KR102593416B1 - Cement composition and method for producing the same - Google Patents

Abstract

It contains ordinary Portland cement clinker with C ₃ S of 51 to 62% by mass and C ₄ AF of 7 to 10% by mass calculated by the Borg formula, and an adjuvant containing gypsum, limestone, and alkanolamine, and the above ordinary The content of the alkanolamine in the total amount of the Portland cement clinker, the gypsum, and the above aid is 10 to 210 mg/kg, and the content of the limestone in the total amount of the ordinary Portland cement clinker, the gypsum, the preparation, and the limestone is 10 to 210 mg/kg. 3 to 10% by mass, the lattice volume of the C ₄ AF exceeds 0.4290 nm ³ , and the Blaine specific surface area is 2800 to 3500 cm ² /g. The cement composition has high strength and excellent fluidity.

Description

Cement composition and method for producing the same

The present invention relates to cement compositions and methods for producing the same.

In order to improve the strength of mortar and concrete, various studies are being conducted.

For example, in Patent Document 1, in order to provide an admixture or cement composition for mortar or concrete used in civil engineering structures or concrete secondary products that exhibits the effect of increasing both 7-day strength and 28-day strength, trialkane It is an admixture containing olamine and diethylene glycol, and a cement composition containing cement and the admixture is disclosed.

In addition, for example, in Patent Document 2, when manufacturing buildings, civil structures, or secondary concrete products, the shortcoming of the low initial strength of fly ash can be overcome and fly ash can be actively mixed into the cement used. In order to provide improved cement admixtures and cement compositions, cement admixtures containing fly ash, trialkanolamine, and 0.05 to 0.5 parts by weight of diethylene glycol based on 100 parts by weight of fly ash, or cement and diethylene glycol. It is a cement admixture containing col and trialkanolamine, and a cement composition further containing cement, fly ash, trialkanolamine, and diethylene glycol is disclosed.

Japanese Patent Publication No. 2000-203909 Japanese Patent Publication No. 2000-281404

However, the fluidity of the cement compositions described in Patent Documents 1 and 2 has not been examined.

The purpose of the present invention is to provide a cement composition with high strength and excellent fluidity, and a method for producing the same.

The present invention provides the following <1> to <7>.

<1> An adjuvant containing ordinary Portland cement clinker with 51 to 62% by mass of C ₃ S and 7 to 10% by mass of C ₄ AF calculated by the Borg formula, gypsum, limestone, and alkanolamine. ), the content of the alkanolamine in the total amount of the ordinary Portland cement clinker, the gypsum, and the preparation is 10 to 210 mg / kg, and the content of the ordinary Portland cement clinker, the gypsum, the preparation, and the limestone are 10 to 210 mg / kg. A cement composition in which the content of the limestone in the total amount is 3 to 10% by mass, the lattice volume of the C ₄ AF exceeds 0.4290 nm ³ , and the Blaine specific surface area is 2800 to 3500 cm ² /g.

<2> The cement composition according to <1>, wherein the content of the auxiliary in the total amount of the ordinary Portland cement clinker, the gypsum, and the auxiliary is 80 to 350 mg/kg.

<3> The cement composition according to <1> or <2>, wherein the auxiliary agent contains an aliphatic polyhydric alcohol.

<4> The cement composition according to any one of <1> to <3>, wherein the content of the gypsum in the total amount of the ordinary Portland cement clinker, the gypsum, and the adjuvant is 0.7 to 2.8% by mass in terms of SO ₃ .

<5> The alkanolamine is at least one selected from the group consisting of diethanolisopropanolamine, triisopropanolamine, ethanoldiisopropanolamine, N-methyldiethanolamine, and N-n-butyldiethanolamine. The cement composition according to any one of > to <4>.

<6> The cement composition according to any one of <3> to <5>, wherein the aliphatic polyhydric alcohol is at least one selected from the group consisting of glycerin and diethylene glycol.

<7> Ordinary Portland cement clinker in which C ₃ S is 51 to 62% by mass and C ₄ AF is 7 to 10% by mass calculated by the Borg equation, and the lattice volume of the C ₄ AF exceeds 0.4290 nm ³ , and gypsum and an adjuvant containing limestone and an alkanolamine, the mixing amount of the alkanolamine in the total amount of the ordinary Portland cement clinker, the gypsum, and the above aid is 10 to 210 mg/kg, and the ordinary Portland cement clinker, the above-mentioned alkanolamine. A method for producing a cement composition, wherein the cement composition according to any one of <1> to <6> is produced by mixing 3 to 10% by mass of the limestone in the total amount of gypsum, the adjuvant, and the limestone.

