JPH09255387A - Spray material and spray technique using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spray material capable of reducing spray thickness, capable of realizing a reduction of the executing cost and a shortening of the executing time and capable of making a working environment good since the spray material is capable of spraying to a natural ground surface exposed in a tunnel, large in initial and log term strength manifesting property, capable of reducing rebound amount, excellent in adhesion and capable of reducing markedly dust amount and to provide a spry technique. SOLUTION: In the spray material, a cement mortar consisting essentially of cement and gypsum, calcium aluminate, amines and/or a dust reducing agent and a cement admixture consisting essentially of one or >=2 kinds mixing agents selected among alkali aluminate and/or alkali carbonate, a water reducing agent, a setting retarder, a hardening accelerator and superfine power at need are incorporated, and the spray material is used to the spray technique.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spraying material sprayed on a ground surface exposed in a tunnel such as a road, a railway, and a headrace, and a spraying method using the same.
The cement mortar of the present invention is a generic term for paste, mortar, and concrete.

[0002]

2. Description of the Related Art Conventionally, a spraying method of quick-setting concrete in which a quick-setting agent is mixed with concrete has been performed to prevent the collapse of exposed ground such as tunnel excavation (Japanese Patent Publication No. 52-4149). Gazette). This method is usually used to manufacture sprayed concrete at a cement, aggregate, and water metering and mixing plant installed at an excavation work site, which is transported by an agitator vehicle and pressure-fed by a concrete pump. This is a method in which a pipe mixes with a quick-setting agent that has been pressure-fed from the other side and sprays it as quick-setting sprayed concrete on the ground surface to a predetermined thickness. However, in this method, the rebound rate, which is the ratio of the amount of drops that do not adhere to the ground and the amount of spray, is as high as 15 to 30% by weight, and because the amount of dust is large, the working environment is poor. There was a need for a construction method with a small rebound rate and less dust, due to concerns about the influence of pneumoconiosis, etc. However, at present, there is still no satisfactory spraying material or spraying construction method, and improvement thereof is strongly desired.

Further, conventionally used concrete containing a quick-setting admixture has a better initial strength rise than concrete containing no quick-setting admixture, but long-term strength has a quick-setting admixture. The strength development tended to be worse, for example, about 30 to 50% lower than that of concrete not containing. Even so, its long-term strength is sufficient to prevent the stable ground from collapsing in the conventional spraying method, and in fairly unstable ground, it is dealt with by increasing the spray thickness. Came. However, increasing the spraying thickness means using a large amount of sprayed concrete, which is not preferable in terms of economy and work efficiency. Therefore, especially in the excavation of a large cross-section tunnel, considering economic efficiency and work efficiency, it is preferable to increase the strength of the shotcrete and reduce the shotthickness. Can be shortened.

Conventionally, as a method for achieving high strength of sprayed concrete, a method of producing sprayed concrete with fine powder cement and mixing it with a conventional quick-setting admixture, and spraying gypsum and calcium aluminum A method has been proposed in which nate is mixed in advance and mixed with sprayed concrete and sprayed (JP-A-50-16717, JP-A-50-16718, JP-A-50-25623). . However, in the method using fine powder cement, the elongation of strength is smaller than that of shotcrete using ordinary cement, and it has been difficult to obtain sufficient strength expression that is much higher than that.

Further, the method of using a quick-setting admixture containing calcium aluminate and gypsum requires the use of a quick-setting admixture of 10 parts by weight or more with respect to 100 parts by weight of cement. When higher initial strength was required, it was necessary to use 20 parts by weight or more. for that reason,
If it is necessary to stop the spraying work during the spraying process and add a quick-setting admixture, or if the quick-setting admixture runs out during the spraying work, the concrete will not set immediately and there is a risk of falling. Or the amount of dust generated by the quick-setting agent increases,
There is a problem that it is not preferable in terms of workability and safety and hygiene. Furthermore, the quick-setting admixture containing calcium aluminate and gypsum is effective in removing water and free SO ₃ contained in gypsum.
It is believed that the calcium aluminate surface reacts with the calcium aluminate surface, resulting in a decrease in quick setting property. As a result, as the storage time of the quick-setting agent becomes longer, its quick-setting force decreases, and if a quick-setting agent with a long storage period is used, sprayed concrete may fall from the tunnel ceiling, which is the ceiling part of the tunnel, There were problems such as not adhering to the place with spring water and increasing the rebound rate. When calcium aluminate is used as the quick-setting agent, the initial setting force immediately after mixing is not so strong, and therefore the initial condensation force of the shotcrete may be improved by adding and mixing the setting accelerator. is there. However, under the present circumstances, even if the cohesive force is increased, the rebound does not extremely decrease, and it is preferable to increase the adhesive force by making the concrete sticky from the viewpoint of significantly reducing the rebound amount. Furthermore, when the amount of the quick-setting agent used is large, the long-term strength developing property tends to be poor.

