JP4484872B2 - Silicic concrete modifier - Google Patents

Description

  The present invention prevents or inhibits deterioration due to freezing and thawing of concrete, salt damage, and the like, or more severe deterioration caused by combining these, and contributes to reduction of life cycle cost (silica based concrete modifier (surface modifier) )

Concrete is inherently very durable and has been said to have a useful life of 50 to 100 years, but it has recently been found that concrete deterioration is faster than expected. In particular, deterioration of concrete due to freeze-thaw and salt damage and complex deterioration may cause the emergence of structures that do not have the expected useful life and the occurrence of secondary disasters due to the peeling of concrete pieces from the structures. The cause of the cause has been investigated and various countermeasures have been taken. Specifically, the composition of the cement that constitutes the new concrete is changed, the unit water volume is reduced, the composition of the aggregate is specified, and the existing concrete is covered with polymer cement and a mortar containing siliceous waterproofing agent. Proposed methods such as injection, infiltration, and coating with organic resin, cement, and water glass materials have been proposed.
JP2000-44317A

  However, measures by changing the composition of cement and specifying the components of aggregates are effective in preventing deterioration of newly installed concrete, but cannot cope with existing structures that are undergoing deterioration. There is also a problem such as an increase in cost due to a shortage of the amount of cement and admixture used. As for the repair method, when using organic materials, environmental pollution problems due to organic compounds, the coating method requires re-work due to deterioration of the material itself, and changes the design of the concrete surface by construction, Water glass materials harden at the crack surface layer (1-2 mm from the surface layer) and cannot penetrate into the concrete, so the effect is limited. Because it can only fill cracks of 2 mm or more, it improves the surface strength of concrete, and the lithium silicate aqueous solution known as an alkali imparting agent is also highly viscous and difficult to penetrate. The conventional method has many problems, such as being inferior in durability and requiring re-construction in several years.

  Therefore, the present invention is a relatively simple construction method that is simply applied to the surface of new and existing concrete structures, prevents or inhibits deterioration due to freezing and thawing and salt damage, and combined deterioration due to these, and does not change the surface design. It is an object of the present invention to provide a concrete modifier that penetrates deep into the concrete (maintaining the concrete surface condition immediately after placing) and has high durability.

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

  The invention (2) is the modifier of the invention (1), wherein the alkali metal ion source is a water-soluble alkali metal-containing substance.

  The present invention (3) is the modifier according to (1) or (2) above, wherein the alkali metal ions from the alkali metal ion source are sodium ions and potassium ions.

In the present invention (4), the molar ratio of alkali metal ion source to be added to SiO ₂ (in terms of alkali metal ions) is 0.08 to 1.8 (preferably 0.12 to 1.2). It is a modifier according to any one of the inventions (1) to (3).

In the present invention (5), the molar ratio of all alkali metal ions including lithium ions derived from an aqueous lithium silicate solution to SiO ₂ is 0.4 to 2.1 (preferably 0.6 to 1.4). A modifier according to any one of the inventions (1) to (4).

  In the invention (6), the ratio of potassium ions to sodium ions is 0.02 to 2.7 (preferably 0.04 to 1.8) in terms of molar ratio. ) Modifier.

  The present invention (7) forms a two-phase structure of a cloudy gel phase and a transparent solution phase when added to a saturated calcium hydroxide aqueous solution according to the measurement method 1 in the specification, and more preferably two layers of cloudy gel ( The reforming agent according to any one of the inventions (1) to (6), which is divided into a floating layer and a precipitation layer.

  This invention (8) is a modifier for any one of said invention (1)-(7) which is a concrete surface application type | mold. The “concrete surface application type” includes not only an aspect of applying to the concrete surface but also an aspect of injecting from the concrete surface (for example, from a crack).

The present invention (9) is a stock solution of the modifier according to any one of the inventions (1) to (8) obtained by blending an alkali metal ion source in an aqueous lithium silicate solution, wherein the aqueous lithium silicate solution The total amount of SiO ₂ and Li ₂ O in terms of equivalent oxide is 15 to 30% by weight with respect to the total weight of the aqueous solution, and their molar ratio (SiO ₂ / Li ₂ O) Is a modifier stock solution of 3-8.

  In the present invention (10), any one of the modifiers of the inventions (1) to (6) or the modifier obtained by diluting the stock solution of the invention (9) with water is applied to the concrete surface. Alternatively, it is a method for preventing or preventing deterioration of concrete, including a step of applying (for example, applying) a plurality of times. In addition, although the dilution rate of the undiluted | stock solution with water changes according to the surface state etc. of concrete, it is 1 to 5 times, for example.

  The present invention (11) further includes a step of applying (for example, applying) an aqueous calcium hydroxide solution to the concrete surface before or during the one or more times of applying the modifier (for example, a modifying agent applying step). Including the method of the invention (10).

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

The concrete modifier according to the present invention firstly imparts the property of reducing moisture permeability and salt permeability to concrete. Specifically, the alkali metal-containing lithium silicate in the agent reacts with calcium hydroxide, which is a pore solution component of water or concrete present on the aggregate interface or in the internal voids, to form a gel. This gel formation results in densification of the voids. As a result, it inhibits the invasion of water, which is a factor that promotes various deteriorations. With respect to chloride ions that cause salt damage, the charge on the gel surface increases with densification. Diffusion is also suppressed by becoming negative and electrically repelling. Furthermore, by taking in void water inside the concrete that causes freezing and thawing during gelation, voids that are not filled with water increase, and a space is created to release the pressure when water and gel freeze and expand. Further, by increasing the concrete surface tensile strength by 1.5 to 2 times inside the crack, the expansion and progression of the crack that greatly affects the concrete deterioration is prevented or suppressed.

  Secondly, the concrete modifier according to the present invention has the property of penetrating deeper into the concrete (for example, to a depth of about 40 mm) as compared with conventional alkali imparting agents. The reason for this is understood to be that the reaction rate is very slow compared to conventional ones (such as water glass modifiers) (so that it can penetrate deep into the concrete). In various conventional research reports, there have been many reports that lithium compounds are effective in preventing various deterioration of concrete. However, since this component can penetrate only about 1 to 2 mm from the surface, it can only be used as a concrete admixture or a surface coating material. The present invention is epoch-making in that it provided an osmotic surface coating agent based on this second property of deep penetration.

For ease of understanding, the mechanism of the present invention will be described with reference to FIG. FIG. 1A is a schematic view of a concrete cross section showing a mortar matrix 1 containing fine aggregates, a coarse aggregate 2, pores, cracks, and the like 3. And the figure which expanded the square enclosure part in Fig.1 (a) is FIG.1 (b)-(d). In FIG. 1 (b), 3 also indicates a fragile tissue portion at the aggregate interface, 4 is a fine aggregate, and 5 is a 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 the voids and the like. The modifier that has penetrated into the voids reacts with calcium hydroxide and water in the pore solution to form a gel. FIG. 1 (d) shows the state of the gel 7 generated from the present modifier. FIG. 1 (e) shows the actual state of the square box in FIG. 1 (d).

