WO2005082813A1

WO2005082813A1 - Silicious concrete modifier

Info

Publication number: WO2005082813A1
Application number: PCT/JP2005/003122
Authority: WO
Inventors: Toyoharu Nawa; Yoshiro Yamakita; Miki Suzuki; Hiroshi Naganuma
Original assignee: B-Brain Corporation; Hokkaido Technology Licensing Office Co., Ltd.; Minamigumi Co., Ltd.; Urakawa Namaconcrete Corporation
Priority date: 2004-02-26
Filing date: 2005-02-25
Publication date: 2005-09-09
Also published as: JP4484872B2; JPWO2005082813A1

Abstract

A concrete modifier, characterized in that it comprises an aqueous lithium silicate solution and an alkali metal ion source. The concrete modifier allows the prevention or inhibition of the deterioration by the freezing and thawing action, the salt attack or a combination thereof by the use of a relatively simple process wherein it is only applied on the surface of a newly constructed or existing concrete structure, and it permeates into a deep inside part of a concrete structure without changing the surface design thereof (with the retention of the state of the surface immediately after placing) and exhibits high durability.

Description

Specification

Silicic concrete modifier

Technical field

[0001] The present invention relates to a silicate-based concrete reforming system that prevents or suppresses deterioration due to freezing and thawing or salt damage of concrete, and prevents or suppresses deterioration due to a combination thereof, thereby contributing to a reduction in life cycle cost. Agent (surface modifier). Background art

[0002] Although concrete has originally been said to have extremely high durability and a service life of 50 to 100 years, it has recently been found that concrete deteriorates faster than expected. In particular, concrete degradation due to freezing and thawing, salt damage, etc. may cause deterioration of concrete and complex deterioration, which may lead to the emergence of structures that do not have the expected useful life or the occurrence of secondary disasters due to peeling of concrete fragments from the structures. Investigation of causes of deterioration factors and various countermeasures have been taken. Specifically, the composition of cement that constitutes new concrete is changed and the unit water volume is reduced, aggregate components are specified.For existing concrete, a method of coating the deteriorated surface with polymer cement, and mortar containing a siliceous waterproofing agent is used. There is a proposal of a coating method using an organic resin, cement, or water glass based material.

Patent document 1: JP-A-2000-44317

Disclosure of the invention

Problems to be solved by the invention

[0003] However, while measures such as changing the composition of cement and specifying the components of aggregates are effective in preventing the deterioration of newly installed concrete, they cannot cope with existing structures that are undergoing deterioration. In addition, there are problems such as shortage of excellent aggregates and increase in cost due to increase in the amount of cement and admixture used. Regarding the repair method, when organic materials are used, there is a problem of environmental pollution due to organic compounds, and in the case of the coating method, the rebuilding is required due to deterioration of the material itself, and the design of the concrete surface is changed due to the construction. In addition, water-glass based materials harden at the surface layer of the cracks (1-2 mm from the surface layer) and cannot penetrate into concrete, so the effect is limited.For cement-based materials, use ultra-fine cement. Even 0.2mm Only the above cracks can be filled, the surface strength of concrete is improved, and the aqueous solution of lithium silicate, which is known as an alkali imparting agent, has a high viscosity and is difficult to penetrate.

The conventional method has a number of problems, such as the fact that it is only about 1-2 mm, and it is inferior in durability and needs to be rebuilt in several years.

[0004] Therefore, the present invention prevents or suppresses deterioration due to freezing and thawing or salt damage, or a composite deterioration due to them by a relatively simple construction method of simply applying the composition to the surface of a new or existing concrete structure, and also provides a surface design. It is an object of the present invention to provide a concrete modifier which penetrates deep into the concrete (maintains the condition of the concrete surface immediately after casting) without changing the concrete, and has high durability and high durability.

Means for solving the problem

[0005] The present invention (1) is a concrete modifier characterized by blending an alkali metal ion source with a lithium silicate aqueous solution.

[0006] The present invention (2) is the modifier of the above-mentioned invention (1), wherein the alkali metal ion source is a water-soluble alkali metal-containing substance.

[0007] The present invention (3) is the modifier according to the above (1) or (2), which is an alkali metal ion force sodium ion and potassium ion from an alkali metal ion source.

In the present invention (4), the molar ratio of the added alkali metal ion source to SiO (alkali gold

2

(1) one of (1)-(3), wherein the modifier is 0.08-1.8 (preferably 0.12-1.2). .

In the present invention (5), the molar specific force of all alkali metal ions including lithium ions derived from an aqueous solution of lithium silicate to SiO is 0.4.2-1. 1 (preferably, 0.6.1.4. )

2

The modifier according to any one of the inventions (1) to (4).

[0010] The present invention (6) relates to the specific power molar ratio of potassium ion to sodium ion of 0.02 to 2

.7 (preferably 0.04-1.8) according to the invention (3) or (4).

[0011] In the present invention (7), when added to a saturated aqueous calcium hydroxide solution according to the measuring method 1 in the specification, a two-phase structure of a cloudy gel phase and a transparent solution phase is formed, more preferably The turbid gel is one of the modifiers according to the invention (1)-(6), which is separated into a force layer (a floating layer and a sedimentation layer). [0012] The present invention (8) is the modifier according to any one of the aforementioned inventions (1)-(7), which is a concrete surface application type. The “concrete surface application type” includes not only a mode of applying to a concrete surface but also a mode of injecting a concrete surface force (for example, from a crack).

[0013] The present invention (9) is a stock solution of the modifier according to any one of the inventions (1) and (8), which is obtained by mixing an alkali metal ion source with a lithium silicate aqueous solution. , SiO and Li 2 O (equivalent oxide equivalent) in the lithium silicate aqueous solution are the total amount of them.

twenty two

Is 15 30% by weight based on the total weight of the aqueous solution, and their molar ratio (SiO 2

2

/ Li O) 3-8.

2

[0014] The present invention (10) provides the above-mentioned invention (1)-(6), wherein the modifying agent obtained by diluting the undiluted solution of the invention (9) with water is: This is a method for preventing or suppressing deterioration of concrete, including a step of applying (for example, applying) one or more times to a concrete surface. The dilution ratio of the stock solution with water varies depending on the surface condition of the concrete, and is, for example, 115 times.

[0015] The present invention (11) is to apply an aqueous solution of calcium hydroxide to the concrete surface before or during the one or more times of applying the modifying agent (for example, applying the modifying agent) (for example, The method according to the invention (10), further comprising the step of:

[0016] The present invention (12) is a concrete in which deterioration is prevented or suppressed by the method of the invention (10) or (11).

The invention's effect

[0017] First, the concrete modifier according to the present invention imparts a property of reducing concrete to moisture permeability and salt permeability. Specifically, the alkali metal-containing lithium silicate in the agent reacts with water present on the interface of the aggregate or in the internal voids or calcium hydroxide, which is a pore solution component of concrete, to form a gel. . As a result of the formation of the gel, the pores are densified. As a result, the intrusion of water, which is a factor promoting various kinds of deterioration, is hindered. At the same time, diffusion on the surface of the gel is suppressed by making the charge on the gel surface negative and electrically repelling. Furthermore, by taking in pore water inside the concrete that causes freeze-thaw during gelation, voids that are not filled with water increase, and a space is created to release pressure when water and gel freeze-expand. Furthermore, inside the crack, By increasing the concrete surface tensile strength by 1.5 to 2 times, the expansion and progression of cracks, which have a significant effect on concrete deterioration, are prevented or suppressed.