As a result of various studies on the problems in the case of improving the strength of shotcrete, the present inventor has obtained the knowledge that the above-mentioned problems can be solved by carrying out the spraying work using a specific spraying material. The present invention has been completed.

[0007]

That is, the present invention provides a cement mortar containing cement and gypsum as main components, a quick-setting agent containing calcium aluminate as a main component, an amine and / or a dust reducing agent. It is a spraying material that contains, and the heat-setting agent contains calcium aluminate and alkali aluminate and / or alkali carbonate as main components, or calcium aluminate corresponds to a composition of 12CaO · 7Al ₂ O ₃ It is a spray material characterized by being an amorphous substance obtained by quenching a substance, and further, one or more admixtures selected from the group consisting of water reducing agents, setting retarders, setting accelerators, and ultrafine powder. It is a spray material containing a material, and is a spray material characterized by being mixed with 100 parts by weight of cement and 1 to 25 parts by weight of gypsum. And, a spraying method using the spraying material, dry cement mortar obtained by mixing cement and gypsum, or cement mortar obtained by mixing cement, gypsum, and water, and calcium aluminate as a main component. 7. The spraying method according to claim 6, wherein the rapid-setting agent is mixed and mixed while flowing.

Hereinafter, the present invention will be described in detail.

[0009] The present invention is to increase the strength by the action of gypsum, improve the adhesion of sprayed concrete to the ground by the action of amines, and reduce the decrease in the elongation of long-term strength development when a large amount of a quick-setting agent is added. In addition, by reducing the amount of dust generated by the action of the dust reducer, the problem of long-term strength reduction due to the addition of a conventional quick-setting agent is improved, and the strength can be greatly exceeded compared to concrete without a quick-setting agent. The present invention relates to a spraying material for cohesive sprayed concrete and a spraying method thereof.

As the cement used in the present invention, various portland cements which are usually commercially available, such as normal, early strength, moderate heat, and super early strength, and various kinds of these portland cements mixed with fly ash, blast furnace slag, etc. Examples include mixed cement and commercially available fine particle cement, and various Portland cements and cements obtained by pulverizing mixed cement can also be used.

The gypsum used in the present invention is to be mixed with cement for the purpose of increasing the strength of shotcrete, and, for example, anhydrous gypsum, semi-water gypsum, and dihydrate gypsum can be used. Two or more types can be used. Among them, anhydrous gypsum is preferably used from the viewpoint of strength development. The particle size of gypsum is preferably such that it is usually used during the production of cement, for example, about 3,000 cm ² / g in terms of Blaine value, and more preferably pulverized to a level exceeding 3,000 cm ² / g. The amount of gypsum used is 10
The amount is preferably 1 to 25 parts by weight, more preferably 5 to 20 parts by weight, based on 0 parts by weight. If it is less than 1 part by weight, the long-term strength is difficult to improve, and if it exceeds 25 parts by weight, the initial setting may be delayed and the adhesion to the ground may be reduced. After a long time, it may expand and concrete may be destroyed. .

The aggregate used in the present invention preferably has a low water absorption rate and a high aggregate strength, but is not particularly limited. The fine aggregate preferably has a maximum diameter of 5 mm or less, and river sand, mountain sand, lime sand, silica sand and the like can be used. As the coarse aggregate, the maximum diameter is preferably 5 to 20 mm,
In consideration of the pumping property, the one having a diameter of 5 to 15 mm is more preferable.

The cement mortar of the present invention is a mixture of at least cement and gypsum, and either dry cement mortar which is not mixed with water or cement mortar which is mixed with water can be used.

The amount of water used depends on the water cement ratio (hereinafter W / C
Is 60% or less, more preferably 45% or less. If it exceeds 60%, it may be difficult to obtain strength, and the amount of the quick-setting agent used may increase and the cost may increase.

In the present invention, one or more admixtures selected from the group consisting of water reducing agents, setting retarders, setting accelerators, and ultrafine powders can be used in combination with cement mortar.

