JP2018177596A - Admixture composition for cement and production method therefor, and cement composition and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an admixture composition for cement that exhibits sufficient strength under a low-temperature environment, has excellent hydration activity and shows good quick-hardening performance and at the same time can sufficiently ensure predetermined flowability, and can suppress occurrence of initial shrinkage crack due to its self-shrinkage and a production method therefor, and to provide a cement composition and a production method therefor.SOLUTION: An admixture composition for cement includes a quick-hardening additive for cement containing CA-based mineral phase, gypsum, an alkali sulfate compound, a calcium salt and lithium carbonate, contains 36 to 55 mass% of CA-based mineral, 0.3 to 1.7 mass% of an alkali sulfate compound (in terms of sodium sulfate), 0.01 to 1.3 mass% of lithium carbonate (in terms of lithium) and 1 to 14 mass% of a calcium salt (in terms of calcium hydroxide), has a mass ratio of gypsum content (in terms of anhydrous gypsum)/CA-based mineral phase content of 0.5 to 1.2 and has a crystallite diameter of CA-based mineral phase of 150 to 500 nm and a lattice constant of 11.940 to 11.975Å as measured by X-ray diffraction. The cement composition contains the quick-hardening additive for cement, gypsum, an alkali sulfate compound and a calcium salt, lithium carbonate and cement.SELECTED DRAWING: None

Description

  The present invention relates to an admixture composition for cement, a method for producing the same, and a cement composition and a method for producing the same, and in particular, it is possible to develop sufficient initial strength even at low temperatures and to suppress the occurrence of initial shrinkage cracking. The present invention relates to a cement admixture composition and a method for producing the same, and a cement composition and a method for producing the same.

Cracks that occur in the early stages of concrete construction are referred to as early cracks, but there are also several types of early cracks.
For example, a settlement crack is a crack that occurs on concrete due to the occurrence of bleeding, which causes the surface of the concrete to settle and the difference in the amount of settlement. Settlement cracking can be reduced by suppressing bleeding.

Among the initial cracks, shrinkage cracks, which are caused by constraining contraction, are particularly problematic.
Shrinkage cracks are caused by self-shrinkage of the concrete itself, drying shrinkage, thermal contraction due to heat of hydration being accumulated inside the concrete structure and then radiating heat, which is the cause of causing shrinkage cracks.
Such a shrinkage crack has a problem that, for example, when the strength is increased, the self-shrinkage becomes large, and the suppression of the crack becomes difficult.

Drying shrinkage is related to curing conditions such as humidity and wind, but can be prevented by applying a curing agent to the surface of the structure after construction.
The thermal contraction is a contraction that occurs when the temperature inside the structure rises due to the heat of hydration of cement, and a tensile stress is generated due to the restraint of a reinforcing bar or the like to cause a crack.
Auto-shrinkage is a combination of chemical shrinkage, which is a phase volume change caused by hydration of cement, and capillary void change, and occurs whenever cement reacts and solidifies. In particular, materials such as quick-hardened materials, in which cement is rapidly hydrated and solidified, have large self-shrinkage, and cracking is likely to occur.

Hitherto, as cement having rapid hardening, there is rapid hardening cement such as jet cement. As clinkers used for these cements, jet cement clinkers, Irwin clinkers containing C ₄ A ₃ SO ₃ as a main component, alumina cement clinkers containing CA as a main component, etc. are used.
There is also a method of obtaining amorphous C ₁₂ A ₇ by melting a clinker containing C ₁₂ A ₇ as a main component, which is a rapid hardening component, and then quenching it.

In particular, the conventional jet cement clinker is a clinker containing a calcium silicate phase as a main component and about 20 to 30% by mass of C ₁₁ A ₇ · CaF ₂ as a rapid curing component, and C ₁₁ A ₇ CaF ₂ or C ₄ AF And so forth, and the like. Therefore, if the content of C ₁₂ A ₇ which is a rapid hardening component is set to the above range or more, the melt phase becomes too much, the clinker melts, and for example, it becomes extremely difficult to manufacture in a real machine.

The Erwin-based clinker is used as a clinker for quick-hardening cement because it contains 70% by mass or more of Erwin (C ₄ A ₃ SO ₃ ) having quick-hardness, but due to the characteristics of the quick-hardening component, it is particularly low temperature There is a problem that it is inferior to the
Furthermore, the alumina cement clinker containing CA as a main component is inferior in rapid hardness to a clinker containing C ₁₂ A ₇ as a main component.

On the other hand, as a cement composition, it has been conventionally practiced to blend calcium aluminate and gypsum in portland cement in order to impart rapid hardening.
However, cement compositions containing calcium aluminate and the rapid hardening component of gypsum have difficulty in obtaining sufficient rapid hardening at low temperatures.

Therefore, in JP 2014-201462 A (patent document 1), the amorphous composition has a chemical composition of 35 to 50 mass% of CaO, 35 to 50 mass% of Al ₂ O _{3, and} 7 to 18 mass% of SiO _2. % Of super fast-hardening clinker, Blaine specific surface area 4000-9000 cm ² / g, content of particles over 30 μm is 5% by mass or less, content of particles less than 1.0 μm is 5 mass The cement composition containing 25 to 200 parts by mass of gypsum with respect to 100 parts by mass or less of the ultra rapid-hardening clinker crushed by weight is as described in JP 2014-196245 A (patent document 2). Containing calcium, polycarboxylic acid-based water reducing agent and melamine-based water reducing agent, 2 to 5 parts by weight of calcium nitrite per 100 parts by weight of cement, 0.1 to 2 of polycarboxylic acid-based water reducing agent 5 parts by weight, melamine-based water reducing agent containing 0.1 to 2.5 parts by weight, the cement composition is disclosed.

However, in a low temperature environment, the hydration reaction can be promoted to obtain the desired rapid hardening, for example, sufficient strength for 3 hours, and it is difficult to sufficiently ensure the fluidity of the cement, which is an appropriate amount The conditions for generating the melt phase of the solid solution and the solid solution state of the rapid hardening component, that is, the conditions for maximizing the hydration activity do not necessarily coincide, and designing for maximizing the hydration activity of the rapid hardening component is difficult. there were.
Furthermore, in a low temperature environment, it is difficult to promote hydration and to effectively suppress the generation of initial shrinkage cracks due to self-contraction.

JP 2014-201462 A JP, 2014-196245, A

  It is an object of the present invention to provide a cement admixture which can exhibit sufficient strength even in a low temperature environment, exhibits excellent hydration activity and exhibits good rapid hardening performance, and can suppress the occurrence of initial shrinkage cracks due to self-shrinkage. A composition and a method of producing the same, and a cement composition and a method of producing the same.

  In particular, an admixture composition for cement and a method for producing the same, a cement composition and a method for producing the same, which can suppress initial shrinkage cracking due to self-shrinkage of a mortar-concrete structure even at a low temperature such as 5 ° C. To provide.

The admixture composition for cement according to claim 1 comprises a rapid hardening additive for cement containing a C ₁₂ A _7- based mineral phase, gypsum, an alkali sulfate compound, a calcium salt and lithium carbonate, and C ₁₂ A 36-55% by mass of ₇ series minerals, 0.3-1.7% by mass of alkali sulfate compound (in terms of sodium sulfate), 0.01-1.3% by mass of lithium carbonate (in terms of lithium), calcium salt (water Containing 1 to 14 mass% of calcium oxide), the mass ratio of the content of gypsum (equivalent to anhydrous gypsum) / C ₁₂ A _7- based mineral phase is 0.5 to 1.2, and measured by X-ray diffraction It is a miscible composition for cement, characterized in that a crystallite diameter of a C ₁₂ A _7- based mineral phase is 150 to 500 nm and a lattice constant is 11.940 to 11.975 Å.

The admixture composition for cement according to claim 2 is the admixture composition for cement according to claim 2, wherein the C ₁₂ A _7- based mineral phase is a mixed phase of C ₁₁ A ₇ CaX ₂ (X is a halogen) and C ₁₂ A ₇ It is a mixing composition for cement characterized by the above.