  Summarizing the above, when the modifier according to the present invention is applied to the concrete surface, the agent mainly composed of alkali metal-containing lithium silicate propagates through the interface of cracks and aggregates, and penetrates deeply into the concrete. It penetrates into fine voids in the rough portion of the composition in contact with the interface. Further, when gelling by reacting with water and calcium hydroxide present on the interface or inside the voids, the reaction rate is very slow compared to the prior art, and therefore, it can penetrate deep into the concrete. As a result, the present invention is a relatively simple construction method that is simply applied to the surface of new and existing concrete structures, and prevents or inhibits deterioration due to freezing and thawing and salt damage and composite deterioration due to these without changing the surface design. There is an effect that can be done.

  Furthermore, since the modifier according to the present invention is a completely inorganic material that does not substantially contain an organic component, it also has an effect of having durability against ultraviolet deterioration.

  Furthermore, the modifier according to the present invention also has an effect that it can be applied to a structure that has been deteriorated, which is not effective in the prior art. In particular, when applying this modifier to deteriorated concrete, either apply a calcium hydroxide aqueous solution to the concrete in advance, or apply a calcium hydroxide aqueous solution between the modifier applying step and the modifier applying step. When applied, it is more effective.

The concrete modifier according to the present invention is characterized in that an alkali metal ion source is blended in an aqueous lithium silicate solution. Hereinafter, the configuration requirements of the present invention will be described. In this specification, “Li ₂ O”, “Na ₂ O”, and “K ₂ O” are equivalent oxide equivalents.

The “aqueous lithium silicate solution” refers to a kind of colloidal silica in which the alkali portion is lithium. Here, the “aqueous solution” does not mean that these raw material components are completely dissolved, but indicates a state in which at least a part of the raw materials is dissolved in some form. Therefore, even if one of the raw materials (especially SiO ₂ ) exists in a colloidal state, even if a part of the raw material is dissolved and a part is in a colloidal state, all of these states are included. Moreover, these raw materials may exist in any form in the liquid.

The lithium silicate aqueous solution 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 resulting colloidal silica with Li. Examples of commercially available products include lithium silicate 45 manufactured by Nissan Chemical Industries, Ltd. {20.0 to 21.0 parts by weight of SiO _{2 with} respect to 100 parts by weight of aqueous solution, 2.1 to 2.4 weights of Li ₂ O. Parts, SiO ₂ / Li ₂ O molar ratio 4.5}, lithium silicate 75 {20.0-21.0 parts by weight of SiO _{2 with} respect to 100 parts by weight of aqueous solution, 1.2-1.4 parts by weight of Li ₂ O SiO ₂ / Li ₂ O molar ratio 7.5}, lithium silicate 35 {20.0-21.0 parts by weight of SiO _{2 with} respect to 100 parts by weight of aqueous solution, 2.6-3.3 parts by weight of Li ₂ O, A SiO ₂ / Li ₂ O molar ratio of 3.5} can be used.

The “alkali metal ion source” according to the present invention is not particularly limited as long as it causes alkali metal ions to be present in an aqueous lithium silicate solution when added to water. For example, when added to water, Dissociating substances, 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 or alkali metal ion aqueous solutions Can do. 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 blended in the lithium silicate aqueous solution is not necessarily one type, and is 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 lithium silicate aqueous solution. Alternatively, a plurality of types (for example, a combination of sodium hydroxide and potassium hydroxide) in which different alkali metal ions are present in an aqueous lithium silicate solution may be used.

  A preferred alkali metal ion is a combination of sodium and potassium ions. In particular, the molar ratio of potassium ions to sodium ions is preferably 0.02 to 2.7, 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 blending ratio of sodium hydroxide and potassium hydroxide is 1.3 to 2.5 (more preferably 1.7 to 2.2) in weight ratio (sodium hydroxide / potassium hydroxide). ).

Furthermore, the addition amount of the alkali metal ion source is preferably 0.08 to 1.8, more preferably 0.12 to 1 with respect to SiO _{2 in} terms of molar ratio (calculated as alkali metal ions). .2.

  Furthermore, the modifier according to the present invention preferably forms a two-phase structure of a cloudy gel phase and a transparent solution phase when added to a saturated calcium hydroxide aqueous solution according to the following measurement method 1. .

Measurement method 1: 2.7 mL of a saturated aqueous solution of calcium hydroxide filtered into a cuvette for a spectrophotometer (made of polystyrene, inner dimension = 1 × 1 × 4.5 cm, volume 4.5 mL) is added with 0.3 mL of a modifier. Drip slowly. After mixing, the container is sealed with parafilm and allowed to stand, and observed from immediately after dropping until the seventh day.

  Next, a method for producing a stock solution of a concrete modifier according to the present invention will be described. The stock solution of the modifier according to the present invention is produced by blending an alkali metal ion source with an aqueous lithium silicate solution. It should be noted that if the order is changed and an alkali metal ion source is added to water and then an aqueous lithium silicate solution is added, gelation may occur.

Here, a suitable aqueous solution of lithium silicate is such that the total weight of SiO ₂ and Li ₂ O is 15 to 30% by weight (more preferably 20 to 25% by weight) with respect to the total weight of the aqueous solution. Is added to water at a molar ratio (SiO ₂ / Li ₂ O) of 3 to 8 (more preferably 4 to 5).

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

  After adding an alkali metal ion source to the lithium silicate aqueous solution and stirring well, a required amount of water is added to obtain a stock solution of the modifier according to the present invention. This water is added for the purpose of reducing the viscosity. The water to be used is preferably pure water or ion exchange water.

  It should be noted that the lithium silicate aqueous solution, which is a raw material, should be stored at +5 to 25 ° C., and the material gelled in a sub-freezing environment should not be used as much as possible. Moreover, it is preferable to perform temperature control of + 5-25 degreeC even if it hits manufacture.

Further, in the production, the mixing method and the order of introducing the materials are basically not limited. Examples of specific preparation means are shown below.
(1) A solution prepared using sodium hydroxide, potassium hydroxide or lithium silicate dissolved in part or all of ion-exchanged water in advance (2) Order in which hydroxide (granular or aqueous solution) is added (I) Sodium-potassium in order, (ii) Potassium-sodium in order, (iii) Sodium and potassium added simultaneously (3) Hydroxide (granular) (I) A solution that is added in small amounts, or (ii) a solution that is added all at once. (4) When adding ion-exchanged water, (i) A solution prepared by diluting the stock solution to a predetermined dilution rate (for example, 2 times) after being prepared to a concentration to be a stock solution, (ii) Concentration of dilution of each raw material at a predetermined dilution rate (for example, 2 times) from the beginning Solution prepared in such a way that

  The stock solution thus obtained preferably contains 65 to 85% by weight (more preferably 70 to 80% by weight) of water based on the total weight of the stock solution. Moreover, the suitable viscosity (measured with a Canon-Fenske viscometer, 20 ° C.) of the stock solution is 1.0 to 15 mPa · s (more preferably 1.5 to 10 mPa · s).