According to the present invention, a cement composition having high strength and excellent fluidity and a method for producing the same can be provided.

In this specification, the numerical range "AA to BB" means "AA or more and BB or less."

<Cement composition>

The cement composition of the present invention contains ordinary Portland cement clinker with 51 to 62% by mass of C ₃ S and 7 to 10% by mass of C ₄ AF calculated by the Borg formula, gypsum, limestone, and alkanolamine. Including the adjuvant, the content of alkanolamine in the total amount of ordinary Portland cement clinker, gypsum, and adjuvant is 10 to 210 mg/kg, and the content of limestone in the total amount of ordinary Portland cement clinker, gypsum, adjuvant, and limestone is 3 to 3 mg/kg. It is 10% by mass, the lattice volume of C ₄ AF exceeds 0.4290 nm ³ , and the Blaine specific surface area is 2800 to 3500 cm ² /g.

Cement compositions are usually obtained by calcining the combined raw materials in a rotary kiln, adding gypsum and limestone to the obtained clinker, and pulverizing them with a finishing mill until the desired blane specific surface area is reached.

When pulverizing cement using a finishing mill, it is common to add a dispersing agent such as diethylene glycol to the material to be pulverized to prevent a decrease in grinding efficiency caused by agglomeration of particles. Control of strength development, which is the main physical property of Portland cement, is generally carried out by adjusting the combination of raw materials and the fineness (Blaine specific surface area) of the cement. The Blaine specific surface area of the cement composition is adjusted through a grinding process using a finishing mill, and is a quality control item in that it is a factor that controls the strength level at each age.

Increasing the specific surface area of the blank increases the initial strength of mortar and concrete, while lowering the fluidity during mixing of the cement paste, thereby lowering work efficiency. Increasing the amount of chemical admixture to maintain fluidity increases costs, and increasing the quantity increases drying shrinkage of the hardened body, encouraging cracking in the hardened body and impairing durability.

In addition, when cement is stored in a silo, the higher the specific surface area of the cement particles, the greater the reactivity of the cement particles with moisture in the air and carbon dioxide, which lowers the hydration activity on the surface of the cement particles, making so-called weathering more likely to occur. Weathered cement causes abnormal setting after water pouring, decreased fluidity, decreased strength of the hardened body, etc.

Additionally, calcium hydroxide generated on the surface of cement particles due to weathering reacts with carbon dioxide to form calcium carbonate, which promotes agglomeration of cement particles. For this reason, lumps are generated within the silo, causing so-called caking.

In this regard, it is desirable to reduce the Blaine specific surface area of the cement composition as much as possible within the range where the desired strength is obtained. Also, from the viewpoint of production, it is desirable to reduce the specific surface area of the cement composition. As previously explained, the Blaine specific surface area of the cement composition is adjusted through a grinding process using a finishing mill, and reducing the Blaine specific surface area leads to a reduction in power during the finishing mill operation.

In addition, control of strength development can be achieved not only by adjusting the specific surface area of the brine, but also by adjusting the proportion of limestone in the raw materials. For example, by increasing the proportion of limestone in the raw material, the amount of aelite in the cement mineral increases, and the strength development especially in the initial stage of hydration increases.

In this way, the strength can be improved by relatively increasing the amount of limestone in the clinker raw material and increasing the amount of alite in the produced cement mineral. However, if the amount of alite increases, the cement raw material becomes incombustible, so the amount of time required for firing is reduced. Fuel increases. The increase in the raw material of limestone and the increase in coal, which is the main fuel, also has the aspect of increasing carbon dioxide emissions.

In contrast, the cement composition of the present invention suppresses the blank specific surface area of the cement composition to a low level, suppresses the amount of limestone in the clinker raw material, improves strength, and has excellent fluidity. The reason for this is not clear, but it is presumed to be due to the following reasons.

The alkanolamine contained in the cement composition of the present invention dissolves the ferrite phase among the four major cement minerals, alite, belite, aluminate, and ferrite, and thereby improves the strength of the cement. You can. Specifically, by dissolving the ferrite phase present on the surface of cement particles synthesized from various minerals, the surface area of the cement particles increases, and hydration of the cement minerals inside is promoted by contact with water. In addition, iron hydroxide produced by dissolution of ferrite covers the surface of clinker particles and inhibits hydration by inhibiting the diffusion of Ca ions eluted from clinker minerals such as aelite, but alkanolamine is the Fe ion of the iron hydroxide. Since it has the effect of dissolving , it is also thought to have the effect of promoting the hydration of alite.