[0018] Second, the concrete modifier according to the present invention has a property that, when compared with a conventional alkali imparting agent, penetrates deeper into the concrete (for example, to a depth of about 40 mm). Then! It is understood that the reason for this is that the reaction rate is much slower than that of conventional ones (such as a water glass-based modifier) (it can penetrate deep into the concrete). In various conventional research reports, there are many reports that lithium compounds are effective in preventing various types of concrete deterioration. However, since this component can penetrate only about 1-2 mm from the surface, it could only be used as a concrete admixture / surface coating material. The present invention is epoch-making in that it provides a penetrating surface coating agent based on this second property of deep penetration.

Note that, for easy understanding, the mechanism of the present invention will be described with reference to FIG. FIG. 1 (a) is a schematic diagram of a concrete section, in which a mortar matrix 1 containing fine aggregate, coarse aggregate 2, pores and cracks 3 are shown. Figure 1 (b)-(d) is an enlarged pictorial diagram of the square box in Fig. 1 (a). In FIG. 1 (b), 3 also shows the fragile tissue portion at the aggregate interface, 4 is fine aggregate, and 5 is cement paste. Inside 3 is a pore solution containing ions such as calcium. When the modifier according to the present invention is applied to the concrete surface, it penetrates into the interior through cracks, voids, and aggregate interfaces. FIG. 1 (c) shows a state in which the present modifier 6 has penetrated into voids and the like. The modifier that has penetrated into the voids reacts with the hydroxide and water in the pore solution to form a gel. FIG. 1 (d) shows the appearance of gel 7 produced from the present modifier. Fig. 1 (e) shows the actual state of the square box in Fig. 1 (d).

[0020] Summarizing the above, when the modifier according to the present invention is applied to the concrete surface, the chemical power containing the alkali metal-containing lithium silicate as a main component will penetrate deep into the concrete through the interface between the crack and the aggregate. In addition, it penetrates into fine voids in the rough portion of the composition in contact with the interface. In addition, when gelling in response to water and calcium hydroxide present on the interface or in the void, the reaction rate is much slower than in the past, so that it can penetrate deep into the concrete. As a result, the present invention provides a table of new and existing concrete structures. With a relatively simple construction method that only applies to the surface, it is possible to prevent or suppress deterioration due to freezing and thawing and salt damage, and composite deterioration due to them, without changing the surface design.

Further, since the modifier according to the present invention is a completely inorganic material containing substantially no organic components, it also has the effect of having durability against ultraviolet deterioration.

[0022] Further, the modifier according to the present invention has an effect that the conventional one is effective and can be applied to a structure in which deterioration is progressing. In particular, when applying the present modifier to degraded concrete, an aqueous solution of calcium hydroxide is applied to the concrete in advance, or the calcium hydroxide is added between the steps of applying the modifier. It is more effective to apply an aqueous solution.

BEST MODE FOR CARRYING OUT THE INVENTION

[0023] The concrete modifier according to the present invention is characterized in that a lithium silicate aqueous solution is mixed with an alkali metal ion source. Hereinafter, the components of the present invention will be described. In this specification, “Li O, & 0” and “0” are expressed in terms of equivalent oxidation products.

2 2 2

“Lithium silicate aqueous solution” refers to a type of colloidal silica in which the alkali portion is lithium. Here, “aqueous solution” does not mean that these raw material components are completely dissolved, but refers to a state in which at least a part of the raw material is dissolved in some form. Therefore, even if one of the raw materials (especially SiO 2) exists in colloidal form,

2

Even if a part is dissolved and a part is colloidal, all of these states are included. In addition, these raw materials may exist in any form in the liquid!

[0025] The aqueous solution of lithium silicate according to the present invention can be produced by boiling silica in an aqueous solution of sodium hydroxide or potassium hydroxide, and replacing Na and K in the obtained colloidal silica with Li. Examples of commercially available products include, for example, Nitrogen Lithium Silicate 45 (manufactured by Nissan Chemical Industries, Ltd.) SiO 20.0-21.0 parts by weight, LiO 2.1-2.4 parts by weight per 100 parts by weight of aqueous solution.

twenty two

Parts, SiO / Li O molar ratio 4.5}, lithium silicate 75 {aqueous solution 100 parts Si

twenty two

O 20.0—21.0 parts by weight, Li O 1.2—1.4 parts by weight, SiO / Li O molar ratio 7.5}

2 2 2, Lithium silicate 35 (100 parts by weight of aqueous solution, SiO 20.0—21.0 parts by weight, Li O

twenty two

2. 6-3. 3 parts by weight, SiO / Li O molar ratio 3.5} can be used. The “alkali metal ion source” according to the present invention is not particularly limited as long as the alkali metal ion is present in the aqueous solution of lithium silicate when added to water. Substances that dissociate into alkali metal ions, for example, water-soluble alkali metal-containing substances such as alkali metal hydroxides, alkali metal oxides or alkali metal salts (for example, alkali metal carbonates), alkali metals themselves and alkali metal ions Aqueous solutions can be mentioned. The “alkali metal ion” is not particularly limited, and may be any of lithium, sodium, potassium, rubidium, and cesium. Furthermore, the alkali metal ion source to be added to the aqueous solution of lithium silicate is not limited to one type but may be a plurality of types (for example, a combination of sodium hydroxide and sodium carbonate) in which the same alkali metal ion is present in the aqueous solution of lithium silicate. Alternatively, a plurality of different alkali metal ions may be present in the aqueous lithium silicate solution (for example, a combination of sodium hydroxide and potassium hydroxide).

[0027] Suitable alkali metal ions are those obtained by combining sodium ions and potassium ions. In particular, the specific molar ratio of potassium ion to sodium ion is preferably 0.02 to 2.7, and more preferably 0.04 to 1.8. In this case, a suitable alkali metal ion source is a combination of sodium hydroxide and potassium hydroxide. With respect to these combinations, the preferred compounding ratio of sodium hydroxide and potassium hydroxide is 1.3-2.5 (by weight ratio). More preferably, it is 1.7-2.2.2).

[0028] Further, the added amount of alkali metal ion source in the alkali metal ion source is preferably 0.08-1.8 with respect to SiO 2 in terms of molar ratio (in terms of alkali metal ion), and more preferably. It is 0.12-1.2.

2

Furthermore, the modifier according to the present invention forms a two-phase structure of a cloudy gel phase and a transparent solution phase when added to a saturated aqueous sodium hydroxide solution according to the following measurement method 1. It is preferred that there be.

Measurement method 1: 2.7 mL of a saturated aqueous calcium hydroxide solution was put into a cuvette for spectrophotometer (made of polystyrene; inner size = 1 × 1 × 4.5 cm, capacity 4.5 mL), and modifier 0 Add 3 mL slowly and drop. After mixing, seal the container with parafilm and leave it as it is. Immediately after dripping, observe until the 7th day. Next, a method for producing a stock solution of the concrete modifier according to the present invention will be described. The stock solution of the modifier according to the present invention is produced by mixing an alkali metal ion source with an aqueous solution of lithium silicate. It should be noted that, if the order is changed and an alkali metal ion source is added to water and then an aqueous solution of lithium silicate is added, gelling may occur.

