JP2023094091A - Cement composition and method for producing the same - Google Patents

Abstract

To provide: a cement composition which has excellent long-term mortar strength even when a content of MgO in Portland cement is high; and a method for producing a cement composition, capable of improving the long-term mortar strength even when the content of MgO in Portland cement is high.SOLUTION: A cement composition comprises: Portland cement which satisfies (1) and (2); and 0.001-0.025 pt.mass of an alkanolamine based on 100 pts.mass of the Portland cement. (1) 0.55≤MgO/Fe2O3+CL'SO3/SO3≤0.95 (2)0≤▵C4AF.SELECTED DRAWING: None

Description

The present invention relates to a cement composition and a method for producing the same.

Clinker contains minor components such as Mg, Na, and K depending on raw material conditions, and the content varies.
For example, in Non-Patent Document 1, it is known that cement under high MgO conditions is replaced with Ca, which is also an alkaline earth metal. It is known that long-term strength such as 28-day age decreases due to the decrease in . Non-Patent Document 3 has found that increasing SO ₃ may improve strength even with high MgO.

In addition, in Patent Document 1, if the MgO content in the cement clinker after firing exceeds 1.0% by mass, the strength expression in the long-term material age of the cement decreases. It is disclosed that the raw materials are prepared by adjusting the MgO content to 1.0% by mass or less.
Furthermore, in Patent Document 2, a cement clinker having a 2CaO·SiO ₂ content of 30 to 60% by mass calculated by the Borg formula, wherein the cement clinker has a MgO content of 1.2% by mass or more, less than 1.9% by weight and a cement clinker characterized by a SO ₃ content of 0.4-1.2% by weight.

JP 2009-013023 A JP 2018-65750 A

Crystal Chemistry of Tricalcium Silicate Solid Solution, in 5th I.P. S. C. C, Vol. 1, 61-66 (1969) Annual Report of Cement Technology, Vol. 22, 62-66 (1968) Cement Science and Concrete Technology, Vol. 70

However, it is difficult to control because the cement components under high MgO conditions are adjusted, and the methods described in Non-Patent Documents 1 to 3 cannot stably maintain long-term strength. The problem is that mines that produce limestone, which is a raw material, sometimes contain a large amount of dolomite. Therefore, as in Patent Document 1, it was necessary to reduce the MgO content. In Patent Document 2, it is explained that even if the content of MgO in cement is high, it is possible to prevent deterioration of the long-term strength development of cement. had to be less than

The present invention provides a cement composition excellent in long-term strength of mortar even when the MgO content in Portland cement is high, and a cement composition capable of improving long-term strength of mortar even when the MgO content in Portland cement is high. The object is to provide a manufacturing method.

The present invention provides the following <1> to <10>.
<1> Portland cement that satisfies the following (1) and (2);
With respect to 100 parts by mass of the Portland cement, 0.001 to 0.025 parts by mass of alkanolamine,
A cement composition comprising:
( ₁ ) 0.55≤MgO/ _Fe2O3 + _CL'SO3 / _SO3≤0.95
(2) 0≦ΔC ₄ AF
In (1) above, MgO represents the mass (% by mass) of MgO in the Portland cement, Fe ₂ O ₃ represents the mass (% by mass) of Fe ₂ O ₃ in the Portland cement, and SO ₃ represents the mass (% by mass) of It represents the SO ₃ equivalent amount (mass%) of Portland cement, and CL'SO ₃ represents the SO ₃ equivalent amount (mass%) of the clinker of the Portland cement.
In (2) above, ΔC ₄ AF is The mass (% by mass) of C ₄ AF and B. It represents the difference ( _R.C.sub.4 AF- _B.C.sub.4 AF) from the mass (% by mass) of _C.sub.4 AF. Here, the R.I. C ₄ AF represents the C ₄ AF value of the Portland cement measured with a powder X-ray diffractometer; _C4AF stands _{for 3.04xFe2O3} . The above B. Fe ₂ O ₃ in C ₄ AF represents the mass (% by mass) of Fe ₂ O ₃ in the Portland cement.

<2> The cement composition according to <1>, wherein the MgO/Fe ₂ O ₃ in (1) exceeds 0.35.
<3> The Portland cement contains 45 to 75% by mass of C ₃ S, 5 to 25% by mass of C ₂ S, 7 to 11% by mass of C ₃ A, and 7 to 7% by mass of C ₄ AF calculated by the Borg formula. The cement composition according to <1> or <2>, which is 11% by mass of ordinary Portland cement.
<4> The cement composition according to any one of <1> to <3>, wherein the alkanolamine content is 0.005 to 0.02 parts by mass with respect to 100 parts by mass of the Portland cement.
<5> The alkanolamine is at least one selected from the group consisting of diethanolisopropanolamine, triisopropanolamine, ethanoldiisopropanolamine, triethanolamine, N-methyldiethanolamine, and Nn-butyldiethanolamine. The cement composition according to any one of 1> to <4>.