Hereinafter, the cement composition of the present invention will be described in detail.

[Blaine specific surface area]

The cement composition of the present invention has a Blaine specific surface area of 2800 to 3500 cm ² /g.

If the Blaine specific surface area is less than 2800 cm ² /g, the effect of promoting hydration by alkanolamine is obtained, but the mortar strength decreases. If the Blaine specific surface area exceeds 3500 cm ² /g, fluidity decreases, and dissolution of C ₄ AF by alkanolamine becomes limited, and the strength improvement effect is not obtained.

From the viewpoint of further improving strength, the Blaine specific surface area of the cement composition is preferably 3000 to 3400 cm ² /g, and more preferably 3150 to 3350 cm ² /g.

The Blaine specific surface area of the cement composition can be measured in accordance with JIS R 5201:2015 "Physical test method for cement."

[Clinker]

The clinker used in the cement composition of the present invention is an ordinary Portland cement clinker with 51 to 62% by mass of C ₃ S and 7 to 10% by mass of C ₄ AF calculated by the Borg method.

The total amount of C ₃ S (3CaO·SiO ₂ ) and C ₂ S (2CaO·SiO ₂ ) in the clinker is approximately constant at 88% by mass, and when C ₃ S is 51 to 62% by mass, the content of C ₂ S is It is 16-27% by mass. In addition, the total amount of C ₃ A (3CaO·Al ₂ O ₃ ) and C ₄ AF (4CaO·Al ₂ O _{3 ·} FeO ₃ ) in the clinker is approximately constant at 18.5% by mass, and C ₄ AF is 7 to 10% by mass. When , the content of C ₃ A is 8.5 to 12.5 mass%.

(C ₃ S, C ₂ S)

If the C ₃ S content in the clinker is less than 51% by mass, the mortar strength is not excellent, and even if the mortar strength can be increased, the fluidity is not excellent. In addition, the strength improvement effect due to the addition of alkanolamine cannot be expected for the following reasons.

If the C ₃ S content in the clinker is less than 51% by mass, the content of C ₂ S, which has relatively poor crushability, increases. As a result, the grinding time required to achieve a constant Blaine specific surface area of the cement composition becomes longer, and minerals other than C ₂ S (C ₃ S, C ₃ A, and C ₄ AF), which have good grindability, are used excessively. By being pulverized, the specific surface area of the blade increases. In addition, the strength improvement mechanism by the addition of alkanolamine is to selectively dissolve C ₄ AF in the clinker, thereby increasing the opportunity for C ₄ AF adjacent to C ₄ AF to come into contact with water, thereby promoting hydration and increasing strength. However, when clinker is over-pulverized, clinker particles, which originally exist as a composite of each mineral, tend to exist as individual minerals, so dissolution of C ₄ AF does not lead to promotion of hydration of C ₄ AF. Therefore, the effect of improving strength by adding alkanolamine is not obtained.

If the C ₃ S content in the clinker exceeds 62% by mass, it is not preferable in the production of clinker because the cement raw material becomes incombustible, unreacted lime (f.CaO) increases, and fuel consumption increases.

From the viewpoint of improving strength and fluidity and suppressing fuel consumption, the content of C ₃ S in the clinker is preferably 53 to 61% by mass, and more preferably 55 to 59% by mass.

(C ₄ AF, C ₃ A)

If the content of C ₄ AF in the clinker is less than 7% by mass, the content of C ₄ AF is excessively low, so even if alkanolamine is added, the promotion of the reaction of C ₃ S by promoting the dissolution of C ₄ AF is limited and there is no significant reaction. It cannot exert a strength-enhancing effect. In addition, in the efficient production of clinker, it is necessary to keep the liquid amount (C ₃ A + C ₄ AF) constant, so a decrease in C ₄ AF means a relative increase in C ₃ A, and the amount of C ₃ A is As it increases, fluidity deteriorates as a large amount of needle-like crystals of ettringite are produced by the reaction between C ₃ A and gypsum during initial hydration.

When the content of C ₄ AF in the clinker exceeds 10 mass%, alkanolamine dissolves C ₄ AF on the surface of the clinker particles, temporarily promoting hydration of C ₃ S, but dissolution of Fe ions in C ₄ AF The large amount of iron hydroxide gel generated thickly covers the surface of the clinker particles, delaying hydration.