Here, a preferable aqueous solution of lithium silicate is SiO and Li 2 O 3 based on the total weight of the aqueous solution.

These components are combined in a molar ratio (SiO 2 / Li O) 3-8 (more preferably 4

It is obtained by adding kanji to water at a ratio of 2 2 5).

[0033] When an alkali metal hydroxide is used as the alkali metal ion source, since an exothermic reaction occurs, the alkali metal hydroxide is added little by little to the aqueous lithium silicate solution.

[0034] An alkali metal ion source is added to the aqueous solution of lithium silicate, and the mixture is stirred well, and then a necessary amount of water is removed to obtain a stock solution of the modifier according to the present invention. The addition of water is performed for the purpose of lowering the viscosity. The water used is preferably pure water or ion-exchanged water.

It should be noted that, when manufacturing, it is preferable that the aqueous solution of lithium silicate as a raw material is stored at +5 to 125 ° C., and a material that has been gelled in a subzero environment is not used as much as possible. Further, it is preferable to perform temperature control of +5 to 25 ° C. even in the production.

[0036] Further, in the production, basically, the mixing method and the order of supplying the materials are not limited. Examples of specific preparation means are shown below.

(1) A solution prepared beforehand by dissolving sodium hydroxide, potassium hydroxide or lithium silicate in part or all of ion-exchanged water

(2) Hydroxide (granular or aqueous) was added in the order of (i) sodium and potassium, (ii) potassium and sodium, and (iii) sodium and potassium were injected at the same time. Any solution

(3) The amount of the hydroxide (particulate or aqueous solution) to be charged is either (i) the solution that is added little by little, or (ii) the solution that is added all at once. (4) When adding ion-exchanged water, (i) first adjust the concentration of each raw material to be a stock solution, and then dilute the stock solution to a predetermined dilution ratio (for example, 2 times); A solution prepared from the beginning to a concentration at a specified dilution ratio (for example, 2 times)

[0037] The stock solution thus obtained preferably contains water in an amount of 65 to 85% by weight (more preferably 70 to 80% by weight) based on the total weight of the stock solution. The preferred viscosity of the stock solution (measured with a Cannon-Fenske viscometer, 20 ° C.) is 1.0 to 15 mPa's (more preferably 1.5 to 10 lOmPa's).

[0038] Further, the pH of the stock solution thus obtained is preferably in the range of 12.0 to 13.5, and more preferably in the range of 12.4 to 12.9. Further, it is preferable that the pH of the diluent is also generally within the above range.

Next, a method for using the modifier according to the present invention (a method for preventing or suppressing deterioration of concrete) will be described. First, the stock solution of the modifier according to the present invention is stirred as necessary (step 1), where necessary (hereinafter, a two-fold dilution will be described as an example). Then, before applying this modifier to the concrete, water is sprayed to keep the concrete on the application surface wet (step 2). After that, check the wet condition of the concrete and apply the modifier diluted twice with water using a low-pressure sprayer, brush, roller, etc. (select according to the construction site conditions) (Step 3). Here, the amount of the modifier per concrete lm ² is, for example, 200cc / m ^{2 (2} times those diluted), the undiluted base is lOOccZm ^2. Next, water is sprayed at a low pressure after application and before drying (step 4). At this time, if drying is quick with wet curing (basic 90 minutes), watering should be performed (Step 5). Step 2—Step 4 is repeated (Step 6). Check if the modifying agent remains on the surface (Step 7). Watering is performed at a low pressure as the final step, and if residual is confirmed in step 6, it is washed by brushing or the like so that it does not remain on the concrete surface (step 8). Then, air dry (Step 9). It can be used immediately after the completion of Process 8 (if the floor is on white pavement, heavy vehicles can be moved or heavy objects can be moved). At the time of construction, it is preferable that the outside air temperature is + 5 ° C or higher, and when it is lower than + 5 ° C, it is preferable to control the temperature by heating and curing. If the coating is coated with a coating material that inhibits permeation, such as paint or polymer cement, apply this modifier after removing the coating material. [0040] The type of concrete in which the modifier according to the present invention can be used is not particularly limited, and is effective for all types of concrete in which the type and composition of cement are changed. For example, examples of the cement include ordinary Portland cement, early-strength Portland cement, belite cement, eco cement, blast furnace cement, fly ash cement, and low heat cement. Concrete includes, for example, ordinary concrete, high-strength concrete, low-heating concrete, underwater non-separable concrete, underwater concrete, factory concrete, marine concrete, shotcrete, fiber reinforced concrete, pre-knocked concrete, Examples include fluidized concrete, light (aggregate) concrete, steel-concrete composite structures, prestressed concrete, and recycled aggregate concrete. Incidentally, for example, admixtures such as fly ash, blast furnace slag fine powder, and silica fume may be mixed.

[0041] Here, with respect to the degraded structure due to the leaching of calcium and the concrete having a low calcium content and using blast furnace slag cement, prior to the modifying agent application step or a plurality of modifying agent application steps, It is preferable to apply calcium hydroxide to the concrete in the middle of the process to supply calcium to the concrete. For example, there may be mentioned an embodiment in which water is first applied to concrete, then a modifier is applied, and then an aqueous solution of calcium hydroxide is applied. Further, there may be mentioned an embodiment in which the present modifier is mixed with another material (for example, cement) and the mixture is applied to the concrete surface. Further, for example, when a crack is generated, the present modifier may be applied to the concrete surface and injected into the concrete through a crack that does not readily occur.

Example

Hereinafter, the present invention will be specifically described with reference to examples. The present invention is not limited by the examples.

[0043] Production Example 1 (LN422)

Lithium silicate 45 (manufactured by Nissan Chemical Industries, Ltd.

2

20.0 21.0 parts by weight, Li O 2.1-2.4 parts by weight, SiO / Li O molar ratio 4.5) 85.70 g

2 2 2

Was measured in a beaker, and sodium hydroxide (manufactured by Kanto Chemical Co., Ltd., purity: 97%) was mixed little by little with a glass rod. After all the sodium hydroxide is completely dissolved, potassium hydroxide (purity 8 (6%) 1. 96 g was added little by little, and 8.22 g of ion-exchanged water was gently added to the place where it was completely dissolved, and the mixture was stirred well with a glass rod to obtain a stock solution of the concrete modifier according to this production example. (Viscosity: 7.32 mPa-s) The composition of each component is shown in Table 1 (where the values of lithium oxide, sodium oxide and potassium oxide are converted to equivalent oxides. Production Example 2) To 7).

[table 1]

(Production example 20LN723)

Lithium silicate 75 (manufactured by Nissan Chemical Industries, Ltd.

0.0-21.0 parts by weight, Li〇 1.2-1.4 parts by weight, SiO / Li O molar ratio

7.5) 85. 56g is weighed into a beaker, and sodium hydroxide (Kanto Chemical Co., Ltd., purity: 97%) 4. While mixing well with 12g with a glass rod, the input amount is dissolved little by little, added. After the sodium hydroxide was completely dissolved, 3.91 g of potassium hydroxide (manufactured by Kanto Chemical Co., Ltd., purity: 86%) was added little by little, and 6.41 g of ion-exchanged water was gently added to the place where it was completely dissolved. Then, the mixture was thoroughly stirred with a glass rod to obtain a stock solution of the concrete modifier according to this production example. Table 2 shows the composition of each component.

