JP2020055748A - Rapid hardening grout composition - Google Patents

Abstract

To provide a rapid hardening grout composition having desired work life in a high temperature environment such as summer, and capable of imparting good initial strength development property.SOLUTION: The rapid hardening grout composition is characterized by containing a cement, calcium aluminate analogs, gypsum, a foaming agent, a setting retarder, a thickener, a water-reducing agent and aggregates; per 100 pts.mass of a binder containing the cement, calcium aluminate analogs and gypsum, the thickener content is 0.01-0.1 pts.mass, the setting retarder content is 0.3-1.5 pts.mass, and the aggregate content is 105-175 pts.mass.SELECTED DRAWING: None

Description

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

2. Description of the Related Art A cement-based grout material having a high fluidity is used in construction or repair of a civil engineering structure or a building structure, installation of a machine, or the like. When construction time is limited, such as when repairing structures such as roads and railways, it may be desirable to use a grout material that quickly develops strength after filling with grout material. Grouting materials have been proposed.
In recent years, the performance required for grout materials used in civil engineering and building structures has been advanced, and studies have been made on securing a pot life, developing strength and non-shrinkage. In many cases, conventional grout materials are provided with an initial expandability, that is, a non-shrinkage property, in order to integrate with the existing structure. A grout material in which aluminum powder or sodium percarbonate is blended as a foaming component in order to impart an initial expandability has been proposed (for example, see 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 setting modifier are mixed with a specific hard component has been proposed (for example, see Patent Document 3).

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

However, even a quick-hardening grout material having good initial strength development may require a relatively long pot life (time during which fluidity is maintained) as well as quick-hardening. In the case of a quick-hardening grout material, it is difficult to set a sufficient pot life at a high temperature in summer of 30 ° C. or more, even if a stable pot life can be secured at room temperature of 20 ° C. . Generally, the pot life can be adjusted by adding a retarding agent such as citric acid in a 20 ° C environment, but in a high temperature environment of 30 ° C or more, it is possible to increase the amount of the retarding agent added. Ensuring that the working time is not as effective as in a 20 ° C. environment, there is a possibility that the hydration of the cement may be delayed and the quick setting property may not be obtained.
An object of the present invention is to provide a quick-hardening grout composition that can obtain a good initial strength while maintaining a predetermined pot life even in a high-temperature environment such as summertime.

  Therefore, the present inventor has made various studies to solve the above-mentioned problems, and as a result, while adjusting the amount of aggregate of the quick-curing grout material, combining a certain amount of a thickener and a setting retarder in combination. As a result, it has been found that a quick-setting grout composition having good initial strength can be obtained after securing a predetermined pot life, and the present invention has been completed.

That is, the present invention provides the following [1] to [4].
[1] Even in a high-temperature environment of 25 ° C. or more, a fast-curing grout composition capable of imparting good strength development while ensuring a sufficient pot life, comprising cement, calcium aluminates, gypsum, It contains a setting retarder, a thickener, a water reducing agent , a foaming agent, and an aggregate, and the content of the thickener is 0.1 part by mass based on 100 parts by mass of the binder containing the cement, calcium aluminates, and gypsum. A fast-curing grout composition having a content of from 0.01 to 0.1 part by mass, a setting retarder content of from 0.3 to 1.5 parts by mass, and an aggregate content of from 105 to 175 parts by mass.
[2] The quick-setting grout composition according to [1], further comprising one or two kinds of alkali metal carbonates selected from sodium carbonate, potassium carbonate and lithium carbonate.
[3] The quick-setting 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 quick-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, even in a high-temperature environment such as summertime, a sufficient hardening time can be ensured, and a fast-curing grout composition that can impart good initial strength can be obtained. .

The quick-setting 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 binder is 100 parts by mass, the content of the thickener is 0.01 to 0.1 part by mass, the content of the setting retarder is 0.3 to 1.5 parts by mass, and the amount of the aggregate. It is characterized in that the content is 105 to 175 parts by mass.

The quick-hardening property referred to in the present invention means a material having a performance of expressing a compressive strength of 10 N / mm ² or more at a material age of 4 hours.