The water reducing agent is used for the purpose of improving the fluidity of the cement mortar, and either a liquid type or a powder type can be used. Specifically, a polyol derivative,
Examples thereof include lignin sulfonates and their derivatives, and high-performance water reducing agents. Among them, it is preferable to use high-performance water reducing agents from the viewpoint of imparting high strength development. Here, as the high-performance water-reducing agent, naphthalene sulfonate, formalin condensate of alkylallyl sulfonate, condensate of melamine sulfonate, polycarboxylic acid-based polymer compound, etc. can be used, and liquid or powder Either can be used. The amount of the high-performance water reducing agent used is preferably 0.05 to 5 parts by weight, and more preferably 0.1 to 3 parts by weight in terms of solid content, relative to 100 parts by weight of cement. If it is less than 0.05 parts by weight, the effect is not obtained, and if it exceeds 5 parts by weight, the viscosity of the cement mortar is too strong, and the workability may decrease.

The setting retarder and the setting accelerator can be used together from the viewpoint of controlling the setting time of the cement mortar and the quick setting agent.

As the setting retarder, organic acids, alkali carbonates and the like can be used. Examples of the organic acids include gluconic acid, tartaric acid, citric acid, malic acid, lactic acid and salts thereof, and one or more of these can be used. The amount of organic acid used is preferably 0.01 to 3 parts by weight, more preferably 0.05 to 2 parts by weight, based on 100 parts by weight of cement. If it is less than 0.01 parts by weight, no effect is obtained, and if it exceeds 3 parts by weight, curing may be delayed too much, resulting in poor curing.

Examples of the alkali carbonates (hereinafter referred to as carbonates) include sodium carbonate, potassium carbonate, sodium bicarbonate and the like, and one or more of these can be used. The amount of carbonate used is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of cement. If it is less than 0.01 parts by weight, no effect is obtained, and if it exceeds 10 parts by weight, curing may be delayed too much, resulting in poor curing.

The coagulation accelerator promotes initial coagulation, and specific examples thereof include alkali hydroxides and sulfates, and one or more of these can be used. Examples of alkali hydroxides (hereinafter referred to as hydroxides) include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide, and slaked lime. Sulfate also promotes initial setting, and specifically,
Examples thereof include sodium sulfate, potassium sulfate, aluminum sulfate, and alum, and one or more of these can be used. The amount of the setting accelerator used is preferably 0.05 to 20 parts by weight with respect to 100 parts by weight of cement. If it is less than 0.05 parts by weight, there is no effect, and if it exceeds 20 parts by weight, the piping may be blocked.

The ultrafine powder used in the present invention means an average particle size of 10
It is less than μm and can be used in combination with cement mortar and quick-setting admixture, which can reduce the amount of cement, dust and improve the pumpability of concrete. It is effective. Specifically, ultrafine powder such as fine powder slag, fly ash, bentonite, kaolin, and silica fume can be used, and among these, silica fume is preferable because of its high effect. Further, fine powder having an average particle size of more than 10 μm can be used together unless the object of the present invention is impaired.
The amount of ultrafine powder used is 1 to 100 parts by weight of cement.
100 parts by weight is preferable, and 2 to 30 parts by weight is more preferable.
If it is less than 1 part by weight, there is no effect, and if it exceeds 100 parts by weight, setting and curing may be delayed.

The quick-setting agent used in the present invention is mainly composed of calcium aluminate. Here, calcium aluminate is a quick-setting component that causes the setting of concrete in the early stage. CaO raw material or Al ₂ O ₃ raw material is used for firing in a kiln or melting in an electric furnace. It is obtained by heat treatment such as. As the mineral component of calcium aluminate, CaO is C and Al ₂ O ₃ is
When _{A, C 3 A, C 12} A 7, CA, and those obtained by pulverizing the calcium aluminate Cook indicated as CA ₂ like. In addition, as a mineral component of calcium aluminate, calcium aluminosilicate containing a large amount of SiO ₂ , C ₁₂ A
₇ One CaO halides, for example, can also be used those containing C ₄ A ₃ · SO ₃ or the like comprising C ₁₁ A ₇ · CaF _2, and SO ₃ component was replaced with CaF _2. Of these, C ₁₂ A
Amorphous calcium aluminate obtained by rapidly cooling a heat-treated product corresponding to ₇ composition is preferable from the viewpoint of reaction activity. The grain size of calcium aluminate is preferably 3,000 cm ² / g or more in terms of Blaine value from the viewpoint of quick setting property and initial strength development property, and 4,000 cm ²
/ g or more is more preferable. If it is less than 3,000 cm ² / g, the quick-setting strength may decrease. The amount of calcium aluminate used is preferably 0.5 to 20 parts by weight, more preferably 5 to 15 parts by weight, based on 100 parts by weight of cement. If it is less than 0.5 part by weight, initial setting may not occur, and if it exceeds 20 parts by weight, long-term strength development may be hindered.

