JP6595906B2 - Quick-hardening fiber grout composition - Google Patents

Description

  The present invention mainly relates to a fast-setting grout composition used in the civil engineering and construction industry.

  In the civil engineering / architecture field, there are many cases where a grout material having good fluidity is filled in the gap between concrete and concrete. In the field, fast-hardening grout materials that harden early are attractive for work efficiency, and are becoming indispensable grout materials. In particular, fast-hardening grout materials are required for emergency construction at night and work in a low-temperature environment (Patent Documents 1 and 2).

JP 2006-104013 A JP 2007-230833 A

However, the use of fast-hardening components such as calcium aluminate is essential for grout materials with fast-hardening properties. Conventionally, it has been difficult to adjust the fluidity and pot life by using a fast-hardening component. In particular, in a low-temperature environment, the short-term strength may be poorly expressed, and there is a problem that adjustment is difficult.
Accordingly, the present invention provides a grout composition that is easy to adjust fluidity and pot life, and has good strength development in a low-temperature environment, even though it is a fast-hardening grout composition having a fast-hardening component. The task is to do.

  Therefore, the present inventor has made various studies on the adjustment of the fluidity and pot life of the quick-hardening grout material containing calcium aluminate. Mixing specific amounts of wood, alkali metal carbonate, retarder, water reducing agent and fiber, especially reducing the amount of fine aggregates and using nylon fiber as the fiber, the fluidity and pot life can be adjusted. The present invention has been completed by finding that a grout composition that is easy and has good strength development under a low temperature environment can be obtained.

  That is, the present invention provides the following [1] to [3].

[1] A grout composition containing cement, calcium aluminate, gypsum, fine aggregate, alkali metal carbonate, retarder, water reducing agent, and nylon fiber, and comprising a cement, calcium aluminate, and gypsum 3 to 15 parts by mass of fine aggregate, 0.2 to 1.0 parts by mass of alkali metal carbonate, 0.05 to 0.2 parts by mass of retarder, and 0.15 to 0 of water reducing agent for 100 parts by mass of the material A quick-hardening fiber grout composition containing 4 parts by weight and 0.05 to 0.3 parts by weight of nylon fibers.
[2] The content molar ratio of CaO to Al ₂ O ₃ in calcium aluminate is CaO / Al ₂ O ₃ = 1.0 to 1.8, and the vitrification rate is 10% or more. Fast-hardening fiber grout composition.
[3] The fast-hardening fiber grout composition according to [1] or [2], wherein the fiber length of the nylon fiber is 3 to 15 mm.

  A grout composition can be obtained in which the fluidity and pot life can be easily adjusted, and the strength development under a low temperature environment is good.

  Hereinafter, the present invention will be described in detail.

  The fast-hardening fiber grout composition in the present invention refers to a grout composition having quick-hardness and containing fibers.

As the cement used in the present invention, various portland cements such as normal, early strength, super early strength, low heat, and moderate heat, various mixed cements obtained by mixing blast furnace slag, fly ash, or silica with these portland cements, Filler cement mixed with blast furnace slow-cooled slag fine powder such as limestone powder, environmentally friendly cement manufactured using various industrial wastes as the main raw material, so-called eco-cement, etc. More than one species can be used together. In the present invention, it is preferable to select ordinary Portland cement or early-strength Portland cement from the viewpoint of initial strength development and material separation resistance.
The amount of the cement used in the present invention is 65 to 80 parts by mass with respect to 100 parts by mass of the binder (cement, calcium aluminate and gypsum) in terms of strength development, quick curing, and ease of kneading. Is preferable, 68-80 mass parts is more preferable, and 70-80 mass parts is further more preferable.

The calcium aluminate used in the present invention is improved in initial setting and strength development, and a mixture of a CaO raw material, an Al ₂ O ₃ raw material or the like is baked in a kiln or melted in an electric furnace. This is a fast-curing component that causes the cement composition to coagulate in the initial stage after water injection.

