JPS60200851A - Admixing agent and composition for underwater concrete - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to underwater concrete admixtures and compositions. More specifically, the present invention relates to admixtures and compositions for so-called underwater concrete or underwater mortar used when placing concrete or mortar underwater.

Conventional admixtures for underwater concrete or underwater mortar include water-soluble polymer thickeners such as polyvinyl alcohol, polyacrylamide, sodium polyacrylate, polyethylene oxide, and cellulose ether (Japanese Patent Laid-Open No. 57
-815804) are miscible with water or have poor solubility), tend to form a lump, and the mixing of cement and aggregate with the thickening agent is insufficient, and when applied underwater) cement, aggregate There was a problem in that it was not possible to prevent the dispersion of such substances into the water.

There is also an aqueous dispersion made by crosslinking a cellulose ether thickening agent (Japanese Patent Application Laid-open No. 58-18-5468), but this has the problem that it does not have the strength of concrete.

The present inventors have made extensive studies to solve these problems, and as a result, have arrived at the present invention. That is, the present invention provides an admixture for concrete or mortar in water (first invention) consisting of a vinyl polymer emulsion (a) with a pure acid value of 4f7 in the range of 100 to 500, and an admixture with a pure acid value of 100 to 500.
An underwater concrete or mortar composition consisting of a vinyl polymer emulsion (a) in the range of 2nd invention)
It is.

In the polymer emulsion (a) used in the present invention, a polymer composed of a carboxyl group-containing monomer and other monomers is used as the polymer.

Examples of carboxyl group-containing monomers include the following or two or more of these: (1) Unsaturated monocarboxylic acids (meth)acrylic acid, crotonic acid, etc. (2) Unsaturated polycarboxylic acids maleic acid, itaconic acid , fumaric acid, etc. Preferred among these are acrylic acid, methacrylic acid, maleic acid and itaconic acid, with methacrylic acid being particularly preferred.

Other monomers include the following and two or more of these.

(1) Hydrophobic monomer (a) Unsaturated carboxylic acid ester (meth)acrylic acid alkyl (alkyl group has 1 to 12 carbon atoms) ester [methyl (meth)acrylic acid,
ethyl-2n- or isopropyl-9n- or isobutyl-22-ethylhexyl ester, etc.]; diesters of itaconic acid, diesters of maleic acid, etc. (b) Aromatic vinyl monomers, styrene, etc. (c) Vinyl esters Vinyl acetate (e) Halogen-containing monomers Vinyl chloride, chloroprene, etc. (2) Hydrophilic monomers without acid value Amide group-containing monomers [(meth)acrylamide] (A small amount may be used.) Preferred among these are alkyl (alkyl group having 1 to 4 carbon atoms) esters of (meth)acrylic acid.

The above polymer may contain a crosslinking agent (a crosslinking monomer or a crosslinking compound) if necessary, and the crosslinking agent includes (I) a monomer having at least two polymerizable double bonds; ,
(■) A monomer having at least one polymerizable double bond and at least one functional group reactive with the monomer; (I) A monomer having at least two functional groups reactive with the monomer. Compounds with functional groups, (
(2) Examples include polyvalent metal compounds that can form ionic crosslinks. Examples include the following and two or more of these.

1. Monomer of Il (1) di- or polyvinyl compound divinylbenzene, divinyltoluene, divinylxylene, divinyl ether, divinyl ketone, trivinylbenzene (2) di- or polyester of unsaturated mono- or polycarboxylic acid and polyol Di- or tri(meth)acrylic acid esters of polyols (ethylene glycol, trimethylolpropane, glycerin, polyethylene glycol, polypropylene glycol, etc.) e.g. di(meth) of ethylene glycol
Acrylate.

(3) Di- or polyallyl ester of polycarboxylic acid Diallyl fumarate, diallyl maleate.

Diallyl phthalate, etc. (4) Bis(meth)acrylamide N, N-methylenebis(meth)acrylamide, etc.) Crosslinking agent having at least two polymerizable double bonds as described in U.S. Pat. No. 4,076.668 can also be used.

