JPWO2014203788A1 - Cement rapid hardener, method for producing the same, and cement composition - Google Patents

Abstract

Provided are a cement quick-hardening material capable of ensuring a pot life after placing concrete and having excellent storage stability, a method for producing the same, and a cement composition including the same. Cement rapid hardening material containing calcium sulfoaluminate hydrate produced by mixing calcium aluminate, gypsum and a water-containing compound by a high-speed shearing method having a rotational speed of 20 m / s or more, the cement rapid hardening material and cement A cement composition comprising

Description

  The present invention relates to a cement rapid hardening material for concrete used in the field of civil engineering and construction, a method for producing the same, and a cement composition using the same.

It is known that early strength development can be obtained by mixing a mixture of calcium aluminate and gypsum into cement (see Patent Document 1).
In addition, in order to secure a pot life in using a cement hardened material composed of a mixture of calcium aluminate and gypsum, a method of containing water in the mixture composed of calcium aluminate and gypsum (see Patent Document 2), calcium aluminum A method of mixing an nate with a small amount of water in the presence of sulfuric acid (see Patent Document 3), calcium aluminate and calcium sulfate coated with hydrate, aluminum sulfate, alkali metal sulfate, or alkali metal A method of blending carbonate (see Patent Document 4), a method of blending gypsum made of anhydrous gypsum whose surface is coated with two water gypsum and calcium aluminate (see Patent Document 5), and the like are known.
Moreover, the injection material formed by mixing a rapid hardening component and cement with the mixture of anhydrous gypsum and dihydrate gypsum is known (refer patent document 6).

Furthermore, a cement hardener is known that is obtained by blending calcium aluminate or a mixture of calcium aluminate and anhydrous gypsum with one or two kinds selected from semi-water gypsum and dihydrate gypsum and pulverizing them simultaneously ( (See Patent Document 7).
Furthermore, the heating change of ettringite (ettringite) has been studied in detail (see Non-Patent Document 1).

Japanese Unexamined Patent Publication No. 48-1024 Japanese Unexamined Patent Publication No. 53-125431 Japanese Unexamined Patent Publication No. 54-157129 Japanese Unexamined Patent Publication No. 2005-60154 Japanese Unexamined Patent Publication No. 2007-176744 Japanese Unexamined Patent Publication No. 2005-162949 Japanese Unexamined Patent Publication No. 2012-121774

Sakauchi Hideo, Nakagawa Koji, Ettringite heating change, gypsum and lime, No. 97, pp. 11-17, 1968

  An object of the present invention is to provide a cement hardened material that can secure a pot life after placing concrete and is excellent in storage stability, a method for producing the same, and a cement composition using the same.

That is, this invention has the summary of the following (1)-(12).
(1) A cement rapid hardening material containing calcium sulfoaluminate hydrate produced by mixing calcium aluminate, gypsum and a water-containing compound by a high-speed shearing method having a rotational speed of 20 m / s or more.
(2) In a total of 100 parts of calcium aluminate, gypsum and water-containing compound, 25 to 75 parts of calcium aluminate, 25 to 75 parts of gypsum, and 1 to 10 parts of water-containing compound are mixed in the above (1 ) Cement rapid hardening material as described in).
(3) The cement hardened material according to (1) or (2) above, wherein the amount of water desorbed by heating at 50 to 120 ° C. is 0.05 to 0.50 mass%.
(4) The cement hardener according to any one of (1) to (3), wherein the calcium aluminate is an amorphous calcium aluminate.
(5) The cement hardened material according to any one of the above (1) to (4), wherein the gypsum is at least one selected from the group consisting of anhydrous gypsum, semi-water gypsum and dihydrate gypsum.
(6) The cement rapid hardening material according to any one of the above (1) to (5), wherein the hydrous compound is a sulfate or a carbonate.
(7) The cement hardened material according to any one of (1) to (6), wherein the fineness is 3000 to 9000 cm ² / g in terms of Blaine specific surface area.
(8) A cement composition comprising cement and the cement hardener according to any one of (1) to (7) above.

