JPH10212149A - Spraying material and spraying technique using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spraying material and a spraying method by which the initial and long-term strength can be developed in a good state and little dust is produced. SOLUTION: This spraying material contains a cement mortar essentially comprising cement and gypsum, and a liquid accelerator. Further, the spraying material may contain one or more kinds of mixing material selected from among a setting retarder, water reducing agent, thickener, ultrafine powder and fibrous material. In the spraying method, a cement mortar essentially comprising cement and gypsum, and a liquid accelerator are separately fed under pressure, mixed and sprayed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spraying material to be sprayed on an exposed ground surface in a tunnel such as a road, a railway, and a headrace, and a spraying method using the same.

[0002]

2. Description of the Related Art Conventionally, in order to prevent collapse of an exposed ground such as excavation of a tunnel, a method of using a quick-setting sprayed concrete in which a quick-setting agent is mixed with concrete has been used (Japanese Patent Publication No. 52-4149). No.). This method is usually
Cement, aggregate,
And water are mixed to prepare a shotcrete, transported by an agitator truck, pumped by a concrete pump, mixed with a quick-setting agent pumped from the other by a confluence pipe provided on the way, and ground as quick-setting spray concrete. This is a method of spraying a predetermined thickness on the mountain surface. Calcium aluminate, alkali aluminate,
And alkali carbonates are known (Japanese Patent Application Laid-Open No. Sho 64-5).
No. 1351, JP-B-56-27457, JP-A-61-26538, JP-A-63-21050
No.).

[0003]

However, since the quick-setting agent used in the quick-setting shotcrete is a powder, it is well mixed when the cement mortar and the quick-setting agent are mixed by air pressure. However, there is a problem that the dust may be scattered in the air in the form of a powder, and the amount of dust generated may be increased, thereby making the working environment unfavorable. As a result of intensive studies, the present inventor has obtained knowledge that can solve the above-mentioned problem of reducing the amount of generated dust by performing spraying using a specific spraying material, thereby completing the present invention. Reached.

[0004]

That is, the present invention is directed to a spray material comprising a cement and a cement mortar containing gypsum as a main component, and a liquid quick-setting agent. This spraying material is characterized by containing one or more admixtures selected from a retarder, a water reducing agent, a thickener, an ultrafine powder, and a fibrous substance. Then, a cement mortar containing cement and gypsum as main components and a liquid quick-setting admixture are separately pumped, then mixed and sprayed, and sprayed.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
In the present invention, cement paste, cement mortar, dry cement mortar, concrete, and dry concrete are collectively referred to as cement mortar.

As the cement used in the present invention, there are various kinds of portland cements which are usually commercially available, such as ordinary, fast strength, moderate heat, and ultra fast strength, and various kinds of mixture of these portland cements with fly ash or blast furnace slag. Examples thereof include mixed cement and fluorocement containing fluorocalcium aluminate, which may be used after pulverized. Of these, ordinary Portland cement is preferred because the fluidity after kneading the cement mortar does not decrease. When using early strength Portland cement, long-term strength development is excellent,
After kneading the cement mortar, the fluidity may be significantly reduced.

The gypsum used in the present invention is mixed with the cement mortar to enhance the strength of the cement mortar. Examples of the gypsum include anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum. May be used alone or in combination of two or more. Among them, anhydrous gypsum is preferred from the viewpoint of strength development. The particle size of the gypsum is generally good for use in cement and the like, and for example, a Blaine value of about 3000 cm ² / g is preferable.
It is preferable to pulverize so as to exceed 000 cm ² / g. The amount of gypsum used is preferably 1 to 25 parts by weight, more preferably 5 to 20 parts by weight, based on 100 parts by weight of cement. If it is less than 1 part by weight, it is difficult to promote long-term strength development, and if it exceeds 25 parts by weight, initial setting is delayed, and adhesion to ground may be reduced.