As mineral components of calcium aluminate, C ₃ A (3CaO · Al ₂ O ₃ ), C ₁₂ A ₇ (12CaO · 7Al ₂ O ₃ ), CA (CaO · Al ₂ O ₃ ) and CA ₂ (CaO · 2Al) Examples include those obtained by pulverizing a calcium aluminate heat-treated product represented by ₂ O ₃ ). Further, as other components, calcium aluminosilicate containing SiO ₂ , C ₁₁ A ₇ · CaX ₂ (X is a halogen such as fluorine) in which one CaO of C ₁₂ A ₇ is replaced with a halide such as CaF ₂ , C ₄ As · SO ₃ containing SO ₃ component and calcium aluminate in which alkali metals such as sodium, potassium and lithium are partly dissolved are listed. One or more of these can be used. .
Among these, calcium aluminate obtained by quenching a heat-treated product having a CaO / Al ₂ O ₃ molar ratio of 1.0 to 1.8 in terms of reaction activity is preferable. When the CaO / Al ₂ O ₃ molar ratio is 1.0 or more, excellent short-term strength development is obtained, and when it is 1.8 or less, excellent fluidity is obtained.
Moreover, in order to give calcium aluminate sufficient quick hardening, the thing of 10% or more of vitrification rate is preferable. Here, the vitrification rate can be derived by the following method. That is, the mass; the mass of each mineral contained in the cement composition of MS was quantified by internal standard method, etc. by powder X-ray diffraction, and the total mass of the contained mineral phase that could be quantified; MC was calculated, and the balance was the pure glass phase Therefore, the vitrification rate is obtained by the following formula.

  The amount of calcium aluminate used in the present invention is preferably 10 to 25 parts by mass with respect to 100 parts by mass of the binder (cement, calcium aluminate and gypsum) from the viewpoint of fast curing and short-term strength development. -22 mass parts is more preferable, and 10-20 mass parts is further more preferable.

The gypsum used in the present invention promotes the setting, and is, for example, anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum, and one or more of these can be used. Among these, anhydrous gypsum is preferable in terms of the effect of promoting the setting.
The amount of gypsum used in the present invention is preferably 5 to 20 parts by mass with respect to 100 parts by mass of the binder (cement, calcium aluminate and gypsum) from the viewpoint of fast curing and long-term strength development. 18 mass parts is more preferable, and 5-15 mass parts is further more preferable.

Specific examples of the fine aggregate used in the present invention include, for example, a silica sand system, a limestone system, a blast furnace granulated slag system, and a recycled aggregate system. In the present invention, a silica sand system is used from the viewpoint of acid resistance and the like. Is preferably selected.
The amount of fine aggregate used in the present invention is 3 to 15 parts by mass with respect to 100 parts by mass of the binder (cement, calcium aluminate and gypsum). 4-13 mass parts is preferable, 5-10 mass parts is more preferable, and 6-10 mass parts is the most preferable. If the amount is less than 3 parts by mass, it may be difficult to ensure the pot life. If the amount exceeds 15 parts by mass, excellent fluidity may not be obtained, and the filling property in a small gap may be deteriorated.

The alkali metal carbonate used in the present invention is not particularly limited. For example, lithium carbonate, sodium carbonate, potassium carbonate, etc. are mentioned. Considering the effect of initial setting and cost, lithium carbonate and sodium carbonate are preferable.
The usage-amount of the alkali metal carbonate in this invention shall be 0.2-1.0 mass part with respect to 100 mass parts of binders (cement, calcium aluminate, and gypsum). 0.3-0.8 mass part is preferable, 0.4-0.7 mass part is more preferable, and 0.4-0.6 mass part is the most preferable. If the amount is less than 0.2 parts by mass, the effect of promoting the initial setting may be reduced. If the amount exceeds 1.0 parts by mass, the fluidity may be deteriorated.