The admixture composition for cement according to claim 3 further comprises, in the admixture composition for cement, C ₃ A / C ₁₂ A ₇ mineral phase ≦ 7 (mass%), and TiO ₂ / C ₁₂ A ₇ mineral phase ≦ It is an admixture composition for cement characterized by Fe ₂ O ₃ / C ₁₂ A ₇ mineral phase ≦ 2.0 (% by mass) at 1.4 (% by mass).

The cement composition according to claim 4 comprises a rapid hardening additive for cement containing a C ₁₂ A _7- based mineral phase, gypsum, an alkali sulfate compound, a calcium salt, lithium carbonate and cement, and C ₁₂ the a ₇ based mineral 5 to 40 mass%, include sulfate alkali compound (sodium sulfate equivalent) 0.5 to 1.0 wt%, lithium carbonate (Li _{conversion) / C} 12 mass content of _{a 7} mineral phases Ratio: 0.05 to 3% by mass, mass ratio of calcium salt (in terms of calcium hydroxide) / C ₁₂ A _7- based mineral phase is 3 to 40% by mass, gypsum (in terms of anhydrous gypsum) / C ₁₂ A ₇ The mass ratio of the content of the mineral phase is 0.6 to 1.4, and the crystallite diameter of the C ₁₂ A ₇ mineral phase measured by X-ray diffraction is 150 to 500 nm and the lattice constant is 11.940 to 11. Characterized by being It is a cement composition.

Cement composition of claim 5, wherein, in the above cement composition, the _C 12 _{A 7} based mineral phase _C 11 _A 7 _CaX 2 (X is halogen) and characterized by a mixed phase of and _C 12 _{A 7} It is a cement composition.

The method for producing the admixture composition for cement according to claim 6 is for cement wherein the crystallite diameter of the C ₁₂ A _7- based mineral phase measured by X-ray diffraction is 150 to 500 nm and the lattice constant is 11.940 to 11.975 Å. 36 to 55% by mass of C ₁₂ A ₇ based mineral, 0.3 to 1% by weight of alkali sulfate compound (sodium sulfate conversion), rapid hardening additive, gypsum, alkali sulfate compound, lithium carbonate and calcium salt .7 mass%, 0.01 to 1.3 mass% of lithium carbonate (in terms of lithium), and 1 to 14 mass% of calcium salt (in terms of calcium hydroxide), and gypsum (in terms of anhydrous gypsum) / C ₁₂ A ₇ It is a manufacturing method of the mixing composition for cement characterized by mixing so that mass ratio of content of a type | system | group mineral phase may be 0.5-1.2.

In the method for producing the admixture composition for cement according to claim 7, in the method for producing the admixture composition for cement, the rapid-hardening additive for cement is formed by pulverizing and mixing the raw materials, and molding at 1250 to 1400 ° C. by baked to cool at a cooling rate 40 ° C. / min or less, the crystallite size of the _C 12 _{a 7} mineral phase as measured by X-ray diffraction lattice constant of _C 12 _{a 7} based mineral phase in 150 to 500 nm 11 It is a method of producing a mixing composition for cement, characterized in that it is produced as .940 to 11.975 Å.

The cement composition according to claim 8 is a method for producing a cement composition according to claim 8, wherein the crystallite diameter of the C ₁₂ A _7- based mineral phase measured by X-ray diffraction is 150 to 500 nm and the lattice constant is 11.940 to 11.975 Å. Hard additive, gypsum, alkali sulfate compound, lithium carbonate, calcium salt, cement, 5 to 40% by mass of C ₁₂ A ₇ based mineral, 0.5 to 1.0 mass of alkali sulfate compound %, And the mass ratio of the content of lithium carbonate (lithium equivalent) / C ₁₂ A _7- based mineral phase is 0.05 to 3 (mass%), calcium salt (calcium hydroxide equivalent) / C ₁₂ A _7- based mineral phase The mass ratio of the content of 3 to 40 (mass%), and the mass ratio of the content of gypsum (equivalent to anhydrous gypsum) / C ₁₂ A _7- based mineral phase is 0.6 to 1.4. A method of producing a cement composition characterized by .

In the method for producing a cement composition according to claim 9, in the method for producing a cement composition, the quick-hardening additive for cement powderizes a raw material, shapes the powdered raw material, and bakes at 1250 to 1400 ° C. The C ₁₂ A _7- based mineral phase has a crystallite diameter of 150 to 500 nm of the C ₁₂ A _7- based mineral phase measured by X-ray diffraction by cooling the formed body after the firing at a cooling rate of 40 ° C./min or less. And a lattice constant of 11.940 to 11.975 Å.

  The admixture composition for cement of the present invention can be blended with any cement, whereby cement mortar and concrete using the admixture composition for cement of the present invention exhibit sufficient strength in a low temperature environment. Initial shrinkage cracking can be sufficiently suppressed.

  In addition, in the cement composition of the present invention, cement mortar and concrete using the cement composition can have sufficient strength in a low temperature environment and can sufficiently suppress initial shrinkage cracking.

  Furthermore, in addition to the above-mentioned effects, it is possible to secure a predetermined pot life with predetermined fluidity, and to ensure, for example, excellent workability in pumpability and the like.

  Moreover, the method for producing the admixture composition for cement of the present invention and the method for producing the cement composition can effectively prepare the admixture composition for cement of the present invention and the cement composition.

  In particular, a cement admixture composition containing a specific cement quick-hardening additive is compounded with any cement, water, or a cement composition comprising a specific cement quick-hardening additive is mixed with water Thus, cement mortar and concrete can be easily obtained on site.

  In addition, it is added while adjusting it on site together with water, accelerator, admixture, etc. which it is mixed with an optional cement, if necessary, in a simple manner in an arbitrary amount according to the initial strength desired for a specific cement admixture composition. Or by adding the specific cement composition in an arbitrary amount according to the desired initial strength, and adjusting it together with an accelerator, an admixture, etc. which is added as needed, and water, etc. It is easy to design on-site rapid hardening in the field, and it is possible to produce cement mortar and concrete in the field, which is excellent in the development of initial strength at low temperatures such as 5 ° C, and can suppress initial shrinkage cracks. It becomes possible.

It is a figure which shows typically the form for implementing a crack test.

The present invention will be described by the following embodiments, but is not limited thereto.
(Mixing composition for cement)
The admixture composition for cement according to the present invention comprises a rapid hardening additive for cement containing a C ₁₂ A _7- based mineral phase, gypsum, an alkali sulfate compound, a calcium salt and lithium carbonate, and is a C ₁₂ A _7- based material. 36 to 55% by mass of mineral, 0.3 to 1.7% by mass of alkali sulfate compound (in terms of sodium sulfate), 0.01 to 1.3% by mass of lithium carbonate (in terms of lithium), calcium salt (calcium hydroxide) the equivalent) containing 1-14 wt%, the mass ratio of the content of gypsum (anhydrite _{equivalent) / C} 12 _{a 7} mineral phase is 0.5 to 1.2, _{C 12} measured by X-ray diffraction crystallite size of a ₇ mineral phase lattice constant at 150~500nm a 11.940～11.975A, a cement admixture composition.

Preferably, in the cement admixture composition of the present invention, the _C 12 _{A 7} based mineral phase is preferably a mixed phase of _C 11 _A 7 CaX ₂ (halogen), and _C 12 _{A 7.}

  By having the above composition, the admixture composition for cement according to the present invention is excellent in initial strength development even at a low temperature of about 5 ° C., and can suppress the occurrence of initial shrinkage cracking, and can ensure fluidity. It becomes a thing.