Furthermore, the pH of the stock solution thus obtained is preferably in the range of 12.0 to 13.5, more preferably in the range of 12.4 to 12.9. Further, it is preferable that the pH of the diluted solution is 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 modifying agent according to the present invention is diluted as necessary (hereinafter described by taking a 2-fold dilution as an example) and stirred well (step 1). And before apply | coating this modifier to concrete, water is sprinkled in order to make the concrete of an application | coating surface into a moist state (process 2). Thereafter, the wet state of the concrete is confirmed, and this modifier diluted twice with water is applied with a low-pressure sprayer, a brush, a roller, etc. (selected according to the construction site conditions) (step 3). Here, the amount of the present modifier used per 1 m ^{2 of} concrete is, for example, 200 cc / m ² (2 times diluted), and 100 cc / m ² based on the stock solution. Next, after application, water is sprayed at a low pressure before drying (step 4). At this time, if the wet curing (basic 90 minutes) seems to dry quickly, water is sprayed (step 5). Step 2 to Step 4 are repeated (Step 6). It is confirmed whether this modifier remains on the surface (step 7). As a final step, water is sprayed at a low pressure, and when remaining is confirmed in step 6, it is washed by brushing or the like so as not to remain on the concrete surface (step 8). Thereafter, it is naturally dried (step 9). In addition, it can be used immediately after the end of the step 8 (in the case of a floor surface such as a white road pavement, it is possible to run heavy vehicles or move heavy objects). Moreover, at the time of construction, it is preferable that the outside air temperature is + 5 ° C. or more, and when it is less than + 5 ° C., it is preferable to control the temperature by heating and curing. In addition, when it coat | covers with the coating | coated material which inhibits penetration | penetration like a coating or polymer cement, after this coating | coated material is peeled, this modifier is applied.

  Moreover, the kind of concrete which can use the modifier concerning this invention is not specifically limited, It is effective for all the concretes which changed the cement kind and mixing | blending. For example, examples of the cement include ordinary Portland cement, early-strength Portland cement, belite cement, ecocement, blast furnace cement, fly ash cement, and low heat cement. Also, as concrete, for example, ordinary concrete, high strength concrete, low heat concrete, underwater non-separable concrete, underwater concrete, factory product concrete, marine concrete, shotcrete, fiber reinforced concrete, prepacked concrete, high fluidity concrete, Lightweight (aggregate) concrete, steel concrete composite structure, prestressed concrete, recycled aggregate concrete and the like can be mentioned. In addition, for example, admixtures such as fly ash, blast furnace slag fine powder, and silica fume may be mixed.

  Here, regarding the deteriorated structure from which calcium is leached and the concrete using the blast furnace slag cement having a low calcium content, prior to the modifier coating process or in the middle of a plurality of modifier coating processes, It is preferable to apply calcium hydroxide to the concrete to replenish the concrete with calcium. For example, the aspect which apply | coats water to concrete first, applies a modifier after that, and applies calcium hydroxide aqueous solution after that can be mentioned. Furthermore, the aspect which mixes this modifier with another material (for example, cement), and applies the said mixture to a concrete surface can also be mentioned. Furthermore, for example, in the case where a crack has occurred, an embodiment in which the present modifier is not applied to the concrete surface but injected into the concrete through the crack can be mentioned.

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

Production Example 1 (LN422)
Lithium silicate 45 (manufactured by Nissan Chemical Industries, Ltd., 20.0-21.0 parts by weight of SiO _2, 2.1-2.4 parts by weight of Li ₂ O with respect to 100 parts by weight of aqueous solution, SiO ₂ / Li ₂ O mole) Ratio 4.5) 85.70g was weighed into a beaker, and sodium hydroxide (Kanto Chemical Co., Ltd., purity 97%) 4.12g was mixed well with a glass rod in small increments until the amount was completely dissolved. added. After all of the sodium hydroxide has dissolved, add 1.96 g of potassium hydroxide (manufactured by Kanto Chemical Co., Inc., 86% purity) little by little, and gently add 8.22 g of ion-exchanged water to the place where it has completely dissolved. The mixture was thoroughly stirred with a stick to obtain a concrete modifier stock solution according to this production example ( viscosity: 7.32 mPa · s ). In addition, the composition of each component is shown in Table 1 (here, the values of lithium oxide, sodium oxide and potassium oxide are converted to equivalent oxides. The same applies to Production Examples 2 to 7).

Production Example 2 (LN723)
Lithium silicate 75 (manufactured by Nissan Chemical Industries, Ltd., 20.0-21.0 parts by weight of SiO _2, 1.2-1.4 parts by weight of Li ₂ O with respect to 100 parts by weight of an aqueous solution, SiO ₂ / Li ₂ O mole) 7.5) 85.56g was weighed into a beaker, and sodium hydroxide (Kanto Chemical Co., Ltd., purity 97%) 4.12g was mixed well with a glass rod in small increments until the amount was completely dissolved. added. After all the sodium hydroxide has dissolved, add 3.91 g of potassium hydroxide (manufactured by Kanto Chemical Co., Inc., 86% purity) in small amounts, and slowly add 6.41 g of ion-exchanged water to the place where it has completely dissolved. By thoroughly stirring with a stick, a stock solution of a concrete modifier according to this production example was obtained. Table 2 shows the composition of each component.

Production Example 3 (LN312)
Lithium silicate 35 (manufactured by Nissan Chemical Industries, Ltd., 20.0-21.0 parts by weight of SiO _2, 2.6-3.3 parts by weight of Li ₂ O with respect to 100 parts by weight of aqueous solution, SiO ₂ / Li ₂ O mole) Ratio 3.5) Weigh 90.89 g in a beaker, and gradually mix 0.83 g of sodium hydroxide (manufactured by Kanto Chemical Co., Inc., purity 97%) with a glass rod little by little, after the charged amount is completely dissolved. added. After all the sodium hydroxide has dissolved, add 1.96 g of potassium hydroxide (manufactured by Kanto Chemical Co., Inc., 86% purity) little by little, and gently add 6.32 g of ion-exchanged water to the place where it has completely dissolved. By thoroughly stirring with a stick, a stock solution of a concrete modifier according to this production example was obtained. Table 3 shows the composition of each component.

