JP6967819B2 - Fast-curing grout composition - Google Patents

Description

The present invention relates to a fast-curing grout composition.

Highly fluid cement-based grout materials are used in the construction or repair of civil engineering structures and building structures, or in the installation of machines. When the workable time is limited, such as repair work for structures such as roads and railways, it may be desirable to use grout material that develops strength immediately after filling with grout material, and it is fast-curing. Grout material has been proposed.
In recent years, the performance required for grout materials used in civil engineering and building structures has become more sophisticated, and studies have been conducted on securing pot life, developing strength, and non-shrinkage. Many of the conventional grout materials are provided with initial expandability, that is, non-shrinkage, in order to integrate with the existing structure. A grout material containing aluminum powder, sodium percarbonate, or the like as a foaming component in order to impart initial swellability has been proposed (see, for example, Patent Documents 1 and 2). Further, in order to obtain good short-term strength development, a grout material in which sodium aluminate, an inorganic carbonate and a coagulation adjuster is mixed with a specific hardened component has been proposed (see, for example, Patent Document 3).

Japanese Patent No. 3916326 JP-A-2015-120624 Japanese Unexamined Patent Publication No. 2007-230833

However, even in a fast-curing grout material having a good initial strength development, there are cases where a relatively long pot life (time for maintaining fluidity) is required in addition to the fast-curing material. In the case of a fast-curing grout material, it is possible to secure a stable pot life at room temperature of 20 ° C, but it is difficult to set a sufficient pot life in the high temperature season of summer of 30 ° C or higher. .. Generally, the pot life can be adjusted by adding a retarder such as citric acid in a 20 ° C environment, but in a high temperature environment of 30 ° C or higher, the amount of the retarder added can be increased. Securing the usage time is not as effective as in an environment of 20 ° C, and there is a risk that the hydration of the cement will be delayed and quick hardening will not be obtained.
It is an object of the present invention to provide a fast-curing grout composition capable of obtaining good initial strength development while ensuring a predetermined pot life even in a high temperature environment such as summer.

Therefore, as a result of repeated studies to solve the above problems, the present inventor adjusts the amount of aggregate of the fast-curing grout material and blends a certain amount of a thickener and a setting retarder in combination. As a result, it was found that a fast-curing grout composition having good initial strength development can be obtained while securing a predetermined pot life, and the present invention has been completed.

That is, the present invention provides the following [1] to [4].
[1] A fast-curing grout composition capable of imparting good strength development even in a high-temperature environment of 25 ° C. or higher while ensuring sufficient pot life, such as cement, calcium aluminates, gypsum, and the like. The content of the thickener is 0. With respect to 100 parts by mass of the binder containing the cement, calcium aluminate and gypsum, which contains a setting retarder, a thickener, a water reducing agent , a foaming agent and an aggregate. A fast-curing grout composition having a content of 01 to 0.1 parts by mass, a content of a setting retarder of 0.3 to 1.5 parts by mass, and a content of aggregate of 105 to 175 parts by mass.
[2] The fast-curing grout composition according to [1], which further contains one or two alkali metal carbonates selected from sodium carbonate, potassium carbonate and lithium carbonate.
[3] The fast-curing grout composition according to [1] or [2], wherein the content of the foaming agent is 0.05 to 0.4 parts by mass with respect to 100 parts by mass of the binder.
[4] The fast-curing grout composition according to any one of [1] to [3], wherein the foaming agent is sodium percarbonate.

According to the present invention, when a grout material is used, a fast-curing grout composition capable of imparting good initial strength development while ensuring sufficient pot life even in a high temperature environment such as summer can be obtained. ..

The fast-curing grout composition of the present invention contains cement, calcium aluminates, gypsum, a setting retarder, a thickener, a water reducing agent , a foaming agent and an aggregate, and the cement, calcium aluminates and gypsum. The content of the thickener is 0.01 to 0.1 parts by mass, the content of the setting retarder is 0.3 to 1.5 parts by mass, and the aggregate contains 100 parts by mass of the binder. The content is 105 to 175 parts by mass.