<6> Portland cement that satisfies the following (1) and (2);
With respect to 100 parts by mass of the Portland cement, 0.001 to 0.025 parts by mass of alkanolamine,
A method for producing a cement composition by mixing
( ₁ ) 0.55≤MgO/ _Fe2O3 + _CL'SO3 / _SO3≤0.95
(2) 0≦ΔC ₄ AF
In (1) above, MgO represents the mass (% by mass) of MgO in the Portland cement, Fe ₂ O ₃ represents the mass (% by mass) of Fe ₂ O ₃ in the Portland cement, and SO ₃ represents the mass (% by mass) of It represents the SO ₃ equivalent amount (mass%) of Portland cement, and CL'SO ₃ represents the SO ₃ equivalent amount (mass%) of the clinker of the Portland cement.
In (2) above, ΔC ₄ AF is The mass (% by mass) of C ₄ AF and B. It represents the difference ( _R.C.sub.4 AF- _B.C.sub.4 AF) from the mass (% by mass) of _C.sub.4 AF. Here, the R.I. C ₄ AF represents the C ₄ AF value of the Portland cement measured with a powder X-ray diffractometer; _C4AF stands _{for 3.04xFe2O3} . The above B. Fe ₂ O ₃ in C ₄ AF represents the mass (% by mass) of Fe ₂ O ₃ in the Portland cement.

<7> The method for producing a cement composition according to <6>, wherein the MgO/Fe ₂ O ₃ in (1) exceeds 0.35.
<8> The Portland cement contains 45 to 75% by mass of C ₃ S, 5 to 25% by mass of C ₂ S, 7 to 11% by mass of C ₃ A, and 7 to 7% by mass of C ₄ AF calculated by the Borg formula. The method for producing a cement composition according to <6> or <7>, which is 11% by mass of ordinary Portland cement.
<9> The cement composition according to any one of <6> to <8>, wherein the amount of the alkanolamine added is 0.005 to 0.02 parts by mass with respect to 100 parts by mass of the Portland cement. Production method.
<10> The alkanolamine is at least one selected from the group consisting of diethanolisopropanolamine, triisopropanolamine, ethanoldiisopropanolamine, triethanolamine, N-methyldiethanolamine, and Nn-butyldiethanolamine. 6> A method for producing a cement composition according to any one of <9>.

INDUSTRIAL APPLICABILITY According to the present invention, a cement composition having excellent long-term strength of mortar even when the MgO content in Portland cement is high and a cement composition capable of improving long-term strength of mortar even when the MgO content in Portland cement is high. A method for manufacturing an object can be provided.

FIG. 4 is a graph plotting the values of ΔC ₄ AF against the conditions ^** of Examples and Comparative Examples. FIG. It is the graph which plotted the value of the mortar enhancement strength difference with respect to conditions ^** in the 7-day age and 28-day age of an Example and a comparative example.

The notation of a numerical range from "AA to BB" in this specification means "from AA to BB".

<Cement composition>
The cement composition of the present invention contains Portland cement satisfying the following (1) and (2) and 0.001 to 0.025 parts by mass of alkanolamine per 100 parts by mass of the Portland cement.
( ₁ ) 0.55≤MgO/ _Fe2O3 + _CL'SO3 / _SO3≤0.95
(2) 0≦ΔC ₄ AF
In (1), MgO represents the mass (mass%) _of MgO in Portland cement, _Fe2O3 represents the mass (mass%) _{of Fe2O3} in Portland cement, and _SO3 represents SO of Portland cement. ₃ equivalent amount (% by mass), and CL'SO ₃ represents the SO ₃ equivalent amount (% by mass) of Portland cement clinker.
In (2), ΔC ₄ AF is the The mass (% by mass) of C ₄ AF and B. It represents the difference ( _R.C.sub.4 AF- _B.C.sub.4 AF) from the mass (% by mass) of _C.sub.4 AF. Here, R.I. C ₄ AF represents the C ₄ AF value of Portland cement measured with a powder X-ray diffractometer; _C4AF stands _{for 3.04xFe2O3} . B. Fe ₂ O ₃ in C ₄ AF represents the mass (mass %) of Fe ₂ O ₃ in Portland cement.
Portland cement that satisfies the above (1) and (2) is hereinafter referred to as "portland cement in the present invention" or simply "cement in the present invention".
In other words, the cement composition of the present invention contains clinker, gypsum and alkanolamine, Portland cement containing clinker and gypsum satisfies the above (1) and (2), and the alkanolamine content is Range.

If the MgO content in the cement is high, for example, 1.30% by mass or more, the hydration of calcium decreases, which relatively reduces the strength of the mortar.
In order to improve strength, it is known to use an auxiliary agent such as alkanolamine. On the contrary, it tended to decrease.
However, the long-term strength of the mortar can be improved by making the content of the cement composition as described above. Although the reason for this is not clear, it is presumed to be due to the following reasons.

