JPH10279341A - Cement composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure initial strength exhibiting property and superior flowability by incorporating cement, calcium aluminosilicate glass, an inorg. sulfate and a polycarboxylic acid polymer. SOLUTION: This cement compsn. contains 100 pts.wt. cement, 10-50 pts.wt. set accelerating agent prepd. by mixing 100 pts.wt. calcium aluminosilicate glass with 50-300 pts.wt. inorg. sulfate such as II type anhydrous gypsum and 0.01-5 pts.wt. polycarboxylic acid polymer. The calcium aluminosilicate glass consists of 30-60 wt.% CaO, 20-60 wt.% Al2 O3 and 5-25 wt.% SiO2 and has >=50% rate of vitrification. The polycarboxylic acid polymer is a copolymer of polyoxyalkylene glycol alkenyl ether of the formula R1 O(AO)m R2 [where R1 is vinyl or allyl, AO is 2-4C oxyalkylene (n) is 1-100 and R2 is H or 1-4C alkyl] with maleic anhydride or a hydrolyzate of the copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement composition used in the field of civil engineering and construction, particularly for applications requiring high strength and fluidity.

[0002] In the present invention, concrete is
A generic term for paste, mortar, and concrete.

[0003]

2. Description of the Related Art In recent years, for the purpose of multi-functionality of concrete, for example, as a concrete having both fluidity, low heat generation, low shrinkage, and high durability at the same time, it is called "high performance concrete". A new concept has been proposed (Public Works, Vol. 30, No. 10, p.
27 ('89) and Annual Report on Concrete Engineering 11-1 p699 ('8
9) etc.).

[0004]

However, at present, concrete having both initial strength development and fluidity has not yet been put to practical use.

[0005] The present inventors have conducted various studies to obtain concrete having both initial strength and fluidity, and as a result, have found that this object can be achieved by using a specific composition. Thus, the present invention has been completed.

[0006]

That is, the present invention is a cement composition containing cement, calcium aluminosilicate glass, inorganic sulfate, and a polycarboxylic acid polymer.

Hereinafter, the present invention will be described in detail. Calcium aluminosilicate glass according to the present invention (hereinafter referred to as CAS glass) as its composition region, CaO30～60 wt%, Al ₂ O ₃ 20 to 60 wt%, and SiO ₂ 5 to 25
% By weight, CaO 30 to 55% by weight, Al ₂ O ₃
30-60 wt%, and SiO ₂ 10 to 20 wt% is more preferable. CaO is less than 30% by weight or Al ₂ O ₃
If Ca exceeds 60% by weight, rapid hardening tends to be inferior. Conversely, if CaO exceeds 60% by weight or Al ₂ O ₃ is less than 20% by weight, a large amount of the setting modifier is added. They are instantaneously formed, which is not preferable in terms of workability. Also,
If the content of SiO ₂ is less than 5% by weight, a long-term elongation of strength cannot be expected, while if it exceeds 25% by weight, the initial strength tends to be small.

The general industrial raw materials described below include Mg.
Naturally, impurities such as O, Fe2O3, TiO2, K2O, and Na2O are included. These impurities are CaO-A
In order to extend the vitrified region of the l2O3-SiO2 system, the presence of less than 10% by weight is preferable, and there is no problem in various properties such as rapid hardening, workability, and elongation of long-term strength.

In addition, when producing CAS glass, addition of alkali nitrates such as NaNO3 and KNO3, calcium fluoride, borax, etc., which are common glass fluxes,
It is preferable because it lowers the melting point of glass.

[0010] The glass in the present invention means "a glass exhibiting a glass transition point" obtained from thermal analysis. In addition, not all need to be glassy, and a vitrification rate is preferably 50% or more, more preferably 70% or more,
Most preferably, it is 80% or more. If it is less than 50%, the initial strength tends to decrease.

In the present invention, for example, in the present invention, CAS glass is melted by heating at 1,000 ° C. for 2 hours, and then gradually cooled at a cooling rate of 5 ° C./min. Area S0 of the main peak of the crystal mineral determined by powder X-ray diffraction and area S0 of the main peak of the crystal in the CAS glass
From Equation 1 according to the following equation.