The term "fast-hardening" as used in the present invention refers to a material having a ability to develop a compressive strength ^{of 10 N / mm 2 or more at a material age of 4 hours.}

The cement used in the present invention includes various Portland cements such as ordinary, early-strength, ultra-fast-strength, low-heat and moderate heat, eco-cement, and fly ash, blast furnace slag, silica fume or limestone fine powder in these Portland cement or eco-cement. Examples thereof include various mixed cements in which the above are mixed, and these can be used alone or in combination of two or more. The cement referred to here is cement mainly composed of hard-hardening components such as calcium aluminates, such as alumina cement, Taiheiyo Cement's "Super Jet Cement" (trade name), and Sumitomo Osaka Cement's "Jet Cement" (commodity). Name) and other ultrafast hard cements are not included, and these are included in calcium aluminates. Since the pot life is long and the initial strength development is high, a mixture of ordinary Portland cement or early-strength Portland cement or ordinary Portland cement and early-strength Portland cement is preferable as the cement.

The calcium aluminates used in the present invention _{include C 3} A, C ₂ A, and C _{12 when CaO is represented as C, Al 2} O ₃ is represented as A, Na ₂ O is represented as N, and Fe ₂ O ₃ is represented as F. Calcium aluminate having a mineral composition labeled as A ₇ , C ₅ A ₃ , CA, C ₃ A ₅ , or CA _2, etc., calcium aluminoferrite, calcium aluminate labeled as _{C 2} AF and C _{4 AF, etc.} Calcium haloaluminate in which halogen such as fluorine is dissolved or replaced, _{calcium sodium aluminate labeled as C 8} NA ₃ or C ₃ N ₂ A ₅ etc., calcium lithium aluminate, alumina cement, manufactured by Pacific Cement Co., Ltd. but a generic term for super jet cement "(trade name) and manufactured by Sumitomo Osaka cement Co., Ltd." jet cement "ultra-fast hard cement (trade name), and the like, as well as calcium sulfoaluminate that appears when C _{3 a 3 ·} CaSO _4, etc. be. As the calcium aluminates, any of crystalline, amorphous, and a mixture of amorphous and crystalline can be used, and it is particularly preferable to use those containing amorphous. It is possible to use one or more of the calcium aluminates. As the calcium aluminates used in the present invention, calcium aluminates are preferable, and alumina cement is more preferable.

In the present invention, the content of calcium aluminates is preferably 5 to 50 parts by mass, preferably 5 to 50 parts by mass with respect to 100 parts by mass of cement, particularly considering the properties at high temperature from the viewpoint of compatibility between quick curing and pot life. 30 parts by mass is more preferable.

The gypsum used in the present invention is not particularly limited as long as it is a powder containing anhydrous gypsum, dihydrate gypsum or hemihydrate gypsum as the main component, but gypsum containing type II anhydrous gypsum as the main component is preferable from the viewpoint of strength enhancing action. .. Gypsum reacts with aluminate phases in the cement and calcium aluminate, and the like to produce ettringite _{(3CaO · Al 2 O 3 ·} 3CaSO 4 · 32H 2 O), with fast curing is obtained by this, grout cured body Shrinkage can be suppressed. The gypsum used has a specific surface area of 3000 cm ² / g or more according to the Blaine method, which is preferable because the reaction activity can be obtained. More preferably, gypsum having a powderiness of 6000 cm ² / g or more is preferable. The upper limit of the degree of powderiness is not particularly limited, but the effect is slowed down in spite of the increased cost of increasing the degree of powderiness, so about 15,000 cm ² / g or less is appropriate.

In the present invention, the content of gypsum is preferably 5 to 50 parts by mass, more preferably 10 to 30 parts by mass with respect to 100 parts by mass of cement, because it is easy to secure fluidity and pot life and the initial strength is high.

Here, the binder in the present invention contains, but is not limited to, cement, calcium aluminates and gypsum. The binder may be an inorganic material that has hydraulic or latent hydraulic properties and contributes to the development of strength. In addition to the above, blast furnace slag fine powder, pozzolan such as fly ash and silica fume, quicklime, slaked lime, expansion material, etc. Can be used. However, inorganic salts added in small amounts such as alkali metal carbonates shall be excluded.