[Table 2]

Replacement form (Rule 26) Production Example 3 (LN312)

Lithium silicate 35 (Nissan Chemical Industries, Ltd.

20.0 to 21.0 parts by weight, Li 2.6 to 3.3 parts by weight, SiO / Li monolate ratio 3.5) 90.89 g is weighed into a beaker, and sodium hydroxide (Kanto Chemical Co., Ltd.) 0.83 g was mixed well with a glass rod. After the sodium hydroxide has completely dissolved, add 1.96 g of potassium hydroxide (manufactured by Kanto Chemical Co., Ltd., purity: 86%) little by little, and gently add 6.32 g of ion-exchanged water to the place where it is completely dissolved.

Replacement form (Rule 26) Then, the mixture was thoroughly stirred with a glass rod to obtain a stock solution of the concrete modifier according to the present production example. Table 3 shows the composition of each component.

[Table 3]

(Production example 40LN721)

Lithium silicate 75 (manufactured by Nissan Chemical Industries, Ltd., SiO 20.0-21.0 parts by weight, Li O 1.2-1.4 parts by weight, SiO 2 / Li O molar ratio 7.5 per 100 parts by weight of aqueous solution) 88.84 g was weighed into a beaker, and sodium hydroxide (Kanto Chemical Co., Ltd., purity: 97%) was added.4.12 g was mixed well with a glass rod. . After the sodium hydroxide was completely dissolved, 0.39 g of potassium hydroxide (Kanto Chemical Co., Ltd., purity: 86%) was added little by little, and 6.65 g of ion-exchanged water was gently added to the place where it was completely dissolved. In addition, the mixture was stirred well with a glass rod to obtain a stock solution of the concrete modifier according to this production example. Table 4 shows the composition of each component.

[Table 4]

Replacement form (Rule 26) (Example 5 N411)

Lithium silicate 45 (manufactured by Nissan Chemical Industries, Ltd.

20.0 to 21.0 parts by weight, Li〇 2.1-2.4 parts by weight, SiO / Li〇 molar ratio 4.5) 90.14 g is weighed into a beaker, and sodium hydroxide (manufactured by Kanto Chemical Co., Ltd.) (Purity: 97%) 0.82 g was mixed with a glass rod little by little, and the added amount was completely dissolved and added sequentially. After the entire amount of sodium hydroxide was completely dissolved, 0.39 g of potassium hydroxide (manufactured by Kanto Corporation, purity: 86%) was added little by little, and 8.65 g of ion-exchanged water was added to the place where it was completely dissolved. The mixture was added gently and stirred well with a glass rod to obtain a stock solution of the concrete modifier according to this production example. Table 5 shows the composition of each component.

Replacement form (Rule 26) [Table 5]

Production example 6 (LN433)

Lithium silicate 45 (manufactured by Nissan Chemical Industries, Ltd., SiO 20.0-21.0 parts by weight, Li O 2.1-2.4 parts by weight, SiO / Li O molar ratio 4.5 with respect to 100 parts by weight of aqueous solution) 80.15g is weighed into a beaker and sodium hydroxide (manufactured by Kanto Chemical Co., Ltd., purity: 97%) 8. While mixing well with 25g with a glass rod, the input amount is dissolved little by little and added. After sodium hydroxide was completely dissolved, 3.91 g of potassium hydroxide (manufactured by Kanto Chemical Co., Ltd., purity: 86%) was added little by little, and 7.69 g of ion-exchanged water was gently added to the place where it was completely dissolved. In addition, the mixture was stirred well with a glass rod to obtain a stock solution of the concrete modifier according to this production example. Table 6 shows the composition of each component.

[Table 6]

Production Example 7 (LN733)

Lithium silicate 75 (manufactured by Nissan Chemical Industries, Ltd., SiO 20.0-21.0 parts by weight, Li O 1.2-1.4 parts by weight, SiO 2 / Li O molar ratio 7. 5) Weigh 81.72g into a beaker, mix sodium hydroxide (manufactured by Kanto Idani Kagaku Co., Ltd., purity 97%). Carapara was added sequentially. After sodium hydroxide is completely dissolved, potassium hydroxide (Kanto Chemical Co., Ltd., purity 8

Replacement form (Rule 26) 3.91 g was added little by little, 6-11.2 g of ion-exchanged water was gently added to the place where it was completely dissolved, and the mixture was stirred well with a glass rod to obtain a stock solution of the concrete modifier according to this production example. . Table 7 shows the composition of each component.

[Table 7]

Replacement form (Rule 26) Ingredients Chemical Formula Weight%

Water H ₂ 0 72.33

Lithium oxide Li ₂ 0 1.14

Sodium oxide Na ₂ 0 6.40

Silicon dioxide SiO _z 17.21

Potassium oxide κ ₂ ο 2.92 Here, Table 8 shows the molar ratio of each component in each of the modifier stock solutions according to Production Examples 1 to 7. “Two-layer separation” in the table means whether the cloudy gel is separated into two layers (floating layer and sedimentary layer).

[Table 8] Molar ratio of each modifier sample used in Examples (in terms of alkali metal ions)

Test Example 1 (SEM immersion. Confirmation test)

The mortar specimen coated with the modifier was cut out in the direction perpendicular to the casting surface, and observed by SEM at each depth from the casting surface. The product obtained by mixing the modifier with a saturated calcium hydroxide aqueous solution simulating a pore solution was also observed by SEM.

OPC mortar with an ice cement ratio of 60% fine aggregate / mortar volume ratio of 55% was cast into a mold with a diameter of 5 cm and a height of 10 cm. The mold was removed after 24 hours, and then cured in water. Four days after casting, it was molded to a height of 5 cm.

Modifier obtained by diluting the stock solution obtained in Production 1 two-fold with water

The above modifier was placed on the casting surface of the wet specimen 1.07

Replacement form (Rule 26) L / m ^{2 was} applied and water was sprayed 90 minutes later. Thereafter, the above-mentioned modifier was applied at 0.31 L / m ^2, and water was sprayed 90 minutes later. The body was kept wet for 7 days, and then air-cured. 68 days after application, the product was cut out in a direction perpendicular to the casting surface with a thickness of 5 nm and immersed in acetone for 24 hours. The observation surface was polished smoothly, carbon deposited, and subjected to SEM. For comparison, the other was left untreated and aged for 68 days.

Replacement form (Rule 26) <Result>

The observed SEM images are shown in Fig. 2 (a) to (g). Figures 2 (a) to 2 (d) show the specimens of the mortar coated with the modifier {depth from the casting surface (a) lmm, (b) 20mm, (c) 30mm, (d) 40mm}. Figs. 2 (e) and (f) are SEM images of the uncoated mortar specimen {depth of the casting surface force (e) 5mm, (i) 20mm}. ) Is an SEM image of the product obtained from the modifier and saturated Ca (OH) solution. As can be seen from these electrophotographs, a rod-like substance with a thickness of about 0.3 micron was formed inside the specimen coated with the modifier {Fig. 2 (a) to (d)}. The existence was confirmed to a depth of 40 mm. Such a product was not confirmed in the uncoated specimen {Fig. 2 (e)-(f)}. This product is similar in shape to the reaction product obtained by mixing the test solution shown in Fig. 2 (g), and it is presumed that a similar product was formed.Test Example 2 (XRF Motoyasu analysis)

As shown in the SEM image of Fig. 2 (g), the gel obtained by dropping the modifier into a saturated calcium hydroxide aqueous solution (hereinafter referred to as `` LN gel J '') was analyzed by a fluorescent dilute analyzer (XRF). Elemental analysis was performed using a tube voltage of 30 kV and a tube current of 0.813 mA.