Monomer 2 (■) An ethylenically unsaturated monomer containing at least one carboxyl group, a group reactive with a carboxylic acid anhydride group, such as N-methylol (meth)acrylamide.

Compounds of glycidyl (meth)acrylate 3, polyfunctional compounds having reactive groups with carboxyl groups and carboxylic acid anhydride groups, such as polyhydric alcohols (such as ethylene glycol), polyamines (alkylene diamines, such as ethylene diamine; polyalkylene polyamines, etc.) ) 4. (IV) Compounds Polyvalent metal compounds capable of forming ionic crosslinks, such as alkaline earth metals (Ca, Mg, etc.), oxides, hydroxides, carbonates, organic acid esters of zinc, aluminum, etc. CaO, Ca(OIL)2/magnesium carbonate, calcium acetate.

Among these compounds, divinyl-1-luene is preferred.

These are diallyl maleate, diallyl phthalate, and polyethylene glycol diacrylate.

In the polymer, the content of carboxyl group-containing monomers is usually from 20 to 75 inches, based on the weight of the total monomers.

Preferably it is 80-70%. The content of hydrophobic monomers is usually from 25 to 80%, preferably from 30 to 70%, based on the weight of total monomers.

Further, the weight ratio of the hydrophilic monomer having no acid value and the carboxyl group-containing monomer is usually 0:100 to 50:5.
0, preferably o:ioo to 25:75.

The content of crosslinking agent is usually θ~2 based on the weight of total monomers.
%, preferably 0 to 1%.

A polymer emulsion can be obtained by mixing, emulsifying or dispersing a monomer and water using an emulsifier and polymerizing the mixture.

Examples of emulsifiers used for emulsification or dispersion include anionic emulsifiers such as sulfate ester salts (alkyl sulfate salts, polyoxyethylene alkyl sulfate salts, polyoxyethylene alkylphenyl sulfate salts, etc.), sulfonate salts (alkylbenzene sulfonate salts, etc.), salt, etc.).

Phosphate ester salt (alkyl phosphate ester salt.

polyoxyethylene alkyl phosphate ester salts, etc.))
and higher fatty acid salts) and nonionic emulsifiers, such as polyoxyethylene alkyl ethers, holoxyethylene alkylphenyl ethers, and polyoxyethylene fatty acid esters, which may be used alone or in combination of two or more.

Among these, preferred are polyoxyethylene alkylphenyl sulfate salts and holoxyethylene alkyl ether sulfate salts.

The amount of emulsifier used is usually 0.5 to 0.5 based on the weight of the monomer.
10%, preferably 1 to 5 inches.

Examples of methods for emulsification and dispersion include a method in which a monomer, an emulsifier, and water are added and stirred, and a method in which the monomer and emulsifier are mixed in advance, water is added, and the mixture is stirred. The stirring temperature is usually θ to 70°C.

As the stirring device, a normal stirring device such as a propeller stirring M
A. A homogenizer, static mixer, etc. can be used.

Examples of the polymerization method include methods using a polymerization catalyst, ultraviolet rays, radiation, etc.) A method using a polymerization catalyst is preferred.

When polymerizing, a method in which all or most of the monomers (for example, 80 units or more) are charged into a reaction vessel and polymerized (so-called bulk charging polymerization) is a method in which a part of the monomer mixture (for example, less than 80 units) is charged in advance. Compared to the method of adding the remaining monomer mixture continuously or in portions, this method is preferable because stable polymerization can be performed without producing a large amount of coagulated material during polymerization.

Examples of polymerization catalysts include persulfates (sodium salts, potassium salts, ammonium salts, etc.) and peroxides (t-butyl hydroperoxide, hydrogen peroxide, etc.).

Redox catalysts (peroxides and persulfates/reducing agents such as potassium persulfate/sodium sulfite).

hydrogen peroxide/ferrous salts, etc.). Among these, preferred are redox catalysts.