The liquid quick-setting agent used in the present invention includes an aqueous solution in which an alkali such as an alkali hydroxide is dissolved in water, a sulfate, and an alkali such as an alkali aluminate, an alkali carbonate and an alkali silicate. An aqueous solution in which a salt is dissolved in water, a colloidal aqueous solution of silica, and the like can be given. Calcium aluminate cannot be used as an aqueous solution because it reacts with water and immediately sets. The use of the liquid quick-setting admixture has the effect of eliminating the generation of dust and making the working environment favorable.

Examples of the alkali hydroxide include sodium hydroxide, potassium hydroxide, lithium hydroxide, and slaked lime. Among them, sodium hydroxide is preferred in view of economy and solubility in water. The amount of the alkali hydroxide to be used is preferably 0.3 to 10 parts by weight, more preferably 0.5 to 5 parts by weight in terms of solid content, based on 100 parts by weight of cement. Less than 0.3 parts by weight has no effect and 1
If the amount exceeds 0 parts by weight, the long-term strength development may be impaired.

Examples of the sulfate include those excluding gypsum such as sodium sulfate, potassium sulfate, lithium sulfate, magnesium sulfate, and aluminum sulfate. Among these, aluminum sulfate is preferred because of its high solubility in water and initial coagulation force. The amount of sulfate used is 0.3 to 10 in terms of solid content, based on 100 parts by weight of cement.
Part by weight is preferable, and 0.5 to 7 part by weight is more preferable.
If the amount is less than 0.3 part by weight, there is no effect, and if the amount exceeds 10 parts by weight, the long-term strength development may be impaired.

Examples of the alkali aluminate include sodium aluminate, potassium aluminate, lithium aluminate and the like. Alternatively, an alkali metal hydroxide and aluminum hydroxide which are mixed by heating in an aqueous solution or the like and dissolved may be used. Among these, potassium aluminate is preferred from the viewpoint of solubility. The amount of the alkali aluminate to be used is preferably 0.3 to 10 parts by weight, more preferably 0.5 to 5 parts by weight in terms of solid content, based on 100 parts by weight of cement. Less than 0.3 parts by weight has no effect,
If it exceeds 10 parts by weight, the long-term strength development may be impaired.

Examples of the alkali carbonate include sodium carbonate, potassium carbonate, lithium carbonate and the like.
Further, an alkali hydrogencarbonate may be used. Among them, sodium carbonate and potassium carbonate are preferable in terms of economy and solubility. The amount of the alkali carbonate used is 0.3 to 1 in terms of solid content with respect to 100 parts by weight of cement.
0 parts by weight is preferable, and 0.5 to 7 parts by weight is more preferable. If the amount is less than 0.3 part by weight, there is no effect, and if the amount exceeds 10 parts by weight, the long-term strength development may be impaired.

As the alkali silicate (hereinafter referred to as alkali silicate), sodium silicate, potassium silicate,
And lithium silicate. Alkali silicate undergoes a solidification reaction with calcium ions and magnesium ions in the cement component, whereby the curing is promoted at an early stage. Generally, items 1 and 2 specified by JIS
No. 3 and No. 3 water glass, which may be used as they are, or may be diluted with water in some cases. Further, an alkali silicate obtained by dissolving a powdered alkali silicate in water at an arbitrary ratio may be used, and the concentration thereof is not particularly limited, but may be used as long as it is in the range of 10 to 60% by weight. it can. From the viewpoint of availability and price, generally commercially available water glass is preferable.

The amount of alkali silicate used is
The amount is preferably 5 to 30 parts by weight, more preferably 10 to 20 parts by weight, based on 0 part by weight in terms of solid content. If the amount is less than 5 parts by weight, it is difficult to impart sufficient coagulation force at the beginning,
If it exceeds 30 parts by weight, the long-term strength development may be impaired.

Among these alkalis and alkali salts,
From the viewpoint of initial coagulation properties, alkali aluminates and alkali carbonates are preferred. Further, an alkali aluminate and an alkali carbonate may be used in combination. These alkalis and alkali salts are used as an aqueous solution dissolved in water. In some cases, the slurry may be used, or the aqueous solution and the slurry may be used in combination.