From the viewpoint of improving strength and fluidity and suppressing fuel consumption, the content of C ₄ AF in the clinker is preferably 7 to 9% by mass, and more preferably 8 to 9% by mass.

[Grid volume of C ₄ AF]

The lattice volume of C ₄ AF exceeds 0.4290 nm ³ .

If the lattice volume of C ₄ AF is 0.4290 nm ³ or less, the solubility of C ₄ AF in alkanolamine decreases, so the effect of promoting hydration of C ₃ S is not obtained, and the mortar strength decreases.

The lattice volume of C ₄ AF is preferably 0.4295 nm ³ or more, and more preferably 0.4300 nm ³ or more. The upper limit of the lattice volume of C ₄ AF is not particularly limited, but is usually 0.4320 nm ³ or less.

The lattice volume of C ₄ AF can be calculated by the Whole Pattern Fitting (WPF) analysis method from the lattice constant of C ₄ AF measured using the Rietveld analysis method using powder X-ray diffraction.

〔pharmacy〕

The cement composition of the present invention contains an alkanolamine-containing adjuvant, and the alkanolamine content in the total amount of Portland cement clinker, gypsum, and adjuvant is usually 10 to 210 mg/kg.

The aid specifically means a grinding aid, and the alkanolamine also acts as a strength enhancer. The aid may contain components other than alkanolamines, and examples include aliphatic polyhydric alcohols.

If the content of alkanolamine in the cement composition of the present invention is less than 10 mg/kg, the strength enhancing effect cannot be obtained because the concentration is too low to promote hydration of allite by dissolution of C ₄ AF. When the alkanolamine content in the cement composition of the present invention exceeds 210 mg/kg, the initial strength improvement effect is significant, but at 28 days of age, the hydration structure becomes rough due to the initial hydration activity being active, resulting in strength improvement. The effect will not be obtained.

(Alkanolamine)

Examples of alkanolamine include monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, methylethanolamine, methylisopropanolamine, N-n-butylethanolamine, and N-methyldiethanolamine. Ethanolamine, N-n-butyldiethanolamine, N-methyldiisopropanolamine, diethanolisopropanolamine, diisopropanolethanolamine, tetrahydroxyethylethylenediamine, N,N,N',N'-tetrakis (2 Examples include -hydroxypropyl)ethylenediamine and tris(2-hydroxybutyl)amine.

Only one type of alkanolamine may be used, or two or more types may be used.

Among them, alkanolamines include diethanolisopropanolamine (DEIPA), triisopropanolamine (TIPA), ethanoldiisopropanolamine (EDIPA), N-methyldiethanolamine (MDEA), and N-n-butyldiethanolamine ( BDEA), preferably at least one selected from the group consisting of diethanolisopropanolamine (DEIPA), triisopropanolamine (TIPA), and N-methyldiethanolamine (MDEA). is more preferred, and diethanolisopropanolamine (DEIPA) is more preferred.

(aliphatic polyhydric alcohol)

It is preferable that the aid contains an aliphatic polyhydric alcohol.

The aliphatic polyhydric alcohol preferably has 3 to 20 carbon atoms, and more preferably has 3 to 10 carbon atoms.

The aliphatic polyhydric alcohol preferably has a hydroxyl group number of 2 to 8, and more preferably has a hydroxyl group number of 2 to 4.

The aliphatic polyhydric alcohol preferably has a molecular weight of 70 to 420, and more preferably 70 to 210.

Aliphatic polyhydric alcohols specifically include glycols such as ethylene glycol, diethylene glycol, and polyethylene glycol; Glycerin, etc. can be mentioned. Only one type of aliphatic polyhydric alcohol may be used, or two or more types may be used.

The aliphatic polyhydric alcohol is preferably at least one selected from the group consisting of glycerin and diethylene glycol, and more preferably contains diethylene glycol.

In addition, it is generally preferable that the content of the adjuvant in the total amount of Portland cement clinker, gypsum, and adjuvant is 80 to 350 mg/kg.

Hereinafter, "total adjuvant" means "content of adjuvant in the total amount of ordinary Portland cement clinker, gypsum, and adjuvant."