The amount of catalyst used is usually 0.01 to 0.5% by weight based on the total monomers. The polymerization initiation temperature is usually 20 to 80"Q, preferably 30 to 70°C. If the polymerization initiation temperature exceeds 80°C, the degree of polymerization will decrease, and if it is less than 20°C, polymerization will hardly proceed. The polymerization temperature is Usually 20-80°C, preferably 30-80°C.

Note that the pure acid value of the polymer emulsion is 100 to 500.
It is manufactured to have an acid value of 100 to 50 from the beginning.
In addition to the method of manufacturing so that the acid value is 0, it is also possible to partially neutralize with an alkali so that the acid value becomes the above value (in the form of a partial salt).

When using the compound (■) as a crosslinking agent, it is preferably added after the polymer emulsion is prepared.

The resulting polymer emulsion usually has a solid content concentration of 15 to 40, preferably 20 to 30, on a weight basis. The viscosity of polymer emulsions is usually 3 to 20 cps (
(Measured at 80°C, B-type viscometer, 12 revolutions per minute).

The acid value of the pure component (polymer) in the polymer emulsion is ioo
-500, preferably 200-450, most preferably 250-400. If the acid value is less than 100, the thickening effect obtained by contact with an alkali such as cement will not be sufficient and diffusion of mortar or concrete into water will occur. If it still exceeds 500, it becomes difficult to create a stable polymer emulsion.

The viscosity of the polymer in the polymer emulsion is such that the viscosity of an aqueous solution of the polymer after neutralization with sodium chloride is usually 100 cps or more, preferably aoocps or more.

Cement used in the present invention includes ordinary Portland cement, other Portland cements (early strength, super early strength, moderate heat, white Portland cement, etc.), mixed Portland cement (blast furnace cement, fly ash cement, silica cement, etc.), etc. can be given.

Examples of the aggregate used in the present invention include river sand, sea sand, chestnut stone, crushed stone, and fly ash. Fine aggregate is usually used for mortar, and coarse and fine aggregate is usually used for concrete.

Examples of the concrete fluidizing agent used in the present invention include lignin-based sulfonates, melamine-based sulfonates, polycyclic aromatic sulfonates, and naphthalene-based sulfonates.

In the composition of the present invention, a vinyl polymer emulsion (
The amount of a) to be added to cement (b) is usually 0.01 to 10% by weight as pure polymer, preferably O1 to
It is 5chi. If the amount is less than 0.01%, the thickening effect will be sufficient, but if the amount is more than 10%, the mortar will not be able to prevent the concrete from spreading. The viscosity of the concrete becomes too high, and unless more concrete fluidizing agent is added, it becomes fluid, which is uneconomical.

The amount of aggregate is usually 1:2 to 1:4 in the weight ratio of cement to fine aggregate in the case of mortar, and 1:2 in the weight ratio of cement to fine aggregate and coarse aggregate in the case of concrete. :1
~1:5:20.

The amount of the concrete fluidizing agent (d) relative to the cement (1) is usually 0 to 10 g, preferably 0.
~5chi.

When using mortar, the water-cement ratio is usually 40 to 12.
0%, and for concrete it is usually 40-80%.

In producing the composition of the present invention, there are no particular restrictions on the blending procedure; cement (b), aggregate (C), concrete fluidizer (d), and water (e) are appropriately mixed in a mixer, and the final A method of adding the admixture (,l) of the present invention to;
A method of charging and mixing the entire composition in a mixer at once;
However, the former method is preferable from the viewpoint of thickening effect.

There is no special method for applying the composition of the present invention in water, and commonly used methods such as pumping with a hose, natural dropping with a hose, chute or packet, and dropping with a tremie tube are possible.

The composition of the present invention includes the above (a) + (b), (cl,
In addition to component (d), a cement quick-setting agent that accelerates the hardening of cement, such as sodium aluminate and potassium aluminate.

Water glass, soda carbonate, sodium sulfate, organic acid soda, calcium chloride, aluminum sulfate, calcium aluminate, calcium haloaluminate.