As described above, the calcium aluminate phase C ₁₂ A _7- based mineral phase contained in the admixture composition for cement of the present invention is contained at 36 to 55% by mass, preferably 40 to 52% by mass.
Such a C ₁₂ A _7- based mineral phase is derived from a rapid hardening additive for cement, which is added when preparing the mixing composition for cement.
By containing the C ₁₂ A _7- based mineral phase, preferably in the above content, sufficient rapid hardness and excellent initial strength can be obtained even at low temperatures, and the desired effects of the present invention can be obtained. It becomes possible.

The mixing composition for cement of the present invention does not contain Erwin.
The measurement of the content of C ₁₂ A ₇ mineral phase is a calcium aluminate phase in the resultant cement admixture for composition, measured the content of C ₁₂ A ₇ mineral phase is a calcium aluminate phase If possible, any known measurement method can be applied, and for example, measurement can be performed by the following X-ray diffraction / Lietveld method.

The C ₁₂ A _7- based mineral in the admixture composition for cement of the present invention has a crystallite diameter of 150 to 500 nm, preferably 150 to 300 nm, of a C ₁₂ A _7- based mineral phase measured by X-ray diffraction.
When the crystallite diameter of the C ₁₂ A _7- based mineral phase is in such a range, excellent initial strength development and excellent fluidity that can ensure a pot life can be obtained even at low temperatures.
The crystallite diameter is, for example, a value measured by powder X-ray diffraction, and is a numerical value measured using an X-ray diffraction / Lietveld method (apparatus: D4 Endeavor manufactured by Bruker, analysis software: Topas).
Tube voltage: 45kV Tube current: 40mA

Furthermore, the C ₁₂ A _7- based mineral in the admixture composition for cement of the present invention is one having a C ₁₂ A _7- based mineral phase lattice constant of 11.940 to 11.975 Å as measured by X-ray diffraction.
By setting the lattice constant in such a range, it is possible to secure predetermined fluidity and to have excellent rapid hardness, thereby achieving the effects of the present invention.
The lattice constant is, for example, a value measured by powder X-ray diffraction, a value measured using an X-ray diffraction / Lietveld method (apparatus: PANalytical X'Pert MPD, analysis software: HighScore Plus) It is.
Tube voltage: 45kV Tube current: 40mA

As gypsum (calcium sulfate) contained in the admixture composition for cement of the present invention, anhydrous gypsum, hemihydrate gypsum, gypsum dihydrate, or a mixture thereof can be exemplified.
The content of such gypsum is such that the mass ratio of the content of gypsum / C ₁₂ A _7- based mineral phase is 0.5 to 1.2, preferably 0.7 to 1.1 in the admixture composition for cement. Included. However, the gypsum content is an amount calculated as a total amount in terms of all CaSO 4 _(anhydrite).
In addition, for the measurement of the content of gypsum in the obtained admixture composition for cement, any known measurement method can be applied as long as the content of gypsum (in terms of anhydrous gypsum) can be measured, for example, X It can be measured by a line diffraction / Lietveld method.

Moreover, as a sulfated alkali compound contained in the mixing composition for cement of this invention, alkali metal sulfates, such as mirabilite (sodium sulfate) and potassium sulfate, can be illustrated, for example.
As the content of the alkali sulfate compound, any known measurement method can be applied as long as the content of the alkali sulfate compound can be measured. For example, the amount of Na or K is measured according to JCAS I-04. It is desirable that the total content be all converted to Na ₂ SO ₄ and be contained at 0.3 to 1.7% by mass, preferably 0.5 to 1.5% by mass in the admixture composition for cement .

Furthermore, as the calcium salt contained in the admixture composition for cement of the present invention, for example, salts which are not sparingly soluble in water such as slaked lime and quicklime can be used, but calcium hydroxide is desirable, and calcium salts are calcium hydroxide Preferably, it is contained in an amount of 1 to 14% by mass, preferably 2 to 12% by mass.
In addition, the content of the calcium salt (in terms of calcium hydroxide) in the obtained admixture composition for cement may be any known measuring method as long as the content of the calcium salt (in terms of calcium hydroxide) can be measured. For example, it can be measured by the above-mentioned X-ray diffraction / Lietveld method.

Furthermore, 0.01 to 1.3 mass% of lithium carbonate (in terms of lithium) is preferably contained in the admixture composition for cement of the present invention, and preferably 0.01 to 1.0 mass%.
Moreover, as long as the content of lithium carbonate (lithium conversion) can be measured, the content of lithium carbonate (lithium conversion) in the obtained admixture composition for cement can be applied to any known measurement method, for example, , ICP emission spectroscopy can be used.

  The above effects of the present invention can be effectively exhibited by containing gypsum, an alkali sulfate compound, a calcium salt and a lithium carbonate together with the following quick-hardening additive for cement in the mixing composition for cement within the above range. Is possible.

Preferably, fluorine (F) may be contained in the admixture composition for cement of the present invention, which is derived from the quick-hardening additive for cement contained, and the content thereof is fluorine / C It is desirable that the content be such that the mass ratio of the content of the ₁₂ A _7- based mineral phase is 0.6 to 4.0 mass%, more preferably 1.0 to 3.5 mass%.
When the amount of F to be contained is in such a range, it is possible to have more excellent initial strength development, to sufficiently secure the pot life, and to exhibit the effect of the present invention more effectively. .

In addition, the mixing composition for cement of the present invention can be further excellent in strength development for 3 hours even at a low temperature, for example, 5 ° C., by suitably satisfying the following formula. ,desirable.
X = −0.93 (F / Q) −Qa + 11.98 ≧ 0
In the above formula, F is the content (% by mass) of fluorine in the admixture composition for cement, Qa is the lattice constant (Å) of the C ₁₂ A _7- based mineral phase in the admixture composition for cement, and Q is the admixture for cement It represents the content (% by mass) of the C ₁₂ A ₇ mineral phase in the composition.

In addition, preferably, C ₃ A is preferably substantially not contained in the admixture composition for cement of the present invention, and at most C ₃ A / C ₁₂ A ₇ type mineral ≦ 7 (% by mass) Is desirable.
This is because when the amount of C ₃ A increases, the content of the C ₁₂ A _7- based mineral phase decreases, and thus a sufficient initial strength may not be obtained. The C ₃ A in the cement admixture composition is derived from the cement rapid hardening additive contained.

Furthermore, it is desirable that Ti, Fe, C ₂ S and C ₂ AS are substantially not contained in the admixture composition for cement of the present invention, and at most, TiO ₂ / C ₁₂ A ₇ ≦ 1.4. It is desirable that (the ratio of mass% of the content) be Fe ₂ O ₃ / C ₁₂ A ₇ ≦ 2.0 (the ratio of mass% of the content). Such TiO ₂ and Fe ₂ O ₃ in the cement admixture composition are derived from the cement rapid hardening additive contained. It will be excellent in rapid hardness at low temperature, for example, initial strength development (5 hours after construction, etc.) at 5 ° C. or less.

  The cement mortar / concrete obtained by adding the admixture composition for cement according to the present invention to any cement or the like available on the market by the composition described above has excellent initial strength development even at low temperatures, and initial shrinkage. The occurrence of cracks can be suppressed, and the fluidity can be secured.

(Cement composition)
The cement composition of the present invention includes a cement rapid hardening additive material containing C ₁₂ A ₇ based mineral phase, and gypsum, and sulfuric acid alkali compound, a calcium salt, a lithium carbonate and cement, C ₁₂ A ₇ Containing 5 to 40% by mass of a group mineral, 0.5 to 1.0% by mass of an alkali sulfate compound (in terms of sodium sulfate), and having a mass ratio of lithium carbonate (in terms of lithium) / C ₁₂ A _7- based mineral phase 0.05-3 wt%, calcium salt (calcium hydroxide _{terms) / C} 12 weight ratio of the content of _{a 7} mineral phase 3 to 40 wt%, gypsum (anhydrite _{converted) / C} 12 _{a 7} minerals The mass ratio of phase content is 0.6 to 1.4, and the crystallite diameter of the C ₁₂ A _7- based mineral phase measured by X-ray diffraction is 150 to 500 nm and the lattice constant is 11.940 to 11.975 Å It is a cement composition.