Production Example 4 (LN721)
Lithium silicate 75 (manufactured by Nissan Chemical Industries, Ltd., 20.0 to 21.0 parts by weight of SiO _2, 1.2 to 1.4 parts by weight of Li ₂ O, and SiO ₂ / Li ₂ O mol per 100 parts by weight of aqueous solution 7.5) 88.84g was weighed into a beaker, and sodium hydroxide (Kanto Chemical Co., Ltd., purity 97%) 4.12g was mixed well with a glass rod in small increments. added. After all of the sodium hydroxide has dissolved, add 0.39 g of potassium hydroxide (manufactured by Kanto Chemical Co., Inc., purity 86%) in small portions, and slowly add 6.65 g of ion-exchanged water to the place where it has completely dissolved. By thoroughly stirring with a stick, a stock solution of a concrete modifier according to this production example was obtained. Table 4 shows the composition of each component.

Production Example 5 (LN411)
Lithium silicate 45 (manufactured by Nissan Chemical Industries, Ltd., 20.0-21.0 parts by weight of SiO _2, 2.1-2.4 parts by weight of Li ₂ O with respect to 100 parts by weight of aqueous solution, SiO ₂ / Li ₂ O mole) 4.5) Weigh 90.14 g in a beaker, and gradually add 0.82 g of sodium hydroxide (Kanto Chemical Co., Ltd., purity 97%) with a glass rod in small increments until the charged amount is completely dissolved. added. After all of the sodium hydroxide has dissolved, add 0.39 g of potassium hydroxide (manufactured by Kanto Chemical Co., Inc., purity 86%) in small portions, and gently add 8.65 g of ion-exchanged water to the place where it has completely dissolved. By thoroughly stirring with a stick, a stock solution of a concrete modifier according to this production example was obtained. Table 5 shows the composition of each component.

Production Example 6 (LN433)
Lithium silicate 45 (manufactured by Nissan Chemical Industries, Ltd., 20.0-21.0 parts by weight of SiO _2, 2.1-2.4 parts by weight of Li ₂ O with respect to 100 parts by weight of aqueous solution, SiO ₂ / Li ₂ O mole) 4.5) Weigh 80.15 g in a beaker, and gradually add 8.25 g of sodium hydroxide (manufactured by Kanto Chemical Co., Inc., purity 97%) with a glass rod in small increments until the charged amount is completely dissolved. added. After all of the sodium hydroxide has dissolved, add 3.91 g of potassium hydroxide (manufactured by Kanto Chemical Co., Inc., purity 86%) in small portions and gently add 7.69 g of ion-exchanged water to the place where it has completely dissolved. By thoroughly stirring with a stick, a stock solution of a concrete modifier according to this production example was obtained. Table 6 shows the composition of each component.

Production Example 7 (LN733)
Lithium silicate 75 (manufactured by Nissan Chemical Industries, Ltd., 20.0-21.0 parts by weight of SiO _2, 1.2-1.4 parts by weight of Li ₂ O, and SiO ₂ / Li ₂ O mole with respect to 100 parts by weight of aqueous solution) 7.5) 81.72 g was weighed into a beaker, and 8.25 g of sodium hydroxide (manufactured by Kanto Chemical Co., Inc., purity 97%) was mixed little by little with a glass rod. added. After all the sodium hydroxide has dissolved, add 3.91 g of potassium hydroxide (manufactured by Kanto Chemical Co., Inc., 86% purity) in small portions, and slowly add 6.12 g of ion-exchanged water to the place where it has completely dissolved. By thoroughly stirring with a stick, a stock solution of a concrete modifier according to this production example was obtained. Table 7 shows the composition of each component.

Here, in Table 8, the molar ratio of each component about each modifier stock solution which concerns on manufacture examples 1-7 is shown. The “two-layer separation” in the table means whether or not the white turbid gel is divided into two layers (floating layer and precipitated layer).

Test Example 1 (Penetration confirmation test by SEM)
<Outline of experiment>
A mortar specimen coated with the modifier was cut out in a direction perpendicular to the placement surface, and observed by SEM for each depth from the placement surface. Moreover, the product obtained by mixing the modifier and a saturated aqueous solution of calcium hydroxide simulating a pore solution was also observed by SEM.
<Mortar specimen>
OPC mortar with a water cement ratio of 60% fine aggregate / mortar volume ratio of 55% was placed in a mold having a diameter of 5 cm and a height of 10 cm, demolded after 24 hours, and then cured in water. Molded to a height of 5 cm 4 days after placement.
<Modifier>
A modifier obtained by diluting the stock solution obtained in Production Example 1 twice with water <Coating method>
1.07 of the modifier is applied to the surface of the wet specimen.
After application of L / m ² , water was sprayed after 90 minutes. Thereafter, 0.31 L / m ^{2 of the} modifying agent was applied, watered after 90 minutes, wet for 7 days, and then cured in the air. 68 days after application, the film was cut to 5 mm in thickness and perpendicular to the casting surface, and immersed in acetone for 24 hours. The observation surface was polished smoothly, subjected to carbon deposition, and subjected to SEM. For comparison, the other was untreated and then cured in air for 68 days.
<Result>
The observed SEM images are shown in FIGS. 2 (a) to 2 (d) show the SEM having a modifier-coated mortar specimen {depth from the placement surface (a) 1 mm, (b) 20 mm, (c) 30 mm, (d) 40 mm}. 2 (e) and (f) are SEM images of the uncoated mortar specimen {depth from the placement surface (e) 5mm, (f) 20mm}, and FIG. 2 (g) , SEM image of the product obtained from the modifier and saturated Ca (OH) ₂ solution. As can be seen from these electrophotographs, a rod-like substance having a thickness of about 0.3 microns is formed inside the specimen {FIGS. 2 (a) to (d)} to which the modifier is applied. Existence was confirmed. Such a product was not confirmed in the uncoated specimen {FIG. 2 (e) · (f)}. Further, the shape of this product is close to that of the reaction product obtained by mixing the test solution shown in FIG. 2 (g), and it is assumed that the same product was produced.

Test Example 2 (XRF elemental analysis)
<Experiment method>
As shown in the SEM image of FIG. 2 (g), a gel (hereinafter referred to as “LN gel”) obtained by dripping a modifier into a saturated calcium hydroxide aqueous solution is converted into an X-ray fluorescence analyzer (XRF). Elemental analysis was performed using The measurement conditions were a tube voltage of 30 kV and a tube current of 0.813 mA.
<Modifier>
A modifier obtained by diluting the undiluted solution obtained in Production Example 1 with water <measurement sample>
The gel formed 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 with a centrifuge. Thereafter, the sample was washed with ion-exchanged water to remove unreacted calcium ions and dried.
<Result>
FIG. 3 shows the measured spectrum, Table 9 shows the analysis result values converted into oxides, and Table 10 shows the values of Ca / Si and Ca / Al, which are the main components of the hardened cement.

As can be seen from Table 10, the molar ratios of Ca / Si and Ca / Al are 0.788 and 54.6, respectively, and the composition is clearly evident even when compared with the values of known components produced in the hardened cement. Different. From these results, the rod-shaped substance seen in FIGS. 2 (a) to 2 (d) is formed by the reaction of the present modifier that has penetrated into the specimen with Ca ions in the solution in the pores. Conceivable. Further, since Ca <Si, it is assumed that the LN gel is negatively charged.