Modifier obtained by diluting the stock solution obtained in Production Example 1 twice with water

Measurement sample>

The gel produced by mixing the filtered saturated calcium hydroxide aqueous solution and the modifier at a volume ratio of 9: 1 was first separated from the liquid phase by a centrifuge. Then, the sample was washed with ion-exchanged water and force dried to remove unreacted calcium ions.

Fig. 3 shows the measured spectrum, Table 9 shows the analytical results converted to oxides, and Table 10 shows the values of Ca / Si and Ca / Al of the main components of the hardened cement.

Replacement form (Rule 26) [Table 9]

Replacement form (Rule 26) [Table 10]

[0053] As is clear from Table 10, the molar ratios of Ca / Si and Ca / AI are 0.788 and 54.6, respectively, and are clear even when compared with the values of the known components generated in the hardened cement. Have different compositions. Based on these results, the rod-like substance shown in Figs. 2 (a) to 2 (d) was formed by the reforming agent that penetrated inside the specimen reacting with Ca ions in the pore solution. It is considered. Since Ca <Si, the LN gel is presumed to be negatively charged.

Test Example 3 (Test for confirming immersion by alkali component analysis)

A powder sample obtained by polishing the same specimen as in Test Example 1 from the coated surface for every lmm thickness was mixed and filtered with 2 md / L hydrochloric acid, and the filtrate was analyzed by ion chromatography.

K Modifier>

Fig. 4 shows the content of each ion species per lg of calcium. Mg reached almost the same value, whereas values of Li, Na and K decreased as the content became larger and closer to the coated surface. Since Li, Na and K are components contained in the modifier, it is presumed that the modifier gradually penetrates into the specimen. Since Mg is a component derived from cement and fine aggregate, it is considered that the values are almost uniform.

Test example 4 {诱 Water test (1)}

Test Overview>

Water permeability, in accordance with the test method of JIS A 1404 building cement waterproofing agents, drying the mortar (M60) specimen having a diameter of 10cm thickness lcm until mass no longer changes, the 10 kgf / cm ²

Replacement form (Rule 26) The water permeability was measured up to 20 hours after the application of water pressure, and the water permeability was calculated by the following equation (1). Figure 5 (a) shows the outline of the test equipment.

Shaving

Replacement form (Rule 26) Kw

PA

Here, in the above equation (1), Kw: permeability coefficient (cm), P: applied pressure (kgf / _cm ² ), A: cross-sectional area of specimen (cm ² ), h: thickness of specimen (Cm), ω: Unit volume mass of water (kg m ³ ), Q: Water permeability (cmVs).

[0058] Formulation of specimens>

Mortar made of ordinary Portland cement with a water cement ratio of 60% (hereinafter referred to as ΓM60J) was used as the test piece. The composition is shown in Table 11.

[Table 11]

[0060] <Modifier>

This modifier (Linack) obtained by diluting the stock solution obtained in Production Example 1 twice with water and a commercially available concrete modifier as a comparative example {Registered trademark: RC Guard (hereinafter, “RC”) And ヽ.)}

Specimen conditions>

The mortar was prepared using a mold with a diameter of 10 cm and a height of 1.4 cm.After removal from the mold, the casting surface and the bottom surface were polished to a height of lcm, and a siliceous modifier (Linack and RC) was applied. . Each specimens was by Ri wet watering 0. 15L / m ² was coated, subjected to water spray curing after 90 minutes, and further coated again watering cured after 90 minutes 0. lL / m ^2, 24 Watering was continued after hours. After that, it was wet-cured for 10 days and dried in an oven at 80 ° C. until the mass no longer changed (24 hours). After that, the test was performed after 1 hour in indoor air.

[0061] Test results and discussion>

As shown in Fig. 5 (b), the permeability of the specimen coated with this modifier (Linack) was reduced to about 1/7 compared to the case where it was not coated, indicating high water barrier performance. Compare to this

Replacement form (Rule 26) Even with the RC guard coating in the example, the force ^s , which is lower than the value without coating, the ratio is about 1Z2. Test example 5 {诱 Water test (2)}

Test Overview>

M60 mortar was used to confirm the change in permeability in the depth direction due to the penetration of the modifier.

Replacement form (Rule 26) Permeability test by the output method was carried out. M60 mortar of φ100 × 200mm was cured in water until the age of 14 days, the side was sealed, and then the modifier (Lin ack) and RC guard were applied only to the casting surface. After curing to a material age of 28 days, the amount of permeated water was measured under a pressure of 0. IMPa, using a specimen obtained by cutting horizontally from the casting surface every 10 mm. Permeable water flow rate in steady state The change in water permeability calculated by equation (1) with depth was evaluated in comparison with the case of no application.

This modifier (Linack) obtained by diluting the stock solution obtained in Production Example 1 twice with water and a commercial concrete modifier (RC) as a comparative example

Figure 6 shows the change in permeability in the depth direction. In the uncoated specimens, the permeability increased at a distance of 5 mm from the surface layer where the permeability was greatest at the surface layer of 5 mm. This is considered to be due to the change in permeability due to the increase in WZC near the surface due to the breathing and sedimentation of cement particles and aggregates. On the other hand, in the specimen coated with this modifier, on the other hand, the permeability of the surface is rather low, and there is no significant change due to the depth that can be seen without coating. In addition, the permeability of this modifier is less than that of no application at about 40 mm, which is consistent with the depth at which permeability was confirmed in Test Example 1. Therefore, it is probable that the hydration force generated inside the mortar by the application of this modifier had a significant effect of improving the water barrier properties, especially at the surface layer. In the RC guard coated specimen, the value was lower than that of this modifier only at the depth of 5 mm, and at a depth of 20 mm or less showing the hydraulic conductivity, the value was larger than that of the non-coated.

Test, Test Example 6 (chloride ion electrophoresis ¾: scattering test)

Electrophoresis of salt-dyeing ions in concrete using a potential difference.As shown in Fig. 7 (a), 0.5mol / L'NaCl and 0.5mol / L'NaCl were added to both sides of a concrete specimen 10cm in diameter and 5cm in height. By distributing a 0.3 mol / NaOH aqueous solution and applying a constant DC voltage of 15 V, chloride ions on the cathode side are electrophoresed through the pores of the concrete to the anode side. The effective diffusion coefficient is calculated from the rate of increase in the concentration of the chloride ions on the anode side. Also, concrete structures Frequently used for surface finishing etc., salt easily penetrates! / Testing with mortar is also performed.

<0064> <Specimen composition>

Specimens include water-cement ratio (W / C) 50% ordinary concrete (OPC50), W / C50% blast furnace type B concrete (BB50), W / C30% low heat concrete (LH30) and W / C30% / C60% ordinary mortar (hereinafter M60) was used. Table 12 shows the formulations.

