WO2005042432A1 - Rapidly curable composition for cement and process for producing the same - Google Patents

Abstract

A rapidly curable composition for cements which is satisfactory in initial gel strength and short-time gel strength and enables cement placing in, e.g., lands having many voids or a large amount of running water; a production process; and an application method. The rapidly curable composition for cements comprises calcium aluminate and an inorganic sulfuric acid salt, the amount of the inorganic sulfuric acid salt being preferably 50 to 200 parts by weight per 100 parts by weight of the calcium aluminate, and has a Blaine specific surface area of 7,500 cm2/g. The rapidly curable composition is preferably produced by mixing calcium aluminate having a Blaine specific surface area of 4,000 to 6,000 cm2/g with an inorganic sulfuric acid salt having a Blaine specific surface area of 3,000 to 6,000 cm2/g and pulverizing the mixture so that it comes to have a Blaine specific surface area of 7,500 cm2/g or higher.

Description

 Description Rapid hardening composition for cement and method for producing the same

 The present invention relates to a rapidly hardening composition for cement, a method for producing the same, and a construction method using the rapidly hardening composition for cement. Background art

 Conventionally, a rapid-hardening composition for cement comprising calcium aluminate and an inorganic sulfate is mixed and kneaded with a kneading suspension containing cement as a kneading suspension kneaded with water to which a setting modifier has been added, For example, it is used for ground improvement such as a method of measuring water stoppage by injecting it into a spring in the soil in civil engineering work (see Japanese Patent Application Laid-Open No. 57-01689).

 Here, the cement-based injectable material such as the rapid-hardening composition used is in the process of hardening due to its lack of fluidity.If the gel is not strong, it becomes sludge by applying force to the gel. However, for example, when there is running water, the injection effect cannot be exerted, so that the gel must be strong enough not to be broken. In the present invention, this is referred to as “gel rising strength”.

Conventionally, the rapidly hardening composition used is a calcium aluminate or an inorganic sulfate having a Blaine specific surface area value of at least 300 cm ² Zg, and further, at least 500 cm ² / g. It is widely used for soil improvement such as tunnels, roads, and sewage systems since the fluidity retention time can be freely adjusted by the amount of the setting modifier added, and the strength can be adjusted by the amount of cement.

 However, rapid-hardening compositions are greatly affected by the type of cement used. Therefore, crushed materials such as blast furnace slag and limestone are admixed in accordance with the revision of the JIS standard (JISR5201) for cement. As a result, there was a tendency that the rising strength of the gel in a high water content formulation was reduced. For this reason, there has been a problem that it is difficult to inject a conventional rapidly hardening composition into a predetermined position when it is injected into a mountain or the like where a large amount of flowing water flows. Disclosure of the invention

The present invention relates to a kneading suspension in which a setting regulator is added to a rapid-hardening composition containing calcium aluminate and an inorganic sulfate and kneaded with a high water content, and a cement which is also kneaded with a high water content. Used for construction methods where the suspension is combined at the time of construction and filled at the target location. A rapid-hardening composition for cement that has good gel rising strength and short-time strength, and that can be filled into voids or grounds where there is a lot of running water. The purpose is to do.

 As a result of various studies to achieve the above object, the present inventor has found that a rapidly hardening composition containing calcium aluminate and an inorganic sulfate and having a very high Blaine specific surface area value, which has never existed before, In particular, in each case, a rapidly hardened composition obtained by mixing and grinding calcium aluminate and inorganic sulfate to a specific fineness to obtain a specific extremely high fineness has a high water content. It has become possible to improve the rising strength and initial strength of the gel even in a kneaded suspension in the mixing ratio, and have obtained new knowledge that the above-mentioned object can be achieved. Based on this, the present invention has been completed.

 Thus, the present invention has the following features.

(1) A rapidly hardening composition for cement, comprising calcium aluminate and an inorganic sulfate, and having a Blaine specific surface area value of 7500 cm ² / g or more.

 (2) The rapid-setting composition for cement according to (1), which contains 50 to 200 parts of an inorganic sulfate based on 100 parts of calcium aluminate.

(3) Blaine specific surface area of the 4000~ 6 0 0 0 cm ² calcium Zg aluminate one Bok, Blaine specific surface area value of ^{300 0~ 6 0 0 0 cm 2} Zg an inorganic sulfate, Blaine specific surface area The method for producing a rapidly hardening composition for cement according to the above (1) or (2), wherein the powder is mixed and ground to 7500 cm ² Zg or more.