In the present invention, calcium aluminate is
It is preferable to use a quick-setting agent in which an aluminate alkali salt and / or carbonate is used in combination. It is also possible to use calcium aluminate in combination with a setting accelerator such as an alkali hydroxide or a sulfate. Alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, slaked lime, and sodium sulfate, potassium sulfate,
It is also possible to use a setting accelerator such as aluminum sulfate and a sulfate such as alum.

The alkali aluminate salt (hereinafter referred to as aluminate) used in the present invention means one that promotes initial setting, and specifically, lithium aluminate, sodium aluminate, potassium aluminate, etc. And one or more of these can be used. The amount of the aluminate used is preferably 0.1 to 50 parts by weight, more preferably 2 to 25 parts by weight, based on 100 parts by weight of calcium aluminate. If it is less than 0.1 part by weight, no effect is obtained, and if it exceeds 50 parts by weight, long-term strength development may be hindered.

The carbonate used in the present invention is one that improves the initial strength development, and when used in combination with an aluminate, the quick-setting strength can be improved. Specifically, sodium carbonate, potassium carbonate, And sodium bicarbonate and the like, and one or more of these can be used. The amount of carbonate used is preferably 0.1 to 200 parts by weight, more preferably 0.5 to 50 parts by weight, based on 100 parts by weight of calcium aluminate. If it is less than 0.1 part by weight, it is not effective, and if it exceeds 200 parts by weight, the long-term strength may decrease.

As the alkali hydroxide of the setting accelerator,
Examples thereof include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, and slaked lime.
The amount of the hydroxide used is preferably 0.1 to 50 parts by weight, more preferably 0.5 to 30 parts by weight, based on 100 parts by weight of calcium aluminate. If it is less than 0.1 part by weight, it is difficult to promote the initial setting, and if it exceeds 50 parts by weight, the long-term strength development may be impaired.

Further, the sulfate salt promotes initial setting, and specific examples thereof include sodium sulfate, potassium sulfate, aluminum sulfate, and alum, and one or more of these can be used. The amount of the sulfate used is preferably 0.1 to 50 parts by weight, more preferably 0.5 to 30 parts by weight, based on 100 parts by weight of calcium aluminate. If it is less than 0.1 part by weight, it is difficult to promote the initial setting, and if it exceeds 50 parts by weight, the long-term strength development may be impaired.

The amount of the quick-setting agent used is not particularly limited, but is preferably 0.5 to 20 parts by weight, more preferably 5 to 15 parts by weight, based on 100 parts by weight of cement. If it is less than 0.5 part by weight, initial setting may not be likely to occur, and if it exceeds 20 parts by weight, long-term strength development may be hindered.

The amines used in the present invention mean that the sprayed concrete enhances the adhesion to the ground while maintaining the original setting force, reduces the amount of rebound, and tends to develop strength by the addition of a quick-setting agent. It is added to cement mortar and / or quick setting agent for the purpose of improvement. By using amines in combination with a quick-setting agent and a setting accelerator, it is possible to improve the adhesive force of concrete while maintaining the original setting force. Further, if the amount of the quick-setting agent added is increased, an effect of reducing the tendency that the long-term strength development is poor in elongation can be imparted. Examples of the amines used in the present invention include trimethylamine, diethylamine, triethylamine, propylamine, allylamine, cyclohexylamine, cyclobutylamine, monoethanolamine, diethanolamine, triethanolamine, hexamethylenediamine, pyridine, and aniline. Among these, it is preferable to use monoethanolamine, triethanolamine, or the like, which has a good affinity with water or with an alkaline substance such as cement. The amount of amines used is 10
0.5 to 20 parts by weight, preferably 1 to 10 parts by weight,
Parts by weight are more preferred. If it is less than 0.5 parts by weight, it may be difficult to improve the cohesive strength, adhesive force, and strength development when a quick-setting agent is added, and if it exceeds 20 parts by weight, strength development may be impaired.

The dust-reducing agent used in the present invention is one in which the unmixed quick-setting agent and cement components generated in spraying are discharged together with air, or the sprayed concrete bounces off. It has a reducing effect and is added to cement mortar and / or a quick-setting agent. Specifically, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl methyl cellulose,
Cellulose ethers such as hydroxypropyl methyl cellulose and hydroxyethyl ethyl cellulose, natural polymer compounds such as alginic acid, sodium alginate and casein, vinyl acetate, ethylene, vinyl chloride, methacrylic acid, acrylic acid, sodium acrylate, and unsaturated Examples thereof include vinyl polymers such as carboxylic acids or copolymers thereof, and emulsions such as vinyl acetate polymers or copolymers thereof saponified and modified into a polyvinyl alcohol skeleton. The amount of the dust reducing agent used is preferably 0.01 to 1 part by weight, more preferably 0.05 to 0.5 part by weight, based on 100 parts by weight of cement. If the amount is less than 0.01 part by weight, it is difficult to suppress the generated dust, and if it exceeds 1 part by weight, the strength development of shotcrete may be impaired. In the present invention, it is also possible to use ultrafine powder as the dust reducing agent.