Preferably, in the above cement composition, wherein the _C 12 _{A 7} based mineral phase is preferably (the X halogen) _C 11 _A 7 _CaX 2 is a mixed phase of and _C 12 _{A 7.}

  The cement composition of the present invention is excellent in initial strength development even at a low temperature of about 5 ° C by having the above-mentioned configuration, and can suppress the occurrence of initial shrinkage cracking and can ensure fluidity. Become.

As described above, the calcium aluminate phase C ₁₂ A _7- based mineral phase contained in the cement composition of the present invention is 5 to 40% by mass, preferably 5 to 36% by mass, in the cement composition. Preferably, it is contained by 10-30 mass%.
Such a C ₁₂ A _7- based mineral phase is derived from a rapid hardening additive for cement, which is added when preparing a cement composition.
By containing the C ₁₂ A _7- based mineral phase, preferably in the above content, sufficient rapid hardness and excellent initial strength can be obtained even at low temperatures, and the desired effects of the present invention can be obtained. It becomes possible.
The cement composition of the present invention does not include Erwin.
The measurement of the content of C ₁₂ A ₇ mineral phase is a calcium aluminate phase in the resultant cement composition, if the measurement is the content of C ₁₂ A ₇ mineral phase it is a calcium aluminate phases, Any known measurement method can be applied, and as described above, it can be measured, for example, by the following X-ray diffraction / Lietveld method.

The above-mentioned C ₁₂ A _7- based mineral in the cement composition of the present invention is derived from the above-mentioned quick-hardening additive for cement contained in a cement composition, and the C ₁₂ A _7- based mineral phase measured by X-ray diffraction The crystallite diameter is 150 to 500 nm, preferably 150 to 300 nm.
When the crystallite diameter of the C ₁₂ A _7- based mineral phase is in such a range, excellent initial strength development and excellent fluidity that can ensure a pot life can be obtained even at low temperatures.
The crystallite diameter is, for example, a value measured by powder X-ray diffraction, and is a numerical value measured using an X-ray diffraction / Lietveld method (apparatus: D4 Endeavor manufactured by Bruker, analysis software: Topas).
Tube voltage: 45kV Tube current: 40mA

Furthermore, the C ₁₂ A _7- based mineral in the cement composition of the present invention is one having a C ₁₂ A _7- based mineral phase lattice constant of 11.940 to 11.975 Å as measured by X-ray diffraction.
By setting the lattice constant in such a range, it is possible to secure predetermined fluidity and to have excellent rapid hardness, thereby achieving the effects of the present invention.
The lattice constant is, for example, a value measured by powder X-ray diffraction, a value measured using an X-ray diffraction / Lietveld method (apparatus: PANalytical X'Pert MPD, analysis software: HighScore Plus) It is.
Tube voltage: 45kV Tube current: 40mA

As gypsum (calcium sulfate) contained in the cement composition of the present invention, anhydrite, hemihydrate gypsum, gypsum dihydrate, or a mixture thereof can be exemplified as in the case of gypsum contained in the cement admixture composition. .
Such gypsum is contained in the cement composition in such a content that the mass ratio of the content of gypsum / C ₁₂ A _7- based mineral phase is 0.6 to 1.4, preferably 0.8 to 1.3. Be However, the gypsum content is an amount calculated as a total amount in terms of all CaSO 4 _(anhydrite).
In addition, for the measurement of the content of gypsum in the obtained cement composition, any known measurement method can be applied as long as the content of gypsum (in terms of anhydrous gypsum) can be measured, for example, the above X-ray diffraction / It can be measured by the Rietveld method.

Moreover, as the sulfated alkali compound contained in the cement composition of the present invention, for example, alkali metal sulfates such as sodium sulfate (sodium sulfate), potassium sulfate and the like are used similarly to the sulfated alkali compound contained in the mixing composition for cement. It can be illustrated.
As the content of the alkali sulfate compound, any known measurement method can be applied as long as the content of the alkali sulfate compound can be measured. For example, the amount of Na or K is measured according to JCAS I-04. It is desirable for the cement composition to be contained in an amount of 0.5 to 1.0% by mass, preferably 0.6 to 1.0% by mass, based on the total amount converted to Na ₂ SO ₄ .

Furthermore, as the calcium salt contained in the cement composition of the present invention, similarly to the calcium salt contained in the mixing composition for cement, for example, salts which are not sparingly soluble in water, such as slaked lime and quicklime can be used. , Calcium hydroxide is desirable.
The calcium salt is such that the mass ratio of the content of the calcium salt / C ₁₂ A _7- based mineral phase in the cement composition is 3 to 40 (mass%), preferably 5 to 35 (mass%) Included. However, the calcium salt content is an amount calculated as the total amount converted to calcium hydroxide.
Moreover, if content of a calcium salt (calcium hydroxide conversion) can be measured, content of the calcium salt (calcium hydroxide conversion) in the obtained cement composition can apply an arbitrary well-known measuring method. For example, it can be measured by the above-mentioned X-ray diffraction / liet belt method.

Moreover, lithium carbonate contained in the cement composition of the present invention has a mass ratio of lithium carbonate (lithium equivalent) / C ₁₂ A _7- based mineral phase of 0.05 to 3 (mass%) in the cement composition. Preferably, it is contained by the content which will be 0.05-2.5 (mass%).
If the content of lithium carbonate (lithium conversion) can be measured, the content of lithium carbonate (lithium conversion) in the obtained cement composition can be applied to any known measurement method, for example, ICP emission spectroscopy It can measure using an analysis method.

  By containing the gypsum, the alkali sulfate compound, the calcium salt and the lithium carbonate in the cement composition within the above range, the above-mentioned effects of the present invention can be effectively exhibited.

  As cement included in the cement composition of the present invention, any cement commercially available can be applied, for example, early-strength Portland cement, ultra-early-strength Portland cement, ordinary Portland cement, moderate heat Portland cement, low heat At least one selected from Portland cement, sulfate resistant Portland cement, fly ash cement, blast furnace cement, silica cement and the like can be exemplified.

Preferably, fluorine (F) may be contained in the cement composition of the present invention, which is mainly derived from a cement rapid hardening additive, and the content thereof is fluorine / C ₁₂ A ₇ It is desirable that the content be such that the mass ratio of the content of the mineral phase is 0.8 to 4.0 (mass%), more preferably 1.5 to 3.5 (mass%).
For example, the fluorine content in the raw material portland cement is at most 0.05% by mass, and the fluorine content (for example, about 0.5 to 3.0% by mass) contained in the cement rapid hardening additive The amount of fluorine contained in the resulting cement composition is almost the same as that of the rapid hardening additive for cement because it is extremely small in comparison.
When the amount of F to be contained is in such a range, it is possible to have more excellent initial strength development, to sufficiently secure the pot life, and to exhibit the effect of the present invention more effectively. .

Further, the cement composition of the present invention preferably has the following formula: lattice constant of the C ₁₂ A _7- based mineral phase (Å) ≦ [(0.05-fluorine content (% by mass))] / C ₁₂ It is particularly desirable to have a relationship satisfying the content (mass%) + 11.98 of the A _7- based mineral phase, and by having such a relationship, it has excellent initial strength development even at low temperatures, for example 5 ° C. It becomes more possible to secure a usable time.

Furthermore, it is desirable that substantially no Ti is contained in the cement composition of the present invention, and the content of C ₁₂ A _7- based mineral phase (mass%) ≧ 83 × (TiO ₂ content (mass%) It is desirable to satisfy the relationship of -0.3).

  In the cement composition of the present invention, as long as the above effects are not impaired, if necessary, for example, a setting regulator (lignin sulfonic acid type, oxycarboxylic acid type, saccharides such as saccharides, alkali of various organic acids or organic acids) Metal salts and alkalinity class metal salts) and water reducing agents (alkyl allyl sulfonic acid type, naphthalene sulfonic acid type, melamine sulfonic acid type, polycarboxylic acid type, AE water reducing agent, high performance water reducing agent, high performance AE water reducing agent Etc. can be blended.