[Condition (1)]
Condition (1) is that "MgO/Fe ₂ O ₃ +CL'SO ₃ /SO ₃ " is 0.55 to 0.95.
Although the details are not clear, it is possible that the mass of MgO relative to the mass of Fe ₂ O ₃ increases, and the SO ₃ equivalent amount (mass standard) in clinker relative to the SO ₃ equivalent amount (mass standard) in cement increases. , which is thought to be related to the solid solution of the ferrite phase. “MgO/Fe ₂ O ₃ +CL′SO ₃ /SO ₃ ” can be considered as an indicator of the solid solution amount of the ferrite phase.
The alkanolamine contained together with the Portland cement in the present invention dissolves iron and the like in the ferrite phase, dissolves it in the gel, promotes watertightness by uniformly permeating, and has the function of increasing the strength of the mortar. It is considered that the solid solution of SO ₃ in the ferrite phase further enhances the mortar strength enhancing effect of the alkanolamine, thereby improving the long-term strength of the mortar.

When "MgO/Fe ₂ O ₃ +CL'SO ₃ /SO ₃ " is less than 0.55, the solid solution amount of the ferrite phase is small, and the mortar strength enhancing effect due to the alkanolamine cannot be sufficiently obtained, and the long-term strength of the mortar is low. Not good for
When "MgO/Fe ₂ O ₃ +CL'SO ₃ /SO ₃ " exceeds 0.95, it becomes difficult to obtain the strength increasing effect of alkanolamine, and alkanolamine, unreacted MgO and MgSO ₄ become excessive. It causes expansion cracks and the mortar strength cannot be maintained.
From the viewpoint of further improving the long-term strength of the mortar, "MgO/Fe ₂ O ₃ +CL'SO ₃ /SO ₃ " is preferably 0.60 to 0.90, more preferably 0.70 to 0.80. is more preferred.

Furthermore, in condition (1), MgO/Fe ₂ O ₃ preferably exceeds 0.35.
The mass of MgO _with respect to the mass _of Fe ₂ O ₃ in the cement _is considered to represent the solid solution amount of C ₄ AF. can promote
From the viewpoint of increasing the solid solution amount of the ferrite phase, MgO/Fe ₂ O ₃ is preferably 0.36 to 0.60, more preferably 0.40 to 0.50.

From the viewpoint of increasing the solid solution amount of alkanolamine, the mass of MgO in the condition (1), that is, the mass of MgO in the cement, is preferably 3.5% by mass or less, and 0.5 to 3.0% by mass. and more preferably 1.0 to 2.5% by mass.

From the viewpoint of solid solution stabilization of the ferrite phase, the mass of Fe ₂ O ₃ in the condition (1), that is, the mass of Fe ₂ O ₃ in the cement, is preferably 2.0 to 4.0 mass%, It is more preferably 2.5 to 3.5% by mass, even more preferably 2.7 to 3.4% by mass.

From the viewpoint of promoting C ₄ AF solid solution and ensuring cement fluidity, in condition (1), CL'SO ₃ , that is, the SO ₃ equivalent amount of clinker is preferably 2.5% by weight or less, and 0 .2 to 2.0% by mass, more preferably 0.5 to 1.5% by mass.

From the viewpoint of securing cement fluidity, in condition (1), the range of SO ₃ which is the denominator of CL'SO ₃ /SO ₃ , that is, the SO ₃ equivalent amount of cement is 3.5% by weight or less. It is preferably from 0.5 to 3.0% by mass, and even more preferably from 1.5 to 2.5% by mass.

[Condition (2)]
Condition (2) is that ΔC ₄ AF is 0 points or more.
Note that the 0 point is, for example, when the C ₄ AF (R.C ₄ AF) obtained by Rietveld analysis is 10.1% by mass, the C ₄ AF (B.C ₄ AF) calculated by the Borg formula is also 10.1% by mass.
ΔC ₄ AF was determined by R. The mass of C ₄ AF and B. Represents the difference (RC ₄ AF-BC ₄ AF) from the mass of C 4 AF, and C ₄ AF obtained by Rietveld _analysis (RC ₄ AF) and C ₄ calculated by the Borg formula This is the difference from AF (B.C ₄ AF). Since the Borg formula does not consider magnesium, the solid solution amount of MgO can be estimated from ΔC ₄ AF, and ΔC ₄ AF increases as the MgO content in cement increases. In the present invention, from the viewpoint of improving the long-term strength of mortar under high MgO conditions, it is a condition that ΔC ₄ AF is 0 or more.
Since the increase in the amount of dissolved ferrite phase in which MgO is dissolved by alkanolamine affects the increase in strength, ΔC ₄ AF is preferably 0.3 to 1.5 points, and 0.5 to 1.5 points. It is more preferable to have

R. C ₄ AF is determined by the following steps.
First, X-ray diffraction measurement of cement is performed to obtain a profile. The obtained profile is analyzed by the Rietveld method to quantify cement minerals. Minerals to be analyzed are C ₃ S-M1 (M1 phase), C ₃ S-M3 (M3 phase), C ₂ S-α'H (α'H phase), C ₂ S-β (β phase), C ₃ A-cubic (cubic), C ₃ A-ortho (orthorhombic), and C ₄ AF. In the Rietveld analysis, based on the basic crystal structure data of each mineral, refinement operation is performed so that the measured profile and the theoretical profile are fitted with parameters such as lattice constant and scale factor. From the finally refined scale factor, the mass ratio of each of the above minerals was calculated. Obtain the C ₄ AF content (% by mass).
Specific measurement conditions for the X-ray diffractometer are shown in Examples.