[Table 12]

The present modifier (Linack) obtained by diluting the stock solution obtained in Production Example 1 twice with water, and a commercially available concrete modifier (RC) as a comparative example

Concrete is 5cm from a 10cm diameter, 20cm high formwork.

Cut out to thickness. The mortar was prepared using a mold having a diameter of 10 cm and a height of 10 cm, cut out to a thickness of 2 cm, and applied with a siliceous concrete modifier or the like. Regardless of the application conditions, no application (NO), and as a comparative example, 0.15 L each of a commercially available siliceous concrete modifier (trade name: RC Guard (RC)) and this modifier (Linack) 90 minutes after the application of / m ² , watering and curing were performed. Further, 0.1 l / m ² was applied, and after 90 minutes, watering and curing were performed again. Watering was performed 24 hours later.

[0067] <Test Results and Discussion>

Table 13 shows the effective diffusion coefficients. Fig. 7 (b) (Concrete blend) and Fig. 7 (c) Rutar blend) show the ratio to no coating.

Replacement form (Rule 26) 13]

Effective diffusion coefficient ({θΛηΛ

Replacement form (Rule 26) [0069] Table 3 shows that the effective diffusion coefficient differs greatly depending on the type of cement and the difference in water cement ratio. However, as shown in Fig. 7 (b), the application of this modifier (Linack) confirmed the effect of suppressing salt penetration regardless of the type of cement and the ratio of water cement. The ratio of the specimen coated with the RC guard (comparative example) to the uncoated effective diffusion coefficient in OPC50 is 80%, which is much lower than that of the specimen coated with the modifier (Linack). It was a very low figure of 20%. In general, the lower the W / C ratio of concrete, the higher the salt-shielding property. According to the regression formula in the 2002 Concrete Standard Specification (Construction), the diffusion coefficient of W / C is 40%, The ratio of C50% is 43%, and that of WZC60% is 22%. The value of 20% for the non-application of OPC50 by applying this modifier (Linack) is 40% of W / C, which is thought to prevent salt penetration, compared to 60% of W / C, which is considered to be easy for salt penetration. It can be said that the salt permeation suppression effect is very high. Since BB50 mixed with blast furnace slag has a high effect of suppressing salt penetration, this experiment also showed a low diffusion coefficient of less than lPC of OPC50. However, in the specimen coated with this modifier (Linack), the effective diffusion coefficient was even lower, and the salt shielding performance was improved. On the other hand, with LH30, which has a lower W / C, the amount of water required for salt diffusion is very small. (Linack) application reduced the diffusion coefficient force S. The same results were obtained for OPC and BB monoletal. Experimental force Using the obtained effective diffusion coefficient, the number of years until the chloride ion concentration at the steel position of a concrete structure with a cover thickness of 5 cm reaches the corrosion limit (here, 1.2 kg / m3) Was analyzed from the diffusion equation, and the results obtained are shown in Table 14.

[Table 14]

Replacement form (Rule 26) The chloride ion concentration on the surface of the structure was set at three levels depending on the distance of the coastal force. Taking the harshest spray zone as an example of the salt environment, a replacement sheet until chloride ions reach the reinforcing bar position (Rule 26) The number of years is only 3 years without general OPC50 application. However, when this modifier is applied, it will be 17 years, and the durability will be about 6 times. With LH30 and BB50, the same spray zone is applied for 30 years and 50 years without application, respectively. The application of this modifier can greatly extend the useful life of concrete with such a high salt-shielding property. LH30 is 1.6 times 50 years and BB50 is 1.9 times 151 Year. Note that there is no significant change in RC guard application. In this case, the concentration of the salt ion on the concrete surface was not considered, and it is estimated that the number of years in the actual environment will be longer.

Test example 7 (Surface potential measurement test)

There are two possible reasons for the salt barrier effect of this modifier application in Test Example 6, in addition to the densification of the structure by hydrates as seen in Test Example 1, and two other electrostatic effects. . Here, the latter effect was examined by measuring the surface potential using cement paste. Using a φ100 X 5 mm cement paste specimen (WZC50%), pressurize the NaCl aqueous solution in contact with the surface of the specimen coated with the modifier, and finely distribute the Na ions or C1 ions when passing through the pores. The surface potential was measured indirectly by measuring the electromotive force generated between the charge on the pore surface and the charge. Figure 8 (a) shows the outline of the test equipment.

Using OPC and BB cement with different electrical properties after curing, cast a 50% cement paste of WZC into a φ100 X 8mm formwork, grind the casting surface and bottom surface after demolding, and obtain a thickness of 5mm. Formed. At 14 days of age, modifiers (Linack and RC) were applied over the entire surface, and then wet-cured for 14 days and subjected to a force test.

The test results are shown in Fig. 8 (b). In the case of OPC, a force that showed a positive potential in the case of no application changed significantly to negative by application of this modifier. BB showed a negative potential even when the coating was not applied, and changed to a much more negative value when the modifier was applied. The surface potential of cement paste depends on the presence of Ca ions. Has been reported to be affected. In OPC, the force indicating a positive charge due to Ca (OH) generated by hydration. This Ca (OH) force ¾B is consumed for the hydration reaction of blast furnace slag.

twenty two

Therefore, it is thought that it shows a more negative charge than OPC. On the other hand, when this modifier is applied, it is considered that the charge changes greatly to negative because a new hydrate is generated and Ca ions are consumed. If the charge on the surface of the hardened cement shows a large negative value, C1 ions will be strongly inhibited from penetrating by repulsion, and this will be a factor in the high salt shielding effect obtained by applying this modifier obtained in Test Example 7. it is conceivable that. On the other hand, in the RC guard (comparative example) coated specimen, the OPC slightly changed negatively, but the BB changed greatly positively, and it was difficult to relate the effect on C1 ions. Possible Test Example 8 (Chloride ion penetration test by seawater immersion)

This test simply measures the penetration depth of all chloride ions diffused into the hardened cement body.

A 1171 Polymer cement mortar was tested in accordance with the test method. The specimen is immersed in salt water (artificial seawater) for 14 days, and the reagent (silver nitrate solution and peranine aqueous solution) is sprayed on the section of the cracked specimen, and the discolored part is measured as the penetration depth. The measurement points were 3 points per cross section, for a total of 6 points.

(a) Modifier obtained by diluting the stock solutions obtained in Production Example 1, Production Example 2, and Production Example 3 two-fold with water

(b) Modifier obtained by diluting the stock solution obtained in Production Examples 1, 4 and 5 with water two-fold

A 4 X 4 X 16 cm OPC mortar (WZC 50%) specimen aged in water up to the specified age is cut into 4 X 4 X 4 cm, completely covered with a sealing agent except one side, and coated with a modifier. After the moist curing for a predetermined number of days, the test was performed. Saltwater Pio IS

A 6205 Persons specified in 3.2.1 (Salt solution) Engineering seawater was used.

(a) Underwater curing up to 7 days of age, wet curing for 7 days after application

(b) Curing in water up to 14 days of age, moist curing for 14 days after application

The results are shown in FIG.

