JP5143782B2 - Elastic composition-forming material and elastic composition - Google Patents

Description

  The present invention mainly relates to an elastic composition forming material and an elastic composition used in the civil engineering / architecture field.

Techniques to reduce the damage of underground structures due to earthquakes by modifying the surroundings of underground structures with polyvinyl alcohol hydrogel are being studied. A composition using polyvinyl alcohol and titanium lactate has been proposed as a polyvinyl alcohol-based hydrogel. (Patent Document 1).
A technique for stopping water by injecting an elastic composition into a water leakage point of a concrete structure has been studied. As an elastic composition, a composition comprising polyvinyl alcohol, titanium lactate, and a calcium aluminate compound has been proposed (Patent Document 2). Moreover, the aqueous solution containing a titanium peroxo compound and polyvinyl alcohol is disclosed (patent document 3).

JP 2006-22145 A JP 2007-31662 A JP 2008-184502 A

  In general, an aqueous polyvinyl alcohol solution containing titanium lactate increases the viscosity by making the liquid property alkaline. However, when conventional titanium lactate is mixed with an aqueous polyvinyl alcohol solution, the viscosity gradually increases even in the acidic region, and the fluidity is impaired after several days. Further, when calcium aluminate is blended, an elastic composition having good elasticity and compressive strength is obtained, but maintenance and improvement of elasticity over a long period of time have been demanded.

  Through various experimental studies, the present inventors have studied the improvement of the stability of an aqueous polyvinyl alcohol solution containing a titanium compound and the improvement of the elasticity maintenance of an elastic composition containing a calcium aluminate to complete the present invention. It came.

That is, the present invention includes (1) an elastic composition-forming material that is an aqueous solution containing titanium lactate sodium salt and polyvinyl alcohol, and (2) titanium lactate having a molar ratio of sodium to 0.5 mole of titanium of 0.5 to 1.5. (1) Elastic composition-forming material using sodium salt, (3) Solid content concentration of polyvinyl alcohol is 4 to 10% by mass, and titanium concentration is 0.5 to 3.2 % by mass (1) or (2 (4) An elastic composition comprising the elastic composition-forming material of any one of (1) to (3) and a calcium aluminate compound and a latent hydraulic substance, (5) Polyvinyl The volume of alcohol solids is larger than the volume of the calcium aluminate compound and the latent hydraulic substance, (4) the elastic composition, (6) and further contains a filler Elastic composition characterized (4) or (5) a.

  The elastic composition-forming material of the present invention can be mixed in advance because the polyvinyl alcohol aqueous solution blended with the titanium compound is excellent in stability, and can reduce the time and error of measurement at the construction site. Moreover, the elastic composition which is excellent in elasticity over a long period of time can be provided by mix | blending a calcium aluminate compound and a latent hydraulic substance with an elastic composition formation material.

  Unless otherwise specified, parts and% used in the present invention are based on mass.

  Polyvinyl alcohol (hereinafter abbreviated as PVA) used in the present invention includes fully saponified PVA and partially saponified PVA. Any modified PVA to which acrylic acid, crotonic acid, maleic acid, acrylamide or the like is added may be used as long as it has a hydroxyl group and substantially retains water solubility. As for the average degree of polymerization of PVA used for this invention, 500-3000 are preferable. If the degree of polymerization of PVA is less than 500, the elasticity of the elastic composition may not be sufficient, and if it is 3000 or more, the viscosity of the PVA aqueous solution becomes remarkably high, and is uniform with titanium lactate sodium salt, calcium aluminate compound and blast furnace granulated slag. May not be able to mix. The saponification degree of PVA is preferably 80 mol% or more. If the degree of saponification of PVA is outside the above range, the elasticity of the elastic composition may be insufficient.