The retarder used in the present invention is not particularly limited. Specific examples thereof include, for example, oxycarboxylic acids such as citric acid, tartaric acid, malic acid, gluconic acid, and succinic acid, or sodium salts, potassium salts, calcium salts, magnesium salts, ammonium salts, and aluminum salts thereof. These salts are preferred, and one or more of these can be used.
The amount of retarder used in the present invention is 0.05 to 0.2 parts by mass with respect to 100 parts by mass of the binder (cement, calcium aluminate and gypsum). 0.06-0.12 mass part is preferable, and 0.06-0.1 mass part is more preferable. If it is less than 0.05 parts by mass, it may be difficult to ensure the pot life, and if it exceeds 0.2 parts by mass, the strength development may be deteriorated.

In the present invention, it is preferable to use a water reducing agent in order to easily obtain fluidity. The water reducing agent used 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 are used. I can do it. Specific examples include naphthalene sulfonic acid-based water reducing agents, lignin sulfonate-based water reducing agents, polycarboxylic acid-based water reducing agents, and melamine sulfonate-based water reducing agents.
The usage-amount of the water reducing agent in this invention shall be 0.15-0.4 mass part with respect to 100 mass parts of binders (cement, calcium aluminate, and gypsum). 0.17-0.3 mass part is preferable, and 0.2-0.25 mass part is more preferable. If it is less than 0.15 parts by mass, fluidity may not be sufficient, and if it exceeds 0.4 parts by mass, material separation may occur.

In the present invention, nylon fibers are used as the fibers. Fibers other than nylon fibers, such as polypropylene fibers, are not preferred because they have poor dispersibility and fluidity, poor fillability in narrow spaces, and large variations in cured product properties.
The amount of nylon fiber used in the present invention is 0.05 to 0.3 parts by mass with respect to 100 parts by mass of the binder (cement, calcium aluminate and gypsum). 0.07-0.27 mass parts is preferable and 0.1-0.2 mass part is more preferable. If the amount is less than 0.05 parts by mass, the short-term strength development in a low-temperature environment may be deteriorated. If the amount exceeds 0.3 parts by mass, excellent fluidity may not be obtained.
The nylon fiber used in the present invention preferably has a fiber length of 3 to 15 mm. If it is less than 3 mm, the short-term strength development in a low temperature environment may be deteriorated, and if it exceeds 15 mm, excellent fluidity may not be obtained. The preferred fiber length is 3 to 13 mm, more preferably 3 to 12 mm.

In the present invention, in order to integrate the grout material with the structure, the grout mortar that has not yet solidified works to prevent subsidence or shrinkage, and to improve crack resistance when placed in a dry state. It is preferable to use a foaming agent such as a peroxide material or aluminum powder. As the foaming agent used in the present invention, it is preferable to use a peroxide material because it can stably suppress settlement during curing. The peroxide material used in the present invention is not particularly limited. For example, sodium percarbonate, potassium percarbonate, ammonium percarbonate and the like can be mentioned, and one or more of these can be used.
In the present invention, the amount used in the case of using a peroxide substance can suppress settlement at the time of curing and easily obtain a high initial strength, so that it is based on 100 parts by mass of the binder (cement, calcium aluminate and gypsum). 0.03-0.1 mass part is preferable, 0.04-0.09 mass part is more preferable, and 0.04-0.06 mass part is further more preferable.
In addition, the amount of aluminum powder used as a foaming agent can be set to suppress the settlement during curing, and high initial strength can be easily obtained. Therefore, the amount used is 100 parts by mass of the binder (cement, calcium aluminate and gypsum). 0.003-0.01 mass parts is preferable.
The amount of water used is not particularly limited because it varies depending on the purpose and application of use and the blending ratio of each material, but it has good fluidity, suppresses large calorific value, and develops short-term strength. From the viewpoint of securing, the water binder ratio is preferably 34 to 38%.

  In the present invention, one or two or more clay minerals such as an antifoaming agent, a thickening agent, a rust preventive agent, a shrinkage reducing agent, a polymer, and bentonite are used within a range that does not substantially impair the object of the present invention. It is possible.