[0012]

(Equation 1)

The CAS glass has, for example, an average chemical composition of 40 to 43% by weight of CaO, 5 to 8% by weight of MgO,
l ₂ O ₃ 13 to 15 wt%, and a SiO ₂ 31 to 35 wt%, is completely different from the composition of the granulated blast furnace slag by-produced like in metallurgy or metal paste. Further, the CAS glass is completely different from the composition of the alumina cement. That is, the SiO2 content of ordinary alumina cement is less than 5% by weight [Junichi Kasai, Concrete Engineering, No. 22
Vol. 8, No. 67, pp. 67 (1984)].
%, Published in 1964 by the City of London Academic Press, Inc.,
HFWTaylor, The Chemistry of Cement (T
he Chemistry of Cement), Volume 2, page 16].

The raw materials for producing CAS glass according to the present invention include CaO raw materials, Al2O3 raw materials, and SiO2 raw materials. As the CaO-based raw material, quicklime, slaked lime, limestone, etc., and as the Al2O3-based raw material,
Alumina, bauxite, diaspore, feldspar, clay and the like, and further, as a SiO2 raw material, silica sand,
White clay, diatomaceous earth and the like can be used. It is also possible to supplement a relatively inexpensive blast furnace slag with a CaO-based raw material and an Al2O3-based raw material.

The CAS glass according to the present invention comprises the above CaO
Raw material, Al2O3 raw material, and SiO2 raw material are blended in a predetermined ratio, and are melted using a direct current melting furnace or a high-frequency furnace, and the obtained melt is blown off with compressed air or high-pressure water, Alternatively, it is manufactured by a method of pouring into water. Further, it can be produced by melting in a rotary kiln and quenching. CAS
The finer the fineness of the glass, the higher the reactivity.
cm ₂ / g or more is preferable.

The inorganic sulfate according to the present invention is a sulfate of an alkali metal or an alkaline earth metal. Of these, anhydrous, hemihydrate and dihydrate calcium sulfate are preferable, and use of type II anhydrous gypsum is particularly preferred. This is particularly preferred from the viewpoint of Type II anhydrous gypsum indicates the type of type II CaSO4 in the X-ray diffraction pattern, and is not limited by impurities industrially contained. The fineness of the inorganic sulfate is 2000 to 8000 c in Blaine specific surface area.
About m2 / g is preferable. The amount of inorganic sulfate used is CAS
50 to 300 parts by weight, preferably 100 to 200 parts by weight, based on 100 parts by weight of glass. If the amount is less than 50 parts by weight, it is not preferable from the viewpoint of strength development, and if it exceeds 300 parts by weight, it exhibits expandability, cracks may occur, and long-term stability may be impaired.

In the present invention, a mixture of CAS glass and an inorganic sulfate is used as a rapid hardening material to obtain the initial strength.

[0018] The cement according to the present invention is not particularly limited, and is usually used in ordinary, early strength,
Various Portland cements such as ultra-high strength, various mixed cements obtained by mixing blast furnace slag, fly ash, or silica with these Portland cements, and expanded cements obtained by mixing an expanding material with Portland cements, alumina cements, moderate heat Specific cements such as cement, white cement, and colloid cement are exemplified.

In the present invention, a mixture of CAS glass and inorganic sulfate is used as a rapid hardening material. The amount of the quick hardening material is preferably 10 to 50 parts by weight, and more preferably 15 to 50 parts by weight, based on 100 parts by weight of cement. -30 parts by weight are more preferred. If the amount is less than 10 parts by weight, it is difficult to sufficiently develop the initial strength,
Exceeding parts by weight, such as dimensional stability of the cement composition,
It is not preferable because long-term stability may be impaired.

The polycarboxylic acid polymer used in the present invention is a dispersant having a cement dispersing effect, a water reducing effect, and a fluidity retaining effect, such as a polymer having a carboxyl group in a side chain, There is a polymer having a carboxyl group and a polyalkylene oxide structure in the chain.

Examples of the polycarboxylic acid-based polymer having a carboxyl group in the side chain that can be used in the present invention include, for example, JP-A-60-161363 and JP-A-61-14677.
6, JP nominal 6 3 -5346 JP, Sho 62-
(Meth) acrylic acid, α-hydroxyacrylic acid, (meth) acrylic acid ester described in JP-A-83344, JP-B-7-17421, JP-A-58-173142, JP-B-5-75711 and the like. Homopolymers or copolymers of unsaturated dicarboxylic acids such as unsaturated monocarboxylic acids such as maleic acid (anhydride), itaconic acid (anhydride) and citraconic acid (anhydride), isobutylene, amylene,
Examples of the copolymer include an unsaturated vinyl monomer such as pentene, styrene, α-methylstyrene, sulfonated styrene, and vinyl ether, and an unsaturated dicarboxylic acid.