(4) It is characterized by comprising a kneaded suspension containing calcium aluminate and an inorganic sulfate, having a Blaine specific surface area value of at least 750 cm ² / g, a setting regulator, and water. Rapid hardening kneading suspension.

(5) To a mixer containing water containing a setting modifier, a rapid-hardening composition containing calcium aluminate and inorganic sulfate and having a Blaine specific surface area of 7500 cm ² Zg or more is added. The method for producing a rapid-hardening kneading suspension according to (4), wherein the kneading is performed.

(6) Use of 100 to 200 parts of calcium aluminate, 50 to 200 parts of inorganic sulfate, and 0.5 to 4 parts of a coagulation modifier to 100 parts of calcium aluminate and inorganic sulfate (5) The method for producing a rapid-hardening kneading suspension according to (5).

 (7) A construction method in which the rapid-hardening kneading suspension described in (4) and the kneading suspension of cement and water are separately transported, mixed immediately before construction, and injected into the ground. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, the present invention will be described in more detail.

In the present invention, “parts” and “%” are based on mass unless otherwise specified. Calcium aluminate to be used in the present invention, CaO and A1 ₂ 0 ₃ as chemical components The are those containing as an active ingredient, for _{example, 12CaO '7A1 2 0 3,} HCaO - 7A1 2 0 3 • CaF 2, CaO' Al 2 0 3, and the molten product or baked such 3CaO · A1 ₂ 0 ₃ The product can be used, and either crystalline or amorphous can be used.

Further, calcium aluminate Natick Bok used in the present invention, it is possible to use calcium aluminosilicate, such as metallurgical slag containing a large amount of force Cie © beam aluminate fired product and Si0 ₂ containing an alkali metal.

Of these, 12CaO, 7A1 ₂ 0 ₃ and calcium aluminate amorphous such _{llCaO · 7 A1 2 0 3 ·} CaF 2 is, in particular, rapid hardening is large, more preferred.

The fineness of calcium aluminate is from 4000 to 6000 cm ² / g, preferably from 5000 to 6000 cm ² Zg, in terms of Blaine specific surface area (hereinafter also referred to as Blaine value). Outside this range, rapid hardening effect cannot be expected so much, and the grinding efficiency may be reduced.

 The inorganic sulfate used in the present invention is one that enhances the amount of ettringite monosulfate hydrate produced. Typical examples thereof include gypsum, anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum. One or more of these can be used. The use of anhydrous gypsum is most preferable from the viewpoint of improving strength development.

Fineness of inorganic sulfate is 30 0 0~ 600 0 cm ² Zg in Blaine value, 5 00 0-6000 cm ² / g is preferred. 30 00 cm is less than ² Z g may segregation prone to rapid hydraulic composition obtained by mixing, in some cases rapid hardening effect can not be expected even beyond 6 0 0 0 cm ² Zg.

 The amount of the inorganic sulfate to be used is preferably 50 to 200 parts, more preferably 100 to 150 parts, per 100 parts of calcium aluminate. Outside this range, the short-term strength of the rapidly hardening composition may decrease.

The rapid-hardening composition of the present invention is obtained by mixing calcium aluminate having a fineness of 4000 to 6000 cm ² / g with a Blaine value and inorganic sulfate having a fineness of 300 to 6000 cm ² / g with a Blaine value. Pulverized to a Blaine value of 7500 cm ² Zg or more is preferred. Without using calcium aluminate having a Blaine value of 4000 to 6000 cm ² / g and inorganic sulfate having a Blaine value of 3000 to 6000 cm ² Zg, the Blaine value is out of the range of the present invention described above. When calcium aluminate and inorganic sulfate are mixed and ground with a fineness smaller than the above range and the Blaine value of the rapidly hardening composition is set to 7500 cm ² Zg or more, it is considered in Examples described later. As you can see, it doesn't get much better. This is thought to be because the hardness of calcium aluminate and inorganic sulfate is very different, so that only inorganic sulfate is preferentially pulverized, and calcium aluminate is not ground to the point where it obtains a large rapid hardness. It is. In the present invention, the above-mentioned mixed grinding of calcium aluminate and inorganic sulfate is not particularly limited as long as the Blaine value of the rapidly hardened composition after the mixed grinding becomes 7500 cm ² Zg or more. For example, a force of 400 to 600 cm ² Zg in Blaine value is mixed with a calcium aluminate and an inorganic sulfate of 300 to 600 cm ² / g in Blaine value, and the resulting mixture is co-ground. When a batch-type mill is used, calcium aluminate with a Blaine value of 4000 to 6000 cm ² Zg and a Brain value of 3000 to 600 cm are used. ² Zg of inorganic sulfate can be put into a pulverizer without mixing beforehand, and pulverized while mixing in a pulverizer.