The colloidal aqueous solution of silica used in the present invention is an aqueous solution in which particles or hydrates of silicon oxide are dispersed in a colloidal state, and is formed by a coagulation reaction with calcium ions or magnesium ions in a cement component. Early cure is accelerated. Further, aluminum oxide may be used instead of silicon oxide. The particle size of silicon oxide is
It is preferably 40 nm or less from the viewpoint of the dispersibility of the colloid particles.
Colloidal solution of silica (hereinafter referred to as colloidal silica)
Preferably, the colloid particle size is 10 to 20 nm, the silicon oxide content is 30 to 31% by weight, and the sodium oxide content is 0.6% by weight or less. Generally, commercially available ones may be used as they are. Since it is mixed with water at any ratio, it may be used diluted. The amount of colloidal silica to be used is preferably 5 to 30 parts by weight, more preferably 10 to 20 parts by weight, based on 100 parts by weight of cement in terms of solid content of silicon oxide or aluminum oxide contained. 5
If the amount is less than 10 parts by weight, it is difficult to impart a sufficient coagulation force at the beginning, and if the amount exceeds 30 parts by weight, the development of long-term strength may be inhibited. Among these liquid quick-setting agents, alkali aluminates are preferred from the viewpoint of initial setting and initial strength development.

The solution concentration of these aqueous solutions is not particularly limited, since the solubility in water varies depending on each substance, but an aqueous solution having the highest possible concentration is preferred.
The lower the concentration, the greater the proportion of water in the aqueous solution,
In order to obtain the effect, it is necessary to use a large amount of the aqueous solution, and accordingly, the amount of water used also increases, and there is a possibility that the strength expression may be impaired. Therefore, the solid content concentration is 30 to 60
% By weight, more preferably from 40 to 55% by weight.
If the amount is less than 30% by weight, there is no effect. If the amount exceeds 60% by weight, the solubility is reduced and a slurry is formed. May have to be done.

In the present invention, in order to improve the properties before setting and hardening of the cement mortar and the strength properties after setting and hardening, the cement mortar is selected from the group consisting of a setting retarder, a water reducing agent, a thickener, an ultrafine powder, and a fibrous substance. It is preferable to use one or more selected admixtures.

The setting retarders are those which retard the setting of cement. Examples of the setting retarder include organic acids and phosphates.

Examples of the organic acid include citric acid, tartaric acid, gluconic acid, malic acid, and sodium and potassium salts thereof, and one or more of these may be used in combination. Among them, citric acid is preferred because it hardly inhibits the strength expression. The amount of organic acid used is
With respect to 00 parts by weight, 0.01 to 3 parts by weight is preferable,
0.05 to 1 part by weight is more preferable. If the amount is less than 0.01 part by weight, the effect is not obtained. If the amount is more than 3 parts by weight, the curing is excessively delayed, which may result in poor curing.

As the phosphate, monosodium phosphate,
Examples thereof include disodium phosphate, trisodium phosphate, sodium tripolyphosphate, sodium hexametaphosphate, sodium pyrophosphate, and sodium tetrapolyphosphate, and one or more of these may be used in combination. Further, a potassium salt may be used instead of the sodium salt. Among these, sodium tripolyphosphate is preferred because it hardly inhibits the strength expression. The amount of the phosphate used is preferably 0.01 to 3 parts by weight, more preferably 0.05 to 1 part by weight, based on 100 parts by weight of the cement.
If the amount is less than 0.01 part by weight, the effect is not obtained. If the amount is more than 3 parts by weight, the curing is excessively delayed, which may result in poor curing.