Examples of the polycarboxylic acid-based polymer having a carboxyl group and a polyalkylene glycol structure in the side chain include, for example, JP-A-6-256054 and JP-B-6-56054.
And unsaturated vinyl monomers such as vinyl ether-maleic anhydride copolymer, olefin-maleic anhydride copolymer and styrene-maleic anhydride copolymer described in JP-A-88818 and JP-B-6-88817. There is an esterified product of a dicarboxylic acid copolymer with an alkylene glycol compound.

Further, Japanese Patent Publication No. 61-21486, Japanese Patent Publication No. 62-25163, and Japanese Patent Publication No. 58-38380
JP, JP-B-59-18338, JP-B 1-3
No. 8408, Japanese Patent Publication No. 1-34866, Japanese Patent Publication No. 1-367487, Japanese Patent Publication No. 1-364888,
JP-A-59-162157, JP-A-59-195
565, JP-A-61-77652, JP-B4-68323, JP-B2-7898, JP-A-63-285140, JP-A-8-48852.
Patent Documents, etc., having a functional group such as a (meth) acrylate ester group, a vinyl ether group, an allyl ether group, and a methallyl group as an unsaturated group, and having a hydroxyl group, an alkoxy group, and the like as a terminal group not involved in polymerization. There are copolymers containing a monomer composed of a polyalkylene glycol derivative having a linear or branched structure and an unsaturated carboxylic acid monomer such as an unsaturated monocarboxylic acid or an unsaturated dicarboxylic acid as an essential component.

Also, JP-A-6-271347, JP-A-6-298555, JP-A-6-298556, JP-A-7-157348, and JP-A-7-15
No. 7349, JP-A-7-187742, etc., an esterified product of a polyalkylene glycol-based compound of a copolymer comprising a polyalkylene glycol derivative having a vinyl ether group or an allyl ether group as an unsaturated group and maleic anhydride is used. is there.

Further, JP-A-8-12396, JP-A-62-216950, and JP-A-1-226557.
JP-A-6-206750, a polyalkylene glycol derivative having a (meth) acrylate group as an unsaturated group, an unsaturated monocarboxylic acid or unsaturated dicarboxylic acid, allylsulfonic acid, There is a copolymer of a monomer having a sulfonic acid group such as rilsulfonic acid.

Japanese Patent Application Laid-Open Nos. 7-53249, 7-215746, 8-165157
And a copolymer comprising a monomer comprising a polyoxyalkylene derivative described in JP-A-7-232945 and a carboxyl group-containing monomer as essential components.

Among these, from the viewpoint of fluidity retention performance, a copolymer comprising polyalkylene glycol alkenyl ether represented by the following general formula (1) and maleic anhydride, or a hydrolyzate and / or hydrolyzate thereof Most preferred is the use of a polycarboxylic acid-based polymer comprising a salt of a product.

[0028]

Embedded image

(R 1 is a vinyl group, an allyl group, AO is an oxyalkylene group having 2 to 4 carbon atoms, n is an integer of 1 to 100, R 2 is hydrogen or an alkyl group having 1 to 4 carbon atoms)

In the general formula (1), examples of the oxyalkylene group having 2 to 4 carbon atoms represented by AO include an oxyethylene group, an oxypropylene group, and an oxytetramethylene group. Particularly, an oxyethylene group having 2 carbon atoms is preferable from the viewpoint of properties. In addition, as long as the water solubility of the obtained copolymer is not impaired, an oxypropylene group, a random or block copolymer with an oxyalkylene group such as an oxytetramethylene group, or a polyalkylene glycol alkenyl ether having each oxyalkylene group. One or more mixtures can be used.

The average addition mole number n of the oxyalkylene group can be in the range of 1 to 100 mol. If it exceeds 100 moles, the dispersing performance deteriorates. Further, it is not preferable because the polymerizability with maleic anhydride decreases.

The functional group represented by R 1 is an allyl group,
A vinyl group is exemplified, but a vinyl group is preferred from the viewpoint of copolymerizability with maleic anhydride. R2 is hydrogen or an alkyl group having 1 to 4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl,
A tertiary butyl group is exemplified, and a methyl group is preferred from the viewpoint of water solubility and production cost.