[0074] Trial, experiment 9 (freezing and thawing trial, experiment)

Based on the JIS-A-1148 A method and JIS-A-1171, a freeze-in-water thawing test in concrete and mortar was performed. The normal test (A: OPC50, BB60 concrete), the test start age was 7 days, and the initial frost damage before application (B: OPC50 concrete) was used to evaluate the effect of artificial seawater on frost damage in a salt environment. The object to be considered was (C: 50 OPC mortar). In addition, in order to examine the effect of applying the modifier after frost damage deterioration, the modifier was applied to the deteriorated specimen until the relative dynamic elastic modulus (RDM), which is considered to be the frost damage durability limit, was about 60%. Further, the sample subjected to the freeze-thaw test is designated as (D: OPC50 mortar). The measurement was performed every 30 cycles for concrete and every 10 to 30 cycles for mortar in accordance with the progress of deterioration.

[0075] <Modifier>

(A) and (B) The modifier (Linack) obtained by diluting the stock solution obtained in Production Example 1 two-fold with water and a commercially available concrete modifier (RC) as a comparative example

(C) This modifier obtained by diluting the stock solution obtained in Production Examples 1, 4, 6, and 7 with water two-fold and a concrete modifier commercially available as a comparative example (RC)

(D) The present modifier (Linac k) obtained by diluting the stock solution obtained in Production Example 1 two-fold with water

The dimensions of the test piece were 100 x 100 x 400 mm for concrete and 40 x 40 x 160 mm for mortar. The modifier was applied to the concrete only on the casting surface and to the mortar on all surfaces except the bottom.

<Test Results and Discussion (A)> In the case of OPC50 shown in Fig. 10 (a), the RDM of the uncoated specimen started to decrease immediately after the test, and the rate of decrease in the 250-cycle force sharply increased, and became less than 60% in 300 cycles. RDM60% is a limit value as an indicator of frost damage resistance, and it can be said that frost damage resistance without application of OPC50 is low. On the other hand, in the test specimen coated with this modifier, the RDM exceeded 100% at the beginning of the test, and remained almost at 100% until the end of the test, showing high frost damage resistance. Was. Also, in the test specimen coated with the modifier (RC) of the comparative example, the RDM started to decrease at a force of 300 cycles, which showed a high value. Deterioration due to freezing and thawing means that the moisture that has entered from the outside freezes on the surface of the concrete as the temperature decreases, and the expansion pressure causes the structure to break down inside the concrete. Concrete coated with this modifier (Linack) is densified by the gel generated from the surface layer to the inside, and prevents moisture from entering from the outside. In addition, since the internal water is consumed when the gel is formed, voids that are not filled with water are maintained in the concrete, and the expansion pressure due to freezing can be reduced. From these, it is considered that the application of this modifier (Linack) brings high frost resistance to concrete. Similarly, in the case of mass change, the non-application continued to decrease in force immediately after the start of the test, while the modifier (Linack) applied exerted a force less than the mass at the start of the test even at the end of the test. In the case of BB60 shown in Fig. 10 (b), the RDM of the uncoated specimen started to drop sharply by 150 cycles, and became less than 80% at 300 cycles.

BB forms a denser structure than OPC due to the pozzolanic reaction of the mixed blast furnace slag and also consumes water, so it has high frost resistance. Even with this BB60, the RDM maintained a value of 100% or more for this modifier (Linack) coated specimen up to 300 cycles. On the other hand, the RC guard application showed a value of 100% or less from the start of the test, and decreased slightly at 300 cycles.

The results are shown in FIG. As can be seen from FIG. 11, the deterioration progressed slowly even without application, but the durability was further improved by applying this modifier.

[0079] <Test Results and Discussion (C)>

The results are shown in Fig. 12 (a)-(d). Freezing and thawing in a salinity environment compared to pure water It is said that the deterioration progressed violently, and in this test, the deterioration progressed early, especially in non-AE with poor freeze-thaw resistance. In the case of no application, the relative kinematic elasticity coefficient was already 60% in 15 cycles. On the other hand, application of this modifier (two compound types) improved the durability by reaching the RDM limit value of about 28 cycles. Even with AE mortar with improved durability against freezing damage, the relative kinetic elasticity coefficient was 60% in about 50 cycles without application. On the other hand, the application of this modifier (3 types) increased to 60% or more until 200 cycles. In particular, LN733 maintained a high dynamic elasticity of 92%. Regarding the change in mass, without application, the mass rapidly decreased after 100 cycles, and decreased by 10% at 200 cycles, and the tissue was greatly damaged. On the other hand, when the present modifier was applied, no mass reduction was observed up to 150 cycles in any of the formulations. In particular, LN422 has no loss of mass up to 200 cycles.As shown in Fig. 13, the force completely loses the surface layer without application.With the application of this modifier (LN422), it remains almost the same as at the start of the test. And showed high scaling resistance. In the case of the RC guard coating of the comparative example, the middle of the surface layer was lost, and the improvement in scaling resistance was lower than that of the present modifier.

In order to confirm the modification effect by applying the modifier after deterioration, use OM 50 mortar aged in water until the age of 28 days, and suspend at the stage after the freeze-thaw cycle until the RDM reaches 70% and 50%. The present modifier was applied. After 7 days of moist curing together with the uncoated specimen, the freeze-thaw cycle was restarted in artificial seawater. When applying this modifier, it was thought that Ca (OH) in the surface layer had leached out due to deterioration.

A 22 saturated aqueous solution was applied. The test applied after degradation to RDM 70% was D70, and the case of 50% was D50. The RDM and mass change of each test are shown in Fig. 14 (a)-(d). At D70, the RDM and mass of the uncoated specimen dropped sharply after resumption. This is considered to be due to the fact that the surface part before the interruption was relatively remaining, and the separation and damage were promoted by the effect of artificial seawater after the resumption. On the other hand, in the specimens coated with this modifier, the RDM value increased to 100% after resumption, and was over 60% at the end. The mass also showed little decrease until about 80 cycles after the restart. Even in the case of D50, where the deterioration condition below the frost damage durability limit was resumed, the RDM and mass continued to decrease when no coating was performed. On the other hand, this modifier application In RMS, the RDM gradually increased after the restart, and reached 60% or more in 50 cycles after the restart. The mass also showed a slight increase, and no decrease was observed up to 80 cycles after restart.

[0081] From these results, the improvement of the frost damage resistance by applying the present modifier is effective not only for newly-constructed concrete but also for existing and frost-damage-degraded concrete, and is also highly effective for scaling. , Was found to exhibit resistance.

[0082] The above test results are summarized below.

(1) It has been confirmed that the present modifier (for example, Linack) has penetrated to a depth of 40 mm, indicating that the permeability is much higher than that of a conventional permeability modifier.

(2) The modifier (for example, Linack) produces a gel with a rod-shaped or massive solid structure in the voids in concrete, and improves the water-blocking performance by densifying the voids. The RC guard, which is a comparative example, also exhibits the same properties. Due to the difference in force penetration depth, the effect of the comparative product is several millimeters on the surface.

(3) In addition to the densification described in (2), this modifier (for example, Linack) repels chloride ions due to the negative charge on the gel surface and exhibits high salt shielding properties. The RC guard of the comparative example has a lower effect of improving the salt-shielding property than the present modifier.

(4) This modifier (for example, Linack) improved the frost resistance regardless of the cement type and water-cement ratio. In addition, it exhibited high durability against combined deterioration with salt damage, and also exhibited high scaling resistance. Although the application of RC guard in the comparative example showed an improvement in frost damage resistance, the performance was lower than that of this modifier (Linack), and the same applies to scaling resistance.