Test Example 3 (Permeability confirmation test by alkali component analysis)
<Experiment method>
A powder sample obtained by polishing a specimen similar to Test Example 1 from the coated surface to a thickness of 1 mm was mixed and filtered with 2 mol / L hydrochloric acid, and the filtrate was analyzed by ion chromatography.
<Modifier>
A modifier obtained by diluting the stock solution obtained in Production Example 1 twice with water <Results>
FIG. 4 shows the content of each ionic species per gram of calcium. While Mg has almost the same value, the content of Li, Na, and K is larger as it is closer to the coated surface, and the value decreases as it becomes deeper. Since Li, Na, and K are components contained in the modifier, it is presumed that the modifier is gradually penetrating into the specimen. Moreover, since Mg is a component derived from cement and fine aggregate, it is considered that the value was almost uniform.

Test Example 4 {Water permeability test (1)}
<Summary>
The water permeability is in accordance with the test method for JIS A 1404 building cement waterproofing agent, a mortar (M60) specimen having a diameter of 10 cm and a thickness of 1 cm is dried until the mass remains unchanged, and a water pressure of 10 kgf / cm ² is applied. Then, the water permeability until 20 hours later was measured, and the water permeability coefficient was calculated by the following formula (1). An outline of the test apparatus is shown in FIG.

Here, in the above formula (1), Kw: hydraulic conductivity (cm / s), P: pressure (kgf / cm ² ), A: cross-sectional area (cm ² ) of specimen, h: thickness of specimen (Cm), ω: unit volume mass of water (kg / cm ³ ), Q: water permeability (cm ³ / s).

<Composition of specimen>
As a specimen, mortar (hereinafter referred to as “M60”) made of ordinary Portland cement having a water cement ratio of 60% was used. The formulation is shown in Table 11.

<Modifier>
The present modifier (Linack) obtained by diluting the stock solution obtained in Production Example 1 twice with water and a commercially available concrete modifier {registered trademark: RC guard (hereinafter referred to as “RC”) as a comparative example. .)}
<Specimen conditions>
The mortar was made of a mold having a diameter of 10 cm and a height of 1.4 cm. After demolding, the casting surface and bottom surface were polished to a height of 1 cm, and siliceous modifiers (Linack and RC) were applied. Apply 0.15 L / m ² to each specimen wetted by watering, perform watering curing after 90 minutes, apply another 0.1 L / m ² , spray watering again after 90 minutes, and then 24 hours later Even watered. Thereafter, it was wet-cured for 10 days and dried in an oven at 80 ° C. until the mass did not change (24 hours). Thereafter, the test was conducted after 1 hour in room air.

<Test results and discussion>
As shown in FIG. 5 (b), the water permeability of the specimen coated with the present modifier (Linack) was reduced to about 1/7 compared to the case of no coating, indicating high water shielding performance. On the other hand, the RC guard coating of the comparative example also had a lower value than the non-coating, but the ratio is about 1/2.

Test Example 5 {Water permeability test (2)}
<Summary>
In order to confirm the change of the permeability coefficient in the depth direction due to the penetration of the modifier, a permeability test by the output method was performed using M60 mortar. The M60 mortar of φ100 × 200 mm was cured in water until the age of 14 days, the side surfaces were sealed, and then this modifier (Linack) and RC guard were applied only to the placement surface. After curing until the age of 28 days, the amount of permeated water was measured under a pressure of 0.1 MPa using a specimen obtained by cutting horizontally every 10 mm from the placement surface. The change due to the depth of the permeability coefficient calculated by the equation (1) from the steady-state permeated water amount was evaluated in comparison with the case of no application.
<Modifier>
The present modifier (Linack) obtained by diluting the stock solution obtained in Production Example 1 with water twice and a commercially available concrete modifier (RC) as a comparative example
<Result>
FIG. 6 shows changes in the hydraulic conductivity in the depth direction. In the uncoated specimen, the 5 mm surface layer had the largest water permeability coefficient, and the water permeability coefficient tended to decrease as the distance from the surface layer increased. This is considered to be due to the change in the hydraulic conductivity because the W / C increases as it gets closer to the surface layer due to breathing and sedimentation of cement particles and aggregates. On the other hand, in the specimen coated with the present modifier, the water permeability coefficient of the surface portion is somewhat low, and there is no significant change due to the depth as seen without coating. Moreover, it is about 40 mm that the water permeability coefficient of this modifier is lower than that of no application, which is consistent with the depth at which permeability was confirmed in Test Example 1. Therefore, it is considered that the hydrate formed inside the mortar by applying the present modifier has brought about a great water-impervious improvement effect particularly in the surface layer portion. The RC guard-coated specimen showed a lower water permeability coefficient than the present modifier only at a depth of 5 mm, but at a depth of 20 mm or less, the value was larger than that of no coating.

Test Example 6 (chloride ion diffusion test by electrophoresis)
<Summary>
Chloride ions are electrophoresed in concrete using a potential difference. As shown in FIG. 7 (a), 0.5 mol / L · NaCl and 0.3 mol are provided on both sides of a concrete specimen having a diameter of 10 cm and a height of 5 cm. / L · NaOH aqueous solution is arranged and a constant DC voltage of 15 V is applied, whereby chloride ions on the cathode side pass through the concrete pores and migrate to the anode side. The effective diffusion coefficient is calculated from the increasing rate of the chloride ion concentration on the anode side. In addition, tests were conducted with mortar that is frequently used for surface finishing of concrete structures and that is easily infiltrated with salt.

<Composition of specimen>
Specimens include water-cement ratio (hereinafter W / C) 50% ordinary concrete (hereinafter OPC50), W / C 50% blast furnace Type B concrete (hereinafter BB50), W / C 30% low heat concrete (hereinafter LH30) and W / C60% ordinary mortar (hereinafter referred to as M60) was used. Each formulation is shown in Table 12.

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

<Specimen conditions>
Concrete is 5cm made from a 10cm diameter and 20cm high formwork.
Cut to thickness. The mortar was prepared with a mold having a diameter of 10 cm and a height of 10 cm, cut into a thickness of 2 cm, and a siliceous concrete modifier or the like was applied thereto. Regardless of the composition of the coating, no coating (NO), commercially available siliceous concrete modifier {trade name: RC guard (RC)} and this modifier (Linack) 0.15 L / each as a comparative example Water spray curing was performed 90 minutes after m ² application, water spray curing was further performed 90 minutes after application of 0.1 L / m ^2, and water spraying was performed 24 hours later.

<Test results and discussion>
Each effective diffusion coefficient is shown in Table 13. Moreover, the ratio with respect to no application | coating is shown in FIG.7 (b) (concrete mixing | blending) and FIG.7 (c) (mortar mixing | blending).