Portland cement in the present invention is not particularly limited as long as it satisfies the above conditions (1) and (2). Portland cement, blast-furnace slag, fly ash, siliceous mixed material (pozzolana), etc. can also be used, and special cement such as alumina cement can be used. preferred.

More specifically, the Portland cement used in the cement composition of the present invention contains 45 to 75% by mass of C ₃ S (3CaO.SiO ₂ ) calculated by the Bogue formula, C ₂ S (2CaO.SiO ₂ ) is 5 to 25% by mass, C ₃ A (3CaO.Al ₂ O ₃ ) is 7 to 11% by mass, and C ₄ AF (4CaO.Al ₂ O ₃ .FeO ₃ ) is 7 to 11% by mass. It is preferred that the
Moreover, the Portland cement used in the cement composition of the present invention preferably has a C ₄ AF (R.C ₄ AF) obtained by Rietveld analysis of 7.5 to 12% by mass.

( _C3S , _C2S )
When the content of C ₃ S in the cement is 45% by mass or more, the addition of alkanolamine has a large strength-enhancing effect, resulting in excellent mortar strength and excellent fluidity. When the content of C ₃ S in cement is 45% by mass or more, the content of C ₂ S, which is relatively poor in grindability, is reduced. As a result, the pulverization time required for the cement composition to have a certain Blaine specific surface area is shortened, and minerals other than _C2S ( _C3S , _C3A , and _C4AF ) that have good pulverizability are mainly used. Excessive pulverization of is suppressed, and an increase in Blaine specific surface area is suppressed. In addition, the mechanism of strength enhancement by the addition of alkanolamine is that the selective dissolution of C ₄ AF in the clinker increases the opportunity for C ₄ AF adjacent to C ₄ AF to come into contact with water, promoting hydration and increasing strength. will increase. By suppressing excessive pulverization of clinker, clinker particles, which are originally composed of various minerals, are less likely to exist as individual minerals, and the dissolution of C ₄ AF tends to lead to the promotion of hydration of C ₄ AF. Therefore, the addition of the alkanolamine tends to increase the strength.
When the content of C ₃ S in cement is 75% by mass or less, the long-term compressive strength of concrete can be sufficiently maintained.
When the content of C ₂ S in cement is 5% by mass or more, the long-term compressive strength of concrete can be sufficiently maintained.
When the content of C ₂ S in cement is 25% by mass or less, the initial compressive strength of concrete can be sufficiently maintained.

From the viewpoint of enhancing strength and fluidity, the content of C ₃ S in cement is more preferably 50 to 70% by mass.

( _C4AF , _C3A )
When the content of C ₄ AF in cement is 7% by mass or more, the dissolution of C ₄ AF is promoted by the addition of alkanolamine, and the reaction of C ₃ S is promoted, resulting in a remarkable strength enhancement effect. can be demonstrated.
When the content of C ₄ AF in cement is 11% by mass or less, the amount of iron hydroxide gel generated by the dissolution of Fe ions in C ₄ AF can be suppressed, and the coating of the clinker particle surface can be suppressed. delay in hydration can be prevented.
_The total of C ₄ AF and C ₃ A is constant at about 18% by mass, and if the content of C ₄ AF in cement increases, the content of C ₃ A decreases, The content of _3A increases.
From the viewpoint of enhancing strength and fluidity, the content of C ₄ AF in cement is preferably 7-9% by mass, more preferably 8-9% by mass.

[Alkanolamine]
The cement composition of the present invention contains 0.001 to 0.025 parts by mass of alkanolamine per 100 parts by mass of Portland cement clinker of the present invention.
Alkanolamines also act as strength enhancers.
If the content of alkanolamine in the cement composition of the present invention is less than 0.001 parts by mass with respect to 100 parts by mass of Portland cement clinker, the effect of increasing strength cannot be obtained. When the content of alkanolamine in the cement composition of the present invention exceeds 0.025 parts by mass with respect to 100 parts by mass of Portland cement clinker, the effect of increasing the initial strength is remarkable. Due to the active hydration activity, the hydrated structure becomes coarse and the strength increasing effect cannot be obtained.
From the above viewpoint, the alkanolamine content in the cement composition of the present invention is preferably 0.005 to 0.02 parts by mass per 100 parts by mass of the Portland cement clinker of the present invention.