In the copolymerization of polyalkylene glycol alkenyl ether and maleic anhydride, the molar ratio is preferably in the range of 1/2 to 2/1, more preferably 1 / 1.2 to 1.2 /. It is one. A known radical polymerization method can be applied to the production of the copolymer. For example, according to the methods described in JP-A-64-109 and JP-A-8-46652, it can be produced by radical copolymerization using a radical initiator in an organic solvent or under the condition of bulk without solvent. It is.

The molecular weight of the copolymer of polyalkylene glycol alkenyl ether and maleic anhydride is based on water-based G
The weight average molecular weight in terms of polyethylene glycol measured by PC is preferably in the range of 3,000 to ⁵ × 10 ⁵ , and particularly preferably in the range of 3,000 to 1 × 10 ⁵ . If the weight average molecular weight is less than 3,000, sufficient dispersion performance cannot be obtained. On the other hand, when the weight average molecular weight is in the range of 5 × 10 ⁵ or more, the dispersing performance is lowered, and the production is difficult and the production cost is increased.

As long as the water-reducing performance and water-solubility of the copolymer are not impaired, maleimides such as styrene and phenylmaleimide, olefins such as α-olefin, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether and isopropyl vinyl ether And copolymerizable monomers such as lower alkyl vinyl ethers such as n-butyl vinyl ether and isobutyl vinyl ether.

The polycarboxylic acid polymer used in the present invention can be used in the form of a powder or an aqueous solution. When used as a powder, if the polycarboxylic acid-based polymer itself is hardly powdered, a method of supporting the powder on an inorganic powder described in JP-A-6-239652. Alternatively, a powder made by a method of forming a salt with a polyvalent metal into a property that can be handled as a powder can also be used.

As a method of pulverizing the polycarboxylic acid copolymer by converting it into a salt with a polyvalent metal, for example, an organic solvent for the copolymer obtained from polyalkylene glycol monoalkenyl ether and maleic anhydride may be used. Solution, aqueous solution of the copolymer or melted copolymer melted by heating, adding calcium hydroxide or calcium hydroxide-water slurry, after neutralization reaction, drying and grinding to obtain copolymer calcium salt, by polymerization After the obtained copolymer-organic solvent solution was turned into a copolymer aqueous solution by stripping with heating steam, it was reacted with calcium hydroxide and dried.
A method of pulverizing to obtain a copolymer calcium salt may, for example, be mentioned.

The average particle size of the polycarboxylic acid polymer used in powder form is preferably from 0.1 to 500 μm. The powder having an average particle diameter of 500 μm or more is not preferable because the original performance cannot be obtained with good reproducibility due to the difference in dissolution rate with respect to the solvent and the segregation when dry-blended with various powder materials.

The amount of the polycarboxylic acid polymer to be used is preferably 0.01 to 5.0 parts by weight, preferably 1.0 to 3.0 parts by weight, based on 100 parts by weight of the binder comprising cement, calcium aluminosilicate glass and inorganic sulfate. 0 parts by weight is more preferred.
If less than 0.01 part by weight, sufficient dispersibility cannot be obtained, and
If the amount exceeds 0 parts by weight, setting delay may be caused, which is not economically preferable.

In the present invention, in addition to the above materials, for example, aggregates such as silica sand, natural sand and gravel, pozzolans and setting modifiers, fibers such as glass fibers, carbon fibers and steel fibers, polymer emulsions Or latex, colorant, AE
Agents, antifoaming agents, rust inhibitors, insoluble additives in water such as methylcellulose, thickeners, water retention agents, waterproofing agents such as calcium chloride and sodium silicate, foaming agents, foaming agents, calcium hydroxide, etc. One or more of a calcium salt, an antifreeze and the like can be used in combination in an amount that does not substantially inhibit the object of the present invention.

Here, the pozzolans include basalts,
Natural pozzolans such as weathered andesite, tuffs, volcanic ash, granite, and Beppu clay, and artificial pozzolans such as clay slag, alum slag, blast furnace slag, fly ash, and silica flower.

In the present invention, it is preferable to use a setting regulator to maintain workability. The setting modifier is used when the CaO content in the CAS glass is large and the setting time is short, or when the CaO content in the CAS glass is small and the setting time is slow.

