JP5438264B2 - Concrete repair / modification agent. - Google Patents

Description

  The present invention relates to a concrete repairing / modifying agent that repairs concrete that has become neutralized or cracked due to aging, and modifies the concrete to prevent further deterioration.

  Concrete used for roads, bridges, building exteriors, etc. is subject to cracks due to loads such as earthquakes and heavy loads, and neutralization due to acid rain and carbon dioxide contained in the air. This causes problems such as deterioration of concrete, corrosion of reinforcing bars, and water leakage.

  As a countermeasure, there has been proposed a method of repairing or modifying deteriorated concrete by applying or injecting a waterproofing agent or a modifying material mainly composed of silicates.

For example, a means for forming an osmotic waterproof protective layer by applying or injecting an inorganic permeable waterproofing agent containing sodium silicate as a main component and permeating concrete by repeating watering several times after drying has been proposed (for example, a patent) Reference 1). In addition, a modifying material in which sodium silicate and potassium silicate are mixed at a molar ratio of 1: 1 and sodium hydroxide is added has been proposed, and the rate of gelation is adjusted by adjusting the amount of sodium hydroxide added. It is described that it can be permeated appropriately according to the state of deterioration of concrete (for example, see Patent Document 2).
Japanese Patent No. 2937309 JP 2002-239523 A (1-5 pages)

  However, in the means described in the above-mentioned Patent Document 1, the inorganic permeable waterproofing agent mainly composed of sodium silicate penetrates into concrete, and is applied or poured and dried, and then waits for 5 to 7 hours for drying and watering. However, it is necessary to repeat three times, and there is a problem that the operation is very complicated and takes a long time.

  In addition, the technical significance of the modifying material described in Patent Document 2 is that the gelation of the silicate is slowed down so that the coated or injected modifying material penetrates deep into the concrete. The penetration rate into the water is not improved, and it is necessary to sprinkle water to promote the reaction between concrete and calcium, so it cannot be said that the workability is good.

  In other words, silicates are widely used for repairing and modifying concrete that has become neutralized or cracked due to aging, but its permeability to concrete is poor, making it difficult to penetrate deeply and complicated work. There was a problem that it took a long time.

  Accordingly, an object of the present invention is to provide a concrete repairing / modifying agent that can permeate quickly and deeply into aged concrete in a short time and repair and improve it with good workability.

As a result of intensive research, the inventors of the present invention quickly applied water, one or more water-soluble silicates, colloidal silicates, and a reducing agent to neutralized and cracked concrete. It was found that it penetrates deeply, and the present invention was completed. That is, the feature of the concrete repairing / modifying agent according to the present invention is that it contains water, at least one water- soluble silicate, colloidal silicate, and a reducing agent.

  The alkali metal constituting the water-soluble silicate and colloidal silicate is preferably one of sodium, potassium and lithium. The reducing agent is preferably either thiourea or thiosulfate.

Here, the “water-soluble silicate” means one represented by the following general formula (I).
M ₂ O · XSiO ₂ (I)
In the above formula (I), M represents an alkali metal belonging to Group 1A of the periodic table, and X is a positive number. Further, the “alkali metal M” is preferably one of sodium (Na), potassium (K), and lithium (Li). “X” is preferably 2.0 to 5.0.

  As “water-soluble silicate”, for example, commercially available products manufactured by Nippon Kagaku Kogyo Co., Ltd., J sodium silicate 1, 2, 3, sodium silicate 4, 1K potassium silicate, C potassium silicate, B potassium silicate, Examples include A potassium silicate, 2K potassium silicate, lithium silicate 30, lithium silicate 40, lithium silicate 45, and lithium silicate 75, but not limited to these, as long as they are represented by the general formula (I). .

  The above “colloidal silicate” means a colloidal solution in which ultrafine particles of silicic anhydride are dispersed using water as a dispersion medium. The particle diameter is 6 to 120 nm, and the group 1A of the periodic table is used for stabilization. Alkali metals belonging to The size of the colloidal silicate is preferably in the range of 6 to 50 nm, but is not particularly limited to this range. The alkali metal for stabilization is preferably any one of sodium, potassium and lithium, for example.

  Examples of colloidal silicates include Snowtex XS, S, 20, 30, 40, 50, N, CM, 20L, XL, ZL, L, MP, UP, and PS-M from Nissan Chemical Industries, Ltd. However, it is not limited to these.

Repair and modifiers of concrete of the present invention, either or content of solids which is the sum of both the colloid-like silicates and two or more water-soluble silicate is preferably 5 to 40 wt% 10 to 25% by weight is more preferable. If it is less than 5% by weight, the effect as a repair / modifier is weak, and if it exceeds 40% by weight, the product is easily gelled.

  Examples of the “reducing agent” include ferrous sulfate, potassium hydrogen sulfite, sodium hydrogen sulfite, ammonium hydrogen sulfite, potassium sulfite, sodium sulfite, ammonium sulfite, lithium sulfite, sodium pyrosulfite, potassium pyrosulfite, and sodium hydroxymethanesulfonate. Thiourea, sodium thiosulfate, ammonium thiosulfate, potassium thiosulfate, ammonium thiosulfate, ascorbic acid, sodium ascorbate, reducing sugar (oligosaccharide, fructose, sucrose), benzaldehyde, etc. Not what you want.

  Preferred as the “reducing agent” is thiourea, sodium thiosulfate, potassium thiosulfate, lithium sulfite, or reducing sugar (oligosaccharide, fructose or sucrose), and the addition amount is 0.001 to 2.0. % By weight is preferable, and 0.01 to 1.0% by weight is more preferable.