  The titanium lactate sodium salt used in the present invention is not particularly limited. For example, a titanium alkoxide obtained by reacting hydroxycarboxylic acid lactic acid with sodium hydroxide is preferable. Excellent stability. In addition, other hydroxycarboxylic acid can also be used instead of lactic acid. The molar ratio of sodium to 1 mol of titanium is preferably 0.5 to 1.5. When the amount is less than 0.5 mol, the mixing stability with the PVA aqueous solution may be impaired, and when the amount is 1.5 mol or more, the sodium content becomes excessive, and the PVA that has been dissolved when mixed in the PVA aqueous solution is precipitated. There is.

  In the present invention, it is desirable that the PVA and the titanium lactate sodium salt are mixed as an aqueous solution in advance. The solid content concentration of PVA in the elastic composition-forming material, which is an aqueous solution containing titanium lactate sodium salt and PVA, is preferably 4 to 12%, more preferably 6 to 10%. If it is less than 4%, the elasticity of the elastic composition may be insufficient. If it exceeds 12%, the viscosity of the aqueous solution may be extremely high, and the calcium aluminate compound and the latent hydraulic material may not be mixed uniformly. Further, the titanium concentration in the elastic composition forming material is preferably 0.5 to 3.2%, more preferably 1.0 to 2.6%. If it is less than 0.5%, sufficient elasticity may not be obtained, and if it exceeds 3.2%, further improvement in elasticity may not be observed, which may be uneconomical.

  In the aqueous solution containing titanium lactate sodium salt and PVA, it is possible to use a rust inhibitor, a preservative, and an antifoaming agent in combination.

The calcium aluminate compound (hereinafter referred to as CA compound) used in the present invention is a substance mainly composed of CaO and Al ₂ O ₃ . Examples of a method for obtaining the CA compound include a method in which a CaO raw material and an Al ₂ O ₃ raw material are blended at a predetermined ratio, heat-treated, and pulverized.
Examples of the CaO raw material include calcium carbonate such as limestone and shells, calcium hydroxide such as slaked lime, calcium oxide such as quick lime, and the like. Examples of the Al ₂ O ₃ raw material include bauxite, aluminum residue ash, and aluminum powder.
A rotary kiln, an electric furnace, or the like can be used as a firing facility for heat treatment.

The vitrification rate of the CA compound is not particularly limited, and it can be used in a crystalline or amorphous state. The CA compounds _{crystalline, 3CaO · Al 2 O 3,} 12CaO · 7Al 2 O 3, CaO · Al 2 O 3, 3CaO · 5Al 2 O 3, CaO · 2Al 2 O 3, CaO · 6Al 2 O 3 or the like Is mentioned. Two or more of these can be used in combination.
When an amorphous component is contained, the vitrification rate is measured by the following X-ray diffraction Rietveld method. A predetermined amount of an internal standard substance such as aluminum oxide or magnesium oxide is added to the pulverized sample, and after sufficient mixing in an agate mortar, powder X-ray diffraction measurement is performed. Analyze the measurement results with quantitative software to determine the vitrification rate. As the quantitative software, “SIROQUANT” manufactured by Sitronics can be used.

The CA compound may contain impurities. Examples of impurities include SiO ₂ , Fe ₂ O ₃ , MgO, TiO ₂ , ZrO ₂ , MnO, P ₂ O ₅ , Na ₂ O, K ₂ O, Li ₂ O, sulfur, fluorine, and chlorine. For example, regarding SiO ₂ , even if it is contained up to 15%, there is no problem. If the total of other impurities is within a range of 5% or less, for example, there is no problem.

The CaO / Al ₂ O ₃ molar ratio of the CA compound used in the present invention is preferably 0.4 to 1.5. Outside this range, the elasticity of the elastic composition may be insufficient.

The fineness of the CA compound is preferably 1500 to 8000 cm ² / g, more preferably 3000 to 6000 cm ² / g in terms of the specific surface area of Blaine. If it is less than 1500 cm ² / g, sufficient strength may not be obtained, and if it exceeds 8000 cm ² / g, the reactivity becomes high, and when added to an aqueous solution containing titanium lactate sodium salt and PVA, sufficient fluidity and The pot life may not be secured.