Table 13 shows that the effective diffusion coefficient varies greatly depending on the type of cement and the water cement ratio. However, as shown in FIG. 7 (b), the application of this modifier (Linack) was confirmed to have a salt permeation suppression effect regardless of the type of cement and the water cement ratio. The ratio of the specimen coated with RC guard (comparative example) to the uncoated effective diffusion coefficient in OPC50 is slightly less than 80%, but the specimen coated with this modifier (Linack) is 20%. A low number was shown. In general, the lower the W / C, the higher the salt shielding property, and according to the regression formula of the Standard Specification for Concrete [Construction] established in 2002, a diffusion coefficient of 40% W / C and a general W / C50 % Ratio is 43% and W / C 60% ratio is 22%. The value of 20% with respect to the non-application of OPC50 by the application of this modifier (Linack) is 40% of W / C, which is considered to prevent salt penetration, and W / C of 40%, which is considered to prevent salt penetration. It can be said that it is very high as a salt permeation suppressing effect. Since BB50 mixed with blast furnace slag has a high effect of suppressing salt permeation, this experiment also showed a diffusion coefficient as low as 1/10 or less of OPC50. However, the effective diffusion coefficient of the specimen coated with the present modifier (Linack) was further lower, and the salt shielding performance was improved. On the other hand, LH30 with a lower W / C also showed a low diffusion coefficient of about 1/8 compared to OPC50 even without application because the amount of water required for salt diffusion was very small. The diffusion coefficient was reduced by application of the agent (Linack). Further, this effect was the same with OPC and BB mortar. Using the effective diffusion coefficient obtained from the experiment, diffuse the number of years until the chloride ion concentration at the steel position of the concrete structure with a cover thickness of 5 cm reaches the corrosion limit (1.2 kg / m ³ here) Table 14 shows the results obtained by analyzing from the equations.

  The chloride ion concentration on the surface of the structure was set at three levels according to the distance from the coast. Taking the severest splash zone as an example of the salinity environment, the number of years until chloride ions reach the position of the reinforcing bar is only 3 years without the general application of OPC50. However, when this modifier is applied, it becomes 17 years, and the durability is about 6 times. In LH30 and BB50, even if it is the same splash band, it will be 30 years and 50 years without application, respectively. Even for concrete with such a high salt-shielding property, the service life can be greatly extended by applying this modifier, and LH30 is 1.6 times 50 years, and BB50 is 1.9 times 151 years. It becomes. In addition, there is no big change in RC guard application. In addition, the concentration of chloride ions on the concrete surface is not considered this time, and it is estimated that the years in the actual environment will be longer.

Test Example 7 (Surface Potential Measurement Test)
<Summary>
As a reason for the salt-blocking effect by the present application of the modifier as seen in Test Example 6, there are two possible electrostatic effects in addition to the densification of the tissue by hydrate as seen in Test Example 1. Here, the influence of the latter was examined by measuring the surface potential with cement paste. Using a specimen paste of φ100 x 5 mm (W / C 50%), pressurizing the NaCl aqueous solution in contact with the surface of the specimen coated with the modifier, and when Na ions or Cl ions pass through the pores The surface potential was indirectly measured by measuring the electromotive force generated between the charge on the pore surface. FIG. 8A shows an outline of the test apparatus.
<Modifier>
The present modifier (Linack) obtained by diluting the stock solution obtained in Production Example 1 with water twice and a commercially available concrete modifier (RC) as a comparative example
<Specimen>
Using OPC and BB cements with different electrical properties after curing, 50% W / C cement paste was cast into a mold of φ100 × 8mm, and after demolding, the cast surface and bottom were polished to a thickness of 5mm Formed. At the age of 14 days, modifiers (Linack and RC) were applied on one side, and then wet-cured for 14 days before being subjected to the test.
<Test results>
The test results are shown in FIG. OPC showed a positive potential when it was not applied, but it changed greatly to negative when this modifier was applied. BB showed a negative potential even without application, and changed more negatively with this modifier application. It has been reported that the surface potential of cement paste is affected by the presence form of Ca ions. In OPC, Ca (OH) ₂ produced by hydration shows a positive charge, but in Ca, this Ca (OH) ₂ is consumed in the hydration reaction of blast furnace slag. Conceivable. When this modifier is applied to these, it is considered that the charge is greatly changed to negative in order to newly generate hydrate and consume Ca ions. If the charge on the surface of the hardened cement body shows a large negative value, Cl ions are strongly inhibited from permeation due to repulsion, which is a factor of the high salt shielding effect by the application of this modifier obtained in Test Example 7. Conceivable. On the other hand, the RC guard (comparative example) coating specimen changed slightly negatively with OPC, but greatly changed positively with BB, making it difficult to correlate the influence on Cl ions. .

Test example 8 (chloride ion penetration test by seawater immersion)
<Summary>
This test is a simple measure of the penetration depth of all chloride ions diffusing into hardened cement.
The test method of A 1171 polymer cement mortar was followed. The specimen is immersed in salt water (artificial seawater) for 14 days, and a reagent (silver nitrate solution and uranin aqueous solution) is sprayed on the split specimen cross section to measure the discolored portion as the penetration depth. A total of 6 measurement points, 3 points per cross section, were used.
<Modifier>
(A) A modifier obtained by diluting the stock solution obtained in Production Example 1, Production Example 2 and Production Example 3 with water (b) Obtained in Production Example 1, Production Example 4 and Production Example 5 A modifier obtained by diluting the obtained stock solution with water 2 times <Specimen>
Cut a 4x4x16cm OPC mortar (W / C50%) specimen cured in water until the specified age to 4x4x4cm, completely cover with a sealing agent leaving one side, It was applied and subjected to a test after wet curing for a predetermined number of days. Salt water is JIS
Artificial seawater defined in 3.2.1 (saline solution) of A 6205 appendix 1 (Method of salt water immersion test for reinforcing bars) was used.
(A) Underwater curing until age 7 days, wet curing for 7 days after application (b) Underwater curing until age 14 days, wet curing for 14 days after application <Test results>
The results are shown in FIG.

Test Example 9 (Freeze-thaw test)
<Summary>
In accordance with JIS-A-1148 A method and JIS-A-1171, an underwater frozen water thawing test using concrete and mortar was performed. Normal test (A: OPC50, BB60 concrete), test start age of 7 days and initial frost damage before application (B: OPC50 concrete), the effect on frost damage in salty environment using artificial seawater The item to be examined was (C: OPC 50 mortar). In addition, in order to examine the effect of applying the modifier after frost damage deterioration, the modifier was applied to the specimen that had been degraded until the relative dynamic elastic modulus (RDM), which is considered to be the limit of frost damage durability, was around 60%. Furthermore, what carried out the freeze thaw test is set to (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.