 In the present invention, the pulverizer used for pulverizing calcium aluminate and Z or the inorganic sulfate is not particularly limited, but preferably a pulverizer such as a pole mill or a vibration mill is used. There are no particular restrictions on the crushing conditions in the crusher, and the crushing is performed under known conditions.

 When using the rapid-hardening composition of the present invention containing calcium aluminate and inorganic sulfate, the kneading suspension A of the rapid-hardening composition and the kneading suspension B of cement are combined and mixed. I do. In the present invention, the setting of the kneading suspension A of the rapid-hardening composition and the setting of the gel time when the kneading suspension A and the kneading suspension B of the cement are mixed and mixed are adjusted. It is preferred to use agents.

 As the setting regulator, a mixture of an organic acid and an alkali carbonate is used. As the organic acid, for example, an organic carboxylic acid such as citric acid or tartaric acid or a salt thereof can be preferably used. As the alkali carbonate, for example, an alkali metal carbonate such as potassium carbonate and small lithium can be preferably used.

 The use ratio of the organic acid and the alkali carbonate is not particularly limited, but the organic acid is preferably 20 to 60 parts with respect to 100 parts of the alkali carbonate. There is a case where the rising strength and the initial strength expression are low. Among them, the proportion of the organic acid and the alkali carbonate is preferably 30 to 50 parts per 100 parts of the alkali carbonate.

In the present invention, the setting modifier is preferably used by adding it to the rapid-hardening composition. The amount of the setting modifier used is preferably 0.5 to 4 parts based on 100 parts of the total amount of calcium aluminate and inorganic sulfate. Outside this range, the kneading time of the mixed suspension of the rapidly hardening composition may be shortened. Among them, the amount of the setting modifier used is preferably 0.5 to 3 parts with respect to 100 parts of the total amount of calcium aluminate and inorganic sulfate. When producing a kneading suspension, the above-described calcium aluminate is mixed with a mixer containing water containing a setting regulator. One method is to add and knead a cement rapid-hardening composition containing a salt and an inorganic sulfate, and having a Blaine value of at least 7500 cm ² Zg, preferably at least 800 cm ² / g. It is good. As the mixer here, a grout mixer such as a single-tank grout mixer, a horizontal two-chamber grout mixer, a vertical two-tank grout mixer, or a mortar mixer is preferably used.

 The construction method using the quick-hardening composition of the present invention is, for example, separately kneading and mixing with cement, and separately mixing the kneading suspension A of the hardening composition and the kneading suspension B of cement separately through the injection hose. It is preferable to inject into the ground by a 1.5-shot method, in which the water is fed into the ground and mixed and mixed immediately before injection into the ground.

 The pumping amount of the kneading suspension A of the rapid-hardening composition and the kneading suspension B of the cement can be either equal injection or proportional injection, but the ratio of the quick-hardening composition to the cement is 10%. It is preferable to mix the rapid-hardening composition so as to be 10 to 40 parts with respect to 0 part. If the rapid hardening composition is less than 10 parts, the rise of the gel may be weak, and if it is more than 40 parts, the long-term elongation of strength is small, and it is not preferable from the viewpoint of economy.

 The amount of water used in the present invention is preferably 250 parts or less, based on the total of 100 parts of the rapid-hardening composition and the cement. If the amount of water is more than 250 parts, the rise of the gel may be weak.

 By using the quick-hardening composition of the present invention, in the injection method of the kneading suspension having a higher water content compared with the conventional method, the gel has good gel rising strength and short-time strength, and has a void or running water. It is possible to fill a lot of ground.

 Example

 Hereinafter, the present invention will be described more specifically with reference to Examples. However, it should be understood that the present invention should not be construed as being limited to such Examples. In the following experimental examples, experiments NO. 1-2 and 110 are comparative examples, and others are examples of the present invention.