Here, citric acid,
Tartaric acid, gluconic acid, succinic acid, and organic acids such as maleic acid or salts thereof, alkali carbonates such as sodium carbonate and potassium carbonate, phosphoric acids or salts thereof, boric acid,
Alkali borate, alkali aluminate, silicofluoride,
Examples include starch, sugars, alcohols and the like, and mixtures thereof, and among them, the use of organic acids is preferred.

In the present invention, in order to adjust the amount of entrained air in the cement composition, lower alcohols, higher alcohols, oils and fats, fatty acids, fatty acid esters, phosphate esters, metal soaps, mineral oils and the like are used. Conventionally known antifoaming agents such as polyethers and silicones can be used. Of these, preferred are polymeric defoamers,
Polyoxyalkylenes such as polyoxyethylene polypropylene adducts, polyoxyalkylene alkyl ethers obtained by etherifying part of the terminal structure of polyoxyalkylene with an alkyl group, part of the terminal structure of polyoxyalkylene is an aryl group or Polyoxyalkylene (alkyl) aryl ethers etherified with an alkylaryl group, acetylene ethers obtained by addition polymerization of acetylene alcohol with alkylene oxide, and polyoxyalkylenes obtained by esterifying a part of the terminal structure of polyoxyalkylene with fatty acid Fatty acid esters, polyoxyalkylene alkyl (aryl) ether sulfates having sulfate groups introduced therein, polyoxyalkylene alkyl phosphates having phosphate groups introduced therein, Polyoxyalkylene defoamer polyoxyalkylene alkylamines such as the introduction of the group is particularly preferred.

The method of using these defoaming agents includes a method of separately using an aqueous solution of a polycarboxylic acid polymer and a solution of an antifoaming agent, and a method of using a previously prepared aqueous solution of a polycarboxylic acid polymer and an antifoaming agent solution. A method using a mixed aqueous solution, a method in which an antifoaming agent component is added in advance in the production process of a polycarboxylic acid-based polymer, and a powdered material is used together with the polycarboxylic acid-based polymer. What was impregnated or supported on an inorganic powder such as silica to obtain a powdery defoaming agent,
A method in which a powdery polycarboxylic acid-based polymer and a powdery antifoaming agent are blended in advance and used, or a method in which a powdery polycarboxylic acid-based polymer and a powdery antifoaming agent are separately added and used.

The amount used is preferably 0.01 to 10 parts by weight, particularly preferably 0.05 to 5 parts by weight, per 100 parts by weight of the polycarboxylic acid polymer. If the amount used is less than 0.01 part by weight, a sufficient defoaming effect cannot be obtained, and if it is 10% by weight or more, not only the defoaming effect is not further improved, but also the amount of entrained air in the composition such as mortar or concrete. May be increased, which is not preferable in terms of both performance and cost.

In the present invention, a thickener can be used in combination for the purpose of improving the viscosity of the cement composition and preventing material separation such as breathing and aggregate sedimentation, and preventing material separation and obtaining high fluidity. Examples of thickeners that can be used in combination include cellulosic polymers such as methylcellulose, ethylcellulose, methylethylcellulose, hydroxyethylcellulose, and hydroxypropylcellulose; starch, natural polysaccharides such as xanthan gum, gum arabic, welan gum, and sodium alginate; polyvinyl alcohol; and polyacryl. And synthetic polymers such as sodium acid, polyvinylpyrrolidone, polyethylene oxide, polyacrylamide, and polyvinyl acetate. Among these, a cellulosic polymer is preferable in that the effect is large.

The amount of the thickener used is preferably 0.0001 to 1.0 part by weight, and
The amount is more preferably from 0.01 to 0.5 part by weight. If it is less than 0.0001 part by weight, there is no effect, and if it exceeds 1.0 part by weight, the viscosity becomes too high, and it becomes difficult to handle concrete, which is not preferable.

The apparatus for mixing the cement composition of the present invention is not particularly limited.
Any existing stirring device such as an omni mixer, a V-type mixer, a Henschel mixer, and a Nauta mixer manufactured by Chiyoda Giken Kogyo KK can be used.

In addition, as a method of mixing each material,
There is no limitation, and each material may be mixed at the time of construction, or some or all may be mixed in advance.

[0051]

EXAMPLES The present invention will be described in more detail with reference to Examples.