<Modifier>
(A) and (B) 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
(C) The present modifier obtained by diluting the stock solution obtained in Production Example 1, Production Example 4, Production Example 6, and Production Example 7 with water twice, and a commercially available concrete modifier (as a comparative example) RC)
(D) This modifier (Linack) obtained by diluting the stock solution obtained in Production Example 1 twice with water.

<Specimen>
Specimen dimensions were 100 × 100 × 400 mm for concrete and 40 × 40 × 160 mm for mortar, and 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 OPC 50 shown in FIG. 10 (a), the RDM of the uncoated specimen began to decrease immediately after the test, and the rate of decrease rapidly increased from 250 cycles, and decreased to 60% or less in 300 cycles. As an index of frost damage resistance, RDM 60% is a limit value, and it can be said that the frost damage resistance without OPC50 coating is low. On the other hand, in the test piece coated with this modifier, the RDM exceeded 100% at the beginning of the test, and kept at a value of nearly 100% until the end of the test, showing high frost damage resistance. . In addition, the RDM coated sample of the comparative example (RC) showed a high value, but began to decrease at 300 cycles. Deterioration due to freezing and thawing is caused by water entering from the outside freezing on the surface of the concrete as the temperature falls outside, and the destruction of the structure progresses into the concrete by the expansion pressure. The concrete coated with the present modifier (Linack) is densified by a gel generated from the surface layer portion to the inside to prevent moisture from entering from the outside. Further, since moisture inside the gel is consumed, a void not filled with water is maintained inside the concrete, and the expansion pressure due to freezing can be reduced. Therefore, it is considered that the application of the present modifier (Linack) brings high frost resistance performance to concrete. The same applies to the change in mass. While no application continued to decrease in mass immediately after the start of the test, this modifier (Linack) application did not fall below the mass at the start of the test even at the end of the test. In BB60 shown in FIG. 10 (b), the RDM of the non-coated specimen started to rapidly decrease from 150 cycles and became 80% or less at 300 cycles.
Since BB forms a finer structure than OPC due to the pozzolanic reaction of the mixed blast furnace slag, and water is consumed, it has a high resistance to frost damage. Even with this BB60, the RDM maintained a numerical value of 100% or more up to 300 cycles in this modifier (Linack) -coated specimen. On the other hand, in RC guard application | coating, the numerical value of 100% or less was shown from the test start, and it fell a little at the time of 300 cycles.

<Test results and discussion (B)>
The results are shown in FIG. As can be seen from FIG. 11, the progress of deterioration was slow even without application, but the durability was further improved by application of this modifier.

<Test results and discussion (C)>
The results are shown in FIGS. In freeze-thawing in a salt environment, deterioration is said to progress more severely than in pure water, and in this test as well, non-AE, which is inferior in freeze-thaw resistance, deteriorated early. In the case of no application, the relative dynamic elastic modulus was already 60% after 15 cycles. On the other hand, in the application of the present modifier (2 blending types), the durability reached an RDM limit value of about 28 cycles. In addition, even with AE mortar with improved frost damage durability, the relative dynamic elastic modulus was 60% after about 50 cycles without application. On the other hand, in the application of the present modifier (3 blending types), all became 60% or more until 200 cycles. In particular, LN733 maintained a high dynamic elasticity of 92%. Even with a change in mass, the mass rapidly decreased after 100 cycles without application, and decreased by 10% at 200 cycles, resulting in significant damage to the structure. On the other hand, when this modifier was applied, no mass reduction was observed up to 150 cycles in any formulation. In particular, with LN422, there was no mass loss up to 200 cycles, and as shown in FIG. 13, the surface layer was completely lost without application, but with this modifier (LN422) application, it remained almost unchanged from the start of the test. And showed high scaling resistance. In addition, in the RC guard application of the comparative example, half of the surface layer is lost, and the improvement in scaling resistance is lower than that of the present modifier.

<Test results and discussion (D)>
In order to confirm the modification effect by applying the modifying agent after deterioration, OM 50 mortar cured under water until the age of 28 days was used, interrupted at the stage where the RDM reached 70% and 50% and passed through the freeze-thaw cycle. A modifier was applied. After 7 days of wet curing with the uncoated specimen, the freeze-thaw cycle was resumed in artificial seawater. In addition, when apply | coating this modifier, since it was thought that Ca (OH) ₂ of the surface layer part was leached by deterioration, Ca (OH) ₂ saturated aqueous solution was apply | coated beforehand. The test applied after degradation to RDM 70% is D70, and the case where it is 50% is D50, and each RDM and mass change are shown in FIGS. 14 (a) to (d). In D70, the RDM and mass of the uncoated specimen rapidly decreased after resumption. This is because the surface layer portion before the interruption remained relatively, and it is considered that peeling and damage were promoted due to the influence in the artificial seawater after resumption. On the other hand, in the specimens to which the present modifier was applied, the RDM value increased to 100% after resumption, and reached 60% or more even at the end. The mass was hardly decreased until about 80 cycles after resuming. Even with D50 restarted from the deterioration state below the frost damage durability limit, both the RDM and mass continued to decrease without application. On the other hand, in this modifier coating, RDM gradually increased after resumption and became 60% or more in 50 cycles after resumption. Also, the mass showed a slight increase, and no decrease was observed until 80 cycles after resumption.

From these results, the improvement of frost damage resistance by the application of this modifier is effective not only for new concrete but also for existing concrete that has suffered from frost damage and has high resistance to scaling. It was accepted to show.

The above test results are summarized below.
(1) It is confirmed that the present modifier (for example, Linack) penetrates to a depth of 40 mm, and it can be said that the penetration performance is very high as compared with the conventional permeability modifier.
(2) This modifier (for example, Linack) produces a gel having a rod-like or lump-like three-dimensional structure in the voids in the concrete and densifies the voids, thereby improving the water shielding performance. The RC guard, which is a comparative example, exhibits similar properties, but due to the difference in penetration depth, the effect of the comparative product is that of several millimeters on the surface.
(3) In addition to the densification described in (2), this modifier (for example, Linack) repels chloride ions and exhibits high salt-blocking properties because the gel surface has a negative charge. In the RC guard of a comparative example, the improvement effect with respect to salt-shielding property is low compared with this modifier.
(4) The present modifier (for example, Linack) improved frost damage resistance regardless of the cement type and water cement ratio. In addition, it showed high durability against complex deterioration with salt damage, and at the same time showed high scaling resistance. Although the improvement of the frost damage resistance was recognized in the RC guard application of the comparative example, the performance was lower than that of the present modifier (Linack), and the scaling resistance was the same.
(5) Even when this modifier (for example, Linack) was applied after degradation due to frost damage, the recovery of the relative kinematic modulus was observed after application, and durability was improved. Moreover, it was confirmed that the effect | action which assists the gel production | generation of this modifier (for example, Linack), and improves durability more is obtained with calcium hydroxide saturated aqueous solution.
(6) From the above, this modifier (for example, Linack) applied to the concrete surface penetrates deep into the concrete, and improves the water-insulating performance, salt-insulating performance, and frost damage resistance performance by the gel produced. Therefore, it is considered to be effective as a preventive or preventive measure against deterioration of concrete due to salt damage and frost damage, and combined deterioration.