Triethanolamine etc. can be added.

Preferred among these are potassium aluminate and calcium haloaluminate.

Addition of such an accelerating agent is preferable from the viewpoint of improving the water flow resistance of the cement composition. The amount of cement quick setting agent added is usually 0 to 10%, preferably 0 to 7%, based on the weight of cement.
It is Chi.

Also, if necessary, dispersion stabilizers (bentonite, CMC, etc.) that increase the dispersion stability of mortar or concrete; cement retarders (gluconic acid, citric acid digypsum, etc.) that retard the hardening of cement.

Various saccharides, etc.); fillers, anti-shrinkage agents; anti-crack agents (organic, inorganic fibers, etc.); antifoaming agents (silicon, alcohol, etc.) may be added as appropriate.

In the case of a cement retarder, the amount added is usually θ to 10% of the cement weight, and in the case of a dispersant, it is usually θ to 5%.

The underwater concrete or mortar composition using the admixture of the present invention has the following effects.

(1) It has a strong effect of preventing 9 diffusion into water.

When the composition of the present invention is used for underwater construction, it has a great effect of preventing cement, aggregate, etc. from dispersing into the water, and as a result, underwater concrete with high strength is produced and there is no problem of water pollution.

(2) Gives concrete or mortar a hardened product with excellent strength (both in water and in air).

The strength of concrete (
However, the composition to which the admixture of the present invention is added has the effect of improving concrete strength, and is fully satisfactory as an underwater concrete.

(3) When making a composition, there is no need to pay special attention to the mixing procedure, and the work procedure is not complicated. Concrete or mortar containing water-soluble polymer thickeners such as soda and polyoxyethylene cellulose ethers (Japanese Unexamined Patent Publication No. 57-81580) has poor miscibility or solubility with water and tends to form lumps. , the cement, aggregate, and thickening agent were insufficiently mixed, and when construction was carried out underwater, it was not possible to prevent the cement, aggregate, etc. from dispersing into the water.Therefore, it is necessary to pay close attention to the mixing procedure. Instead of premixing cement, aggregate, thickening agent, etc.) and adding water and a superplasticizing agent, it is possible to mix the thickening agent with water in advance as an aqueous solution or suspension. .

It was necessary to add it to aggregates, etc. When the highly viscous concrete thus obtained was transported to the site in a mixer truck, the high viscosity remained inside the truck, making it difficult to clean the truck.

On the other hand, the material of the present invention is easily dissolved in water;
There is no need to be particularly careful about the mixing procedure, as it will not turn into a mamako. Additionally, since it is a type of concrete that increases in viscosity when it comes into contact with alkalis such as cement, it is possible to transport the ready-mixed concrete from a concrete factory to the site using a mixer truck, and mix it with an admixture at the time it is pumped during construction. Because of this, some mixers come from the consistency of underwater concrete.

The difficulty of cleaning mixer trucks is eliminated.

Because of these effects, the composition of the present invention exhibits excellent effectiveness in construction work for constructing concrete or mortar structures underwater. For example, it can be used to create gaps between underwater stones and blocks, for consolidation work, and for underwater unreinforced or reinforced concrete work with 1 injection of mortar.

The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto.

Examples 1-8. Comparative Examples 1-2 650 g of water and 12.9 g of sodium polyoxyethylene alkylphenol sulfate in a glass kolben with stirrer
and 250 g of the monomer mixture shown in Table 1",
While introducing nitrogen, the temperature was adjusted to 50°C and emulsified.

Next, 20 g of each of sodium persulfate and sodium sulfite were added as polymerization catalysts in two liquids. After the polymerization started, the polymerization temperature rose to 70 to 75°C, but after reaching the maximum temperature, the Kolben was cooled, and when it reached 50°C, 10g of each 2-part polymerization catalyst was added again. The mixture was aged at the same temperature for 2 hours to consume unreacted monomers. Thereafter, the contents were filtered through a mouth cloth to obtain a vinyl polymer emulsion, which was used as an admixture for underwater conc.