Alkanolamines include monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, methylethanolamine, methylisopropanolamine, Nn-butylethanolamine, N-methyldiethanolamine, N- n-butyldiethanolamine, N-methyldiisopropanolamine, diethanolisopropanolamine, diisopropanolethanolamine, tetrahydroxyethylethylenediamine, N,N,N',N'-tetrakis(2-hydroxypropyl)ethylenediamine, tris(2-hydroxy Butyl) amine and the like can be exemplified.
Only one type of alkanolamine may be used, or two or more types may be used.

Among the alkanolamines are diethanolisopropanolamine (DEIPA), triisopropanolamine (TIPA), ethanoldiisopropanolamine (EDIPA), triethanolamine (TEA), N-methyldiethanolamine (MDEA), and Nn-butyldiethanolamine. (BDEA), preferably at least one selected from the group consisting of diethanolisopropanolamine (DEIPA), triisopropanolamine (TIPA), ethanoldiisopropanolamine (EDIPA) and triethanolamine (TEA) More preferably, it is at least one more selected, and more preferably diethanol isopropanolamine (DEIPA).

Alkanolamine is generally highly viscous and difficult to mix, so it is unsuitable to add during mortar production. Therefore, it is preferable to add it as a grinding aid in the finishing process of cement production. Further, when the alkanolamine is diluted and dissolved in water and used, it becomes easy to mix with cement, and the cement composition of the present invention can be produced efficiently.

〔plaster〕
The cement composition of the present invention contains gypsum.
As gypsum, any of anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum can be used.
The content of gypsum in the cement composition is preferably 0.5-2.5% by mass in terms of SO ₃ .
When the content of gypsum in the cement composition is within the above range, the drying shrinkage of the cement composition can be made appropriate, and the strength exhibited by the cement composition can be increased.
From the above viewpoint, the content of gypsum in the cement composition is more preferably 1.0 to 1.8% by mass in terms of SO ₃ .
The ratio of SO ₃ in gypsum can be measured according to JIS R 5202:2010 "Method for chemical analysis of Portland cement". The ratio of the SO3 _- equivalent mass of gypsum in the cement composition can be obtained from the compounding amount of gypsum and the ratio of _SO3 contained in the gypsum.

[Limestone]
The cement composition of the present invention may contain limestone for the purpose of improving short-term strength and reducing _CO2 emissions through pulverization.
The content of limestone in the cement composition is specified in JIS R 5210: 2009 "Portland cement", but in the present invention, even if limestone is added beyond the range specified in the JIS standard good.
The content of limestone in the cement composition is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, even more preferably 2 to 5% by mass. The limestone content of 0% by mass means that limestone is not added to the production of the cement composition.

[Other ingredients]
To the cement composition of the present invention, fly ash, blast-furnace slag, silica fume, or the like can be further added for adjusting fluidity, hydration rate, strength development, and the like.

(Blaine specific surface area)
The cement composition of the present invention preferably has a Blaine specific surface area of 3000 to 3400 cm ² /g.
When the Blaine specific surface area is 3000 cm ² /g or more, the mortar strength is less likely to decrease, and when it is 3400 cm ² /g or less, the decrease in fluidity is suppressed, and the dissolution of C ₄ AF due to alkanolamine is reduced. can be suppressed to maintain the strength enhancement effect.
From the viewpoint of further increasing strength, the Blaine specific surface area of the cement composition is more preferably 3100 to 3300 cm ² /g.
The Blaine specific surface area of the cement composition may be measured according to JIS R 5201:2015 "Methods for Physical Testing of Cement".

<Method for producing cement composition>
In the method for producing a cement composition of the present invention, Portland cement satisfying the following (1) and (2) and 0.001 to 0.025 parts by mass of alkanolamine are mixed with 100 parts by mass of Portland cement. , a method of making the cement composition of the present invention.
( ₁ ) 0.55≤MgO/ _Fe2O3 + _CL'SO3 / _SO3≤0.95
(2) 0≦ΔC ₄ AF
In (1), MgO represents the mass (mass%) _of MgO in Portland cement, _Fe2O3 represents the mass (mass%) _{of Fe2O3} in Portland cement, and _SO3 represents SO of Portland cement. ₃ equivalent amount (% by mass), and CL'SO ₃ represents the SO ₃ equivalent amount (% by mass) of Portland cement clinker.
In (2), ΔC ₄ AF is the The mass (% by mass) of C ₄ AF and B. It represents the difference ( _R.C.sub.4 AF- _B.C.sub.4 AF) from the mass (% by mass) of _C.sub.4 AF. Here, R.I. C ₄ AF represents the C ₄ AF value of Portland cement measured with a powder X-ray diffractometer; _C4AF stands _{for 3.04xFe2O3} . B. Fe ₂ O ₃ in C ₄ AF represents the mass (mass %) of Fe ₂ O ₃ in Portland cement.