The setting retarder used in the present invention is used to obtain an appropriate pot life of the fast-curing grout material, and is particularly limited as long as it has a delaying action on the setting of a water-hardening substance such as cement. Examples thereof include organic acids such as citric acid, gluconic acid, malic acid and tartrate acid or salts thereof, inorganic acid salts such as sodium borate, saccharides and the like, and one or more of these are used. It is possible. In particular, it is preferable to use one or more selected from citric acid, citrate, tartaric acid and tartaric acid because the fast-curing grout material has a long fluidity and a high initial strength development.

In the present invention, the content of the setting retarder is 0.3 to 1.5 parts by mass with respect to 100 parts by mass of the binder. If it is less than 0.3 parts by mass, it may be difficult to maintain the pot life. On the other hand, if it exceeds 1.5 parts by mass, bleeding may occur or it may be difficult to maintain the pot life. More preferably 0.4 to 1.0 parts by mass.

In the present invention, a thickener is contained from the viewpoint of suppressing the occurrence of bleeding and ensuring the pot life. As the thickener in the present invention, water-soluble cellulose-based, acrylic-based, guar gum-based, and the like can be used, and one or more of these can be used. In particular, water-soluble cellulose is preferable because it has high material separation resistance even in a small amount. The water-soluble cellulose is preferably a cellulosic polymer compound, for example, a water-soluble cellulose ether such as carboxymethyl cellulose, methyl cellulose, hydroxypropylmethyl cellulose, hydroxyethyl cellulose, or hydroxypropyl cellulose, but is not particularly limited.

In the present invention, the content of the thickener is 0.01 to 0.1 parts by mass with respect to 100 parts by mass of the binder. If it is less than 0.01 parts by mass, bleeding may occur and it may be difficult to maintain the pot life. On the other hand, if it exceeds 0.1 part by mass, the setting time may be delayed and the strength development may be lowered. More preferably 0.02 to 0.08 parts by mass.

In the present invention, since it is easy to obtain fluidity, a water reducing agent is further contained. The water reducing agent in the present invention is a cement dispersant such as a water reducing agent, a high-performance water reducing agent, an AE water reducing agent, a high-performance AE water reducing agent, and a fluidizing agent, and one or more of these may be used. can. Specific examples thereof include a naphthalene sulfonic acid-based water reducing agent, a lignin sulfonic acid-based water reducing agent, a polycarboxylic acid-based water reducing agent, and a melamine sulfonic acid-based water reducing agent. In the present invention, the content of the water reducing agent is preferably 0.2 to 0.6 parts by mass, preferably 0.25 to 0.6 parts by mass, based on 100 parts by mass of the binder from the viewpoint of ensuring fluidity and preventing material separation or strength reduction. 0.5 parts by mass is more preferable.

In the present invention, the grout material contains an aggregate because the viscosity of the grout material is reduced to obtain good fluidity and the calorific value is reduced to secure the retention time of fluidity. The aggregate in the present invention is a coarse aggregate and a fine aggregate, for example, river sand, sea sand, mountain sand, crushed sand, artificial fine aggregate, slag fine aggregate, recycled fine aggregate, river gravel, sea. Examples include gravel, mountain gravel, crushed stone, artificial coarse aggregate, slag coarse aggregate, recycled coarse aggregate, etc., and one or more of these can be used, but as aggregate because of their high filling property. It is preferable to use fine aggregate.

In the present invention, the content of the aggregate is 105 to 175 parts by mass with respect to 100 parts by mass of the binder. If it is less than 105 parts by mass, it may be difficult to secure the pot life. On the other hand, if it exceeds 175 parts by mass, bleeding may occur or the strength development may decrease. 105 to 150 parts by mass is more preferable, and 110 to 125 parts by mass is further preferable.

In the present invention, in order to promote the setting time, it is preferable to further contain one or more alkali metal carbonates selected from sodium carbonate, potassium carbonate and lithium carbonate. The content of the alkali metal carbonate is preferably 0.4 to 2.0 parts by mass, preferably 0.6 to 1.0 parts by mass, based on 100 parts by mass of the binder from the viewpoint of non-shrinkage and ensuring pot life. The unit is more preferable.