FIG. 1A is a schematic cross-sectional view of concrete. 1 (b) to 1 (e) are enlarged views of a rectangular box in FIG. 1 (a). FIG.1 (c) is the figure which showed a mode that this modifier had osmose | permeated into the microscopic void | hole shown as 5 in FIG.1 (b) or the weak tissue part of an aggregate interface. FIG. 1 (d) is a diagram showing a state in which the present modifier that has penetrated into the voids reacted with calcium hydroxide and water in the pore solution to form a gel. FIG. 1 (e) is an electrophotography showing an actual state of a square box portion in FIG. 1 (d). In the figure, 1: mortar matrix, 2: coarse aggregate, 3: pores and cracks, 4: fine aggregate, 5: cement paste, 6: the present modifier, 7: gel produced from the present modifier Respectively. FIG. 2 is an SEM image (electrophotography) in Test Example 1 (the present modifier permeation confirmation test). Here, FIGS. 2A to 2D show the modifier-coated mortar specimens {depth (a) 1 mm, (b) 20 mm, (c) 30 mm, (d) 40 mm} from the placement surface}. 2 (e) and (f) are SEM images of uncoated mortar specimens (depth (e) 5 mm, (f) 20 mm from the placement surface), FIG. 2 (g) Figure ₂ is an SEM image of a product obtained from a modifier and a saturated Ca (OH) ₂ solution. FIG. 3 is a measurement spectrum of the LN gel in Test Example 2 (XRF elemental analysis). FIG. 4 is a diagram showing the relationship between the contents of various alkali metals and the depth of the coated surface in Test Example 3 (permeability confirmation test by alkali component analysis). FIG. 5 is a diagram showing an apparatus and results in Test Example 4 {water permeability test (1)}. Here, Fig.5 (a) is the figure which showed the outline | summary of the test apparatus, and FIG.5 (b) is the figure which showed the influence of the application | coating conditions in a water permeability. FIG. 6 is a diagram showing a change in the water permeability coefficient in the depth direction by applying the modifier in Test Example 5 {Water permeability test (2)}. FIG. 7 is a diagram showing an apparatus and results in Test Example 6 (chloride diffusion test by electrophoresis). Here, Fig.7 (a) is the figure which showed the outline | summary of the apparatus which concerns on this test, FIG.7 (b) shows the effective diffusion coefficient (to non-application ratio) of various concrete by modifier application | coating. FIG. 7C is a diagram showing the effective diffusion coefficient (ratio to non-application) of various mortars by applying the modifier. FIG. 8 is a diagram showing an apparatus and results in Test Example 7 (surface potential measurement test). Here, FIG. 8A is a diagram showing an outline of the apparatus according to the present test, and FIG. 8B is a diagram showing surface potentials of various cements by applying the modifier. FIG. 9 is a diagram showing the relationship between various modifiers and the total salt penetration depth in Test Example 8 (chloride ion penetration test by seawater immersion) {(a) age 7 days application, 7 days curing Post-seawater immersion, (b) Age 14 application, 14-day post-curing seawater immersion}. FIG. 10 shows changes in the relative dynamic elastic modulus of OPC50 {FIG. 10 (a)} and changes in the relative dynamic elastic modulus of BB60 when various modifiers are applied in the normal cycle test of Test Example 9 (freeze-thaw test). It is the figure which showed FIG.10 (b)}. FIG. 11 is a diagram showing a change in relative dynamic elastic modulus when the present modifier is applied in the initial frost damage cycle test of Test Example 9 (freeze-thaw test). FIG. 12 shows the change in relative kinetic elastic modulus {FIG. 12 (a)} and mass reduction rate {FIG. 12 (FIG. 12 ()) when various modifiers are applied in the seawater cycle test of Test Example 9 (freeze-thaw test). b)} and AE relative dynamic elastic modulus change {FIG. 12 (c)} and mass reduction rate {FIG. 12 (d)}. FIG. 13 is a diagram showing a scaling state at the end of the test on the specimen placing surface in the freeze-thaw test in artificial seawater of Test Example 9 (c). FIG. 14 shows the change in relative dynamic elastic modulus {FIG. 14 (a)} and the mass reduction rate when the present modifier is applied after degradation to RDM 70% in the cycle test after frost damage degradation in Test Example 9 (freeze-thaw test). {Fig. 14 (b)} and relative dynamic elastic modulus change {Fig. 14 (c)} and mass reduction rate {Fig. 14 (d)} of AE when this modifier is applied after degradation to 50% RDM. FIG.

Claims (8)

Sodium hydroxide and potassium hydroxide are blended in an aqueous lithium silicate solution, and the molar ratio of the sodium hydroxide and potassium hydroxide to SiO ₂ (in terms of alkali metal ions) is 0.08 to 1.8, and the sodium hydroxide A concrete modifier, wherein the ratio of the potassium hydroxide to the molar ratio is 0.02 to 2.7 in molar ratio . Molar ratio SiO ₂ of all alkali metal ions containing lithium ions from a lithium silicate aqueous solution, is from 0.4 to 2.1, the modifier according to claim 1. 2.7 mL of the filtered saturated calcium hydroxide aqueous solution was put into a spectrophotometer cuvette (made of polystyrene, inner dimension = 1 × 1 × 4.5 cm, volume 4.5 mL), and 0.3 mL of the modifier was slowly dropped. after mixing, it was allowed to stand in a sealed container with parafilm, when observed from immediately after dropwise until day 7, to form a two-phase structure of opaque gel phase and a clear solution phase, according to claim 1 or 2, wherein Modifier. The modifier as described in any one of Claims 1-3 which is a concrete surface application type | mold. It is a stock solution of the modifier according to any one of claims 1 to 4 , which is obtained by blending sodium hydroxide and potassium hydroxide in a lithium silicate aqueous solution, wherein SiO ₂ and Li ₂ in the lithium silicate aqueous solution. O (equivalent oxide equivalent) has a total amount of 15 to 30% by weight based on the total weight of the aqueous solution, and a molar ratio (SiO ₂ / Li ₂ O) of 3 to 8. A stock solution of modifier. Concrete comprising the step of applying the modifier according to any one of claims 1 to 4 or the modifier obtained by diluting the undiluted solution according to claim 5 to the concrete surface one or more times. Deterioration prevention or deterioration prevention method. The method according to claim 6 , further comprising applying a calcium hydroxide aqueous solution to the concrete surface before or during the one or more modifier application steps. Concrete which has been prevented or prevented from being deteriorated by the method according to claim 6 or 7 .