In order to improve the initial strength after setting delay,
Organic acids and alkali carbonates may be used in combination. In this case, the mixing ratio of the organic acid and the alkali carbonate is preferably 10 to 300 parts by weight, more preferably 20 to 200 parts by weight, based on 100 parts by weight of the alkali carbonate. If the amount is less than 10 parts by weight, there is no effect. If the amount exceeds 300 parts by weight, curing may be excessively delayed, resulting in poor curing. The amount of the mixture of the organic acid and the alkali carbonate is preferably 0.01 to 3 parts by weight with respect to 100 parts by weight of cement, and is preferably 0.05 to 3 parts by weight.
-1 part by weight is more preferred. If the amount is less than 0.01 part by weight, the effect is not obtained. If the amount is more than 3 parts by weight, the curing is excessively delayed, which may result in poor curing.

Among the setting retarders, those which use an organic acid and an alkali carbonate in combination are preferred from the viewpoint of good initial strength after retardation.

The water reducing agent is used to improve the fluidity of the cement mortar, and may be any of a liquid or a powder. Examples of the water reducing agent include polyol derivatives, lignin sulfonic acid salts and derivatives thereof, and high-performance water reducing agents, and one or more of these may be used in combination. Among these, a high-performance water reducing agent is preferable in terms of exhibiting high strength. By using the high-performance water reducing agent, the spray thickness can be reduced, the spray amount can be efficiently increased, the quick-setting force can be improved, and the amount of the quick-setting agent, the amount of dust generated, and the rebound rate can be extremely reduced. Examples of the high-performance water reducing agent include a formalin condensate of an alkylallyl sulfonate, a formalin condensate of a naphthalene sulfonate, a formalin condensate of a melamine sulfonate, and a polycarboxylic acid polymer compound. Any of powdery materials can be used, and one or more of these may be used in combination. Among these, a formalin condensate of a naphthalene sulfonate and a polycarboxylic acid-based polymer compound are preferable in that the fluidity can be greatly improved. The amount of the high-performance water reducing agent is 0.05 to 100 parts by weight of cement as a solid content.
3 parts by weight is preferable, and 0.1 to 2 parts by weight is more preferable. If it is less than 0.05 part by weight, there is no effect, and if it exceeds 3 parts by weight, the fluidity of the cement mortar increases, but the cement mortar becomes viscous, and the cement mortar adheres to the pumping pipe and the rotating blades of the mixer, resulting in workability. And strength may be reduced.

The thickener imparts viscosity to the cement mortar, suppresses material separation of the cement mortar, prevents dripping immediately after spraying, reduces rebound, and suppresses dust generation. As the thickener, methyl cellulose,
Ethyl cellulose, methyl ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose,
Cellulose such as hydroxyethylmethylcellulose, hydroxypropylmethylcellulose, and hydroxyethylethylcellulose; polysaccharides such as alginic acid, sodium alginate, β-1,3 glucan, pullulan, guar gum, and welan gum; vinyl acetate, ethylene, vinyl chloride, and methacrylic acid , Acrylic acid, sodium acrylate, and vinyl polymers such as unsaturated carboxylic acids and copolymers thereof, and emulsions such as those obtained by saponifying a vinyl acetate polymer or the copolymer and modifying it to a polyvinyl alcohol skeleton. And the like, and one or more of these may be used in combination. Among them, celluloses are preferable because they hardly inhibit the initial setting. The amount of the thickener used is 0.001 parts by weight with respect to 100 parts by weight of cement.
-0.5 weight part is preferable, and 0.005-0.3 weight part is more preferable. If the amount is less than 0.001 part by weight, the viscosity of the cement mortar is small and dripping occurs when sprayed,
If the rebound rate increases or exceeds 0.5 parts by weight, the viscosity of the cement mortar increases, which may hinder the pumpability of the cement mortar or impair the strength development.

The ultrafine powder has an average particle diameter of 10 μm or less, and has an effect of reducing the amount of cement, the amount of dust, and the rebound rate, and improving the pumpability of cement mortar.
Examples of the ultrafine powder include fine powder slag, fine powder fly ash, bentonite, metakaorion, silica fume, and the like. Among these, silica fume is preferable in terms of strength development. The amount of ultrafine powder used is 100 cement
1 to 50 parts by weight, preferably 2 to 30 parts by weight,
Parts by weight are more preferred. Less than 1 part by weight has no effect,
If it exceeds 50 parts by weight, setting and curing may be delayed.