(9) The cement composition according to (8), wherein the content of the cement quick-hardening material is 5 to 50 parts in 100 parts of the cement composition made of cement and the cement quick-hardening material.
(10) A method for producing a cement hardened material comprising mixing calcium aluminate, gypsum and a water-containing compound by a high-speed shearing method having a rotational speed of 20 m / s or more.
(11) The method for producing a cement hardened material according to (10), wherein the rotational speed of the chopper of the mixing device in the high-speed shearing method is 20 m / s or more.

  According to the present invention, a cement rapid hardening material having excellent storage stability can be provided, and the cement rapid hardening material and cement mixture have an early strength development property and can sufficiently secure a pot life.

The “parts” and “percent (%)” used in the present invention are based on mass unless otherwise specified.
Moreover, the concrete as used in the field of this invention is a general term for cement paste, cement mortar, and / or cement concrete.

The calcium aluminate as referred to in the present invention is a general term for compounds mainly composed of CaO and Al ₂ O ₃ . As specific examples, for example, amorphous compounds mainly containing CaO component and _Al 2 _{O 3 component, CaO · 2Al 2 O 3,} CaO · Al 2 O 3, 12CaO · 7Al 2 O 3, 3CaO _{· Al 2 O 3, 11CaO ·} 7Al 2 O 3 · CaF 2, and crystallinity of the calcium aluminate and the like represented as such _{3CaO · 3Al 2 O 3 · CaF} 2. Of these, amorphous calcium aluminate is preferred.
In addition, it is preferable to grind | pulverize calcium aluminate using a ball mill etc. for the improvement of the efficiency at the time of mixing, before mixing with gypsum, a hydrous compound, etc. Fineness of ground calcium aluminate, Blaine specific surface area (hereinafter, referred to as Blaine) 3,000~9,000cm ² / g, with preferably 4,000~8,000cm ² / g.

The gypsum used in the present invention is a general term for minerals mainly composed of calcium sulfate represented by the molecular formula CaSO ₄ . Specifically, it is a general term for anhydrous gypsum, half-water gypsum, and two-water gypsum represented by molecular formulas CaSO ₄ , CaSO ₄ .1 / 2H ₂ O, and CaSO ₄ .2H ₂ O, respectively. Of these, anhydrous gypsum is preferable.

The hydrous compound used in the present invention refers to a compound containing chemically or physically bonded water (crystal water, gel water, etc.), but also includes water itself.
Although not particularly limited, for _{example, Al 2 (SO 4) 3} · 8H 2 O, Al 2 (SO 4) 3 · 18H 2 O, AlNa (SO 4) 2 · 12H 2 O, AlK (SO 4 ) ₂ · 12H ₂ O, Na ₂ SO ₄ · 10H ₂ O, Na ₂ CO ₃ · 10H ₂ O, cement hydrate, ettringite (3CaO · Al ₂ O ₃ · 3CaSO ₄ · 32H ₂ O) and mono Examples thereof include sulfate (3CaO.Al ₂ O ₃ .CaSO ₄ .12H ₂ O) and organic compounds such as C ₆ H ₈ O ₇ .H ₂ O.

Also, of the gypsum, hemihydrate gypsum _{(CaSO 4 · 1 / 2H 2} O) or gypsum _(CaSO 4 · _2H 2 O) is also applicable. Furthermore, hydrates with a constant amount of water are also included, such as hydrated products of Fe ₂ O ₃ .nH ₂ O, tricalcium silicate (3CaO.SiO ₂ ) and dicalcium silicate (2CaO.SiO ₂ ). A certain CaO—SiO ₂ —H ₂ O-based hydrate may be mentioned.

  In the present invention, one or more selected from these hydrous compounds can be used. Among these water-containing compounds, in the present invention, dihydrate gypsum, hemihydrate gypsum, potassium alum 12 hydrate, or sodium sulfate decahydrate is preferably used.

It is preferable that the cement hardened material of the present invention is mixed with calcium aluminate, gypsum and a water-containing compound and then mixed by a high-speed shearing method to generate calcium sulfoaluminate hydrate. The high-speed shear referred to in the present invention is a shear rate of 20 m / s or more.
Calcium sulfoaluminate hydrate is not particularly limited, but ettringite (3CaO · Al ₂ O ₃ · 3CaSO ₄ · 32H ₂ O) or monosulfate (3CaO · Al ₂ O ₃ · CaSO ₄ · 12H) ₂ O) and the like, which are represented by chemical formulas including CaO, Al ₂ O ₃ , CaSO ₄ , H ₂ O and the like. In particular, ettringite is preferred.