In the present invention, the mixing method of each material is not particularly limited as long as cement and gypsum are mixed in advance before mixing with the quick-setting agent. A method in which a specific amount of gypsum is mixed with cement in advance or a method in which gypsum is added when kneading concrete can be used. Furthermore, since the content of sulfur trioxide (SO ₃ ) in cement specified by JIS is 3.0 to 4.5% by weight or less, the amount of gypsum exceeding the JIS specified value at the time of cement production at the cement manufacturing plant. A method of mixing the gypsum is also possible.

In the spraying method of the present invention, the required physical properties,
Spraying work can be performed as dry cement mortar or cement mortar in terms of economy and workability, and either a dry spraying method or a wet spraying method can be used. The spraying method of the present invention is not particularly limited, but in the case of the dry spraying method, cement and gypsum, fine aggregate, coarse aggregate, and quick-setting agent are mixed, pneumatically fed, and Y-shaped on the way. A method of adding water from one side of the pipe and spraying in a wet state can be mentioned. In the case of the wet spraying method, cement and gypsum, fine aggregate, coarse aggregate, and water are added and kneaded, pneumatically fed, and a quick-setting agent is added and sprayed from one of the Y-shaped pipes on the way. Is mentioned. In the spraying method of the present invention, conventional spraying equipment and the like can be used. Usually, the spraying pressure is 3 to 5 kg / cm ² , and the spraying speed is 4 to 20 m ³ / h.

If the spraying equipment is sufficiently sprayed,
It is not particularly limited. For example, for concrete pressure feeding, the product name “Aliver 280” manufactured by Aliver Co., Ltd., and for the quick-setting agent pressure-feeding, the quick-setting agent pressure feeding device (NATOM CLEAT) is used.
Etc. can be used.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments.

Example 1 A cement slurry was prepared by adding 100 parts by weight of cement and 200 parts by weight of water. Further, to 100 parts by weight of cement, 50 parts by weight of gypsum, 50 parts by weight of quick-setting agent composed of calcium aluminate, 5 parts by weight of amines A, and 100 parts by weight of gypsum, quick-setting agent and amines A in total On the other hand, 500 parts by weight of water was added to prepare a quick-setting adhesive slurry,
Volume ratio of cement slurry and quick-setting adhesive slurry is 1: 1
A ground injecting agent was prepared by mixing so that The compressive strength of the prepared ground injection material was measured. As a result, in one day
It was 5.7N / mm ² in 3.4N / mm ^2, 28 days. For comparison, the same result without amines A was 3.0 N / m per day.
It was 4.1N / mm ² in m ^2, 28 days.

<Materials used> Cement: ordinary Portland cement Gypsum: ground anhydrous gypsum on the market, Blaine specific surface area 5,400 cm ² / g amines A: commercial triethanolamine calcium aluminate: main component C ₁₂ A ₇

<Measurement method> Compressive strength: The ground injecting agent is poured into a 4 × 4 × 16 cm mold, and the compressive strength at a predetermined age is measured with a pressure resistance machine.

Example 2 A cement slurry was prepared by adding 100 parts by weight of cement and 200 parts by weight of water. 50 parts by weight of gypsum, 50 parts by weight of a quick-setting agent composed of calcium aluminate, 0.2 parts by weight of a dust reducing agent a, and 100 parts by weight of cement, and
The same procedure as in Example 1 was performed except that 500 parts by weight of water was added to 100 parts by weight of the total amount of gypsum, the quick-setting agent, and the dust reducing agent to prepare the quick-setting agent slurry. As a result, compressive strength was 4.3 N / mm ² at 3.6 N / mm ^2, 28 days 1 day. For comparison, the results were the same without using a dust-reducing agent a, compressive strength was 4.4 N / mm ² at 3.7 N / mm ^2, 28 days 1 day.