The fibrous substance improves the impact resistance and elasticity of the cement mortar, and can be either inorganic or organic. As inorganic fibrous substances, glass fiber, carbon fiber, rock wool, asbestos, ceramic fiber,
And metal fibers. Examples of the organic fibrous substance include vinylon fiber, polyethylene fiber, polypropylene fiber, polyacryl fiber, cellulose fiber, polyvinyl alcohol fiber, polyamide fiber, pulp, hemp, wood wool,
And wood chips. Among these, metal fibers and vinylon fibers are preferable in terms of economy. The length of the fibrous material is preferably 50 mm or less, and more preferably 30 mm or less, from the viewpoints of pumpability and mixing properties. If it exceeds 50 mm, the cement mortar may be blocked during the pumping. The amount of fibrous material used is based on 100 parts by weight of cement.
It is preferably 0.5 to 10 parts by weight, more preferably 1 to 5 parts by weight. If the amount is less than 0.5 part by weight, there is no effect. If the amount is more than 10 parts by weight, there is a possibility that the pumpability is reduced or the effect is lost.

The amount of water used is preferably 35 to 60 parts by weight, more preferably 40 to 55 parts by weight, based on 100 parts by weight of cement. The amount of water used here includes water contained in both the cement mortar and the liquid quick-setting admixture. If the amount is less than 35 parts by weight, the fluidity of the obtained cement mortar becomes small, and there is a possibility that the pumping performance may be impaired. If the amount exceeds 60 parts by weight, the strength development may be reduced.

The aggregate used in the present invention preferably has a low water absorption and a high aggregate strength, but is not particularly limited. As fine aggregate, river sand, mountain sand, lime sand,
And silica sand. The coarse aggregate includes river gravel, mountain gravel, lime gravel, and the like. The maximum size of the coarse aggregate is not particularly limited, but in that the rebound rate is small,
It is preferably 15 mm or less. If it exceeds 15 mm, the rebound rate may increase.

The method of mixing gypsum into the cement mortar according to the present invention is not particularly limited, but a method in which a specific amount of gypsum is previously mixed with cement or a method of mixing gypsum when kneading cement mortar. And the like. Further, the content of sulfur trioxide (SO ₃ ) in cement specified by JIS is about 3.0 to 4.5% by weight or less. Excess amounts of gypsum may be mixed.

In the spraying method of the present invention, a conventional spraying equipment can be used. In the spraying method of the present invention, spraying can be performed as cement mortar from the required physical properties, economy and workability. As the spraying method, it is preferable to separately feed a cement mortar and a liquid quick-setting agent, and then spray a quick-setting spraying mortar in which the two are combined and mixed, and a dry spraying method or a wet spraying method can be used. Dry spraying methods include cement, gypsum,
And a method in which the aggregate is mixed and pneumatically fed, and in the middle, for example, a liquid quick-setting agent or water is added from one of the Y-shaped tubes and sprayed in a wet state. Examples of the wet spraying method include a method in which cement, gypsum, aggregate, and water are mixed, mixed and air-poured, and, for example, a method of adding a liquid quick-setting agent from one of the Y-shaped pipes and spraying on the way. Can be

The admixture can be mixed on either the cement mortar side or the liquid quick setting agent side, and may be used on only one side or on both sides, but it can improve strength, prevent rebound, and control setting. In view of the above, it is preferable to add to the cement mortar side. There is no problem if a quick-setting spray mortar obtained by mixing these materials is finally sprayed. In the spraying method of the present invention, conventionally used spraying equipment and the like can be used. Normally, the spray pressure is 2-5kg /
cm ² , the spray speed is 4 to 20 m ³ / h.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a detailed description will be given based on embodiments.