  As the cement used in the present invention, ordinary, high-strength, ultra-high-strength, various portland cements such as low heat and moderate heat, and these portland cement or eco-cement, fly ash, blast furnace slag, silica fume or limestone fine powder And the like can be used, and these can be used alone or in combination of two or more. The cement referred to here is a cement mainly composed of a rapid hardening component such as calcium aluminate, for example, alumina cement, "Super Jet Cement" (trade name) manufactured by Taiheiyo Cement Co., Ltd., and "Jet Cement" (trade name) manufactured by Sumitomo Osaka Cement Co., Ltd. Ultra-fast-setting cements such as 名) are not included, and these are included in calcium aluminates. From the viewpoint that the pot life is long and the initial strength is high, it is preferable to use a cement made of ordinary Portland cement or Portland cement, or a mixture of ordinary Portland cement and Portland cement.

As calcium aluminates used in the present invention, when CaO is represented by C, Al ₂ O _{3 is represented} by A, Na ₂ O is represented by N, and Fe ₂ O ₃ is represented by F, C ₃ A, C ₂ A, C ₁₂ Calcium aluminate having a mineral composition indicated as A ₇ , C ₅ A ₃ , CA, C ₃ A ₅ , CA _2, etc., calcium alumino ferrite, calcium aluminate indicated as C ₂ AF and C ₄ AF etc. Calcium haloaluminate in which halogen such as fluorine is dissolved or substituted, calcium sodium aluminate, calcium lithium aluminate, alumina cement, alumina cement, and Pacific Ocean Cement, which are expressed as C ₈ NA ₃ or C ₃ N ₂ A ₅ Super fast cement such as "Super Jet Cement" (trade name) and "Jet Cement" (trade name) manufactured by Sumitomo Osaka Cement Co., Ltd. And calcium sulfoaluminate denoted as C ₃ A ₃ .CaSO ₄ or the like. 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. One or more of the calcium aluminates can be used. As the calcium aluminates used in the present invention, calcium aluminates are preferred, and alumina cement is more preferred.

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

The gypsum used in the present invention is not particularly limited as long as it is a powder mainly composed of anhydrous gypsum, gypsum dihydrate or hemihydrate gypsum, but a gypsum mainly composed of type II anhydrous gypsum is preferred from the viewpoint of a strength increasing effect. . The gypsum reacts with the aluminate phase and calcium aluminates in the cement to produce ettringite (3CaO.Al ₂ O ₃ .3CaSO ₄ .32H ₂ O), thereby obtaining a quick-setting property and a hardened grout. Can be suppressed. The fineness of the gypsum to be used is preferably 3000 cm ² / g or more in terms of specific surface area by the Blaine method because reaction activity can be obtained. More preferably, gypsum having a fineness of 6000 cm ² / g or more is good. Although the upper limit of the fineness is not particularly limited, the effect is slowed down in spite of the increased cost of increasing the fineness, so that approximately 15000 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, based on 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 includes, but is not limited to, cement, calcium aluminates and gypsum. The binder may be any inorganic material having hydraulic or latent hydraulic properties and contributing to strength development.In addition to the above, blast furnace slag fine powder, pozzolan such as fly ash and silica fume, quicklime, slaked lime, expanding material, etc. Can be used. However, inorganic salts added in small amounts such as alkali metal carbonates are excluded.

  The setting retarder used in the present invention is used for obtaining an appropriate pot life of the quick-setting grout material, and is not particularly limited as long as it has a retarding effect on setting of a hydraulic substance such as cement. Examples thereof include, for example, organic acids or salts thereof such as citric acid, gluconic acid, malic acid and tartaric acid, inorganic acid salts such as sodium borate, and saccharides, and one or more of these are used. It is possible. In particular, it is preferable to use one or two or more selected from citric acid, citrate, tartaric acid, and tartaric acid, since the quick-setting grout material has a long fluidity time and a high initial strength expression.