The Portland cement used in the method for producing the cement composition of the present invention is the same as the Portland cement contained in the cement composition of the present invention, and preferred embodiments are also the same. That is, MgO/Fe ₂ O ₃ preferably exceeds 0.35, and the Portland cement in the present invention contains 45 to 75% by mass of C ₃ S and 5 to 25% by mass of C ₂ S calculated by the Bogue formula. %, 7-11% by weight of C ₃ A and 7-11% by weight of C ₄ AF.

The amount of alkanolamine to be blended is the same as the content of alkanolamine in the cement composition of the present invention, and the preferred range is also the same. That is, the amount of alkanolamine to be added is preferably 0.005 to 0.02 parts by mass with respect to 100 parts by mass of Portland cement in the present invention.
In addition, the amount of limestone to be blended is synonymous with the limestone content described above, and the preferred range is also the same.

The alkanolamine used in the method for producing the cement composition of the present invention is the same as the alkanolamine contained in the cement composition of the present invention, and preferred embodiments are also the same.
That is, the alkanolamine used in the method for producing the cement composition of the present invention is selected from the group consisting of diethanolisopropanolamine, triisopropanolamine, ethanoldiisopropanolamine, triethanolamine, N-methyldiethanolamine, and Nn-butyldiethanolamine. At least one is preferably selected.
Alkanolamine is generally highly viscous and difficult to mix, so it is unsuitable to add during mortar production. Therefore, it is preferable to add it as a grinding aid in the finishing process of cement production. Further, when the alkanolamine is diluted and dissolved in water and used, it becomes easy to mix with cement, and the cement composition of the present invention can be produced efficiently.

There are no particular restrictions on the means for mixing the components in the method for producing the cement composition of the present invention. Examples include mixers, ball mills, roche mills, and air blending silos. The mixing time can be set within a range in which it is determined that sufficient mixing is performed in the normal production of cement compositions.

In this production method, pulverization is preferably carried out so that the Blaine specific surface area of the cement composition is 3000 to 3400 cm ² /g.

In the method for producing the cement composition of the present invention, in addition to the Portland cement clinker, gypsum, limestone and alkanolamine of the present invention, blast furnace slag, siliceous admixture and fly ash can be further added. .
In the present invention, blast furnace slag and siliceous admixture 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 defined in JIS R 5210:2009 "Portland cement", fly ash type III and fly ash type IV can also be used.

EXAMPLES The present invention will be described in more detail below with reference to examples. However, the present invention is by no means limited to the following examples.

<Components of cement composition>
The following materials were used in the preparation of cement compositions.
1. Clinker Ordinary Portland cement clinker [manufactured by Sumitomo Osaka Cement Co., Ltd.] having the chemical and mineral compositions shown in Tables 1 and 2 was used. In Tables 1 and 2, HM means hydraulic modulus, SM means silicic acid modulus, and IM means iron modulus. "%" in Tables 1 and 2 is based on mass (% by mass).
The chemical composition of clinker is analyzed by the glass bead method using a fluorescent X-ray measuring device (PRIMUS IV, manufactured by Rigaku Co., Ltd.) in accordance with JIS R 5204:2019 "Method for fluorescent X-ray analysis of cement". rice field. 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 formula.
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 x SiO ₂ ) - (0.754 x C ₃ S)
_C3A = ( _2.65 x _Al2O3 ) - ₍ 1.69 x _Fe2O3 )
_{C4AF =} 3.04 x _Fe2O3

(Chemical composition and mineral composition of clinker)
The chemical and mineral compositions of clinker are shown in Tables 1-2.

2. Alkanolamine/DEIPA: diethanol isopropanolamine [manufactured by Tokyo Chemical Industry Co., Ltd.]
・ TEA: Triethanolamine [manufactured by Tokyo Chemical Industry Co., Ltd.]
・ TIPA: triisopropanolamine [manufactured by Tokyo Chemical Industry Co., Ltd.]
・EDIPA: ethanol diisopropanolamine [manufactured by Sigma-Aldrich Japan LLC]

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

4. Gypsum Hemihydrate gypsum was used. Specifically, chemical gypsum (CaSO ₄ (97.8 mol %)) held 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 "Method for chemical analysis of cement". The composition of chemical gypsum is as shown in Table 3.

<Production of cement>
To the clinker shown in Tables 1 and 2, limestone was added so as to be 3.2% by mass in the cement obtained, and gypsum (the above-mentioned hemihydrate gypsum) was added so as to have the composition shown in Table 4. , and mixed in a mixer to obtain cement. In Table 4, CL represents clinker. Also, "%" is based on mass.

(Chemical composition and mineral composition of cement)
The chemical composition of cement was measured by the same method as the chemical composition of clinker, and the mineral composition of cement was calculated by the same method as the mineral composition of clinker. The results are shown in Tables 5-9. "%" in Tables 5 to 9 is based on mass (% by mass).
In addition, the value of "C ₄ AF" in Table 6 is the B.I. C ₄ AF, refer to the values shown in the "Bogue" column of the "C ₄ AF (%)" column in Tables 7-9. The values in the "Rietveld" column in the "C ₄ AF (%)" column in Tables 7 to 9 are the R.I. C ₄ AF, which is the C ₄ AF value of cement measured with a powder X-ray diffractometer. Specifically, it was measured under the following measurement conditions using the Rietveld analysis method using powder X-ray diffraction.