The latent hydraulic substance used in the present invention refers to a substance that does not react when it is simply mixed with water, but reacts in the presence of a small amount of a stimulant such as calcium ion. Examples of the latent hydraulic material include blast furnace granulated slag mainly composed of CaO, Al ₂ O ₃ and SiO ₂ . Blast furnace granulated slag refers to the molten slag discharged from the blast furnace during the steel production process, quenched with water or the like to become vitreous and pulverized into fine powder.

The latent hydraulic substance may be synthesized and used. For example, there is a method in which a CaO raw material, an Al ₂ O ₃ raw material, and an SiO ₂ raw material are blended at a predetermined ratio, heat treated, and pulverized.
Examples of the CaO raw material include calcium carbonate such as limestone and shells, calcium hydroxide such as slaked lime, calcium oxide such as quick lime, and the like. Examples of the Al ₂ O ₃ raw material include bauxite, aluminum residue ash, and aluminum powder. Examples of the SiO ₂ raw material include silica, clay, and siliceous substances by-produced from various industries.
A rotary kiln, an electric furnace, or the like can be used as a firing facility for heat treatment.
The latent hydraulic material may contain impurities. Examples of impurities include SiO ₂ , Fe ₂ O ₃ , MgO, TiO ₂ , ZrO ₂ , MnO, P ₂ O ₅ , Na ₂ O, K ₂ O, Li ₂ O, sulfur, fluorine, and chlorine. If the total of these impurities is in the range of 10% or less, there is no particular problem.

The fineness of the latent hydraulic material is preferably 3000 to 9000 cm ² / g, more preferably 4000 to 8000 cm ² / g in terms of the specific surface area of Blaine. If it is less than 3000 cm ² / g, elasticity over a long period may not be obtained, and if it exceeds 9000 cm ² / g, fluidity may not be ensured.

  The compounding ratio of the CA compound and the latent hydraulic substance is preferably 20 to 80 parts of the CA compound in 100 parts in total of the CA compound and the latent hydraulic substance. If it is less than 20 parts, the elasticity of the elastic composition may be insufficient, and if it exceeds 80 parts, it may be difficult to ensure elasticity over a long period of time.

  The blending ratio of the CA compound and the latent hydraulic material with respect to the aqueous solution containing titanium lactate sodium salt and PVA is important from the aspect of elasticity, and when the volume of PVA solids in the elastic composition is 1.0, The volume of the CA compound and the latent hydraulic material is desirably 0.2 to 1.0. If it is less than 0.2, it may take too much time to change to an elastic composition, and if it exceeds 1.0, elasticity for a long time may not be obtained.

In the present invention, a filler can be blended in the elastic composition.
An inorganic or organic filler can be used. Examples of inorganic materials include aggregates such as silica and limestone, clay minerals such as bentonite, ion exchangers such as zeolite, siliceous fine powder, calcium carbonate, calcium hydroxide, calcium silicate, etc. Examples thereof include fibrous materials such as vinylon fibers, acrylic fibers, and carbon fibers, ion exchange resins, and the like. When these fillers are blended, the deformation followability to the tensile deformation of the elastic composition is improved.
The blending ratio of the filler is preferably 10 to 400 parts with respect to 100 parts of the PVA aqueous solution. If it is less than 10 parts, the improvement of the deformation followability with respect to tensile deformation may not be recognized, and if it exceeds 400 parts, the elasticity may be insufficient.

It is a method of adding a CA compound, a latent hydraulic substance, and a filler, but it may be added directly to the elastic composition forming material and mixed, or it may be mixed in water or a PVA aqueous solution in advance to form a slurry. good.
When the CA compound, latent hydraulic substance, and filler are mixed with water in advance to form a slurry and then added to the elastic composition forming material, the amount of water to be used is not particularly limited, but the CA compound, latent hydraulic property 30-60 parts is preferable with respect to a total of 100 parts of the substance and filler. If the amount is less than 30 parts, kneading may be difficult. If the amount exceeds 60 parts, the amount of water in the elastic composition may increase so that the elasticity may decrease. In addition, it is also possible to make the ratio of water less than 30 parts using a water reducing agent, and it is preferable to reduce the ratio of water because the elasticity of the elastic composition is improved.