  The quick-hardening fiber grout composition of the present invention uses water for kneading. The method used for kneading is not particularly limited in terms of obtaining good fluidity, suppressing large calorific value, and ensuring short-term strength development, for example, adding all the fast-hardening fiber grout composition of the present invention to water. Examples thereof include a kneading method, a method in which the fast-hardening fiber grout composition of the present invention is added to water while kneading and further kneading, a method in which water is added to the quick-hardening fiber grout composition of the present invention while kneading and further kneading. . Moreover, although the apparatus and kneading apparatus used for kneading are not particularly limited, it is preferable to use a mixer because a large amount can be kneaded. The mixer that can be used may be a continuous mixer or a batch mixer, and examples thereof include a grout mixer, an omni mixer, a hand mixer, and a plaster mixer.

  The fast-hardening fiber grout composition of the present invention is easy to adjust the fluidity and pot life despite being excellent in fast-hardening, and has good strength development even in a low-temperature environment. This is useful for emergency construction such as tunnel construction that is required.

  EXAMPLES Hereinafter, although this invention is further demonstrated based on the Example of this invention, this invention is not limited to these.

Example 1
The materials used are shown in Table 1.

[Formulation design]
Peroxide, alkali metal carbonate, retarder, water reducing agent, and fiber are as shown in Table 2 with respect to 100 parts by mass of the binder consisting of 78 parts by mass of cement, 13 parts by mass of calcium aluminate, and 9 parts by mass of gypsum. The formulation was designed.

[Grout production]
Under an environment of 20 ° C., 20 kg of the blended and designed powder was weighed, added to 6.8 L of water weighed in a 26 L cylindrical container, and kneaded for 60 seconds with a hand mixer to prepare a grout. Further, in a 5 ° C. environment, 7.1 L of water was used, and a grout was produced by the same method.
The evaluation test method of the produced grout is shown below.

[Quality evaluation test]
- using a fluid testing Civil Engineering standard JSCE-F 541-1999 J ₁₀ funnel according to "Test Method of Flowability for Filling Mortar", it was measured flow time immediately after and 10 minutes after the start of kneading kneading. Fast-hardening grout mortar (fast-hardening grout material) is used for grout construction in many emergency works, so it does not require a long time (for example, 1 hour) as a filling time (usable time), but 5 minutes Since the above is necessary, both the immediately after kneading and 10 minutes from the start of kneading were very good (◎) when the flow-down time was within the range of 10 seconds, and good when the flow time was within the range of 15 seconds (◯), those outside this range were evaluated as defective (x). The test results are shown in Table 3.

・ Initial expansion coefficient test Immediately after kneading, it is molded into a mold with a diameter of 50 mm and a height of 100 mm, a plastic plate with a diameter of 40 mm and a height of 1.5 mm is placed on the upper surface, and a non-contact sensor is used for 24 hours immediately after molding. Measure the change in length, read the measured values at the age of 5 minutes and 24 hours, and the initial expansion amount after 24 hours of age (after hardening) with respect to the initial expansion amount (expansion amount before hardening) of the material age of 5 minutes (Large amount of expansion) was evaluated as good (◯) and small as poor (×). The test results are shown in Table 3. The initial expansion rate obtained from the initial expansion amount at the age of 24 hours with respect to the initial expansion amount at the age of 5 minutes at the evaluation of “good (◯)” at the test level corresponding to the examples is both greater than 0% and less than 1%. And there was no fear of strength reduction due to overexpansion.

-Compressive strength According to JSCE-G 505-1999 "Testing method for compressive strength of mortar or cement paste using cylindrical specimens", a material age of 1 hour, material age of 1 day and material age in a 20 ° C environment. The compressive strength at 28 days was measured. Moreover, the compressive strength in material age 1 hour and 3 hours was measured in 5 degreeC environment. The dimensions of the specimen were 50 mm in diameter and 100 mm in height. In addition, for the material age of 28 days, the wet curing at 20 ° C. was performed until the mold was removed at the age of 24 hours, and then immediately transferred to 20 ° C. water, followed by 20 ° C. water curing until just before the test. The test results are shown in Table 4.