  The mixing ratio of calcium aluminate, gypsum and water-containing compound is not particularly limited, but usually, calcium aluminate is 25 to 75 parts in total of 100 parts of calcium aluminate, gypsum and water-containing compound, preferably 30 to 70 parts, gypsum is 25 to 75 parts, preferably 30 to 70 parts, and the hydrous compound is 1 to 10 parts, preferably 2 to 8 parts. When the mixing ratio is outside the above range, it may be difficult to ensure the pot life of the concrete or the initial strength development may be poor.

  In addition, after mixing calcium aluminate, gypsum and a water-containing compound, the amount of water desorbed by heating at 50 to 120 ° C. in the sample after mixing by high-speed shearing method is the combined water of calcium sulfoaluminate hydrate. Since it corresponds to a part, it becomes a standard for confirming that a predetermined amount of calcium sulfoaluminate hydrate has been produced. The formation of calcium sulfoaluminate hydrate was identified by observing the surface of calcium aluminate and gypsum particles by SEM observation and confirming that calcium, aluminum and sulfur were contained by elemental analysis.

  The amount of water desorbed by heating at 50 to 120 ° C. can be quantified by, for example, differential thermogravimetric analysis (TG-DTA), differential calorimetry (DSC), Karl Fischer method, or the like. In particular, the Karl Fischer method is preferable because it can directly quantitate moisture desorbed by heating. In the examples, a Karl Fischer analyzer is used to measure the amount of desorbed water at 50 ° C. and the amount of desorbed water at 120 ° C., and the difference is defined as 50 to 120 ° C. desorbed moisture (% by mass).

  In the present invention, the amount of water desorbed by heating at 50 to 120 ° C. is preferably 0.05 to 0.50%, and more preferably 0.10 to 0.45%. Outside this range, it may be difficult to ensure the pot life of the concrete, or the initial strength development of the concrete may be poor.

In the present invention, the mixing method of calcium aluminate, gypsum and water-containing compound is important, and a high-speed shearing method is adopted.
Specifically, the rotation speed of the chopper of the mixing device is preferably 20 m / s or more, and more preferably shear mixing at 40 m / s or more. If it is less than 20 m / s, calcium sulfoaluminate hydrate cannot be formed uniformly, and the pot life and initial strength may not be ensured. The upper limit of the rotation speed is not particularly limited, but is usually preferably 100 m / s or less.
In addition, as a mixing apparatus, it is possible to use a ladyge mixer manufactured by Matsubo.

As for the method of mixing the respective materials at the time of manufacturing the cement hardened material, high speed shearing may be performed after all the materials are charged into the mixer, or the above materials may be sequentially added while continuing high speed shearing. Although there is no restriction | limiting in the injection | throwing-in order of these materials, It is preferable to introduce | transduce other materials, adding calcium aluminate grind | pulverized with the ball mill etc. first and continuing high-speed shearing.
The product in the mixer obtained by mixing by the high-speed shearing method can be used as it is as a cement hardener.

Although the fineness of the cement hardened material obtained by mixing by the high-speed shearing method is not particularly limited, it is usually preferably 3000 to 9000 cm ² / g, and 4000 to 8000 cm ² / g in terms of the specific surface area of branes. More preferred. If it is less than 3000 cm ² / g, the initial strength may be insufficiently developed, and if it exceeds 9000 cm ² / g, it may be difficult to ensure fluidity and pot life. The pot life is preferably 20 minutes to 60 minutes, and preferably 25 minutes to 50 minutes after water injection. In addition, the initial strength is preferably 10 N / mm ² or more, more preferably 12 N / mm ² or more after 3 hours from water injection.

  The blending amount of the cement rapid hardening material of the present invention is not particularly limited because it varies depending on the blending of concrete, but usually 5 to 50 parts in 100 parts of a cement composition composed of cement and cement rapid hardening material. Preferably, 10 to 40 parts is more preferable. If it is less than 5 parts, sufficient rapid hardening performance may not be obtained, and if it is used in excess of 50 parts, strength reduction may occur with long-term aging.