(Example 1) Cement 450k shown in Table 1
g / m ³ , fine aggregate 1014 kg / m ³ , coarse aggregate 686 k
g / m ³ , water 203 kg / m ^3, and gypsum mixed with 100 parts by weight of cement to 10 parts by weight to give sprayed concrete.
0 ". A liquid quick-setting admixture is supplied to this sprayed concrete from a Y-tube provided in the middle so that the amount of liquid quick-setting admixture becomes 100% by weight in terms of solid content based on 100 parts by weight of cement. To form a quick-setting sprayed concrete. The quick-setting spray concrete was sprayed and the compressive strength was measured. Table 1 shows the results.

(Materials used) Cement a: Commercially available ordinary Portland cement, specific gravity 3.16 Cement b: Commercially available early-strength Portland cement, specific gravity 3.14 Fine aggregate: Lime sand from Aomi Town, Niigata Prefecture, surface water content 6 2.5%, specific gravity 2.62 coarse aggregate: lime gravel from Aomi town, Niigata prefecture, surface dry state, specific gravity 2.
66 Gypsum I: Anhydrous gypsum ground product, Blaine value 3800
cm ² / g Liquid quick setting agent A: K ₂ O / Al ₂ O ₃ = 1.5 (molar ratio)
50% by weight potassium aluminate solution prepared in step Liquid quick-setting agent B: 40% by weight solution of aluminum sulfate Liquid quick-setting agent C: 45% by weight solution of sodium hydroxide Liquid quick-setting agent D: 45% by weight solution of potassium carbonate Liquid quick-setting Agent E: water glass No. 3, SiO ₂ 30% by weight, N
a ₂ O 10% by weight solution Liquid quick setting agent F: Liquid quick setting agent A: D = weight ratio of A and D =
4: 1 solution liquid quick setting agent G: liquid quick setting agent A: C =
1: 1 solution liquid quick setting agent H: liquid quick setting agent C: D = weight ratio of C and D =
4: 1 solution Liquid Accelerator I: Colloidal silica, average particle size 15 nm,
Solution of 30% by weight of SiO _{2 and} 0.2% by weight of Na ₂ O (Measurement method) Compressive strength: The adjusted quick-setting sprayed concrete was sprayed. For one hour of age, using a pull-out mold specimen of 25 cm width x 25 cm length, cover the pin with quick-setting spray concrete from the surface of the pull-out mold, pull out the pin from the back side of the mold, and pull out strength at that time Was calculated, and the compressive strength was calculated from the formula: (compressive strength) = (pull-out strength) × 4 / (sample contact area). 50cm width after 1 day
Diameter 5 collected from a mold 50 cm long x 20 cm thick
A specimen having a size of cm × 10 cm in length was measured with a 20-ton pressure machine to determine the compressive strength.

[0036]

[Table 1]

(Comparative Example 1) 100 parts by weight of cement b was mixed with 10 parts by weight of gypsum to give a shotcrete, and 5 parts by weight of a powder quick-setting admixture made of calcium aluminate was mixed with 100 parts by weight of cement. The amount of dust was measured in the same manner as in Example 1 except that the quick-setting spray concrete was used. 1-6. As a result, Experiment No. The dust amount of 1-6 was 0.9 mg / m ³ , whereas the dust amount of Comparative Example 1 was 20.5 mg / m ³ . (Materials used) Calcium aluminate: C ₁₂ A ₇ , amorphous, Blaine value 6200 cm ² / g (Measurement method) Dust amount: Rapid-setting sprayed concrete is sprayed at a spray speed of 4 m ³ / h for 30 minutes with an iron plate. It was sprayed on a simulated tunnel, 3.5 m high and 2.5 m wide, manufactured in the same manner. It was measured every 10 minutes at a fixed position 3 m from the spray location, and the average of the measured values was shown.