  In the present invention, when preparing the gelation time, a retarder can be used. The retarder is not particularly limited, and citric acid, tartaric acid and the like can be used, but citric acid is preferably used from the viewpoint of long-term elasticity and stability of the elastic composition-forming material. The retarder may be added to an aqueous solution containing titanium lactate sodium salt and PVA, or may be blended in a mixture of a CA compound and a latent hydraulic substance.

  Any existing apparatus can be used as the elastic composition forming material and the elastic composition mixing apparatus in the present invention, such as a hand mixer, a tilting cylinder mixer, an omni mixer, a Henschel mixer, a V-type mixer, and a Nauta mixer. It is done.

  Examples of the ground repair method using the elastic composition of the present invention include, but are not particularly limited to, a method of pouring into a cavity or soil around an underground structure such as a tunnel and a sewer pipe. For example, after drilling a hole in a concrete wall or concrete floor slab where cavities or water leakage is seen and setting an injection plug, the elastic composition of the present invention is injected with an equal volume pump to fill the cavity, A method of forming an elastic body excellent in water stoppage and seismic isolation on the back and the lower part is mentioned.

  Examples will be described in detail below.

"Experiment 1"
A PVA aqueous solution and a titanium aqueous solution were mixed at a ratio shown in Table 1. In some blends, anhydrous citric acid was blended at the ratio shown in Table 1. The viscosity of the solution stored for one month immediately after mixing and in a room at 20 ° C. was measured to evaluate the storage stability of the solution. The results are shown in Table 1.

(Materials used)
PVA aqueous solution: manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “B17” (polymerization degree 1700, saponification degree 80.0 mol%) was added to tap water and heated to 80 ° C. to obtain a PVA aqueous solution having a solid content concentration of 10%. thing.
PVA aqueous solution a: manufactured by Denki Kagaku Kogyo Co., Ltd., trade name “B17” (polymerization degree 1700, saponification degree 80.0 mol%) was added to tap water and heated to 80 ° C. to obtain a PVA aqueous solution having a solid content concentration of 6%. thing.
Titanium aqueous solution a: titanium lactate sodium salt, titanium concentration 6.4%, Na / Ti molar ratio = 1.2
Titanium aqueous solution a ′: titanium lactate sodium salt, titanium concentration 6.4%, Na / Ti molar ratio = 0.5
Titanium aqueous solution a ″: titanium lactate sodium salt, titanium concentration 6.4%, Na / Ti molar ratio = 1.5
Titanium aqueous solution b: titanium lactate, titanium concentration 8.2%, Na / Ti molar ratio = 0
Titanium aqueous solution c: titanium peroxocitrate sodium, titanium concentration 4.8%, Na / Ti molar ratio = 3.0
Water: tap water Citric acid: anhydrous citric acid, reagent grade 1

(Test method)
PVA concentration: The elastic composition-forming material was colored using iodine, and then measured by a UV-visible absorption spectrum method using a spectrophotometer (manufactured by JASCO Corporation).
Titanium concentration: It was measured using an ICP emission spectroscopic analyzer (manufactured by SII Nano Technologies).
Sodium concentration: measured using an atomic absorption photometer (manufactured by Shimadzu Corporation).
Solution viscosity: A TV-10 viscometer manufactured by Toki Sangyo Co., Ltd. was used. The measurement was performed in a 20 ° C. environment, and the rotational speed of the rotor was 20 rpm.

"Experimental example 2"
In the same manner as in Experimental Example 1, an aqueous PVA solution and an aqueous titanium solution were mixed to prepare elastic composition-forming materials having the PVA concentration, titanium concentration, and sodium concentration shown in Table 2. Further, the CA compound, the latent hydraulic substance, and water were mixed at a ratio shown in Table 2 to form a slurry, which was added to the previously prepared elastic composition-forming material, and was sufficiently stirred to obtain an elastic composition. In order to adjust the gelation time, citric acid that is 1.5% of the total amount of the CA compound and the latent hydraulic substance was added in advance to the elastic composition-forming material.