  As the cement used in the cement composition of the present invention, various portland cements such as ordinary, early strength, ultra-early strength, low heat, medium heat, etc., various mixed cements obtained by mixing blast furnace slag, fly ash, silica with these cements, and Portland cement such as filler cement mixed with limestone powder, and environmentally friendly cement (eco-cement) manufactured using municipal waste incineration ash and sewage sludge incineration ash as raw materials. It can be used. Among them, it is preferable to select early strong Portland cement.

  In addition to sand, gravel, etc., the concrete containing the cement hardened material of the present invention includes a water reducing agent, a high performance water reducing agent, an AE water reducing agent, a high performance AE water reducing agent, a fluidizing agent, an antifoaming agent, a thickening agent, Rust preventive, antifreeze, shrinkage reducing agent, polymer emulsion, setting modifier, etc., clay minerals such as bentonite, ion exchanger such as zeolite, siliceous fine powder, calcium carbonate, calcium hydroxide, calcium silicate, etc. As such inorganic materials and organic materials, fibrous substances such as vinylon fibers, acrylic fibers, and carbon fibers can be used in combination.

  Examples Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention should not be construed as being limited thereto.

"Experiment 1"
Calcium aluminate (hereinafter referred to as CA) was pulverized to a brain value of 5000 cm ² / g with a ball mill, and as shown in Table 1, calcium aluminate, gypsum, and water-containing compound were blended at 20 ° C. The rotational speed was 60 m / s, and high-speed shear mixing was performed using a Laedige mixer (manufactured by Matsubo). The obtained mixture was used as a cement hardener as it was.

  Next, 10 parts of the obtained cement hardener was used in 10 parts of the total cement composition, 100 parts of cement composition consisting of cement and cement hardener, 150 parts of sand, 30 parts of water, and setting adjustment Cement mortar was prepared in a 20 ° C. room using a mortar mixer. The pot life and compressive strength of the obtained cement mortar were measured.

  In addition, as a comparative example, it is obtained by mixing and pulverizing a cement hardened material “low speed mixing” obtained by low speed mixing (shearing speed 5 m / s) of calcium aluminate, gypsum, and a water-containing compound, or by a ball mill. In the case of the cement rapid hardening material “simultaneously pulverized A”, the same experiment was conducted for “−” when calcium aluminate and gypsum were used without mixing. The results are shown in Table 1.

<Materials used>
CA (6): An amorphous CA having a molar ratio of CaO / Al ₂ O ₃ of 1.7 and containing 3% of SiO ₂ . After melting at 1650 ° C. using reagent-grade first grade calcium carbonate, alumina, and silica, the mixture was quenched and synthesized (10-mesh product).
Gypsum: Commercial product, anhydrous gypsum, 10 mesh passing product.
Hydrous compound (1): dihydrate gypsum, commercially available product, 10 mesh passing product.
Hydrous compound (2): semi-aqueous gypsum, commercial product, 10-mesh product.
Hydrous compound (3): Aluminum sulfate 18 hydrate, commercial product, 10-mesh product.
Hydrous compound (4): Potash alum 12 hydrate, commercially available product, 10-mesh product.
Hydrous compound (5): Sodium sulfate decahydrate, commercially available product, 10-mesh product.
Hydrous compound (6): Sodium carbonate decahydrate, commercial product, 10-mesh product.
Setting controller: A mixture of 25 parts of reagent grade citric acid and 75 parts of reagent grade potassium carbonate.
Sand: JIS standard sand, commercial product.
Cement: Ordinary Portland cement. Commercial product, brain value 3000 cm ² / g.
Water: tap water.

<Measurement method>
Desorption moisture amount: 50 to 120 ° C. Desorption moisture amount: Dehydrated moisture amount at 50 ° C. using a Karl Fischer analyzer (manufactured by Kyoto Electronics Industry Co., Ltd.) to confirm the amount of calcium sulfoaluminate hydrate produced. And the amount of desorbed water at 120 ° C. was measured, and the difference was defined as the amount of desorbed water (mass%) at 50 to 120 ° C.

Pot life: A temperature recorder (manufactured by Keyence Corporation) was used to measure the time until the mortar temperature rose by 2 ° C. from the kneading.
Compressive strength: According to JIS R 5201, a 4 × 4 × 16 cm specimen was prepared, and the compressive strength after 3 hours was measured. (Fully automatic compression tester manufactured by Marui)
The results in “Experimental Example 1” are shown in Table 1 below.