(Comparative Example 2) 100 parts by weight of cement a was mixed with 10 parts by weight of gypsum to give a sprayed concrete, and 100 parts by weight of cement was mixed with 5 parts by weight of a powder setting agent made of potassium aluminate. The amount of dust was measured in the same manner as in Example 1 except that the quick-setting spray concrete was used. 1-6. as a result,
Experiment No. The dust amount of 1-6 was 0.9 mg / m ³ , whereas the dust amount of Comparative Example 2 was 21.7 mg / m ³ .

Example 2 100 parts by weight of cement a was mixed with 10 parts by weight of gypsum to give a shotcrete, and a liquid quick-setting agent consisting of potassium aluminate having a concentration shown in Table 2 was added to 100 parts by weight of cement. 2 in terms of solids
Example 1 was repeated except that parts by weight were mixed to give a quick setting sprayable concrete. Table 2 shows the results.

[0040]

[Table 2]

(Example 3) Gypsum was mixed with 100 parts by weight of cement a in an amount shown in Table 3 to give a shotcrete, and 100 parts by weight of cement was mixed with 2 parts by weight of liquid quick-setting agent A in terms of solid content. The same procedure as in Example 1 was carried out except that the mixture was mixed to form a quick setting sprayable concrete. Table 3 shows the results
Shown in (Material used) Gypsum II: Gypsum dihydrate, Brain value 5400cm
² / g

[0042]

[Table 3]

Example 4 100 parts by weight of cement a and 10 parts by weight of gypsum and an amount of a setting retarder shown in Table 4 were mixed to give a shotcrete.
The same procedure as in Example 1 was carried out except that 2 parts by weight of the liquid quick-setting agent A was converted to a solid content in terms of solids to give a quick-setting sprayable concrete. Table 4 shows the results. (Material used) Setting retarder: Commercial citric acid Setting retarder: Commercial sodium tripolyphosphate Setting retarder: 1: in weight ratio of citric acid to potassium carbonate
Mixture of 1

[0044]

[Table 4]

Example 5 10 parts by weight of gypsum and 100 parts by weight of a water reducing agent shown in Table 5 were mixed with 100 parts by weight of cement a to give a shotcrete. A slump was measured in the same manner as in Example 1 except that A was mixed in an amount of 2 parts by weight in terms of solid content to obtain a rapidly setting sprayable concrete. Table 5 shows the results. (Materials used) Water reducing agent a: Commercially available naphthalene sulfonic acid salt type formalin condensate Water reducing agent a: Commercially available polycarboxylic acid type polymer compound (Measurement method) Slump: According to JIS A1101.

[0046]

[Table 5]

Example 6 10 parts by weight of gypsum and 100 parts by weight of a thickener were mixed with 100 parts by weight of cement a to give a shotcrete. The same procedure as in Example 1 was carried out except that Agent A was mixed in an amount of 2 parts by weight in terms of solid content to give a quick-setting sprayable concrete, and the amount of dust and sag were measured. Table 6 shows the results. (Materials used) Thickener i: Methylcellulose Thickener ii: Hydroxypropylcellulose (Evaluation method) Sag: Rapid-setting sprayed concrete at a spraying speed of 4 m ³ / h for 1 minute, height 3.5 m, width 2. A 5m mock tunnel was sprayed. If there was no dripping immediately after the spraying, it was evaluated as ◎.

[0048]

[Table 6]

Example 7 100 parts by weight of cement a were mixed with 10 parts by weight of gypsum and the amount shown in Table 7 to give a sprayed concrete, and a liquid quick-setting agent was mixed with 100 parts by weight of cement. A was performed in the same manner as in Example 1 except that A was mixed in an amount of 2 parts by weight in terms of solid content to obtain a quick setting shotcrete, and the rebound rate was measured. Table 7 shows the results. (Materials used) Ultrafine powder α: Commercial silica fume, average particle diameter 10 μm or less Ultrafine powder β: Commercial metakaolin, average particle diameter 10 μm or less (Measurement method) Rebound rate: Rapid-setting sprayed concrete at a spraying speed of 4 m ³ / h It was sprayed on a simulated tunnel 3.5 m high and 2.5 m wide for a minute. After spraying, measure the amount of quick-setting spray concrete that fell without adhering, and (rebound rate) = (weight of quick-setting spray concrete that did not adhere to the simulated tunnel during spraying) / Calculated from the formula of (weight of quick-setting spray concrete used for spraying) × 100 (%).