(5) Even when this modifier (for example, Linack) was applied after deterioration due to frost damage, the relative kinetic elasticity was recovered after application and the durability was improved. It was also found that a saturated aqueous solution of calcium hydroxide was used to assist the gel formation of the present modifier (for example, Linack) and further improve the durability.

(6) Based on the above, this modifier (for example, Linack) applied to the concrete surface penetrates deep into the concrete and improves the water-blocking performance, salt-blocking performance, and frost-resistance performance by the generated gel. Therefore, it is considered to be effective as a preventive or preventive measure against the deterioration of concrete due to salt damage and frost damage and their combined deterioration. Brief Description of Drawings

FIG. 1 (a) is a schematic cross-sectional view of concrete. FIGS. 1 (b)-(e) are enlarged views of a portion surrounded by a square in FIG. 1 (a). FIG. 1 (c) is a diagram showing a state in which the present modifier has penetrated into the microvoids or the fragile tissue portion at the interface of the aggregate shown as 5 in FIG. 1 (b). FIG. 1 (d) is a view showing that the present modifier that has permeated into the voids has reacted with calcium hydroxide and water in the pore solution to form a gel. Fig. 1 (e) is an electrophotograph showing the actual state of the portion enclosed by the square in Fig. 1 (d). In the figure, 1: mortar matrix, 2: coarse aggregate, 3: pores and cracks, 4: fine aggregate, 5: cement paste, 6: this modifier, 7: gel generated from this modifier Are shown respectively.

[FIG. 2] FIG. 2 is an SEM image (electrophotograph) of Test Example 1 (the test for confirming the permeability of the modifier). Here, Fig. 2 (a)-(d) shows the specimen of the mortar coated with the modifier {depth of the casting surface (a) lmm, (b) 20mm, (c) 30mm, (d) 40mm}. Fig. 2 (e) and (f) are SEM images of the uncoated mortar specimen (depth from the casting surface (e) 5mm, (f) 20mm), and Fig. 2 (g) Is a SEM image of the product for which the modifier and saturated Ca (OH) solution power were also obtained.

2

FIG. 3 is a measurement spectrum of an LN gel in Test Example 2 (XRF elemental analysis).

FIG. 4 is a diagram showing the relationship between the content of various alkali metals and the depth of the coated surface in Test Example 3 (permeability confirmation test by alkali component analysis).

[FIG. 5] FIG. 5 is a diagram showing an apparatus and results in Test Example 4 {water permeability test (1)}. Here, FIG. 5 (a) is a diagram showing an outline of the test apparatus, and FIG. 5 (b) is a diagram showing the effect of coating conditions on the hydraulic conductivity.

[FIG. 6] FIG. 6 is a diagram showing a change in water permeability in the depth direction due to the application of a modifier in Test Example 5 {water permeability test (2)}.

[FIG. 7] FIG. 7 is a diagram showing an apparatus and results in Test Example 6 (chloride diffusion test by electrophoresis). Here, Fig. 7 (a) is a diagram showing an outline of the apparatus according to this test, and Fig. 7 (b) shows the effective diffusion coefficient (ratio to no application) of various types of concrete by applying the modifier. FIG. 7 (c) is a diagram showing the effective diffusion coefficient (ratio to no application) of various mortars by applying a modifier.

FIG. 8 is a diagram showing an apparatus and a result in Test Example 7 (surface potential measurement test). Here, FIG. 8 (a) is a diagram showing an outline of an apparatus according to the present test, and FIG. 8 (b) is a diagram showing a surface potential of various cements by applying a modifier.

[FIG. 9] FIG. 9 is a diagram showing the relationship between various modifiers and the total salt penetration depth in Test Example 8 (salinity immersion ion penetration test by immersion in seawater). Application, 7 days after immersion in seawater, (b) 14 days of age, 14 days after immersion in seawater}.

[Figure 10] Figure 10 shows the relative kinetic elasticity change of OPC50 when various modifiers were applied in the normal cycle test of Test Example 9 (freeze-thaw test) {Figure 10 (a)} and the relative dynamics of BB60. FIG. 11 is a diagram showing a coefficient of change {FIG. 10 (b)}.

[Fig. 11] Fig. 11 is a diagram showing a change in relative kinetic elastic modulus when the present modifier was applied in an initial frost damage cycle test of Test Example 9 (freeze-thaw test).

[Figure 12] Figure 12 shows the change in the relative kinematic elastic modulus of nonAE when various modifiers were applied in the seawater cycle test in Test Example 9 (freeze-thaw test) {Figure 12 (a)} and the mass loss rate {Fig. 12 (b)}, the change in the relative kinematic elasticity of AE {Fig. 12 (c)}, and the mass loss rate {Fig. 12 (d)}.

[FIG. 13] FIG. 13 is a diagram showing a scaling state at the end of a test on a test piece casting surface in a freeze-thaw test in artificial seawater of Test Example 9 (c).

[Figure 14] Figure 14 shows the change in relative kinetic elasticity of the modified agent after degradation to RMD 70% in the cycle test after frost damage deterioration in Test Example 9 (freeze-thaw test) {Figure 14 (a) } And the mass loss rate {Fig. 14 (b)} and the change in the relative kinematic modulus of AE when this modifier is applied after degradation to RDM 50% {Fig. 14 (c)} and the mass loss rate {Fig. FIG.

Claims

The scope of the claims

[I] A concrete modifier characterized by blending an alkali metal ion source with a lithium silicate aqueous solution.

[2] The modifier according to claim 1, wherein the alkali metal ion source is a water-soluble alkali metal-containing substance.

3. The modifier according to claim 1, wherein the alkali metal ion source has an alkali metal ion force of sodium ion and potassium ion.

[4] Molar ratio of added alkali metal ion source to SiO (calculated as alkali metal ion)

2

The modifier according to any one of claims 13 to 13, which has a force of 0.08-1.8.

[5] The method according to any one of [14] to [14], wherein the molar ratio of all alkali metal ions including lithium ions derived from the aqueous solution of lithium silicate to SiO is from 0.3 to 2.1.

2

Modifier.

[6] The modifier according to claim 3 or 4, wherein the molar ratio of potassium ion to sodium ion is 0.02-2.7.

[7] The method according to any one of claims 116, wherein when added to a saturated aqueous calcium hydroxide solution according to the measuring method 1 in the specification, a two-phase structure of a cloudy gel phase and a transparent solution phase is formed. The modifier as described.

[8] The modifier according to any one of Claims 17 to 17, which is a concrete surface application type.

[9] An undiluted solution of the modifier according to any one of Claims 18 to 18, which is obtained by mixing an alkali metal ion source with an aqueous lithium silicate solution, wherein SiO and Li in the aqueous lithium silicate solution are used. O (equivalent oxide equivalent) means that their total amount is

twenty two

And the molar ratio (SiO 2 / Li 2 O) is 3

A stock solution of a modifier that is 2 2 1 8.

[10] A step of applying the modifier according to any one of claims 18 to 18 or the modifier obtained by diluting the stock solution according to claim 9 with water to a concrete surface one or more times. A method for preventing or suppressing the deterioration of concrete, including:

11. The method according to claim 10, further comprising a step of applying an aqueous solution of calcium hydroxide to the concrete surface before or during the one or more times of applying the modifier. [12] Concrete that has been prevented or deteriorated by the method according to claim 10 or 11.