"Experiment 2"
Except having changed the compounding quantity of the hydrous compound as shown in Table 2, it implemented similarly to Experimental Example 1, and measured and evaluated. The results are shown in Table 2.

"Experiment 3"
Except having changed the kind of calcium aluminate as shown in Table 3, it implemented similarly to Experimental example 1, and measured and evaluated. The results are shown in Table 3.

<Materials used>
CA (1): A 10-mesh product with CaO / Al ₂ O ₃ in a molar ratio of 1.0 and crystalline CA, the main component of which is CaO · Al ₂ O ₃ .
CA (2): CaO / Al ₂ O ₃ is 1.5 in terms of molar ratio, crystalline CA, the main components are CaO · Al ₂ O ₃ and 12CaO · 7Al ₂ O ₃ .
CA (3): CaO / Al ₂ O ₃ is a molar ratio of 1.7, crystalline CA, and the main components are CaO · Al ₂ O ₃ and 12CaO · 7Al ₂ O ₃ .

CA (4): CaO / Al ₂ O ₃ is 2.0 in terms of molar ratio, crystalline CA, the main components are CaO · Al ₂ O ₃ and 12CaO · 7Al ₂ O ₃ .
CA (5): CaO / Al ₂ O ₃ is 1.5 in terms of molar ratio, 3% of SiO ₂ and amorphous CA. After melting at 1650 ° C. using reagent grade 1 calcium carbonate, alumina, and silica, they were synthesized by quenching. 10 mesh passing product.
CA (7): CaO / Al ₂ O ₃ is 2.0 in terms of molar ratio, 3% of SiO ₂ and amorphous CA. After melting at 1650 ° C. using reagent grade 1 calcium carbonate, alumina, and silica, they were synthesized by quenching. 10 mesh passing product.

"Experimental example 4"
Except that CA (6) was 50 parts, gypsum was 49 parts, and the hydrous compound (1) was 1 part, and the amount was fixed, and the chopper rotation speed (shear rate) was changed as shown in Table 4, It implemented similarly to Experimental example 1, and measured and evaluated. The results are shown in Table 4.

  The cement rapid hardening material of the present invention is excellent in storage stability, and the rapid hardening concrete using the cement rapid hardening material can ensure a sufficient pot life and can be widely used in the civil engineering and construction fields.

  It should be noted that the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2013-129923 filed on June 20, 2013 are incorporated herein as the disclosure of the specification of the present invention. Is.

Claims (11)

  A cement hardener comprising calcium sulfoaluminate hydrate produced by mixing calcium aluminate, gypsum and a water-containing compound by a high-speed shearing method having a rotational speed of 20 m / s or more.   2. A total of 100 parts of calcium aluminate, gypsum and water-containing compound, wherein calcium aluminate is mixed in a ratio of 25 to 75 parts, gypsum is 25 to 75 parts, and water-containing compound is mixed in a ratio of 1 to 10 parts. Cement hardener as described in 1.   The cement hardener according to claim 1 or 2, wherein the amount of water desorbed by heating at 50 to 120 ° C is 0.05 to 0.50 mass%.   The cement rapid hardening material of any one of Claims 1-3 whose calcium aluminate is an amorphous calcium aluminate.   The cement hardened material according to any one of claims 1 to 4, wherein the gypsum is at least one selected from the group consisting of anhydrous gypsum, semi-water gypsum and dihydrate gypsum.   The cement-hardened material according to any one of claims 1 to 5, wherein the hydrous compound is sulfate or carbonate. The cement hardened material according to any one of claims 1 to 6, wherein the fineness is 3000 to 9000 cm ² / g in terms of Blaine specific surface area.   A cement composition comprising cement and the cement hardener according to any one of claims 1 to 7.   The cement composition according to claim 8, wherein the content of the cement rapid hardening material is 5 to 50 parts in a total of 100 parts of the cement and the cement rapid hardening material.   A method for producing a cement hardened material comprising mixing calcium aluminate, gypsum and a water-containing compound by a high-speed shearing method having a rotational speed of 20 m / s or more.   The method for producing a cement hardened material according to claim 10, wherein the rotation speed of the chopper of the mixing device in the high-speed shearing method is 20 m / s or more.