[0050]

[Table 7]

(Example 8) 10 parts by weight of gypsum and 100 parts by weight of a fibrous substance were mixed with 100 parts by weight of cement a to give a shotcrete.
The impact resistance was measured in the same manner as in Example 1, except that 2 parts by weight of the liquid quick-setting agent A was added to the parts by weight in terms of solid content to obtain a quick-setting sprayable concrete. Table 8 shows the results. (Materials used) Fibrous substance a: Vinylon fiber, fiber length 10 mm Fibrous substance b: Steel fiber, fiber length 30 mm (Evaluation method) Impact resistance: Shotcrete after 1 hour of material age is width 20
The mold was sprayed on a mold having a size of 20 cm, a length of 20 cm and a thickness of 2 cm, the bottom face was removed, and the piece was placed on flat sand, and a sphere weighing 50 g was dropped from a height of 50 cm. When the number of drops was less than 5 times, cracking and breaking occurred were evaluated as x, cracked but not broken, ○, and cracking was evaluated as ◎.

[0052]

[Table 8]

(Example 9) Table 9 shows 10 parts by weight of gypsum, 0.5 parts by weight of water reducing agent a, and thickener i, fibrous substance a, and ultrafine powder α with respect to 100 parts by weight of cement a. The indicated amount was mixed to give shotcrete, and cement 10
Except that 0 parts by weight of liquid quick-setting agent A was mixed in an amount of 2 parts by weight in terms of solid content to give a quick-setting sprayable concrete, the same procedure as in Example 1 was carried out, and the slump, rebound rate, and impact resistance were measured. It was measured. Table 9 shows the results.

[0054]

[Table 9]

(Example 10) Cement a 450 kg / m
^{3. The} amount of water contained in the spray concrete and the liquid quick-setting agent A was changed with respect to 100 parts by weight of the cement by changing the fine aggregate ratio of 60% and the amount of water in the shotcrete.
0 parts, 100 parts by weight of cement, 10 parts by weight of gypsum and 0.5 parts by weight of water reducing agent a were mixed to give a shotcrete, and 100 parts by weight of cement was mixed with a liquid quick-setting agent. Performed in the same manner as in Example 1 except that 2 parts by weight in terms of minute were mixed to give a quick-setting sprayable concrete.
Slump was measured. Table 10 shows the results.

[0056]

[Table 10]

[0057]

By using the spray material of the present invention, it is possible to obtain an excellent quick-setting spray cement mortar with less dust generation than when using a powder quick-setting agent. By using a cement mortar mainly composed of cement and gypsum, the initial and long-term strength development can be improved. Therefore, it is possible to perform a spraying operation with a good working environment and excellent strength development.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C04B 22/08 C04B 22/08 A 22/10 22/10 22/14 22/14 A 28/14 28/14 E21D 11/10 E21D 11/10 D (72) Inventor Kazuyuki Mizushima 2209 Aomi, Aomi-cho, Nishikubiki-gun, Niigata Inside the Aomi Plant of Denki Kagaku Kogyo Co., Ltd. Inside the Aomi Plant (72) Inventor Akira Watanabe 2209 Aomi, Aomi-cho, Nishikubiki-gun, Niigata Prefecture Inside the Aomi Plant of Denki Kagaku Kogyo Co., Ltd.

Claims (3)

[Claims] 1. A spraying material comprising a cement mortar mainly composed of cement and gypsum, and a liquid quick-setting admixture. 2. A setting retarder, a water reducing agent, a thickener,
The spray material according to claim 1, comprising one or more admixtures selected from ultrafine powder and fibrous substances. 3. A spraying method comprising separately pumping cement mortar mainly composed of cement and gypsum and a liquid quick-setting agent, and then mixing and spraying.