In the present invention, a certain amount of foaming agent is contained from the viewpoint of obtaining sufficient non-shrinkage. Examples of the foaming agent in the present invention include powders of amphoteric metals such as aluminum and zinc, percarbonates, and the like, and one or more of these can be used. In the present invention, the content of the foaming agent is preferably 0.05 to 0.4 parts by mass, preferably 0.1 by mass, because it is easy to obtain fluidity while obtaining sufficient non-shrinkage with respect to 100 parts by mass of the binder. ~ 0.2 parts by mass is more preferable.

The fast-curing grout composition of the present invention includes cement, calcium aluminates, gypsum, setting retarder, thickener, water reducing agent, alkali metal carbonate, foaming agent, aggregate, and other admixtures other than the above. One or more of the additives (agents) of the above can be used in combination as long as the effects of the present invention are not impaired. Examples of the additive include cement polymers, foaming agents, waterproofing agents, rust inhibitors, shrinkage reducing agents, water retaining agents, pigments, fibers, water repellents and the like.

The fast-curing grout composition of the present invention is used by adding water. The amount of water to be added is preferably 35 to 42 parts by mass, more preferably 36 to 40 parts by mass with respect to 100 parts by mass of the binder from the viewpoint of fluidity and quick curing. The amount of water used in the present invention shall also take into consideration the amount of water contained in the liquid admixture material such as an aqueous solution or an emulsion.

The fast-curing grout composition of the present invention is used as a grout material by adding water and kneading it, and then injecting it into cavities, voids, gaps, dents, etc. in the construction and repair of civil engineering structures and building structures. .. In particular, even in a high temperature environment of 25 ° C or higher such as in summer, a grout material having good initial strength development can be obtained after ensuring a sufficient pot life (45 minutes or longer), so that it is used for high temperature. It is suitably used as a fast-curing grout composition.

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

<Example 1>
(Material used)
The materials used are shown below.
・ Cement: Ordinary Portland cement (manufactured by Taiheiyo Cement)
Calcium aluminates: alumina cement (major component: CaO _· Al _{2 O} 3)
-Gypsum: Type II anhydrous gypsum (brain specific surface area: 7100 cm ² / g)
・ Condensation retarder: Sodium citrate (commercially available)
・ Thickener: Water-soluble cellulose ether (commercially available)
-Alkali metal carbonate: Sodium carbonate (commercially available)
・ Foaming agent: Sodium percarbonate (commercially available)
・ Water reducing agent: Naphthalene sulfonic acid-based high-performance water reducing agent ・ Fine aggregate: Limestone aggregate ・ Water: Tap water

(Mixing design)
A thickener, a setting retarder, a fine aggregate, and a water reducing agent were blended and designed so as to be shown in Table 1 with respect to 100 parts by mass of a binder composed of cement, calcium aluminates, and gypsum. Further, 0.15 parts by mass of the foaming agent and 0.85 parts by mass of the alkali metal carbonate were added to 100 parts by mass of the binder.

(Making fast-hardening grout material)
A fast-curing grout composition having the above mixing ratio and a predetermined tap water were kneaded with a mortar mixer to prepare a fast-curing grout material. First, in a metal cylindrical container (diameter: 24 cm, depth: 25 cm), 4.4 kg of tap water of 37.5 parts by mass is put into 100 parts by mass of the binder, and the stirring blade of the mortar mixer comes into contact with water. While rotating the blade in this state, 25 kg of the fast-curing grout composition was added, and then kneaded for 90 seconds. The temperature of each material before kneading was adjusted to 30 ° C., and kneading and quality evaluation tests were conducted in a constant temperature room at 30 ° C. As a quality test of the produced grout material, the following tests were performed. The results are shown in Table 3.