When the total amount of additives is 80 mg/kg or more, the cement composition has excellent pulverization properties. That is, when clinker, gypsum, and limestone are added and pulverized with a ball mill, it is difficult for the pulverized material to adhere to the medium, and inhibition of pulverization is suppressed. When the total amount of preparation is 350 mg/kg or less, the fractionation property is excellent. That is, the air entrainment of the kneaded product is suppressed, preventing a decrease in strength, and the fluidity of the powder is unlikely to be increased more than necessary, so it is difficult to slip during transportation on a belt conveyor and is easy to convey up an uphill gradient, Additionally, slipping and falling due to its own weight is suppressed on a downward slope, and the cement composition can be transported efficiently.

The total amount of preparation is more preferably 100 to 350 mg/kg, and more preferably 150 to 300 mg/kg, from the viewpoint of further improving pulverization and classification properties.

[Limestone]

The cement composition of the present invention contains limestone.

Limestone usually has a content of 3 to 10% by mass in the total amount of Portland cement clinker, gypsum, preparation, and limestone.

Hereinafter, “limestone content” means “the content of limestone in the total amount of ordinary Portland cement clinker, gypsum, preparation, and limestone.”

If the limestone content is less than 3% by mass, the strength improvement effect is not obtained.

Normally, ettringite generated during initial hydration causes a reaction to be converted to monosulfate as hydration of cement progresses, but when limestone and alkanolamine coexist, addition to monocarbonate or hemihydrate is necessary. It contributes to increasing strength by promoting However, if the limestone content is less than 3% by mass, the reaction does not occur significantly and does not lead to an increase in strength.

When the limestone content exceeds 10% by mass, the unit clinker amount in the cement decreases, thereby lowering the mortar strength.

The limestone content is preferably 3 to 9% by mass, and more preferably 4 to 8% by mass, from the viewpoint of further improving strength.

〔gypsum〕

The cement composition of the present invention contains gypsum.

It is preferable that the total content of gypsum, usually Portland cement clinker, gypsum, and adjuvant, is 0.7 to 2.8% by mass in terms of SO ₃ .

Hereinafter, “gypsum content” means “the content of gypsum in the total amount of ordinary Portland cement clinker, gypsum, and adjuvant.”

When the gypsum content is within the above range, the setting time and fluidity after pouring of the cement composition and its changes over time can be appropriately maintained, and strength development and drying shrinkage can be appropriately achieved as properties after hardening.

From the above viewpoint, the gypsum content is more preferably 0.8 to 2.5% by mass, more preferably 0.9 to 2.0% by mass, in terms of SO ₃ .

Gypsum content can be measured according to JIS R 5202:2010 “Chemical analysis method of Portland cement”. The ratio of the mass of gypsum in the cement composition converted to SO ₃ can be obtained from the ratio of the mixing amount of gypsum and the ratio of SO ₃ contained in the gypsum.

As gypsum, anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum can all be used.

[Other ingredients]

To the cement composition of the present invention, fly ash, blast furnace slag, or silica fume may be further added to control fluidity, hydration rate, strength development, etc.

<Method for producing cement composition>

The method for producing the cement composition of the present invention is a method in which C ₃ S is 51 to 62% by mass, C ₄ AF is 7 to 10% by mass calculated by the Borg equation, and the lattice volume of C ₄ AF is usually greater than 0.4290 nm ³ . Portland cement clinker, gypsum, limestone, and an adjuvant containing an alkanolamine. The mixing amount of alkanolamine in the total amount of ordinary Portland cement clinker, gypsum, and adjuvant is 10 to 210 mg/kg, and usually Portland cement clinker, This is a method of producing the cement composition of the present invention by mixing 3 to 10% by mass of limestone in the total amount of gypsum, adjuvant, and limestone.

The compounding amount of alkanolamine is the same as the content of alkanolamine in the cement composition of the present invention, and the preferable range is also the same. In addition, the mixing amount of limestone has the same meaning as the limestone content described above, and the preferable range is also the same.

The order and timing of adding preparations, gypsum and limestone to clinker are not particularly limited. For example, gypsum and limestone may be added to clinker and mixed, and then an adjuvant may be further added and mixed, or an adjuvant may be added to clinker and then gypsum and limestone may be added.

The means for mixing each component in the method for producing the cement composition of the present invention is not particularly limited. Examples include mixers, ball mills, rosh mills, air blending silos, etc. The mixing time can be set in a range where it is judged that sufficient mixing has been performed in the production of a normal cement composition.

In this manufacturing method, it is preferable that grinding is performed so that the Blaine specific surface area of the cement composition is 2800 to 3500 cm ² /g.