  In the present invention, the content of the setting retarder is 0.3 to 1.5 parts by mass based on 100 parts by mass of the binder. If the amount 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. 0.4 to 1.0 part by mass is more preferable.

  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, a water-soluble cellulose type, acrylic type, guar gum type or the like can be used, and one or more of these can be used. In particular, water-soluble cellulose is preferred because it has a high resistance to material separation in a small amount. The water-soluble cellulose is preferably a cellulosic polymer compound, for example, a water-soluble cellulose ether such as carboxymethylcellulose, methylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, or hydroxypropylcellulose, but is not particularly limited.

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

  In the present invention, since a fluidity is easily obtained, a water reducing agent is further contained. The water reducing agent in the present invention is a cement dispersing agent 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. it can. Specific examples include a naphthalene sulfonic acid-based water reducer, a lignin sulfonic acid-based water reducer, a polycarboxylic acid-based water reducer, and a melamine sulfonic acid-based water reducer. In the present invention, the content of the water reducing agent is preferably from 0.2 to 0.6 parts by mass, and more preferably from 0.25 to 0.6 parts by mass, based on 100 parts by mass of the binder, from the viewpoint of securing fluidity and preventing material separation or reduction in strength. 0.5 parts by mass is more preferred.

  In the present invention, an aggregate is contained because the viscosity of the grout material is reduced to obtain good fluidity, and the calorific value is reduced to secure the fluidity retention time. The aggregate in the present invention refers to coarse aggregate and fine aggregate, for example, river sand, sea sand, mountain sand, crushed sand, artificial fine aggregate, slag fine aggregate, recycled fine aggregate, river gravel, sea sand, and the like. Gravel, mountain gravel, crushed stone, artificial coarse aggregate, slag coarse aggregate, recycled coarse aggregate, and the like, and one or more of these can be used. 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 the amount 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 strength developability may decrease. The amount is more preferably from 105 to 150 parts by mass, and still more preferably from 110 to 125 parts by mass.

  In the present invention, in order to accelerate 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 from 0.4 to 2.0 parts by mass, and more preferably from 0.6 to 1.0 part by mass, based on 100 parts by mass of the binder, from the viewpoint of ensuring no shrinkage and pot life. Parts are more preferred.

  In the present invention, a certain amount of a 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 from 0.05 to 0.4 parts by mass, and more preferably from 0.1 to 0.4 parts 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 preferred.

  The fast-setting grout composition of the present invention includes cement, calcium aluminates, gypsum, a setting retarder, a thickener, a water reducing agent, an alkali metal carbonate, a foaming agent, and an aggregate, as well as other admixtures and the like. One or more of the above additives (agents) can be used in combination as long as the effects of the present invention are not impaired. Examples of the additive include a polymer for cement, a foaming agent, a waterproofing agent, a rust preventive, a shrinkage reducing agent, a water retention agent, a pigment, a fiber, a water repellent, and the like.

  The quick-setting grout composition of the present invention is used after adding water. The amount of water to be added is preferably from 35 to 42 parts by mass, more preferably from 36 to 40 parts by mass, per 100 parts by mass of the binder, from the viewpoint of fluidity and rapid curing. The amount of water used in the present invention also takes into account the amount of water contained in a liquid admixture such as an aqueous solution or an emulsion.

  The quick-hardening grout composition of the present invention is used as a grout material by adding water, kneading, and then pouring into cavities, voids, gaps, dents, and the like in construction of civil engineering structures and building structures, repair, and the like. . In particular, even in a high temperature environment of 25 ° C. or more, such as in summer, a grout material having good initial strength can be obtained after securing a sufficient pot life (45 minutes or more). It is suitably used as a quick-setting 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 (made by Taiheiyo Cement Corporation)
・ Calcium aluminates: Alumina cement (main component: CaO.Al ₂ O ₃ )
Gypsum: Type II anhydrous gypsum (Brain specific surface area: 7100 cm ² / g)
・ Set retarder: sodium citrate (commercially available)
・ Thickener: Water-soluble cellulose ether (commercially available)
・ Alkali metal carbonate: sodium carbonate (commercially available)
-Blowing agent: sodium percarbonate (commercially available)
・ Water reducer: High performance water reducer based on naphthalene sulfonic acid ・ Fine aggregate: Limestone aggregate ・ Water: tap water