  By making the cement composition of the present invention into the above configuration, the cement mortar / concrete composition or mortar / concrete using the cement composition of the present invention is excellent in initial strength development even at low temperatures, and has an initial shrinkage crack. The occurrence can be suppressed, and the liquidity can be secured.

(Preparation of mixing composition for cement)
The method for producing the admixture composition for cement of the present invention is prepared so as to have the above-mentioned specific constitution by mixing a rapid hardening additive for cement, gypsum, an alkali sulfate compound, a calcium salt and lithium carbonate.
Although the manufacturing method is not particularly limited, specifically, a specific cement quick-hardening additive, gypsum, an alkali sulfate compound, a calcium salt and lithium carbonate, a C ₁₂ A _7- based mineral of 36 to 55 mass 0.3% to 1.7% by mass of an alkali sulfate compound (in terms of sodium sulfate), 0.01 to 1.3% by mass of lithium carbonate (in terms of lithium) and 1 to 14 of a calcium salt (in terms of calcium hydroxide) Mass%, and the mass ratio of the content of gypsum (equivalent to anhydrous gypsum) / C ₁₂ A _7- based mineral phase is 0.5 to 1.2 and uniformly mixed, for the cement of the present invention Prepare the admixture composition.

The rapid hardening additive for cement added to the admixture composition for cement of the present invention includes calcium raw materials such as quicklime and limestone, aluminum hydroxide, alumina, aluminum raw materials such as bauxite and band shale, and fluorine raw materials such as fluorite, Magnesium raw materials such as dolomite compounded according to need are mixed and crushed, or crushed and mixed, and this powder compound is molded to obtain a molded body, which is used as a heating furnace such as an electric furnace It is used, calcined and cooled to prepare a rapid hardening additive for cement.
In addition, the thing used as the raw material of Ti and Fe contained in the rapid-hardening additive material for cements obtained (for example, a bengara etc.) is not actively mix | blended. Ti and Fe contained in the cement rapid-hardening additive to be compounded may be contained as a result as a result of being contained as an impurity in the compounding raw material, and are not positively contained.

In addition, the rapid hardening additive for cement added to the preparation of the admixture composition for cement of the present invention has a crystallite diameter of 150 to 500 nm, preferably 150 to 150 nm, of a C ₁₂ A _7- based mineral phase measured by X-ray diffraction. It is a rapid hardening additive having a lattice constant of 11.940 to 11.975 Å at 300 nm.
By including in the admixture composition for cement a rapid hardening composition for cement in which the crystallite diameter of the C ₁₂ A _7- based mineral phase and the lattice constant fall within such a range, while promoting hydration activity, water under a low temperature environment The contraction due to the sum activity can be reduced, and excellent fluidity and the like can be obtained which can exhibit excellent initial strength development and pot life even at low temperatures.
The crystallite diameter and lattice constant are values measured by the same measurement method as described above.

In particular, preferably, the rapid hardening additive for cement contains 70% by mass or more of a C ₁₂ A _7- based mineral phase, is substantially free of C ₃ A, Ti, and Fe, and contains as impurities of the raw material. 5.0% by mass or less of C ₃ A, 1.0% by mass or less of Ti in terms of TiO ₂ , 1.5% by mass or less of Fe in terms of Fe ₂ O ₃ , and F of 0.5 to 3 It is desirable that it is a rapid hardening additive containing 0 mass%.
When C ₃ A exceeds 5.0% by mass, the content of the C ₁₂ A _7- based mineral phase decreases, so sufficient rapid hardness can not be obtained by on-site addition, and the initial strength decreases. There is.

The rapid hardening additive for cement containing such a C ₁₂ A _7- based mineral phase as a main component and having a C ₃ A content not more than a predetermined amount is further substantially free of C ₂ S and C ₂ AS desirable.
The term "substantially free" means that these mineral phases do not prevent the case where they are generated by SiO ₂ which is an impurity contained in the raw material, and they are not generated and contained positively. The total content of C ₂ S and C ₂ AS is preferably at most 10% by mass or less.
This is because the content of the C ₁₂ A _7- based mineral phase which is a calcium aluminate phase is not reduced from the above range.

In addition, such a rapid hardening additive for cement is hardly generated of C ₃ S by being prepared by being fired at 1250 to 1400 ° C., preferably 1300 to 1360 ° C. as described below, and it is substantially Not included. Further, C ₄ AF is hardly generated and substantially not contained because Fe ₂ O ₃ in the cement rapid hardening additive is not more than 1.5% by mass.

In addition, it is desirable that the cement rapid-hardening additive does not actively contain Ti, and that it is substantially not contained.
The term "substantially free" means that Ti does not interfere with the case where it is produced by the impurities contained in the raw material, and it is not positively contained.
For example, the content of Ti is 1.0% by mass or less, preferably 0.5% by mass or less in terms of TiO ₂ oxide.
That is, since the rapid hardening additive for cement does not require the formation of a fixed amount of melt phase, it is not necessary to positively contain Ti related to the generation of the melt phase.
By not containing TiO ₂ substantially and making the content not more than the above at most, rapid hardness at low temperature, for example, initial strength development at 5 ° C. or less (for example, 3 hours after construction) is excellent.
When Ti is more than 1.0% by mass in terms of TiO ₂ , C ₃ A is generated over 5.0% by mass, and the effect of the present invention can not be obtained.

In addition, it is desirable that the cement rapid-hardening additive does not actively contain Fe, and that it is substantially not contained.
Substantially free does not prevent Fe from being generated by the impurities contained in the raw material, and is not positively contained.
For example, the Fe content is set to 1.5 mass% or less, preferably 1.0 mass% or less, in terms of Fe ₂ O ₃ oxide conversion.
That is, since the rapid hardening additive for cement does not require the formation of a fixed amount of melt phase, it is not necessary to positively contain Fe related to the formation of the melt phase.
When Fe ₂ O ₃ is contained in excess of the above content, the lattice constant of the C ₁₂ A _7- based mineral phase becomes large, and rapid hardening at low temperatures, for example, initial strength development at 5 ° C. or less (3 hours after construction) Etc.), and the smaller the better.

Further, it is desirable that the above-mentioned cement rapid hardening additive further contain 0.5 to 3.0% by mass, preferably 1.0 to 2.5% by mass of F.
By setting the content of F contained in the rapid hardening additive for cement in the above range, the C ₁₂ A _7- based mineral phase is stably generated, and the lattice constant of the C ₁₂ A _7- based mineral phase becomes an appropriate range. The hydration activity can be enhanced, and the cement composition obtained by post-adding the cement rapid-hardening additive to cement can more effectively exhibit the above effect of the present invention.

The rapid-hardening additive for cement is obtained by, for example, pulverizing and mixing the compounding raw materials and forming a mixed powder, and a molded body obtained at a temperature of, for example, 1250-1400 ° C., preferably 1300-1360 ° C. It can be produced by firing for 5 to 3 hours and then cooling at a cooling rate of 40 ° C./min or less, preferably 5 to 40 ° C./min. In addition, the raw material is blended so as to be the above-mentioned content ratio.
Since the rapid hardening additives for cement thus obtained do not require the formation of a fixed amount of melt phase, the hydration activity of the C ₁₂ A _7- based solid solution can be sufficiently expressed. As such, Ti, Fe, etc. are not substantially contained, and at most these contents are adjusted as described above, post-addition to cement, rapid hardening, particularly at a low temperature such as 5 ° C. It is excellent in the initial strength of

Thus, the C ₁₂ A ₇ system measured by X-ray diffraction by firing a formed body obtained by forming the raw material mixed powder and cooling it at a cooling rate of 40 ° C./min or less, preferably 5 to 40 ° C./min. A rapid hardening additive for cement can be produced, wherein the crystallite diameter of the mineral phase is 150 to 500 nm, preferably 150 to 300 nm, and the lattice constant of the C ₁₂ A _7- based mineral phase is 11.940 to 11.975 Å. .