In the method for producing the cement composition of the present invention, in addition to the addition of the usual Portland cement clinker, gypsum, limestone, and auxiliary agents including alkanolamine, blast furnace slag, siliceous admixture, and fly ash can be further added.

In the present invention, blast furnace slag and siliceous mixture specified in JIS R 5210:2009 "Portland cement" can be used. Regarding fly ash, in addition to fly ash type I and fly ash type II specified in JIS R 5210:2009 "Portland cement", fly ash type III and fly ash type IV can also be used.

Example

Hereinafter, the present invention will be described in more detail through examples. However, the present invention is in no way limited to the following examples.

<Manufacture of cement composition>

The following materials were used to prepare the cement composition.

1. Clinker

Seven types of ordinary Portland cement clinkers (manufactured by Sumitomo Osaka Cement Co., Ltd.), A to G, were used. The chemical composition and mineral composition are shown in Table 1. The chemical composition of the clinker was analyzed by the glass bead method using a fluorescence The mineral composition was calculated from the obtained mass ratios of CaO, SiO ₂ , Al ₂ O ₃ and Fe ₂ O ₃ using the following Borg equation. Additionally, in Table 1, HM refers to hydraulic ratio, SM refers to silicic acid rate, and IM refers to iron rate.

C ₃ S=(4.07×CaO)-(7.60×SiO ₂ )-(6.72×Al ₂ O ₃ )-(1.43×Fe ₂ O ₃ )

C ₂ S = (2.87×SiO ₂ )-(0.754×C ₃ S)

C ₃ A=(2.65×Al ₂ O ₃ )-(1.69×Fe ₂ O ₃ )

C ₄ AF=3.04×Fe ₂ O ₃

The "C ₄ AF lattice volume" in Table 1 was calculated by the WPF analysis method from the lattice constant of C ₄ AF measured using the Rietveld analysis method using powder X-ray diffraction.

(Measuring conditions)

·Powder X-ray diffraction device: X7Pert PRO, manufactured by Panalytical Corporation

Rietveld analysis software: High Score Plus, manufactured by Panalytical

·X-ray tube: Cu (tube voltage: 45kV, tube current: 40mA)

·Slit: divergence slit-variable (irradiation width- 12mm, antiscatter slit- 2°)

·Measurement range: 10 to 70° (step width: 0.0167°)

·Scan speed: 0.1013°/s

[Table 1]

2. Preparation

(1) Alkanolamine

DEIPA: Diethanolisopropanolamine (manufactured by Tokyo Kasei Kogyo Co., Ltd.)

・TIPA: Triisopropanolamine (manufactured by Tokyo Kasei Kogyo Co., Ltd.)

EDIPA: Ethanol diisopropanolamine [manufactured by Sigma Aldrich Japan Limited]

·MDEA: N-methyldiethanolamine (manufactured by Tokyo Kasei Kogyo Co., Ltd.)

BDEA: N-n-butyldiethanolamine (manufactured by Tokyo Kasei Kogyo Co., Ltd.)

(2) Aliphatic polyhydric alcohol

DEG: Diethylene glycol (manufactured by Kanto Chemical Co., Ltd.)

3. Limestone

Made by Kanto Chemical Co., Ltd., calcium carbonate special grade, CaCO ₃ : 99.5%

4. Plaster

Hemihydrate plaster was used. Specifically, calcium sulfate dihydrate grade 1, CaSO ₄ : 98.0+%, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd., and kept in a dryer at 120°C for 12 hours was used. The SO ₃ equivalent amount in gypsum was measured according to JIS R 5202:2015 “Chemical analysis method of cement.”

[Example 1]

With respect to 92.8 mass% ^(*) of clinker of clinker type A, 2.7 mass% of hemihydrate gypsum (1.5 mass% in terms of hemihydrate gypsum SO ₃ ) and 4.5 mass% of limestone were added and mixed with a mixer. Next, as shown in Table 2, diethanolisopropanolamine (DEIPA) and diethylene glycol (DEG) were used as adjuvants at 10 mg/kg and 190 mg, respectively, relative to the total amount of clinker, gypsum, and adjuvant. /kg was mixed. Next, the cement composition of Example 1 was obtained by mixing and grinding with a ball mill so that the Blaine specific surface area value was in the range of 3200 ± 50 cm ² /g.

In addition, regarding the amount indicated in (*), the total of clinker and aid is 92.8% by mass, but when the amount of aid is considered as a ratio of the total of clinker and aid, it has little effect on the amount of clinker, so the amount is small. and the amount of clinker can be said to be 92.8% by mass. The same applies to examples other than Example 1 and comparative examples.