(Measurement condition)
・ Powder X-ray diffractometer: X'PartPowder manufactured by PANalytical
・ Rietveld analysis software: X'Part High Score Plus version 2.1b manufactured by PANalytical
・X-ray tube: Cu (tube voltage: 45 kV, tube current: 40 mA)
・ Slit: divergence slit - variable (irradiation width - 12 mm, Antiscatter slit - 2 °)
・Measuring range: 2θ = 10 to 70° (step width: 0.017°)
・Scanning speed: 0.1012°/s

Using the analysis function based on the Rietveld method installed in the above software, the document "Cement Chemistry Technical Committee Report C-12 Examination of the difference in the amount of clinker minerals due to the difference in the measurement method Part 2 Chapter 4 Powder X-ray diffraction / The ratio (% by mass) of each mineral in the cement was obtained in accordance with Joint Experiment Procedure 2 of "Study on Quantitation by Rietveld Analysis". Further, the sum of the proportions of each mineral is 100% by mass, and the content of C ₄ AF in each example and comparative example, R.V. C ₄ AF (mass %) was obtained.

The values in the " _△ ^* " column in the "C AF (%)" column in Tables 7 to 9 are the values ( _{B .C 4} AF) and the difference (R.C ₄ AF- _{B.C 4} AF).
Also, FIG. 1 shows a graph plotting the values of ΔC ₄ AF against the conditions ^** of the examples and comparative examples.

<Manufacture of cement composition>
[Example 1]
Cements shown in Tables 5 to 7 were used as amine-free cement compositions.
A composition comprising alkanolamine (DEIPA) shown in Table 7 and cement shown in Tables 5 and 7 was prepared as an amine-added cement composition. Specifically, alkanolamine was mixed with cement in an amount such that the concentration of alkanolamine was 10 ppm (0.001 part by mass with respect to 100 parts by mass of cement) in the total amount of cement and alkanolamine.
Next, each of the amine-free cement composition and the amine-added cement composition was mixed and pulverized in a test ball mill so that the Blaine specific surface area value was 3300 cm ² /g, and each cement composition of Example 1 was obtained. Obtained.

[Examples 2 to 19, Comparative Examples 1 to 7]
Cements shown in Tables 5 to 8 were used as amine-free cement compositions.
An amine-added cement composition was prepared in the same manner as in Example 1, except that the cements shown in Tables 5 to 8 were used, and DEIPA was used in an amount that gave the concentration shown in Table 7 or 8 in the total amount of cement and DEIPA. got
Next, each of the amine-free cement composition and the amine-added cement composition was mixed and pulverized in a test ball mill so as to have a Blaine specific surface area of 3300 cm ² /g. -7 cement compositions were obtained.

[Examples 20 to 22]
The cements shown in Tables 5, 6 and 9 were used as amine-free cement compositions.
An amine-added cement composition was obtained in the same manner as in Example 7, except that an alkanolamine shown in "Amine species" in Table 9 was used as the alkanolamine instead of DEIPA.
Next, each of the amine-free cement composition and the amine-added cement composition was mixed and pulverized in a test ball mill so that the Blaine specific surface area value was 3300 cm ² /g, and each cement composition of Examples 20 to 22. got stuff

<Evaluation of cement composition>
Using the amine-free cement composition and the amine-added cement composition of each example and each comparative example, test materials were formed in accordance with JIS R 5201: 2015 "Physical test method for cement", and mortar Compressive strength test was measured.
The mixing ratio of the test material is 11.1% by mass of water, 66.7% by mass of aggregate, and 22.2% by mass of cement. The test material was wrapped in vinyl chloride resin and cured.

The compressive strength of the mortar obtained using the amine-free cement composition is shown in the "Material age (no addition) (a)" column in Tables 7 to 9, and the mortar obtained using the amine-added cement composition. The compressive strength of the mortar obtained is shown in Tables 7 to 9 in the "Age (Amine addition) (b)" column. A higher numerical value means a higher compressive strength of mortar.

In the "△ (ba)" column of Tables 7 to 9, the compressive strength of the mortar obtained using the amine-added cement composition is compared to the compression strength of the mortar obtained using the amine-free cement composition. The intensity subtracted difference (intensity difference) is shown. It means that the larger the numerical value of the intensity difference, the higher the intensity enhancing effect.
Also, FIG. 2 shows a graph plotting the difference in mortar enhancement strength against conditions ^** at 7-day age and 28-day age. Here, "Condition ^** " is a numerical value shown in the "Condition ^** " column of Tables 7 to 9, and corresponds to "MgO/Fe ₂ O ₃ +CL'SO ₃ /SO ₃ ”.