(Materials used)
CA compound: CaO 29%, Al ₂ O ₃ 65%, SiO ₂ 3%, TiO ₂ 3%, CaO / Al ₂ O ₃ molar ratio 0.8, vitrification rate 30%, specific surface area 5000 cm ² / g, density 3 .05g / cm ³
Latent hydraulic material: granulated blast furnace slag, commercial product, CaO 40.6%, Al ₂ O ₃ 14.8%, SiO ₂ 33.2%, MgO 6.7%, specific surface area 6000 cm ² / g, density 2.90 g / Cm ³

(Test method)
Elasticity (restoration rate): Pour the elastic composition into a 2 x 2 x 2 cm mold, demold it at the age of 1 day, and unload it after 0.5 cm from the top using a commercially available pressure tester did. The restoration rate was measured by measuring the height (xcm) of the specimen after unloading. The restoration rate was calculated by [1- (2-x) /0.5] × 100 (%) and used as an index of elasticity. Measurements were also made 1 month and 2 months after placing.

"Experiment 3"
The same procedure as in Experimental Example 2 was performed except that the type of PVA was changed as shown in Table 3. The solid content concentration of the PVA aqueous solution was 10%. The results are shown in Table 3.

"Experimental example 4"
As in Experimental Example 1, an elastic composition-forming material containing PVA, titanium, sodium, and citric acid in the proportions shown in Table 4 was prepared. Moreover, the CA compound, the latent hydraulic substance, the filler, and water in the ratios shown in Table 4 were mixed to form a slurry, which was added to the previously prepared elastic composition forming material and stirred to obtain an elastic composition. Similarly, the elasticity and the deformation follow-up property against tensile deformation were evaluated. In addition, the material used in Experimental Example 1 and Experimental Example 2 was used. The results are shown in Table 4.

(Materials used)
Calcium carbonate powder: Commercial product, 100 mesh

(Test method)
Followability to tensile deformation: Two cylindrical mortar specimens having a diameter of 5 cm and a height of 4.5 cm were prepared, and set with a 1 cm gap in a horizontal cylindrical mold having a diameter of 5 cm and a height of 10 cm. The elastic composition before thickening was poured into this gap and cured at 20 ° C. for 7 days. After 7 days, the mold was removed, and the mortar specimen was pulled up and down by an autograph to evaluate the deformation followability of the elastic composition. In addition, the place where the tensile stress generated when the mortar specimen was pulled reached the maximum value was taken as the yield point, and the tensile displacement at that time was measured. The larger the displacement, the more the deformation can be followed.

  Since the elastic composition-forming material of the present invention is excellent in stability, it can be mixed in advance, which can reduce the time and error of measurement at the construction site. In addition, by blending the CA compound and the latent hydraulic substance with the elastic composition-forming material of the present invention, an elastic composition having excellent elasticity over a long period of time can be provided. Is suitable for applications such as ground stabilization.

Claims (6)

An elastic composition-forming material, which is an aqueous solution containing titanium lactate sodium salt and polyvinyl alcohol. The elastic composition-forming material according to claim 1, wherein a titanium lactate sodium salt having a molar ratio of sodium to 1 mol of titanium of 0.5 to 1.5 is used. The elastic composition-forming material according to claim 1 or 2, wherein the polyvinyl alcohol has a solid content concentration of 4 to 10 mass% and a titanium concentration of 0.5 to 3.2 mass% . The elastic composition formed by containing a calcium aluminate compound and a latent hydraulic substance in the elastic composition formation material of any one of Claims 1-3. The elastic composition according to claim 4, wherein the volume of the solid content of polyvinyl alcohol is larger than the volume of the calcium aluminate compound and the latent hydraulic substance. Furthermore, the elastic composition of Claim 4 or 5 containing a filler.