Since the SO ₃ equivalent amount of gypsum acts on clinker, the amount of gypsum mixed is such that the SO ₃ equivalent amount of hemihydrate gypsum/(total amount of clinker + preparation + hemihydrate gypsum) is 1.5% in all examples and comparative examples. was combined.

[Examples 2 to 19, 23 to 26, Comparative Examples 1 to 4, 7 to 12]

As a clinker, the types of clinkers shown in Tables 2 to 3 are used, and limestone is mixed in the amount shown in Tables 2 to 3, and as an adjuvant, the type and amount shown in the "Additional" column in Tables 2 to 3 is used [alkanolamine] and, if necessary, aliphatic polyhydric alcohol (DEG)] were mixed and mixed and ground with a ball mill so that the Blaine specific surface area value was in the range of ±50 cm ² /g shown in Tables 2 to 3. A cement composition was obtained in the same manner.

In addition, in Comparative Example 1 and Comparative Example 2, alkanolamine was not blended. In addition, in Comparative Example 2, etc., where the value in the "DEG" column was 0, diethylene glycol was not blended.

[Comparative Example 5]

With respect to 96.2% by mass of clinker of clinker type A, 2.8% by mass of hemihydrate gypsum (1.5% by mass in terms of hemihydrate gypsum SO ₃ ) and 1.0% by mass of limestone were added and mixed with a mixer. Next, as shown in Table 3, diethanolisopropanolamine (DEIPA) and diethylene glycol (DEG) were used as adjuvants at 50 mg/kg and 150 mg, respectively, relative to the total amount of clinker, gypsum, and adjuvant. /kg was mixed. Next, the cement composition of Comparative Example 5 was obtained by mixing and grinding with a ball mill so that the Blaine specific surface area value was in the range of 3200 ± 50 cm ² /g.

[Example 20]

With respect to 94.1% by mass of clinker of clinker type A, 2.7% by mass of hemihydrate gypsum (1.5% by mass in terms of hemihydrate gypsum SO ₃ ) and 3.2% by mass of limestone were added and mixed with a mixer. Next, as shown in Table 3, diethanolisopropanolamine (DEIPA) and diethylene glycol (DEG) were used as adjuvants at 50 mg/kg and 150 mg, respectively, relative to the total amount of clinker, gypsum, and adjuvant. /kg was mixed. Next, the mixture was mixed and ground with a ball mill so that the Blaine specific surface area value was in the range of 3200 ± 50 cm ² /g, and the cement composition of Example 20 was obtained.

[Example 21]

With respect to 90.9% by mass of clinker of clinker type A, 2.6% by mass of hemihydrate gypsum (1.5% by mass in terms of hemihydrate gypsum SO ₃ ) and 6.5% by mass of limestone were added and mixed with a mixer. Next, as shown in Table 3, diethanolisopropanolamine (DEIPA) and diethylene glycol (DEG) were used as adjuvants at 50 mg/kg and 150 mg, respectively, relative to the total amount of clinker, gypsum, and adjuvant. /kg was mixed. Next, the cement composition of Example 21 was obtained by mixing and grinding with a ball mill so that the Blaine specific surface area value was in the range of 3200 ± 50 cm ² /g.

[Example 22]

With respect to 88.0 mass% of clinker of clinker type A, 2.5 mass% of hemihydrate gypsum (1.5 mass% in terms of hemihydrate gypsum SO ₃ ) and 9.5 mass% of limestone were added and mixed with a mixer. Next, as shown in Table 3, diethanolisopropanolamine (DEIPA) and diethylene glycol (DEG) were used as adjuvants at 50 mg/kg and 150 mg, respectively, relative to the total amount of clinker, gypsum, and adjuvant. /kg was mixed. Next, the cement composition of Example 22 was obtained by mixing and grinding with a ball mill so that the Blaine specific surface area value was in the range of 3200 ± 50 cm ² /g.

[Comparative Example 6]

With respect to 86.5% by mass of clinker of clinker type A, 2.5% by mass of hemihydrate gypsum (1.5% by mass in terms of hemihydrate gypsum SO ₃ ) and 11.0% by mass of limestone were added and mixed with a mixer. Next, as shown in Table 3, diethanolisopropanolamine (DEIPA) and diethylene glycol (DEG) were used as adjuvants at 50 mg/kg and 150 mg, respectively, relative to the total amount of clinker, gypsum, and adjuvant. /kg was mixed. Next, the cement composition of Comparative Example 6 was obtained by mixing and grinding with a ball mill so that the Blaine specific surface area value was in the range of 3200 ± 50 cm ² /g.