<Materials used> Dust reducing agent a: commercially available methyl cellulose

Example 3 A unit amount of each material was 400 kg / m ^{3 of} cement and 1,055 kg / fine aggregate.
m ^3, a coarse aggregate 713kg / m ^3, and water 200 kg / m ^3, the cement 10
25 parts by weight of gypsum was mixed with 0 parts by weight of gypsum to obtain sprayed concrete. Further, 100 parts by weight of cement was mixed with the amines shown in Table 1, and 100 parts by weight of cement was mixed with calcium aluminate. A quick-setting adhesive consisting of 20
By mixing parts by weight, quick-setting shotcrete was prepared. The prepared quick-setting sprayed concrete was sprayed onto the formwork under the condition of 4 m ³ / h using a spraying machine, product name "Aliver-280" manufactured by Alibaba, and the adhesion condition was confirmed, and the compression strength of each material was confirmed. It was measured. The results are also shown in Table 1.

<Materials used> Fine aggregate: Niigata prefecture Himekawa river sand, surface water 5%, specific gravity 2.61 Coarse aggregate: Niigata prefecture Himekawa river gravel, surface dry condition, maximum diameter
15 mm or less, specific gravity 2.65 Amines B: Commercial monoethanolamine

<Measurement method> Compressive strength: The prepared quick-setting shotcrete was sprayed on a pullout formwork and a formwork of 50 × 50 × 20 cm, and the test piece of the pullout formwork was used for 1 hour and 3 hours of age. So, after age 1 day
The compressive strength at a predetermined material age was measured using a φ5 × 10 cm specimen sampled from a 50 × 50 × 20 cm mold. For short-term strength of 1 hour and 3 hours of age, the pins are covered with sprayed concrete from the surface of the pull-out form, the pins are pulled out from the back side of the form, and the pull-out strength at that time is calculated.
/ Compressive strength is calculated from the formula: surface area of specimen = compressive strength. After 1 day of age, measure a φ5 × 10 cm test piece with a 20 ton pressure machine Adhesion status: When the sprayed thickness reaches about 3 cm, the sprayed concrete is vibrated for 30 seconds with a vibrator, When the sprayed concrete peeled off, it was rated as "bad", and when it did not peel off, it was rated as "good".

[0043]

[Table 1]

Example 4 100 parts by weight of cement was mixed with gypsum shown in Table 2 to obtain sprayed concrete. Further, 5 parts by weight of amines B were mixed with 100 parts by weight of cement to prepare cement.
The same procedure as in Example 3 was carried out except that 100 parts by weight of the calcium aluminate was mixed with a quick-setting agent shown in Table 2 to prepare a quick-setting shotcrete. The results are also shown in Table 2.

[0045]

[Table 2]

Example 5 10 parts by weight of gypsum was mixed with 100 parts by weight of cement to obtain sprayed concrete. Further, 5 parts by weight of amines A was mixed with 100 parts by weight of cement to obtain 100 parts by weight of calcium aluminate. Except that the quick-setting concrete was prepared by mixing 10 parts by weight of the quick-setting admixture containing aluminate and carbonate shown in Table 3 with 100 parts by weight of cement to 100 parts by weight of cement. The same procedure as in Example 3 was performed. The results are also shown in Table 3.

<Materials used> Aluminate: Commercial sodium aluminate Carbonate: Commercial sodium carbonate

[0048]

[Table 3]

Example 6 Dry spray concrete was mixed in the same manner as in Example 3 except that 10 parts by weight of gypsum was mixed with 100 parts by weight of cement, and the mixture was carried into a spraying machine by a belt conveyor. 100 parts by weight of calcium aluminate and 10 parts by weight of aluminate are mixed to form a quick-setting admixture, and on a belt conveyor, dry sprayed concrete is mixed so that it is 20 parts by weight with respect to 100 parts by weight of cement in dry concrete. Was added to. A quick-setting dry sprayed concrete containing a quick-setting agent was pneumatically sent from a spraying machine, and water mixed with amines A to 5 parts by weight with respect to 100 parts by weight of cement was mixed by a Y-tube. / C was adjusted to 47%, dry spraying was performed, and the compressive strength was measured for 1 hour and 28 days. Table 4 shows the results
Shown in For comparison, dry spraying was carried out similarly without adding amines. The results are also shown in Table 4.

[0050]

[Table 4]

Example 7 The unit amount of cement was 450 kg / m ³ , 25 parts by weight of gypsum, 5 parts by weight of aluminate and water reducing agent shown in Table 5, and amines A were mixed with 100 parts by weight of cement. Then, water was added so that the concrete slump would be 20 ± 2 cm, and sprayed concrete was prepared in the same manner as in Example 3, and this was pneumatically fed, and from one side of the Y-shaped tube, to 100 parts by weight of calcium aluminate, A quick-setting admixture containing an aluminate salt and a carbonate shown in 5 was added to 10 parts by weight of 100 parts by weight of cement in sprayed concrete, and wet spraying was carried out. The results are also shown in Table 5.