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

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

(Quality evaluation test)
(1) Fluidity test JIS R 5201 “Physical test method of cement” 11. In the free test, the stationary flow without performing the falling motion 15 times was measured. When the flow value was 200 mm or more, the fluidity was considered to be good.
(2) Bleeding rate The bleeding rate was measured according to JIS A 1123 "Bleeding test method for concrete". Those without bleeding were considered good.
(3) Pot life According to JIS A 1147 “Method for setting test of concrete”, the starting time of the produced quick-hardening grout material was measured. Since the prepared fast-curing grout material is fast-curing, filling work is possible up to just before the starting time, the starting time is evaluated as the pot life, and those having a starting time of 45 minutes or more are good. Those out of the range were evaluated as defective.
(4) Compressive strength The compressive strength at a material age of 4 hours was measured according to JSCE-G 505-2010 "Method of testing compressive strength of mortar or cement paste using cylindrical specimen" (draft). The dimensions of the specimen were 50 mm in diameter and 100 mm in height. Curing was performed in a thermostat in a thermostat until the material age was reached. 10 N / mm ² or more was regarded as good.

(Test results)
Table 2 shows the test results. All of the quick-hardening grout materials according to the examples of the present invention had sufficient fluidity as a grout material, usable life and compressive strength at a material age of 4 hours. (Nos. 1-3, 6, 7, 10, 11)
No. 3 containing no thickener. No. 4, in which the setting retarder and the fine aggregate are respectively blended beyond the predetermined ranges. 9, No. No. 13 causes bleeding. No. 3 in which the thickener is blended beyond the predetermined range. No. 5 has poor fluidity. No. 1 in which the setting retarder and the fine aggregate were each mixed in less than the predetermined range. 8, No. No. 12, it is difficult to secure the pot life.

<Example 2>
Tap water and a quick-setting grout composition were adjusted to 30, 35, 42, and 47 parts by weight with respect to 100 parts by weight of the binder to prepare a quick-setting grout material. Table 3 shows the composition of the fast-curing grout composition and the amount of water. As in Example 1, 0.15 parts by mass of a foaming agent and 0.85 parts by mass of an alkali metal carbonate were added to the fast-curing grout composition based on 100 parts by mass of the binder. The method for producing the quick-curing grout and the quality evaluation test method were carried out in the same manner as in Example 1. Table 4 shows the results.
When the amount of water relative to 100 parts by mass of the binder is small, the fluidity is poor and it is difficult to secure the pot life (No. 14). On the other hand, when the amount of water is large, bleeding occurs and the compressive strength is reduced. (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 as described in A fast-setting grout material was prepared and evaluated in the same manner as in Example 1 except that the composition was the same as that of Example 1 and the environmental temperature was changed. Table 5 shows the results.
Bleeding occurs in an environment of 20 ° C. (No. 18), but in an environment of 25 to 35 ° C., good fluidity, usable life and compressive strength at a material age of 4 hours are obtained (No. 19, 20).

Claims (4)

A quick- setting grout composition capable of imparting good strength development while ensuring a sufficient pot life even in a high-temperature environment of 25 ° C. or more, comprising cement, calcium aluminates, gypsum, a setting retarder , Containing a thickener, a water reducing agent , a foaming agent and an aggregate, and the content of the thickener is 0.01 to 0 with respect to 100 parts by mass of the binder containing the cement, calcium aluminates and gypsum. 0.1 parts by mass, a setting retarder content of 0.3 to 1.5 parts by mass, and an aggregate content of 105 to 175 parts by mass. The quick-setting grout composition according to claim 1, further comprising one or two kinds of alkali metal carbonates selected from sodium carbonate, potassium carbonate and lithium carbonate. The quick-setting grout composition according to claim 1, 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. The quick-setting grout composition according to any one of claims 1 to 3, wherein the blowing agent is sodium percarbonate.