Since the degree of hydration activity, that is, the degree of rapid hardening varies depending on the difference in crystallite diameter, firing is performed at the above-described calcination temperature or the like in order to ensure the pot life and obtain the rapid hardening, By setting the speed, it is possible to obtain a rapid hardening additive for cement having a crystallite diameter in the range of 150 to 500 nm. Moreover, rapid hardness will be more excellent by setting it as the suitable range of 150-300 nm.
The cement mortar / concrete obtained by adding the admixture composition for cement of the present invention containing such a rapid-hardening additive and the like to a range such that the crystallite diameter of the C ₁₂ A _7- based mineral phase is such a range Proper fluidity can be maintained and good initial strength development at low temperatures can be obtained.

In particular, the cement rapid hardening additive is preferably used after being ground to a brane specific surface area of 4500 cm ² / g or more, and if less than 4500 cm ² / g, good rapid hardening may not be obtained in some cases. It is.
Also, if the brane specific surface area is too large, the fluidity will be adversely affected, and the grinding time will be required to lower the productivity and increase the cost, so 5000 to 7000 cm ² / g is desirable.
In addition, a grinding aid (diethylene glycol, triethanolamine, etc.) may be added when grinding.

The admixture composition for cement of the present invention makes the above-mentioned rapid hardening additive for cement into powder, and further contains gypsum, an alkali sulfate compound, a calcium salt and lithium carbonate, and 36 to 55 mass of C ₁₂ A ₇ based mineral 0.3 to 1.7% by mass of an alkali sulfate compound, 0.01 to 1.3% by mass of lithium carbonate, 1 to 14% by mass of a calcium salt, and the content of a gypsum / C ₁₂ A _7- based mineral phase The mixing method is not particularly limited as long as it can be uniformly blended so that the mass ratio of is 0.5 to 1.2, and any mixing method can be used.

The gypsum content is an amount calculated as the total amount converted to CaSO ₄ (anhydrous gypsum), and the content of the alkali sulfate compound is the amount of Na or K according to JCAS I-04. It is the total amount converted into Na ₂ SO ₄ equivalent by measurement, lithium carbonate is the amount converted into lithium, and the calcium salt is the total amount converted into calcium hydroxide.

  Specifically, preparation of the admixture composition for cement can be carried out by adding gypsum to a mixture obtained by mixing gypsum, an alkali sulfate compound, a calcium salt and lithium carbonate in advance and adding an additive for rapid hardening of cement to the mixture. Even if the alkali sulfate compound, calcium salt, lithium carbonate and rapid hardening additive for cement are simultaneously mixed, any method can be used as long as they can be uniformly mixed.

(Preparation of cement composition)
The method of producing the cement composition according to the present invention comprises mixing the rapid hardening additive for cement, the gypsum, the alkali sulfate compound, the calcium salt, the lithium carbonate and the cement to obtain the specific configuration. It is prepared by blending in
Although the production method is not particularly limited, specifically, for example, the above-mentioned specific cement quick-hardening additive, gypsum, alkali sulfate compound, lithium carbonate, calcium salt, cement, C ₁₂ A ₇ Containing 5 to 40% by mass of a group mineral, 0.5 to 1.0% by mass of an alkali sulfate compound, and having a mass ratio of lithium carbonate (lithium equivalent) / C ₁₂ A _7- based mineral phase of 0.05 to 3 (Mass%), mass ratio of calcium salt (calcium hydroxide equivalent) / C ₁₂ A _7- based mineral phase is 3 to 40 (mass%), gypsum (anhydrous gypsum converted) / C ₁₂ A _7- based mineral phase The cement composition of the present invention is prepared using any mixing method, as long as it can be blended and uniformly mixed such that the mass ratio of the content of the component is 0.6 to 1.4.
As the specific cement rapid-hardening additive constituting the cement composition of the present invention, the same cement rapid-hardening additive constituting the cement admixture composition can be used.

  Furthermore, if necessary, in the cement composition of the present invention, for example, a water reducing agent (alkyl allyl sulfonic acid type, naphthalene sulfonic acid type, melamine sulfonic acid type, polycarboxylic acid type, AE water reducing agent, high performance water reducing agent A liquid or powder admixture such as a high performance AE water reducing agent), the above-mentioned setting regulator, etc. can be blended.

Specifically, even if cement is added to and mixed with a mixture obtained by previously blending a gypsum, an alkali sulfate compound, a calcium salt, lithium carbonate and a rapid hardening additive for cement, the cement composition can also be an alkali Even if the compound, calcium salt, lithium carbonate, quick-hardening additive for cement and cement are mixed simultaneously, any method can be used as long as they can be uniformly mixed.
In addition, the above-mentioned admixtures and the like added as necessary may be added simultaneously with the cement etc. as long as they can be uniformly mixed, or added sequentially even when mixing with water at the time of preparing the mortar etc. Even if it is addition by any addition method, it is not specifically limited.

(Preparation of cement mortar and concrete)
A cement mortar / concrete is prepared by blending the mixing composition for cement of the present invention, optional cement and water, or blending the cement composition of the present invention and water. it can.

  Furthermore, if necessary, for example, an accelerator (chloride salt, sulfate, carbonate, nitrite, rhodanate, inorganic oxide, inorganic hydroxide, aluminate) as long as the above effects are not impaired. Liquid, such as salts, water reducing agents (including alkyl allyl sulfonic acids, naphthalene sulfonic acids, melamine sulfonic acids, polycarboxylic acids, AE water reducing agents, high performance water reducing agents, high performance AE water reducing agents), etc. Additives, fine aggregate (river sand, sea sand, mountain sand, crushed sand and mixtures thereof), coarse aggregate (river gravel, sea gravel, crushed stone and mixtures thereof), etc. can be blended.

  The method of mixing with water when preparing cement paste, mortar, concrete or the like is not particularly limited, and after mixing at a predetermined ratio, mixing may be performed using a conventional mixing device.

  Specifically, even if the cement admixture composition of the present invention, optional cement, and water are simultaneously blended to prepare cement mortar and concrete, the cement admixture composition and cement are also mixed. Water may be mixed to prepare cement mortar and concrete, or any method may be used as long as uniform mixing is possible.

  Also, the cement composition of the present invention and water are simultaneously blended to prepare cement mortar and concrete, and even if water is blended to the cement composition and cement mortar and concrete are prepared. Any method may be used as long as it can be uniformly mixed.

  In addition, if necessary, accelerators, admixtures, aggregates, etc. can be uniformly mixed, added simultaneously with cement, etc., or sequentially added, or mixed with water when preparing mortar, etc. There is no particular limitation even if it is added at the time of addition or by any addition method.

  The cement mortar / concrete thus obtained secures the workability such as fluidity even when working at low temperatures, and exhibits excellent initial strength development even at low temperatures of about 5 ° C. The occurrence can be suppressed, and the fluidity can be secured to ensure the constructability.

The present invention will be described based on the following examples, comparative examples and test examples.
1) Preparation of quick-hardening additive for cement CaCO ₃ , SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , MgO, TiO ₂ , CaF ₂ so that the target chemical composition of quick-hardening additive for cement is as shown in Table 1 The rapid hardening additive materials for cement were prepared by blending and mixing and grinding each of the above reagents.

Here, SiO ₂ , Fe ₂ O ₃ , and TiO ₂ are calcium raw materials such as quick lime, slaked lime, limestone, etc., aluminum hydroxide, alumina, bauxite when actually producing a rapid hardening additive for cement in a real machine. When aluminum raw materials such as band and shale, fluorine raw materials such as fluorite, and magnesium raw materials such as dolomite compounded as necessary, SiO ₂ , Fe ₂ O ₃ and TiO ₂ may be contained as impurities as a result. Because it exists (it is not something to be included positively), it is used assuming such a case.