(Quality evaluation test)
(1) Fluidity test JIS R 5201 "Physical test method for cement" 11. In the free test, the static flow without falling motion was measured 15 times. When the flow value was 200 mm or more, it was considered that the fluidity was good.
(2) Bleeding rate The bleeding rate was measured according to JIS A 1123 "Concrete bleeding test method". Those without bleeding were considered good.
(3) Possibility time The starting time of the prepared fast-curing grout material was measured according to JIS A 1147 "Condensation test method for concrete". Since the produced fast-hardening grout material is fast-hardening, filling work can be performed until just before the first starting time. Therefore, the starting time is evaluated as the pot life, and the one with the starting time of 45 minutes or more is good, within this range. Those that deviate from the above were evaluated as defective.
(4) Compressive strength The compressive strength was measured at 4 hours of age according to the JSCE standard JSCE-G 505-2010 "Compressive strength test method for mortar or cement paste using a columnar specimen (draft)". The dimensions of the specimen were 50 mm in diameter and 100 mm in height. In addition, the curing was carried out in a constant temperature bath until just before the age of the material, with the mold still in place. 10 N / mm ² or more was regarded as good.

(Test results)
The test results are shown in Table 2. All of the fast-curing grout materials according to the examples of the present invention had sufficient fluidity as a grout material, a pot life and a compressive strength at a material age of 4 hours. (No. 1-3, 6, 7, 10, 11)
No. that does not contain a thickener. 4. No. 1 in which the condensation retarder and the fine aggregate are blended in excess of the predetermined range. 9, No. In No. 13, bleeding occurs. No. 1 in which the thickener is blended in excess of the predetermined range. No. 5 has poor fluidity. No. 1 containing less than the prescribed range of the setting retarder and the fine aggregate. 8, No. In 12, it becomes difficult to secure the pot life.

<Example 2>
Tap water adjusted to be 30, 35, 42 and 47 parts by mass with respect to 100 parts by mass of the binder and the quick-hardening grout composition were kneaded to prepare a quick-hardening grout material. Table 3 shows the composition and the amount of water of the fast-curing grout composition. In addition, 0.15 part by mass of a foaming agent and 0.85 part by mass of an alkali metal carbonate were added to 100 parts by mass of the binder in the same manner as in Example 1. The method for producing the fast-curing grout and the quality evaluation test method were carried out in the same manner as in Example 1. The results are shown in Table 4.
When the amount of water is small with respect to 100 parts by mass of the binder, the fluidity is poor and it becomes difficult to secure the pot life (No. 14), while when the amount of water is large, bleeding occurs and the compressive strength is high. It decreases (No. 17).

<Example 3>
A test was conducted in which the environmental temperature was changed to 20, 25, and 35 ° C. The formulation of the fast-curing grout composition was No. 1 in Example 1. A fast-curing grout material was prepared and evaluated by the same method as in Example 1 except that the composition was the same as that of No. 1 and the environmental temperature was changed. The results are shown in Table 5.
Bleeding occurs in an environment of 20 ° C. (No. 18), but good fluidity, pot life and compressive strength at a material age of 4 hours can be obtained in an environment of 25 to 35 ° C. (No. 19, 20).

Claims (3)

A fast-curing grout composition that can impart good strength development even in a high-temperature environment of 25 ° C or higher while ensuring sufficient pot life, such as cement, calcium aluminates, gypsum, and setting retarder. , Thickener, naphthalene sulfonic acid-based water reducing agent (excluding other water reducing agents) , foaming agent and aggregate, and the content of the calcium aluminates is 5 to 50 parts by mass of 100 parts of cement. It is a part by mass, and the content of gypsum is 5 to 50 parts by mass with respect to 100 parts by mass of cement, and the thickener is used with respect to 100 parts by mass of the binder containing the cement, calcium aluminates and gypsum. Content is 0. 01 to 0.1 parts by mass, the content of the setting retarder is 0.3 to 1.5 parts by mass, the content of the naphthalene sulfonic acid-based water reducing agent is 0.2 to 0.6 parts by mass, and the content of the foaming agent is 0. A fast-curing grout composition characterized by having a content of 05 to 0.4 parts by mass and an aggregate content of 105 to 175 parts by mass. The fast-curing grout composition according to claim 1, further comprising one or two alkaline metal carbonates selected from sodium carbonate, potassium carbonate and lithium carbonate. The fast-curing grout composition according to claim 1 or 2, wherein the foaming agent is sodium percarbonate.