The test results are shown in Tables 3 and 4. 3 to 15 parts by mass of fine aggregate, 0.03 to 0.1 parts by mass of peroxide, 0.2 to 1.0 parts by mass of alkali metal carbonate, 0.05 to retarder with respect to 100 parts by mass of binder ~ 0.2 parts by mass, water reducing agent 0.15 to 0.4 parts by mass, nylon fiber 0.05 to 0.3 parts by mass can ensure good fluidity and sufficient pot life, and low temperature environment The compressive strength at an age of 1 hour is good, and the initial expansibility is good (No. A-1, -2, -3, -4, -5, -8, -9, -12, -13, -16, -17, -20, -21). In contrast, A-23 in lowering of J ₁₀ funnel under a stream value after 10 minutes from the start of the kneading significantly, it is difficult to ensure the pot life. Moreover, A-7, -10, -14, -19, and -24 have low short-term strength development in a low temperature environment. A-6, -11, -15, -18, and -22 have poor fluidity.

Example 2
With respect to 100 parts by mass of a binder composed of 78 parts by mass of cement, 13 parts by mass of calcium aluminate, and 9 parts by mass of gypsum, 0.06 parts by mass of a peroxide, 0.4 parts by mass of alkali metal carbonate, 0. The composition was designed to be 06 parts by mass, 0.25 parts by mass of a water reducing agent, 0.16 parts by mass of nylon fibers, and 6 parts by mass of fine aggregate. However, the calcium aluminate having a CaO / Al ₂ O ₃ molar ratio and the vitrification ratio shown in Table 5 was used. Other than that was carried out in the same manner as in Example 1.

The test results are shown in Tables 6 and 7. As for calcium aluminate, if the molar ratio of CaO and Al ₂ O ₃ is CaO / Al ₂ O ₃ = 1.0 to 1.8 and the vitrification rate is 10% or more, good fluidity and sufficient The pot life can be secured, and the compressive strength at an age of 1 hour in a low temperature environment is particularly good (B, C, D).

Example 3
With respect to 100 parts by mass of a binder composed of 78 parts by mass of cement, 13 parts by mass of calcium aluminate, and 9 parts by mass of gypsum, 0.06 parts by mass of a peroxide, 0.4 parts by mass of alkali metal carbonate, 0. The composition was designed to be 06 parts by mass, 0.25 parts by mass of a water reducing agent, 0.16 parts by mass of nylon fibers, and 6 parts by mass of fine aggregate. However, nylon fibers having a fiber length shown in Table 8 were used. Other than that was carried out in the same manner as in Example 1.

  The test results are shown in Table 9 and Table 10. If the fiber length of the nylon fiber is 3 to 15 mm, good fluidity and sufficient pot life can be secured, and the compressive strength at an age of 1 hour in a low temperature environment is particularly good (F, G).

Claims (3)

  A grout composition containing cement, calcium aluminate, gypsum, fine aggregate, alkali metal carbonate, retarder, water reducing agent and nylon fiber, 100 mass of binder consisting of cement, calcium aluminate and gypsum 3 to 15 parts by weight of fine aggregate, 0.2 to 1.0 parts by weight of alkali metal carbonate, 0.05 to 0.2 parts by weight of retarder, 0.15 to 0.4 parts by weight of water reducing agent A quick-hardening fiber grout composition, characterized by containing 0.05 to 0.3 parts by mass of nylon fiber. Calcium molar ratio of CaO and Al ₂ O ₃ of aluminate is _{CaO / Al 2 O 3 = 1.0~1.8} , and rapid-fibers according to claim 1, wherein the vitrification rate is 10% or more Grout composition.   The quick-hardening fiber grout composition according to claim 1 or 2, wherein the nylon fiber has a fiber length of 3 to 15 mm.