ion environment by adding about 1 to 2 wt% of the total weight. For example, about 1 g of hydrotalcite is added to 1 kg of mortar, and about 3 g (NaCl 5 g) is added and about 6 g (NaCl 10 g) of chlorine ion is theoretically fixed. However, the amount of chlorine ion that is actually fixed cannot be the same as the theory and will be reduced by various physicochemical factors. Therefore, the proper mixing rate of hydrotalcite should be determined in consideration of the amount of chlorine ion exchange of hydrotalcite.

The test method for measuring the chlorine ion immobilization performance of hydrotalcite is summarized in [Table 1], and the concentration of chlorine ion used in the experiment was set at the same level as the theoretical exchange amount of chlorine ion of hydrotalcite. The results are shown in [Table 2].

Table 1

[Table 2]

As can be seen from Table 2, since 0.5488 g of chlorine ions are fixed to 2 g of hydrotalcite, it can be seen that it has a nearly theoretical fixation capacity of 0.27 g of chlorine ion per unit gram. Therefore, the proper mixing ratio for the cross-sectional recovery mortar is appropriate to add 1-2 wt% of the total weight in consideration of the safety factor.

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

Example 1

The mixing ratio of hydrotalcite should be considered in consideration of the chlorine ion fixation ability and the physical properties of the cross-sectional recovery mortar, and in order to select the optimal amount of hydrotalcite incorporation based on the results of the chlorine ion fixing performance. As described above, the incorporation amount of hydrotalcite in the polymer cross-sectional recovery mortar was 0, 1, 2, 3, 4, 5 wt% of total weight, and the physical properties were evaluated for general properties, chlorine ion permeation resistance, and rust preventing performance.

Table 3

In the flow test for evaluating the fluidity of the polymer cross-sectional recovery mortar, the flow of the sample dropped 15 times to a height of 1.27 cm was measured using a flow table defined in KS L 5111. Air volume and unit volume weight test are currently defined in KS L 3136 "Method for Measuring Air Volume of Hydraulic Cement Mortar", but this method is a gravimetric method, which is difficult in the field application. Therefore, in consideration of the ease of measurement and precision in the field, ASTM C 780 `` A6. MORTAR AIR CONTENT TEST METHOD ”was tested according to the pressure method test method.

The evaluation of the compression and bending strength of the hardened mortar was evaluated in accordance with KS F 2476, "Strength Test Method of Polymer Cement Mortar," and the adhesive strength was performed according to KS F 4716 "Strength Test Method of Polymer Cement Mortar". Ion permeability was tested according to the test method defined in ASTM C 1202.

The properties of the mortar and the chlorine ion permeation resistance and antirust performance of the present invention are summarized in [Table 4], and the results are shown in [Table 5].

Table 4

Table 5

As shown in [Table 5], the result of evaluation of unsteady cross-sectional recovery mortar shows similar results to that of cross-sectional recovery mortar which is not mixed up to 1 ~ 2% of hydrotalcite. It can be seen that the volume weight decreases and the air volume increases. In particular, the physical properties are rapidly deteriorating at a mixing rate of more than 2%, which is related to the closest filling of the material constituting the cross-sectional recovery mortar, and the hydrotalcite of the present invention is an ultra fine powder having an average particle diameter of 0.3 to 0.5 µm. If the proper amount is added, it improves the pore structure due to the close filling action of ultra fine particles, and in addition to the chlorine ion fixing effect of the original purpose, additional physical properties such as water tightness are improved.

However, when the amount of incorporation above the closest charge is increased due to the high specific surface area of the hydrotalcite, the unit quantity for obtaining the required workability is increased, resulting in an increase in the air volume and a decrease in the unit volume weight. That is, the density of the hardened tissue is reduced to facilitate the penetration of chlorine ions, resulting in the adverse effect of the originally intended chlorine ion immobilization.

5 to 7 are graphs showing the results of compressive strength, flexural strength, and adhesive strength at 28 days of age, and through this, it can be seen that the result of incorporation of the closest charge or more.

Therefore, it can be seen that the proper mixing ratio of hydrotalcite suitable for immobilization of chlorine ions while maintaining the physical properties of the cross-sectional recovery mortar is in the range of 1 to 2%.

Example 2

Sectional recovery mortar was formed by using 20wt% cement, 2wt% alumina cement, 11wt% high powder filler, 2.5wt% powder polymer, 0.03wt% water reducing agent, 2wt% hydrotalcite, 0.03wt% reinforcing fiber, and the rest as silica sand. Performance evaluation on chlorine ion resistance was performed.