<Evaluation of cement composition>

1. Crushability

10 kg of high chromium balls of ϕ9.5 mm were put into a ball mill of ϕ0.4m The mill rotation speed was set to 60 times/min, and the grinding time until the specific surface area of the blade reached 3200 cm ² /g was measured.

The shorter the grinding time, the better the cement composition can be crushed. The grinding time is preferably less than 68 minutes. The results are shown in the “Pulverization Effect” column of Tables 2 and 3.

2. Classification

Using a powder tester (TP-X) manufactured by Hosokawa Micron Co., Ltd., the angle of repose, angle of collapse, and dispersion of the cement compositions of Examples and Comparative Examples were measured, and applied to the classification index table of the same device to determine the classification index. Saved.

The smaller the sortability index, the better the sortability of the cement composition. It is desirable that the index is less than 75. The results are shown in the “Classification Index” column of Tables 2 and 3.

3. Mortar strength

In accordance with JIS R 5201 "Physical Test Methods for Cement", the strength of mortars obtained using the cements of Examples and Comparative Examples was evaluated.

The larger the value, the higher the strength of the mortar obtained using the cement composition, and the allowable range is greater than 60 N/mm ² . The results are shown in the “Mortar Strength” column of Tables 2 and 3.

4. Liquidity

The fluidity of the mortar obtained from the cement composition was evaluated in accordance with JIS R 5201 "Physical test method for cement".

Specifically, to the cement compositions of Examples and Comparative Examples, 1.0% of a high-performance water reducing agent (manufactured by Gao Co., Ltd., brand name "Mighty 150") was added as an external agent to prepare mortar, and the obtained mortar was , the 15 dropping movements were not performed, and the flow value was measured at the point when the spread of the mortar stopped after extracting the cone.

The larger the flow value, the better the fluidity of the mortar obtained from the cement composition. The allowable range is over 160mm. The results are shown in the "0 hit flow" column in Tables 2 and 3.

[Table 2]

[Table 3]

Claims (7)

Ordinary Portland cement clinker with 51 to 62% by mass of C ₃ S and 7 to 10% by mass of C ₄ AF calculated by the Borg method,
plaster,
limestone,
Including preparations containing alkanolamines,
The content of the alkanolamine in the total amount of the ordinary Portland cement clinker, the gypsum, and the adjuvant is 10 to 210 mg/kg,
The content of the limestone in the total amount of the ordinary Portland cement clinker, the gypsum, the preparation, and the limestone is 3 to 10% by mass,
The lattice volume of the C ₄ AF exceeds 0.4290 nm ³ ,
A cement composition with a Blaine specific surface area of 2800 to 3500 cm ² /g. According to claim 1,
A cement composition wherein the content of the auxiliary in the total amount of the ordinary Portland cement clinker, the gypsum, and the auxiliary is 80 to 350 mg/kg. According to claim 1,
A cement composition wherein the auxiliary agent contains an aliphatic polyhydric alcohol. According to claim 1,
A cement composition wherein the content of the gypsum in the total amount of the ordinary Portland cement clinker, the gypsum, and the adjuvant is 0.7 to 2.8% by mass in terms of SO ₃ . According to claim 1,
A cement composition wherein the alkanolamine is at least one selected from the group consisting of diethanolisopropanolamine, triisopropanolamine, ethanoldiisopropanolamine, N-methyldiethanolamine, and Nn-butyldiethanolamine. According to claim 3,
A cement composition wherein the aliphatic polyhydric alcohol is at least one selected from the group consisting of glycerin and diethylene glycol. Ordinary Portland cement clinker in which C ₃ S is 51 to 62 mass% and C ₄ AF is 7 to 10 mass% calculated by the Borg formula, and the lattice volume of C ₄ AF exceeds 0.4290 nm ³ ;
plaster,
limestone,
Preparations containing alkanolamines,
The compounding amount of the alkanolamine in the total amount of the ordinary Portland cement clinker, the gypsum, and the above adjuvant is 10 to 210 mg/kg, and
A cement composition in which the cement composition according to any one of claims 1 to 6 is produced by mixing the ordinary Portland cement clinker, the gypsum, the preparation, and the limestone in an amount of 3 to 10% by mass. Manufacturing method.