 Experimental example 1 1 1 1 1 1 1 0

 Pulverized by a vibration mill, blended in an equal amount of calcium aluminate and inorganic sulfate having the Blaine values shown in Table 1, mixed with a Nauta mixer, and re-ground the resulting mixture with a vibration mill to obtain rapid hardening. A composition was prepared.

 In a kneading container filled with 948 cc of water, 1.5 g of the setting regulator was dissolved, and then 150 g of the prepared quick-hardening composition was added and stirred to contain the quick-hardening composition One liter of the kneaded suspension A was prepared.

 On the other hand, 600 g of cement was added to a kneading vessel containing 81 Occ of water and stirred, to prepare a 1-liter kneaded suspension B containing cement.

The kneaded suspension A and the kneaded suspension B thus prepared were mixed and stirred, and the gel time, gel rising strength, and compressive strength were measured. All tests were performed at a temperature of 20 and a humidity of 80 % In a constant temperature and humidity room. The results are shown in Table 1.

 In Table 1, "production method" means "mixing" means only mixing, and "mixed grinding" means grinding after mixing. That is, in Experimental Examples 111 and 112, calcium aluminate and inorganic sulfate having the Blaine values shown in Table 1 were mixed without pulverization.

<Material used>

Calcium Aluminum Natick Bok: in 12CaO · 7A1 ₂ 0 ₃ composition, melt melted in an electric furnace, and the Ri by the quenching amorphous

Inorganic sulfate: II Type I anhydrous gypsum, by-product gypsum, commercially available.

Setting regulator: Main component is a mixture of potassium carbonate and citric acid, a commercial product.

Cement: Normal Portland cement, commercially available.

 <Measurement method>

Gel time: Time required for mixing kneading suspension A and kneading suspension B until the mixture loses fluidity.

Gel rising strength: Mix the kneading suspension A and the kneading suspension B using a Vicat needle device set with a standard needle for terminating the coagulation test shown in JIS R 5201. Filling the cement paste container with the needle penetration of 10 or less.

Compressive strength: According to JIS R 5201, the mortar specimen is filled into a mold for molding and the initial strength is 1.5 hours.

table 1

CA is calcium aluminate, gypsum is inorganic sulfate, raw material fineness and rapid hardening composition fineness are Blaine values (cm ² Zg). As is clear from Table 1, the rapid hardening composition of the present invention has a high fineness. It can be seen that even when the water content is mixed, the gel rising strength is large and the short-term strength is excellent.

Claims

1. A rapidly hardening composition for cement, comprising calcium aluminate and an inorganic sulfate, and having a plain specific surface area of at least 750 cn ^ Zg.

2. The quick-setting composition for cement according to claim 1, wherein the composition contains 50 to 200 parts by mass of an inorganic sulfate based on 100 parts by mass of calcium aluminate.

3. A calcium aluminate with a specific surface area of 400 to 0 to 6000 cm ² g and an inorganic sulfate with a specific surface area of 3000 to 6000 cm ² Zg, a specific surface area of 7500 cm ² 3. The method for producing a rapidly hardening composition for cement according to claim 1, wherein the mixture is pulverized to Zg or more.

 Enclosure

 4. Contains calcium aluminate and inorganic sulfate, and has a Blaine specific surface area of 75

A rapidly hardening kneaded suspension comprising a rapidly hardening composition of 00 cm ² Zg or more, a setting modifier, and a kneaded suspension of water.

5. A cement hardening composition containing calcium aluminate and inorganic sulfate and having a Blaine specific surface area value of 7500 cm ² Zg or more is added to a mixer containing water containing a setting modifier. The method for producing a rapidly hardening kneaded suspension according to claim 4, wherein the kneading is performed.

6. 100 to 100 parts by mass of calcium aluminate, 50 to 200 parts by mass of inorganic sulfate, and 0.5 to 4 parts by mass of coagulation modifier to 100 parts by mass of calcium aluminate and inorganic sulfate. 6. The method for producing a rapid-hardening kneading suspension according to claim 5, which is used.

7-A construction method in which the rapid-hardening kneading suspension according to claim 4 and the kneading suspension of cement and water are individually transported, mixed immediately before construction, and injected into the ground.