The test was carried out according to the test method defined in ASTM C 1202. The 3.0% NaCl solution was filled in the negative electrode of the applied voltage cell, and 0.3N NaOH solution was charged in the positive electrode, followed by 0.2Ω every 30 minutes. The voltage applied to the circuit was converted into a current value, and the experimental process was continued for 6 hours to calculate the total circuit charge through the following equation.

＝ = 900 × (I0 + 2 I30 + 2 I60 + ...... + 2 I330 + 2 I360)

    Where Ｑ = amount of charge through the circuit (Coulombs),

          イ n: Current is indicated when n minutes have passed since the start of the experiment.

The chlorine ion resistance of the cross-sectional recovery mortar was examined by applying the above equation, and for comparison, two cross-sectional recovery mortars and mortars made of ordinary cement were used as the test bodies of the same method. The values of the passing charges obtained in the experiment are shown in [Table 6], and the minimum requirement is 1000 Coulombs when correlating the section recovery mortar with the characteristics of the structure to which it is applied.

Table 6

The chlorine ion permeability test is a method of electrically indicating the amount of chlorine ions moving along a passage (for example, a capillary and a pore water connecting passage, and a cracking portion) existing inside the pore structure of the test body. It is also an experiment that has a direct meaning as a verification of the blocking action on harmful elements. Test results according to the proposed method are shown in [Table 7].

Table 7

As described in [Table 7], the cross-sectional recovery mortar of the present invention can be seen that the chlorine ion permeability is very excellent, and it shows that the result of the test body of the prior art tested for comparison is significantly superior. This means that the chemical barrier by ion exchange exerts a function on the chlorine ions passing through, and it can be seen that there is an effect of inhibiting reinforcing corrosion of chlorine ions.

In addition, as a result of requesting the Korea Construction Quality Testing Institute to suppress the rebar rust, it was proved that the rebar rust inhibiting rate was about 87%, and that the anti-corrosive effect could be achieved without using a corrosion inhibitor.

Example 3

Sectional recovery mortar was formed by using 20wt% cement, 2wt% alumina cement, 11wt% high powder filler, 2.5wt% powder polymer, 0.03wt% water reducing agent, 2wt% hydrotalcite, 0.03wt% reinforcing fiber, and the rest as silica sand. In order to evaluate the rebar rust prevention performance for the hydrotalcite-incorporated cross-section recovery mortar thus prepared, as shown in [Table 8], compared with the conventional anti-corrosive paste coating of hydrotalcite-incorporating cross-sectional recovery mortar, The rust prevention performance was compared and evaluated.

Table 8

The specimens were 160 × 40 mm specimens as shown in FIG. 9 in accordance with the “Quality Standards for Various Repair Materials” in the Durability Survey, Diagnosis and Repair Guidelines for Reinforced Concrete Conditioned Buildings. Ø10㎜ reinforcement was prepared in, and the corrosion of reinforcing bar was accelerated by repeating the autoclave curing and immersion test of 3% NaCl solution for 5 hours at 180 ° C and pressure of 1 MPa after 28 days air curing as shown in FIG. It was.

Corrosion area ratio of the reinforcing bar was extracted by using the reinforcing bar from the test body and using a transparent sheet, corrosion corrosion rate of the reinforcing bar was calculated using the following equation.

Where R _c : rust prevention rate (%), C _rp : corrosion area ratio (%) of the base material portion, C _rn : corrosion area ratio (%) of the repair part.

As a result, in the case of the reinforcing corrosion area ratio, as shown in FIG. 11, the test specimen subjected to the rebar rust prevention treatment by the rust-preventing paste and coated with the anti-corrosion agent-free cross-sectional recovery mortar showed a level of 2.6% in 5 cycles of corrosion promotion. Hydrotalcite-incorporated cross section of recovery mortar showed no corrosion at 5 cycles of corrosion promotion, and hydrotalcite incorporation cross section of the present invention was compared with test specimens coated with antirust paste even at 15 cycles of corrosion promotion. Corrosion area ratios of the recovered mortar specimens were similar to 60% and 58%, respectively. (1 Cycle: Soak in 3% NaCl aqueous solution for 24 hours + Autoclave for 24 hours)

In addition, in the case of rebar rust prevention rate, as shown in Fig. 12, when antirust treatment was performed on the rebar with antirust paste, and the anticorrosive agent-free cross-sectional recovery mortar was applied, it showed 70.5% in 5 cycles of corrosion promotion. In the case of test specimens with desite mixed mixed recovery mortar, 100% was shown in 5 cycles of corrosion promotion, and in the 15 cycles of corrosion promotion, anticorrosive treatment test specimen for rebar and hydrotalcite mixed cross section recovery mortar of the present invention were constructed. The anti-corrosion rate of one specimen was similar to 38% and 37%, respectively.