  The raw materials for the rapid hardening additives for cement described above are pressure-formed, each molded body is fired at 1300 ° C. for 30 minutes in an electric furnace, and then cooled at each cooling rate shown in Table 2, and each shown in Table 2 A rapid hardening additive for cement was obtained.

2) Measurement of the content of TiO ₂ , Fe ₂ O ₃ , F component, etc. Each of the obtained rapid hardening additives for cement was subjected to JIS R 5204 using a fluorescent X-ray analyzer (manufactured by PANalytical; Axios). According to the above, the content ratio of the contained TiO _2, Fe ₂ O _3, F component, etc. was measured.
These results are shown in Table 2.

3) Analysis of minerals of quick-hardening additives for cement (C ₁₂ A ₇ series and C ₃ A)
Each of the obtained cement rapid hardening additives was subjected to X-ray diffraction / liet belt method (apparatus: PANalytical X'Pert MPD, analysis software: HighScore Plus) to obtain a C ₁₂ A ₇ series and C ₃ A mineral The content ratio and the lattice constant of the crystal of the C ₁₂ A _7- based mineral phase were measured. Tube voltage: 45kV Tube current: 40mA
The results are shown in Table 2. Here, the lattice constant of the crystal of the C ₁₂ A _7- based mineral phase was measured using the crystal structure of C ₁₁ A ₇ CaF ₂ .

In addition, the crystallite diameter of the C ₁₂ A _7- based mineral phase crystal is X-ray diffraction / Lietveld method (apparatus: D4 Endeavor manufactured by Bruker, analysis software: Topas) using the C ₁₁ A ₇ CaF ₂ crystal structure. It measured by. Tube voltage: 45kV Tube current: 40mA
The results are shown in Table 2.

4) Preparation of admixture composition for cement (Examples 1 to 10, Comparative Examples 1 to 11)
Next, each of the cement rapid hardening additives was crushed to a Blaine specific surface area of about 5200 ± 200 cm ² / g to obtain cement rapid hardening additive powders.
The obtained quick-hardening additive powder for cement, anhydrous gypsum (trade name: non-clave, manufactured by Sumitomo Osaka Cement Co., Ltd.), Na ₂ SO ₄ (sodium sulfate, reagent), slaked lime (calcium hydroxide: reagent) and lithium carbonate The (reagent) was compounded at the mixing ratio shown in the following Tables 3 to 5 to prepare each admixture composition for cement.
In Tables 3 to 5, lithium carbonate represents a lithium equivalent value.

5) Mineral content of cement admixture composition (C ₁₂ A ₇ system) and a method similar to that described in the measurement above 3) of the lattice constant and crystallite size of the crystals of the C ₁₂ A ₇ mineral phases Then, the content of the C ₁₂ A _7- based mineral phase (Q) in each cement admixture composition, and the lattice constant and crystallite diameter of crystals of the C ₁₂ A _7- based mineral phase were measured.
These results are shown in Tables 3-5.
The C ₁₂ A _7- based mineral phase in the admixture composition for cement is derived from the above-mentioned cement rapid hardening additive.

6) Anhydrite / C ₁₂ A _7- based mineral phase (mass ratio) in the admixture composition for cement
From the C ₁₂ A _7- based mineral phase content in each cement admixture composition measured in the above 5) and the compounding amount of anhydrous gypsum in each cement admixture composition shown in Tables 3 to 5, each cement Anhydrite / C ₁₂ A _7- based mineral phase (mass ratio) in the admixture composition was calculated.
The results are shown in Tables 3 to 5.

7) C ₃ A / C ₁₂ A ₇ mineral phase (% by mass), TiO ₂ / C ₁₂ A ₇ mineral phase (% by mass), Fe ₂ O ₃ / C ₁₂ A ₇ mineral phase (% by mass) in admixture composition for cement mass%)
Amounts of C ₃ A, TiO ₂ and Fe ₂ O _{3 in} Table ₂ and blending amounts of rapid hardening additives for cement in admixture compositions for cement in Tables 3 to 5 and admixture compositions for cement in Tables 3 to 5 C ₃ A / C ₁₂ A ₇ mineral phase (mass%), TiO ₂ / C ₁₂ A ₇ mineral phase (mass%), Fe ₂ based on the content (mass%) of the C ₁₂ A ₇ mineral phase in the oxide O ₃ / _C 12 _{a 7} mineral phase (mass%) was calculated. All, with C ₃ A / C ₁₂ A ₇ mineral phase ≦ 7 (mass%), with TiO ₂ / C ₁₂ A ₇ mineral phase ≦ 1.4 (mass%), Fe ₂ O ₃ / C ₁₂ A ₇ mineral phase It was a thing satisfying <= 2.0 (mass%). The C ₁₂ A _7- based mineral phase, C ₃ A mineral phase, TiO _{2, and} Fe ₂ O ₃ in the admixture composition for cement are derived from the above-mentioned rapid hardening additive for cement.

8) Preparation of cement mortar Early-strength Portland cement (PC: manufactured by Sumitomo Osaka Cement Co., Ltd.), the obtained mixing composition for each cement (Examples 1 to 10, Comparative Examples 1 to 11), and accelerator (water) Each cement mortar was prepared by blending lithium oxide and sodium carbonate), water and the like at the blending ratio described in Table 6.

9) Preparation of cement composition (Examples 11-23, Comparative Examples 12-22)
The above cement rapid hardening additive materials were crushed to a brane specific surface area of about 5200 ± 200 cm ² / g to obtain cement rapid hardening additive powders.
The obtained quick-hardening additive powder for cement, anhydrous gypsum (trade name: non-clave, manufactured by Sumitomo Osaka Cement Co., Ltd.), sodium sulfate (Na ₂ SO ₄ , reagent), slaked lime (calcium hydroxide: reagent), lithium carbonate (Reagent) and early strong portland cement (PC: manufactured by Sumitomo Osaka Cement Co., Ltd.) were blended to prepare cement compositions having content ratios as shown in Tables 7 to 10 below.
In Tables 7 to 10, lithium carbonate represents a lithium equivalent value.

10) Analysis of the mineral content of the cement composition (C ₁₂ A ₇ system) and a method similar to that described in the measurement above 3) of the lattice constant and crystallite size of the crystals of the C ₁₂ A ₇ mineral phases Then, the content of the C ₁₂ A _7- based mineral phase (Q) in each cement composition, the lattice constant and the crystallite diameter of crystals of the C ₁₂ A _7- based mineral phase were measured.
These results are shown in Tables 7-10.
Incidentally, C ₁₂ A ₇ mineral phase of the cement composition are those derived from the cement for rapid hardening additive.

11) Measurement of content of gypsum and content of calcium salt in cement composition The content of gypsum and calcium salt in each cement composition is measured by the same method as the XRD / liet belt method described in the above 3). Each was measured. However, the dihydrate gypsum and hemihydrate gypsum were converted to anhydrous gypsum, and the calcium salt was calculated by converting it to calcium hydroxide as the amount of CaSO ₄ (the amount of gypsum).
The results are shown in Tables 7-10.

12) Measurement of the content of the alkali sulfate compound in the cement composition The content of the alkali sulfate compound in each cement composition is the amount of Na and K according to the analysis method of the water-soluble component of cement (JCAS I-04) The total amount of Na ₂ SO ₄ and Na ₂ SO ₄ converted as Na ₂ SO ₄ and K ₂ SO ₄ was taken as the alkali sulfate compound content.
The results are shown in Tables 7-10.

13) slaked lime (calcium _{hydroxide) / C} 12 _{A 7} based mineral phase (content weight ratio of), the mass ratio of gypsum _{/ C} 12 _{A 7} based mineral phases anhydride (content), lithium _{/ C} 12 _{A 7} carbonated Mineral phase (mass ratio of content)
From the values shown in Tables 7 to 10, from the content of C ₁₂ A _7- based mineral phase, the content of slaked lime, the content of gypsum (anhydrous gypsum conversion) content, and the content of lithium carbonate (lithium conversion) in each cement composition, slaked lime (calcium _{hydroxide) / C} 12 _{A 7} based mineral phase (weight ratio: weight%), gypsum (anhydrite _{terms) / C} 12 _{A 7} based mineral phase (weight ratio), lithium carbonate (Li terms) _{/ C 12} a ₇ mineral phase (weight ratio: weight%) was calculated.
The results are shown in Tables 7-10.