*During polymerization, the entire contents became highly viscous and eventually the emulsion itself was destroyed.

Example 4 An underwater mortar composition having the formulation shown below was obtained.

Mortar composition (per 11rL8) Pabokko land cement: 450 to 9 fine aggregate (river sand): 1450kg Sodium ligninsulfonate: Appropriate amount Water: 80 (1g Admixture of Example 1 20~401cg of sodium ligninsulfonate The amount added is such that the obtained mortar flow value (physical test method for cement JISR-5201) is all 1.
It was adjusted to be 80±5. (θ ~ 9 kFl) The mixing order is to make a mortar by mixing cement, fine aggregate and water, add and stir a predetermined amount of the admixture of Example 1, and finally add an appropriate amount of sodium sulfonate. The flow value was set to 180±5. Pack 1 kg of the obtained raw mortar into a 40-mesh metal bag, and immediately
suspended in the water.

One day later, the amount of solids flowing out of the bag was measured, and the ratio to the charged amount was calculated as the diffusion rate in water. Furthermore, the compressive strength of the obtained mortar after 28 days was measured. Separately, the compressive strength of mortar obtained by air-drying the same raw mortar after 28 days was also measured. The results are shown in Table-2.

Table 2 From these results, the mortar without the admixture of Example 1 has a large underwater diffusivity (in-water diffusivity) ~ The strength of the mortar constructed in water is significantly lower than that of air-drying mortar, but It can be seen that by adding the admixture of Example 1, the dispersibility in water was reduced and the mortar strength was still close to that of air-dry curing.

Example 5 A mortar composition was obtained in the same manner as in Example 4, except that 2 kg of the admixtures of Examples 2 and 3 (purity: 1.1% to cement) was used, and the same tests as in Example 4 were carried out. carried out. The results obtained are shown in Table 3.

Comparative Example 3 The admixture of Comparative Example 1 was added to 20 to 9 (pure content: 1 to cement).
．． A mortar composition was obtained in the same manner as in Example 4 except that 1%) was used, and the same tests as in Example 4 were conducted.

The results follow.

Diffusivity in water = 60 cm Compressive strength of mortar applied in water (kβ): (1000
Air-dried curing mortar p (kβ): 882 Comparative Example 4 Weakly anionic polyacrylamide with a molecular weight of 2 million 5
kg, (11% to cement as pure content), 5 kg of hydroxyethyl cellulose (1% to cement as pure content)
．． A mortar composition was obtained in the same manner as in Example 4, except that 1%') was used, and a mortar composition obtained by the method Because a considerable amount of water-soluble thickening agent was dispersed in a lumpy state (labeled as an after-mix product), the blending procedure was changed, and after premixing cement, aggregate, and water-soluble thickening agent, fluidization was performed. A mortar (indicated as a premix product in the table), which was prepared by adding agent and water and stirring and which produced relatively little mako, was also tested. The results are shown in Table-4.

Claims (1)

[Claims] 1. An admixture for underwater concrete or mortar comprising a vinyl polymer emulsion (a) having a pure acid content in the range of 100 to 500. 2. The admixture according to claim 1, wherein the vinyl polymer is a polymer of an unsaturated carboxylic acid and a hydrophobic monomer. 3. The admixture according to claim 2, wherein the unsaturated carboxylic acid is (meth)acrylic acid. 4. The admixture according to claim 2 or 3, wherein the hydrophobic monomer is an alkyl (alkyl group having 1 to 4 carbon atoms) ester of (meth)acrylic acid. 5. Vinyl polymer emulsion (a) with a pure acid value within the range of 100 to 500, cement (b), aggregate (C) Narahini, and if necessary a concrete fluidizer (DL and/or water (EL)). An underwater concrete mortar composition consisting of 6. The weight of (a) relative to (b) is 0 as a polymer pure content.
．． 6. The composition according to claim 5, wherein the composition has a content of 0.01 to 10%.