Therefore, it can be seen that the present invention, which is intended to secure the anti-rust performance by using a hydrotalcite-containing mortar compared to the existing method of securing the anti-rust performance by applying anti-rust paste to reinforcing bars, exhibits excellent anti-rust performance.

Example 4

Cement 20wt%, Alumina cement 2wt%, High powder filler 11wt%, Powder polymer 2.5wt%, Water reducing agent 0.03wt%, Hydrotalcite 2wt%, Reinforcing fiber 0.03wt%, Residual recovery mortar (AC-RHD) ), And the performance evaluation of the cross-sectional recovery mortar was carried out according to the test method of the quality standard of KS F 4042 cross-sectional recovery mortar. The results are summarized in Table 9 below.

Table 9

Among the conditions under which the designed cross-sectional recovery mortar can be applied to the repair of reinforced concrete structures, the most basic is the long-term physical stability after mortar application. The quality standards for sectional recovery mortar are specified in KS F 4042, and the results of the tests exceeded the standards in all the items presented. Also, the test results commissioned by the accredited academic institutions showed similar results. The general physical properties of the cross-sectional recovery mortars examined were: i) sufficient pot life; ii) no rapid reactions such as abnormal condensation at the beginning; iii) long-term stable cracking resistance due to small shrinkage; iv) excellent adhesion strength over the initial and long term. It is necessary to satisfy the basic items such as HDA. Especially, the application of single-sided recovery mortar by fully automated mechanical construction is very sensitive to the physicochemical change over time inside the hose. Absolutely necessary. It can be seen that the applied cross-sectional recovery mortar of the present invention satisfies all the criteria set forth above.

Referring to the characteristics of the present invention as described above in detail as follows.

1) Ion exchange function

The nitrite base hydrotalcite (or hydrocalumite) added to the cross-sectional recovery mortar composition of the present invention has a double-layered crystal structure, and the chemical formula is Mg ₆ Al ₂ (NO ₂ ) ₂ · nh ₂ O ( Hydrocalcite, Ca ₄ Al ₂ (NO ₂ ) ₂ nH ₂ O). This structure is _{[(Ca) Mg, Al x} ] (OH) 2] x + and [A] _x ^- consists of a double layer structure in which [A] _x ^- NO ₂ in place of the ^- is located. Infiltrated chlorine ion undergoes ion exchange with NO ₂ ^- as in [Scheme 1] below and NO ₂ ^- is released into solution. This concept is different from the functions possessed by the existing cross-sectional recovery mortar, which means that the chlorine ion penetrated directly is stabilized by being fixed in the crystal structure.

[Scheme 1]

In addition, the chlorine ion immobilized in the hydrotalcite (or hydrocalcite) structure is very stable and does not re-dissolve due to changes in physicochemical factors such as temperature and neutralization. It is the first barrier function among the reinforcement corrosion prevention repair methods.

2) Passive film formation function

The chlorine ion penetrating from the outside of the concrete is fixed and NO ₂ ^- released into the solution reaches the reinforcing bar along the pore solution and is released from the hydrotalcite (or hydrocalumite) added to impart ion exchange. NO ₂ ⁻ forms a passive film. The passivation film formed by the NO ₂ ⁻ emitted as described above corresponds to the secondary barrier in the reinforcing corrosion inhibiting repair method having the multi-stage described in the present invention.

As described above, the present invention has a feature of simultaneously exchanging chlorine ion exchange function and passivation film formation function only by adding hydrotalcite (or hydrocalumite).

In the case of repairing the deteriorated portion of the reinforced concrete structure using the mortar composition for cross-sectional recovery of the present invention made as described above, and first to remove the deteriorated portion and to remove the foreign matter on the concrete structure, and It consists of a cross-sectional restoration finishing step in which the mortar for cross-sectional recovery is mixed with mixed water in the ground-treated concrete structure and continuously sprayed or polished.