The difference in mortar strength shown in the "△ (b-a)" column in Tables 7 to 9 is the difference between the mortar obtained using the amine-added cement composition and the mortar obtained using the amine-free cement composition. It shows how much the strength is increased compared to , and the greater the positive value, the greater the strength enhancement effect. Comparing the results of the 3-day age with the results of the 7-day and 28-day ages, it can be seen that the value of Δ(b−a) is larger for the 7-day and older samples, indicating that the strength enhancement effect is greater. A comparison of the 7-day age and 28-day age is shown in FIG.

Claims (10)

Portland cement that satisfies the following (1) and (2);
With respect to 100 parts by mass of the Portland cement, 0.001 to 0.025 parts by mass of alkanolamine,
A cement composition comprising:
( ₁ ) 0.55≤MgO/ _Fe2O3 + _CL'SO3 / _SO3≤0.95
(2) 0≦ΔC ₄ AF
In (1) above, MgO represents the mass (% by mass) of MgO in the Portland cement, Fe ₂ O ₃ represents the mass (% by mass) of Fe ₂ O ₃ in the Portland cement, and SO ₃ represents the mass (% by mass) of It represents the SO ₃ equivalent amount (mass%) of Portland cement, and CL'SO ₃ represents the SO ₃ equivalent amount (mass%) of the clinker of the Portland cement.
In (2) above, ΔC ₄ AF is The mass (% by mass) of C ₄ AF and B. It represents the difference ( _R.C.sub.4 AF- _B.C.sub.4 AF) from the mass (% by mass) of _C.sub.4 AF. Here, the R.I. C ₄ AF represents the C ₄ AF value of the Portland cement measured with a powder X-ray diffractometer; _C4AF stands _{for 3.04xFe2O3} . The above B. Fe ₂ O ₃ in C ₄ AF represents the mass (% by mass) of Fe ₂ O ₃ in the Portland cement. _The cement composition according to claim 1, wherein said MgO/ _Fe2O3 in (1) exceeds 0.35. The Portland cement contains 45 to 75% by mass of C ₃ S, 5 to 25% by mass of C ₂ S, 7 to 11% by mass of C ₃ A, and 7 to 11% by mass of C ₄ AF calculated by the Borg formula. 3. The cement composition according to claim 1 or 2, which is ordinary Portland cement. The cement composition according to any one of claims 1 to 3, wherein the alkanolamine content is 0.005 to 0.02 parts by mass with respect to 100 parts by mass of the Portland cement. wherein the alkanolamine is at least one selected from the group consisting of diethanolisopropanolamine, triisopropanolamine, ethanoldiisopropanolamine, triethanolamine, N-methyldiethanolamine, and Nn-butyldiethanolamine; 5. The cement composition according to any one of 4. Portland cement that satisfies the following (1) and (2);
With respect to 100 parts by mass of the Portland cement, 0.001 to 0.025 parts by mass of alkanolamine,
A method for producing a cement composition by mixing
( ₁ ) 0.55≤MgO/ _Fe2O3 + _CL'SO3 / _SO3≤0.95
(2) 0≦ΔC ₄ AF
In (1) above, MgO represents the mass (% by mass) of MgO in the Portland cement, Fe ₂ O ₃ represents the mass (% by mass) of Fe ₂ O ₃ in the Portland cement, and SO ₃ represents the mass (% by mass) of It represents the SO ₃ equivalent amount (mass%) of Portland cement, and CL'SO ₃ represents the SO ₃ equivalent amount (mass%) of the clinker of the Portland cement.
In (2) above, ΔC ₄ AF is The mass (% by mass) of C ₄ AF and B. It represents the difference ( _R.C.sub.4 AF- _B.C.sub.4 AF) from the mass (% by mass) of _C.sub.4 AF. Here, the R.I. C ₄ AF represents the C ₄ AF value of the Portland cement measured with a powder X-ray diffractometer; _C4AF stands _{for 3.04xFe2O3} . The above B. Fe ₂ O ₃ in C ₄ AF represents the mass (% by mass) of Fe ₂ O ₃ in the Portland cement. 7. The method for producing a cement composition according to claim ₆ , wherein said MgO/ _Fe2O3 in (1) exceeds 0.35. The Portland cement contains 45 to 75% by mass of C ₃ S, 5 to 25% by mass of C ₂ S, 7 to 11% by mass of C ₃ A, and 7 to 11% by mass of C ₄ AF calculated by the Borg formula. The method for producing a cement composition according to claim 6 or 7, which is ordinary Portland cement. The method for producing a cement composition according to any one of claims 6 to 8, wherein the amount of alkanolamine added is 0.005 to 0.02 parts by mass with respect to 100 parts by mass of Portland cement. The alkanolamine is at least one selected from the group consisting of diethanolisopropanolamine, triisopropanolamine, ethanoldiisopropanolamine, triethanolamine, N-methyldiethanolamine, and Nn-butyldiethanolamine. 10. A method for producing a cement composition according to any one of 9.

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