<Materials used> Water reducing agent I: main component sodium naphthalene sulfonate, specific gravity 1.20

[0053]

[Table 5]

Example 8 100 parts by weight of cement, 10 parts by weight of gypsum, 5 parts by weight of amines A, and a set retarder and a set accelerator shown in Table 6 were mixed to obtain sprayed concrete, and 100 parts by weight of calcium aluminate. Part was mixed with 10 parts by weight of aluminate so as to be 7 parts by weight with respect to 100 parts by weight of cement, and wet spraying was carried out in the same manner as in Example 3. The results are also shown in Table 6.

<Materials used> Set retarder a: Organic acids, citric acid, reagent Set retarder b: Alkali carbonate, sodium carbonate Set retarder c: Alkali carbonate, sodium bicarbonate Set accelerator: Calcium hydroxide, Slaked lime, commercial product

[0056]

[Table 6]

Example 9 A unit amount of cement was 450 kg / m ³ , water was mixed so that the slump of concrete would be 20 ± 2 cm, and cement 100
10 parts by weight of gypsum, 5 parts by weight of amines A, and a water reducing agent shown in Table 7 and ultrafine powder were mixed into 100 parts by weight of calcium aluminate and 10 parts by weight of aluminate. Cement 100
Spraying was carried out in the same manner as in Example 6 except that the mixing amount was 10 parts by weight with respect to parts by weight. The results are also shown in Table 7.

<Materials used> Water reducing agent II: Commercially available high performance water reducing agent, main component polycarboxylic acid sodium salt Ultrafine powder α: Commercial fine powder slag, Blaine value 6,500 cm ² / g, average particle size 4 μm Ultrafine powder β: Silica fume , Commercial product Ultrafine powder γ: Kaolin, commercial product

[0059]

[Table 7]

Example 10 To 100 parts by weight of cement, 10 parts by weight of gypsum and the dust reducing agent shown in Table 8 were mixed to obtain sprayed concrete in the same manner as in Example 3, and a quick-setting agent composed of calcium aluminate was used. A quick-setting shotcrete was prepared by mixing 10 parts by weight with 100 parts by weight of cement. The prepared quick-setting sprayed concrete is sprayed by an aliver brand name "Aliver".
280 "was sprayed in a simulated tunnel made of an iron plate in an arch shape under the condition of 4 m ³ / h, and the amount of dust was measured. The results are also shown in Table 8.

<Materials used> Dust reducing material b: Commercial vinyl acetate-ethylene copolymer Dust reducing agent c: Commercial sodium alginate Dust reducing agent d: Commercial kaolin

<Measurement method> Dust amount: Sprayed for 30 minutes at a spraying speed of 4 m ³ / h, and measured every 10 minutes at a fixed position of 3 m from the spraying location.

[0063]

[Table 8]

Example 11 The gypsum shown in Table 9 was added to 100 parts by weight of cement.
Dust reducing agent a was mixed in an amount of 0.1 part by weight to produce sprayed concrete in the same manner as in Example 3, and a quick-setting agent made of calcium aluminate was mixed with 100 parts by weight of cement in the amounts shown in the table to give a quick-set sprayed concrete. Was adjusted. This quick-setting sprayed concrete was sprayed onto the formwork as in Example 3, and the compressive strength of each material was measured. The results are also shown in Table 9.

[0065]

[Table 9]

Example 12 Example 12 was repeated except that the dust reducing agent b was used in place of the dust reducing agent a. Table 10 shows the results.

[0067]

[Table 10]

Example 13 To 100 parts by weight of cement, 10 parts by weight of gypsum and 0.1 part by weight of a dust reducing agent a were mixed to prepare sprayed concrete in the same manner as in Example 3, and to 100 parts by weight of calcium aluminate. Example 10 except that the quick-setting admixture containing aluminate, carbonate, hydroxide and sulfate shown in Table 11 was mixed in an amount of 10 parts by weight with respect to 100 parts by weight of cement. The dust amount was measured in the same manner as 10 and the compression strength was measured in the same manner as in Example 11. The results are shown in Table 11.

<Materials used> Coagulation accelerator: Commercial sodium aluminate Coagulation accelerator: Commercial sodium carbonate Coagulation accelerator: Sulfate, Commercial sodium sulfate

[0070]

[Table 11]

Example 14 To 100 parts by weight of cement, 10 parts by weight of gypsum and 0.1 part by weight of dust reducing agent a were mixed to prepare dry concrete. A quick-set dry concrete was prepared in the same manner as in Example 6 except that the mixing amount was 10 parts by weight. The prepared quick-set dry concrete was pneumatically fed from a spraying machine, and water was added by a Y-tube so that the W / C became 47%, and a dry spraying construction was carried out. As a result, it was possible to carry out the spraying work without trouble such as blockage of the pipe, and the amount of dust generated and the bounce of concrete were small. At that time, the amount of dust and the compressive strength for 1 hour and 28 days of age were measured. Table 12 shows the results. For comparison, the results when the dust reducing agent is not used under the same conditions are also shown.