The background treatment step is to remove the lifting parts and corrosion such as cracks in the surface concrete, coating material dropping and rust prevention (rust generation) of the surface concrete caused by aging such as alkali aggregate reaction, east sea, salt sea or neutralization (carbonation). , Completely remove the deteriorated concrete using a power tool such as a hand tool or a power hammer, and completely remove foreign substances using a high pressure water cleaner (100 to 150 kg / m 2).

The cross-sectional recovery finishing step is to spray the repair site of the reinforced concrete structure from which the deterioration area is removed, and cement, alumina cement, high powder filler, powder polymer, water reducing agent, reinforcing fiber, hydrotalcite, silica, admixture and mixed water. A certain ratio is added to form a cross-sectional recovery mortar, and the cross-section is repaired to a thickness of 10 to 30 mm by spraying or depilation.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by those skilled in the art without departing from the gist of the present invention as claimed in the claims. Of course, such changes will fall within the scope of the claims.

As such, the present invention chemically fixes chlorine ions by cross-sectional restoration of cross-sectional recovery mortar containing nitrite-based hydrotalcite or nitrite-based hydrocalumite in reinforced concrete structures where reinforcing corrosion occurs due to various deterioration factors. By forming dense microstructures to prevent reinforcement corrosion, the material released by ion exchange forms a passive film on the surface of the rebar, which can block or delay the penetration of harmful substances in multiple stages. Can be extended.

In addition, the present invention can be given a composite anti-rust performance by the cross-sectional recovery mortar without a separate anti-rust operation, and can improve the anti-rust performance of the repair site even without the separate rebar anti-rust treatment process, according to the process simplification There are economic effects such as improvement of construction efficiency, air shortening, and labor cost reduction.

In addition, the present invention, compared with the case of using a rust inhibitor, the conventional technique using a rust inhibitor may be limited by the amount of chlorine ions penetrating, the present invention is a composite present as the main composition of the cross-sectional recovery mortar Since chlorine ions are fixed inside the powder, the ionic fixation by the composite powder is determined by the molar ratio of the ion sites substituted in the crystal lattice, so that the amount of ion exchange is determined. There is.

Figure 1 is a hydrotalcite scanning microscope observation photographic example of Example 1 (SEM)

2 is a hydrotalcite X-ray diffractogram (XRD) of Example 1

Figure 3 is an exemplary view showing the structure of the present invention hydrotalcite

Figure 4 is a thermal analysis (DTA) of hydrotalcite in accordance with the present invention

5 is an exemplary view showing the results of the 28-day compressive strength measurement

Figure 6 is an exemplary view showing the results of the 28-day bending strength measurement

7 is an exemplary view showing a measurement result of the bond strength of 28 days of age

8 is an exemplary view showing a result of measurement of chloride ion penetration resistance

9 is an exemplary view showing the configuration of a test specimen for rebar anti-rust performance test

10 is an exemplary view showing a reinforcing bar corrosion acceleration cycle for the test body of FIG.

11 is an exemplary view showing the corrosion degree of reinforcing bars according to the corrosion promotion cycle of FIG.

12 is an exemplary view showing the rebar rust prevention performance

Claims (3)

20-40 wt% of cement, 1 to 5 wt% of alumina cement, 5 ~ 20wt% of slag-based high-molecular filler, mainly composed of gypsum and slag, 1 to 5wt% of one powder polymer selected from the group consisting of polyvinylalcohol, vinyl acetate, vinyl versatate polymer, Naphthalene sulfonic acid water reducing agent 0.05-0.2 wt%, 0.01 ~ 0.1 wt% of reinforcing fiber, Nitrite base hydrotalcite or nitrite base hydrochalumite 1-2 wt%, Mortar composition for the cross-sectional recovery comprising the remaining silica sand. delete A background treatment step of removing the deteriorated portion and removing foreign matter on the concrete structure; 20-40 wt% of cement, 1-5wt% of alumina cement, 5-20wt% of slag-based high-molecular filler including gypsum and slag, polyvinylalcohol, vinyl acetate, vinyl buster on the ground-treated concrete structure 1 to 5 wt% of one powder polymer selected from the group consisting of tate polymer (Vinylacetate and vinyl versatate polymer), 0.05 to 0.2 wt% of naphthalene sulfonic acid water reducing agent, 0.01 to 0.1 wt% of reinforcing fiber, nitrite base hydrotalcite or nitrite base Reinforced concrete using cross-sectional recovery mortar composition, characterized in that the cross-sectional recovery mortar composition consisting of 1 to 2wt% of hydrocalcite and the remainder of silica sand mixed with mixed water and continuously sprayed or polished. Reinforcing corrosion protection method of structure.