Example 1 Production of polycarboxylic acid polymer (1) Production example of polyalkylene glycol alkenyl ether (A) Thermometer, stirrer, reflux device, acetylene gas introduction pipe, nitrogen introduction pipe, acetylene gas flow rate integration A methoxypolyethylene glycol (molecular weight: 2,000, average number of moles of EO added: 44) was placed in a glass autoclave equipped with a meter.
After charging 0 g and potassium hydroxide 5.3 g (30 mol% based on methoxypolyethylene glycol) and confirming that there was no leakage of the device, the temperature in the autoclave was set to 120 g.
While the temperature was raised to ° C, the inside of the apparatus was purged with nitrogen by nitrogen bubbling. The added potassium hydroxide was completely dissolved during this time. After the internal temperature stabilized at 120 ° C, the supply of acetylene was started, and the absorption of acetylene disappeared in about 9 hours.
The supply of acetylene was stopped, and the autoclave was replaced with nitrogen, cooled, and disassembled. The obtained reaction product was subjected to removal of impurities with an acid / alkali adsorbent to obtain a pale yellow-white solid purified product.

(2) Production Example of Dissolved Polycarboxylic Acid Polymer A A polyalkylene glycol alkenyl ether and maleic anhydride used in a 1 L gas autoclave equipped with a thermometer, a stirrer, a dropping device, a vacuum line, and a nitrogen gas inlet tube are used. The polyalkylene glycol vinyl ether (molecular weight: about 2026, EO
Average number of moles added 45) 324 g, anhydrous maleic 16 g
(Molecular weight: 98) and the monomer concentration is 50.
340 g of a toluene solvent was charged so as to be a weight%.
Thereafter, pressure reduction / nitrogen bubbling was repeated to replace the inside of the autoclave with nitrogen, the internal pressure of the autoclave was returned to normal pressure by introducing nitrogen, and the temperature inside the autoclave was raised to 80 ° C. After the internal temperature is stabilized at 80 ° C., 113 ml of an initiator solution composed of 3% by weight of 2,2′-azobisisobutyronitrile in a toluene solvent is divided for a polymerization time of 3 hours while paying attention to heat generated by polymerization heat. Was added. After performing the polymerization reaction for 5 hours while controlling the temperature of the polymerization solution at 80 ° C. while controlling the external temperature, the polymerization solution was sampled, and the polymerization rate was 100% based on maleic anhydride. Next, the autoclave was cooled and disassembled, the polymerization solution was taken out, and the solvent was removed by drying under reduced pressure to obtain a waxy copolymer at room temperature. About the obtained copolymer, GPC (Gel Per
The weight average molecular weight was 30,000 as measured by polyethylene glycol or polyethylene oxide in terms of molecular weight by means of Meatin Chromatography.

The obtained copolymer was dissolved in 17 parts by weight of the copolymer in 100 parts by weight of water, neutralized with sodium hydroxide, and then subjected to a liquid defoaming agent (liquid defoaming agent, Denka Grace product, F
-224) was added in an amount of 0.2% based on the solid content of the copolymer to obtain a liquid polycarboxylic acid polymer A. The copolymer sodium salt obtained by removing water from the liquid water reducing agent A by drying under reduced pressure was solid, but the melting temperature was 50 ° C.
The powder having a particle size of 200 μm or less by pulverization had a high hygroscopicity, and as such, was very difficult to handle as a powdery admixture.

(3) Production Example of Liquid Polycarboxylic Acid Polymer B As polyalkylene glycol alkenyl ether, methoxypolyethylene glycol allyl ether (average molecular weight: 1500, average number of moles of added EO: 33 mol, Nippon Oil & Fat Products UNIOX PKA-5010) It was used. In a 1 L glass autoclave equipped with a thermometer, a stirrer, a dropping device, a vacuum line, and a nitrogen gas inlet tube, methoxypolyethylene glycol allyl was added so that the molar ratio of polyalkylene glycol alkenyl ether and maleic anhydride became 1/1. 653.3 g of ether (molecular weight 1500, average number of moles of added EO: 32), maleic anhydride 4
2.7 g (molecular weight: 98) and 7 g of lauroyl peroxide (LPO) as an initiator were charged. Then,
Nitrogen bubbling was repeated to replace the inside of the autoclave with nitrogen, and the internal pressure of the autoclave was returned to normal pressure by introducing nitrogen.
The temperature inside the autoclave was raised to 80 ° C. After performing a polymerization reaction for 5 hours while controlling the external temperature so as to keep the internal temperature of the polymerization solution at 80 ° C., the polymerization solution was sampled and the polymerization rate was measured. As a result, the polymerization rate was 57% based on maleic anhydride.
Met. Thereafter, the reaction was continued at 80 ° C. for 22 hours while stirring. The polymerization rate at 22 hours was 60% based on maleic anhydride. Then cool the autoclave,
After disassembly, the polymerization solution was taken out to obtain a waxy copolymer at room temperature. The weight average molecular weight of the obtained copolymer was 30,000. The obtained copolymer was dissolved in 17 parts by weight with respect to 100 parts by weight of water and neutralized with calcium hydroxide. By adding 2%, a liquid polycarboxylic acid polymer B was obtained.