  Note that concrete contains metals such as magnesium oxide, iron oxide, and aluminum oxide, and silicates react with these contained metals to be oxidized and deteriorated. When a reducing agent is added, it is presumed that this oxidative deterioration is suppressed and the permeation rate is increased, but the action mechanism is not necessarily clear.

  In order to improve the fluidity and stability of the product, a surfactant, a polyhydric alcohol, a chelating agent, a preservative, and the like may be added to the concrete repairing / modifying agent of the present invention. The “surfactant” is preferably an alkyl ether type nonionic surfactant and a glycol ether type nonionic surfactant, and the polyhydric alcohol is preferably glycerin, propylene glycol, or dipropylene glycol, and the chelating agent is EDTA-4Na and NTA are preferred.

  When using the concrete repairing / modifying agent of the present invention, it may be applied using any equipment, but it is preferable to spray uniformly using a sprayer. Moreover, the injection | pouring using a nozzle etc. is also possible. Usually, it is used as a stock solution, but it can also be diluted as necessary.

  According to the concrete repairing / modifying agent according to the present invention, it is possible to quickly permeate deeply into concrete that has deteriorated over time in a short time and to repair and improve it with good workability. In addition, since conventional concrete modifiers mainly composed of silicates penetrate into concrete after application, it is necessary to perform watering curing work, and the timing of watering was difficult for non-skilled workers. There is no.

  FIG. 1 shows the components contained in the concrete repair / modifying agent according to the present invention, the content (% by weight), and the sources. Note that FIG. 1 shows a blend A, a blend B, and a blend C in which the blending ratios of the components are changed. For comparison with the present invention, as a conventional example, a compound containing no colloidal silicate and a reducing agent is shown as Formulation D, and a compound containing no reducing agent is shown as Formulation E.

  Examples 1 and 2 show the results of confirming the effects of the concrete repairing / modifying agents of these blends A to E.

On the flat concrete surface that has been exposed to the sun for 3 months after construction, the concrete repair / modifiers of the blends A to E shown in FIG. 1 are each sprayed at 300 ml / m ² in a 100 cm × 100 cm section. The time from application to drying and change in color was measured visually. This test was performed twice at an outdoor temperature of 8 ° C. and 15 ° C. in consideration of weather conditions. FIG. 2 shows the results of the test when the outside air temperature is 8 ° C. and no wind. In addition, FIG. 3 shows the results of a test in which the outside air temperature is 15 ° C. and no wind.

  As shown in FIG. 2 and FIG. 3, the concrete repairing / modifying agents (compounding A, blending B, and blending C) according to the present invention are more concrete than the conventional techniques (blending D and blending E). It was confirmed that the permeation rate into the cell increased approximately twice.

  Concrete was cast into a cylinder having a diameter of 10 cm and a height of 10 cm, demolded after 2 days, and cured for 7 days. Then, it was left still in a constant temperature room at 20 ° C. for 60 days to prepare a cylindrical concrete specimen. The components of this concrete specimen are shown in FIG.

Next, this cylindrical concrete specimen was put in an acrylic cylindrical case having a diameter of 10 cm and a height of 15 cm in a constant temperature room at 20 ° C., and the gap between the acrylic case and the concrete specimen was joined with an epoxy resin adhesive. Then repair and modifiers of concrete and sealed put 392.5 ml, 60 min, to measure the decrease of the liquid after 120 min. The measurement result of the decrease amount of this liquid is shown in FIG. Note shown in FIG. 5 "penetration amount (m l / m ^2)" and is divided by the amount of reduction of the liquid cross-sectional area (m ²⁾ of (milliliters) of cylindrical concrete specimens, i.e. milliliters per square meter It is the value converted into.

  As shown in FIG. 5 above, the concrete repairing / modifying agents (compounding A, blending B, and blending C) according to the present invention all penetrated into the concrete as compared with the prior art (blending D and blending E). It was confirmed that the amount increased about twice.

  It has excellent permeability to concrete, and can effectively repair and improve neutralized and cracked concrete to prevent water leakage and corrosion of reinforcing steel, and widely used in industries related to concrete and civil engineering construction. Can do. In addition, since the conventional concrete modifier mainly composed of silicates is applied to the concrete after application, it has been necessary to carry out watering curing, but this work is eliminated. It was difficult for a skilled person to determine the timing of watering, but it was not necessary, and a wide range of contractors could work, so it could be widely used in industries related to concrete and civil engineering.

It is a table | surface which shows one example of the containing component etc. of this invention. It is a table | surface which shows the confirmation test result of the effect of this invention. It is a table | surface which shows the other confirmation test result of the effect of this invention. It is a table | surface which shows the component of the concrete used for the confirmation test of the effect of this invention. It is a table | surface which shows the other confirmation test result of the effect of this invention.

Claims (2)

Including water, one or more water-soluble silicates, colloidal silicates, and a reducing agent;
The water-soluble silicate includes an alkali metal belonging to Group 1A of the periodic table,
The colloidal silicate includes an alkali metal belonging to Group 1A of the periodic table,
The above-mentioned reducing agent is either thiourea or sodium thiosulfate, and is a concrete repair / modification agent. The concrete repairing / modifying agent according to claim 1, wherein the alkali metal constituting the water-soluble silicate and the colloidal silicate is any one of sodium, potassium, and lithium .

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