[0072]

[Table 12]

Example 15 The unit amount of cement was 450 kg / m ³ , 0.1 part by weight of the dust reducing agent a and the water reducing agent shown in Table 13 were added to 100 parts by weight of cement, and the concrete slump was 20 ±. Water was added to 2 cm to make spray concrete in the same manner as in Example 11, and this was pneumatically fed, and from one side of the Y-shaped tube, the aluminate shown in Table 13 was added to 100 parts by weight of calcium aluminate. A quick-setting admixture containing carbonate was added to 10 parts by weight of 100 parts by weight of cement in sprayed concrete, and wet spraying was performed. Table 13 shows the results.
It is described together.

[0074]

[Table 13]

Example 16 100 parts by weight of cement was mixed with 10 parts by weight of gypsum, 0.1 part by weight of dust reducing agent a, and a set retarder shown in Table 14 to give a shotcrete, and calcium aluminate was added.
Wet spraying was carried out in the same manner as in Example 15 except that 100 parts by weight of cement and 100 parts by weight of cement were mixed with 7 parts by weight of a quick-setting admixture, which was a mixture of 100 parts by weight and sodium aluminate. The results are shown in Table 14.

<Materials used> Set retarder D: Commercially available mixture of citric acid / potassium carbonate in a weight mixing ratio of 1/3.

[0077]

[Table 14]

[0078]

EFFECTS OF THE INVENTION By using the spraying material of the present invention, the strength development in the initial and long term can be greatly improved, and by using the amines together, the rebound amount can be reduced and the adhesive strength can be improved. It has the effect of being sprayed concrete. Therefore, it is possible to make the thickness thinner than the conventional spraying thickness, and it is possible to reduce the construction cost and the construction speed. Moreover, since the amount of rebound can be further reduced, the working environment can be improved. Further, by using the dust reducing agent together, the dust amount can be greatly reduced, and the working environment can be improved.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location E21D 11/10 E21D 11/10 // C04B 103: 12 (72) Inventor Kazuyuki Mizushima Oumi-cho, Nishikubiki-gun, Niigata Prefecture Aomi 2209 Address Electrochemical Industry Co., Ltd.Aomi Plant (72) Inventor Isamu Terajima Omi-cho, Nishikaigi-gun, Niigata Prefecture Aomi 2209 Electrochemical Industry Co., Ltd. Aomi 2209 Address Denki Kagaku Kogyo Co., Ltd. Aomi Factory

Claims (12)

[Claims] 1. A cement admixture containing gypsum, a quick-setting agent containing calcium aluminate as a main component, and amines. 2. A cement admixture containing gypsum, a quick-setting agent containing calcium aluminate as a main component, and a dust reducing agent. 3. A spray material containing cement mortar containing cement and gypsum as main components, a quick-setting agent containing calcium aluminate as main components, and amines. 4. A spray material containing a cement mortar containing cement and gypsum as main components, a quick-setting agent containing calcium aluminate as a main component, and a dust reducing agent. 5. A spray material containing a cement mortar containing cement and gypsum as main components, a quick-setting agent containing calcium aluminate as a main component, amines, and a dust reducing agent. 6. The spray material according to claim 3, wherein the quick-setting agent contains calcium aluminate and an alkali aluminate and / or an alkali carbonate as main components. 7. Calcium aluminate is 12CaO.7Al ₂ O
The spray material according to any one of claims 3 to 6, which is an amorphous substance obtained by quenching a heat-treated product corresponding to _three compositions. 8. The method according to claim 3, further comprising one or more admixtures selected from the group consisting of a water reducing agent, a setting retarder, a setting accelerator, and an ultrafine powder. Spraying material according to paragraph. 9. The spray material according to claim 3, wherein 100 parts by weight of cement and 1 to 25 parts by weight of gypsum are mixed. 10. A spraying method using the spraying material according to any one of claims 3 to 9. 11. The spraying method according to claim 10, wherein dry cement mortar obtained by mixing cement and gypsum and a quick-setting agent containing calcium aluminate as a main component are combined and mixed in a flowing state. 12. The spraying method according to claim 11, wherein cement mortar obtained by mixing cement, gypsum, and water and a quick-setting agent containing calcium aluminate as a main component are combined and mixed in a flowing state. .