(4) Production Example of Powdery Polycarboxylic Acid Polymer C The copolymer used for the liquid polycarboxylic acid polymer A is dissolved in water, neutralized with calcium hydroxide, and the calcium salt of the copolymer is dissolved. An aqueous solution was obtained. Water was removed from the aqueous solution of the copolymer calcium salt, and the copolymer calcium salt was taken out and pulverized by a pulverizer to obtain a powder having a particle size of 200 μm or less. 100 parts by weight of the obtained powder and 0.5 part by weight of a powdery antifoaming agent (San Nopco, Deformer SN-DF14HP) were mixed to obtain a powdery polycarboxylic acid polymer C. The obtained powdery water reducing agent C was heated to confirm the change in properties. However, no change was observed even when heated to 80 ° C., the hygroscopicity was low, and the powdered water reducing agent C could be handled as a powdery admixture.

Example 2 A binder having a unit amount of cement and a hardened material of 440 Kg /
As shown in Table 1, a concrete containing m ³ , water 154 Kg / m ³ , fine aggregate 900 Kg / m ³ , and coarse aggregate 914 Kg / m ³ was mixed with a water reducing agent, and slump flow and compressive strength were measured. . The results are also shown in Table 1.

<Materials Used> Cement: Ordinary Portland cement made by Denki Kagaku Kogyo Co., Ltd. CAS Glass A: Weight ratio of CaO / Al2O3 / SiO2 50/40/10 Vitrification ratio 100%, Blaine specific surface area 4000 cm ² /
g CAS glass B: weight ratio of CaO / Al2O3 / SiO2 40/40/20 Vitrification rate 100%, Blaine specific surface area 4500 cm ² /
g CAS glass C: CaO / Al2O3 / SiO2 weight ratio 30/45/25, vitrification ratio 100%, Blaine specific surface area 4900 cm ² / g Inorganic sulfate: Type II anhydrous gypsum, Blaine specific surface area
5900 cm ² / g Fine aggregate: sand from Himekawa, Niigata Prefecture Coarse aggregate: gravel from Himekawa, Niigata Water: tap water Polycarboxylic acid polymer: admixtures A, B, C of Example 1

<Test method> Slump flow value: In accordance with the manual for underwater non-separable concrete, Appendix, "Test of underwater separable concrete, slump flow test" Measure the spread of concrete at two points at right angles. Compressive strength: Measure a specimen of 10φ × 20cm.

[0060]

[Table 1]

[0061]

Industrial Applicability According to the present invention, a cement composition having good initial strength and fluidity can be obtained.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C04B 24:26)

Claims (4)

[Claims] 1. A cement composition comprising cement, calcium aluminosilicate glass, inorganic sulfate, and a polycarboxylic acid polymer. 2. A stiffening agent comprising 50 to 300 parts by weight of inorganic sulfate per 100 parts by weight of calcium aluminosilicate glass per 100 parts by weight of cement, 10 to 50 parts by weight of a polycarboxylic acid polymer The cement composition according to claim 1, wherein the amount is 0.01 to 5 parts by weight. 3. The polycarboxylic acid-based polymer is a polymer having a carboxyl group in a side chain, or a polymer having a carboxyl group and a polyalkylene oxide structure in a side chain. Cement composition. 4. The polycarboxylic acid polymer is a copolymer of a polyalkylene glycol alkenyl ether represented by the general formula (1) and maleic anhydride, or a hydrolyzate and / or a salt of the hydrolyzate thereof. The cement composition according to claim 1, wherein the composition is provided. Embedded image (R1 is a vinyl group, an allyl group, AO is an oxyal group having 2 to 4 carbon atoms, n is an integer of 1 to 100, and R2 is hydrogen or an alkyl group having 1 to 4 carbon atoms)