14) Preparation of mortar Each cement composition of Examples 11 to 20 and Comparative Examples 12 to 22, fine aggregate (silica sand), water, accelerator and admixture (Mighty 150: manufactured by Kao Corporation) are listed in Table 11 below. Each mortar was compounded and uniformly kneaded as described above.

15) Preparation of mortar The cement compositions of Examples 21 to 23 and the control example, fine aggregate (silica sand), water, accelerator and admixture (Mighty 150: manufactured by Kao Corporation) are blended as shown in Table 12 below. The mixture was uniformly kneaded to obtain mortars. In addition, the cement composition as a control example is Hayakenoko Portland cement (PC: manufactured by Sumitomo Osaka Cement Co., Ltd.) itself.

16) Strength measurement and flow value measurement For the mortars of Examples 1 to 23 and Comparative Examples 1 to 22 and the control example obtained above, the 3 hour strength at 5 ° C. and the flow value at 5 ° C. It measured according to 5201.
The results are also shown in Tables 3 to 5 and Tables 7 to 10 above.

17) Crack Test A crack test at 5 ° C. was performed on each of the mortars of Examples 1 to 23, Comparative Examples 1 to 22, and the control obtained as described above as follows.
A mortar specimen was produced according to JSCE-F506 (How to make a cylindrical specimen for compressive strength test of mortar or cement paste). However, as shown in FIG. 1, the formwork used the thing which made the hole in the upper part of cylindrical formwork form frame ((phi) 5 x 10 cm), inserted and fixed the bolt.
Evaluation of the crack measured the crack length which generate | occur | produced on the sample upper surface (bolt upper surface) 3 hours after kneading | mixing in 5 mm unit (rounding up), and made the state 5 mm or less into a pass.
These results are shown in Tables 3-5 and Tables 7-10.

The admixture composition for cement of the present invention and the cement composition of the present invention exhibit sufficient strength even in a low temperature environment, exhibit excellent hydration activity and excellent rapid hardening performance, and have initial shrinkage cracks due to self-shrinkage. It can suppress the occurrence and can be applied to various construction works, civil engineering works, road works, and building structures.

Claims (9)

Cement for rapid hardening additive material containing C ₁₂ A ₇ based mineral phase comprises a gypsum, and sulfuric acid alkali compound, a calcium salt and lithium _carbonate, 36-55 wt% of _C 12 _{A 7} minerals, alkali sulfate 0.3 to 1.7% by mass of a compound (in terms of sodium sulfate), 0.01 to 1.3% by mass of lithium carbonate (in terms of lithium), and 1 to 14% by mass of a calcium salt (in terms of calcium hydroxide) And the mass ratio of the content of gypsum (equivalent to anhydrous gypsum) / C ₁₂ A _7- based mineral phase is 0.5 to 1.2, and the crystallite diameter of the C ₁₂ A _7- based mineral phase measured by X-ray diffraction is An admixture composition for cement, characterized by having a lattice constant of 11.940 to 11.975 Å at 150 to 500 nm. In claim 1 for cement admixture composition according, wherein the _C 12 _{A 7} mineral phase is a mixed phase of _C 11 _A 7 _CaX 2 (X is halogen) and _C 12 _{A 7,} cement Admixture composition. In the admixture composition for cement according to claim 1 or 2, further, C ₂ A / C ₁₂ A ₇ mineral phase ≦ 7 (% by mass), TiO ₂ / C ₁₂ A ₇ mineral phase ≦ 1.4 (% by mass) The mixing composition for cement according to claim 1, wherein Fe ₂ O ₃ / C ₁₂ A ₇ mineral phase ≦ 2.0 (% by mass). Cement for rapid hardening additive material containing C ₁₂ A ₇ based mineral phase, and gypsum, and sulfuric acid alkali compound, a calcium salt, and a lithium carbonate and _cement, the _C 12 _{A 7} mineral 5 to 40 mass% And 0.5 to 1.0% by mass of an alkali sulfate compound (in terms of sodium sulfate), and a mass ratio of lithium carbonate (in terms of lithium) / C ₁₂ A _7- based mineral phase is 0.05 to 3% by mass, The mass ratio of the content of calcium salt (calcium hydroxide equivalent) / C ₁₂ A _7- based mineral phase is 3 to 40 mass%, and the mass ratio of the content of gypsum (based on anhydrous gypsum) / C ₁₂ A _7- based mineral phase is 0.6 to 1.4, characterized in that the crystallite diameter of the C ₁₂ A _7- based mineral phase measured by X-ray diffraction is 150 to 500 nm, and the lattice constant is 11.940 to 11.975 Å. Cement composition. In claim 4 cement composition, wherein the _C 12 _{A 7} based mineral phase is characterized by (X-halogen) _C 11 _A 7 _CaX 2 is a mixed phase of and _C 12 _{A 7,} the cement composition. A rapid hardening additive for cement having a crystallite diameter of 150 to 500 nm and a lattice constant of 11.940 to 11.975 Å of a C ₁₂ A _7- based mineral phase measured by X-ray diffraction, gypsum, an alkali sulfate compound, Lithium carbonate and calcium salt: 36 to 55% by mass of C ₁₂ A _7- based mineral, 0.3 to 1.7% by mass of alkali sulfate compound (in terms of sodium sulfate), 0. 01 to 1.3 mass%, calcium salt (in terms of calcium hydroxide) is contained in an amount of 1 to 14 mass%, and the mass ratio of the content of gypsum (in terms of anhydrous gypsum) / C ₁₂ A ₇ mineral phase is 0.5 to 0.5 A method of producing a mixing composition for cement, comprising mixing so as to be 1.2. In the method for producing the admixture composition for cement according to claim 6, the rapid hardening additive for cement is formed by pulverizing and mixing the raw materials, forming the mixture, calcining at 1250 to 1400 ° C and cooling rate of 40 ° C / min or less By cooling, the crystallite diameter of the C ₁₂ A _7- based mineral phase measured by X-ray diffraction is 150 to 500 nm, and the lattice constant of the C ₁₂ A _7- based mineral phase is 11.940 to 11.975 Å. A method of producing a mixing composition for cement, characterized in that A rapid hardening additive for cement having a crystallite diameter of 150 to 500 nm and a lattice constant of 11.940 to 11.975 Å of a C ₁₂ A _7- based mineral phase measured by X-ray diffraction, gypsum, an alkali sulfate compound, Lithium carbonate (lithium equivalent) containing lithium carbonate, calcium salt, cement, 5 to 40% by mass of C ₁₂ A _7- based mineral, 0.5 to 1.0% by mass of an alkali sulfate compound (sodium sulfate equivalent) Mass ratio of the content of the / C ₁₂ A _7- based mineral phase is 0.05 to 3 (mass%), and the mass ratio of the content of the calcium salt (converted to calcium hydroxide) / C ₁₂ A _7- based mineral phase is 3 Cement composition characterized in that the mass ratio of the content of 40 to 40 (mass%), gypsum (equivalent to anhydrous gypsum) / C ₁₂ A _7- based mineral phase is 0.6 to 1.4. Manufacturing method. 9. The method of producing a cement composition according to claim 8, wherein the rapid hardening additive for cement powderizes the raw material, shapes the powdered raw material, sinters at 1250 to 1400 ° C., and cools the sintered shaped body by cooling at a rate 40 ° C. / min or less, the crystallite size of the _C 12 _{a 7} mineral phase as measured by X-ray diffraction lattice constant of _C 12 _{a 7} based mineral phase in 150 to 500 nm from 11.940 to 11 A method of producing a cement composition, characterized in that it is produced as .975 Å.

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