JPH1067548A - Spraying material and spraying of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a spraying material good in initial strength and long period strength and capable of reducing the temporal lowering of slump, and to provide a method for spraying the same. SOLUTION: This spraying material contains a cement mortar consisting mainly of a cement and gypsum, an accelerating agent consisting mainly of calcium aluminate, and a sulfite salt. The method for spraying the spraying material uses the spraying material. The sulfite salt is preferably a sulfite salt, a bisulfite salt, and a pyrosulfite salt. The accelerating agent may further be mixed with an alkali aluminate salt and an alkali metal carbonate. The spraying material may be mixed with additives such as a high performance water-reducing agent, a retarder, a coagulation accelerator and ultrafine powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spraying method for spraying on the ground surface exposed in tunnels such as roads, railways, and headraces.

[0002]

2. Description of the Related Art Conventionally, a method of spraying quick-setting concrete in which a quick-setting agent is mixed with concrete has been performed in order to prevent collapse of exposed ground such as tunnel excavation (Japanese Patent Publication No. Sho 5).
No. 2-4149). In this method, spray concrete is usually produced at a cement, aggregate, and water metering and mixing plant installed at the excavation site, transported by an agitator truck, pumped by a concrete pump, and installed at the junction pipe. This is a method of mixing with a quick-setting agent pumped from the other side and spraying it as a quick-setting sprayable concrete on the ground surface to a predetermined thickness. According to this method, the rebound (bounce) rate, which is the ratio of the amount of falling without adhering to the ground and the amount of spraying, is as large as 15 to 30% by weight. I was worried about the effects of For this purpose, there has been a demand for a method of reducing the rebound rate and dust, but at present, there is no sufficiently satisfactory spraying material or spraying method, and improvement thereof has been strongly desired.

[0003] In addition, although the concrete containing a quick-setting agent, which has been conventionally used, has a good rise in the initial strength as compared with the concrete containing no quick-setting agent,
The long-term strength was about 30 to 50% smaller than that of the concrete containing no quick-setting agent, and the strength-generating properties tended to be poor. Still, its initial strength is
In the construction method, the strength is sufficient in most cases to prevent the collapse of the ground, and in the considerably unstable ground, it has been dealt with by increasing the sprayed thickness. However, increasing the spray thickness is not preferable in terms of economy and work efficiency. In particular, in the excavation of large section tunnels, it is particularly important to improve the strength of shotcrete to reduce the sprayed thickness, shorten the construction time and the excavation cycle in consideration of economy and work efficiency. It was a point.

Hitherto, as a method for achieving high strength of shotcrete, there has been proposed a method in which a quick-setting agent in which gypsum and calcium aluminate are previously mixed is mixed with shotcrete and sprayed ( JP 50
No. 16717, JP-A-50-16718,
And JP-A-50-25623).

[0005]

However, in this method, a quick setting agent obtained by mixing gypsum and calcium aluminate is required to have a higher setting force and a higher initial strength by 10 parts by weight or more per 100 parts by weight of cement. , It was necessary to add as much as 20 parts by weight or more. For this reason, if it is necessary to interrupt the work during spraying and add a quick-setting agent, if the amount of dust generated increases, or if the quick-setting agent runs out during the spraying operation, concrete However, there is a problem in that it becomes dangerous due to dropping, causing problems in terms of workability, health and safety, and economy. The present inventor has conducted various studies on the problem of imparting high strength to shotcrete. As a result, by performing spraying using a specific spraying material, the long-term strength is improved, and the finding that the problem can be solved is found. To complete the present invention.

[0006]

That is, the present invention relates to a cement admixture containing gypsum, a quick setting agent mainly composed of calcium aluminate and sulfites, and further comprises a water reducing agent, a setting retarder. A cement admixture comprising one or more admixtures selected from the group consisting of an agent, a setting accelerator, an ultrafine powder, and a fibrous substance, wherein cement and gypsum are the main components. Mortar, a quick-setting agent containing calcium aluminate as a main component, and a spraying material containing sulfites, wherein the quick-setting agent contains calcium aluminate and alkali aluminate and / or alkali carbonate as main components. The spraying material characterized in that the sulfites contain one or more selected from the group consisting of sulfates, bisulfites, and pyrosulfites. The spraying material further comprising one or more admixtures selected from the group consisting of a water reducing agent, a setting retarder, a setting accelerator, an ultrafine powder, and a fibrous substance. And a spraying method using the spraying material.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

As the cement used in the present invention, there are various kinds of portland cements which are usually commercially available, such as ordinary, fast, moderate heat, and super fast, and various kinds of portland cement mixed with fly ash, blast furnace slag, etc. Mixed cement, commercially available fine particle cement and the like can be mentioned, and various Portland cements and various mixed cements can be used after pulverized.

The gypsum used in the present invention is mixed with cement to increase the strength of shotcrete, and examples thereof include anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum. Two or more can be used. Among these, anhydrous gypsum is preferred from the viewpoint of strength development. The particle size of the gypsum is generally good for use in cement or the like.
cm ² / g is preferable, and it is more preferable to pulverize it to a degree exceeding 3000 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 the amount is less than 1 part by weight, there is no long-term strength development, and if it exceeds 25 parts by weight, the initial setting is delayed, the adhesion to the ground may be reduced, or the concrete may be expanded and destroyed for a long period of time.

In the present invention, cement mortar in which cement and gypsum are mixed is used to obtain a quick setting force. The cement mortar used in the present invention refers to a general term for cement paste, mortar, and concrete, and any of dry cement mortar in a dry state that does not mix with water, and water and cement mortar mixed with water. Can be used.

The calcium aluminate used in the present invention refers to a quick-setting component that causes concrete to set at an early stage, and its mineral components include CaO, C and Al ₂ O.
_{If 3} is A, C ₃ A, C ₁₂ A ₇ , CA, and CA ₂
And the like. Further, as other mineral components, calcium aluminosilicate containing SiO ₂ , C
₁₂ C ₁₁ A ₇ · CaX ₂ to one CaO was replaced by halide such as CaF ₂ of A ₇ (X is a halogen such as _{fluorine), C 4 A 3 · SO} 3 containing SO ₃ component, alumina cement, and , Sodium, potassium, and calcium aluminate in which alkali metals such as lithium are partially dissolved. Among them, in terms of reaction activity,
Amorphous calcium aluminate obtained by quenching a heat-treated product corresponding to the C ₁₂ A ₇ composition is preferred. The particle size of the calcium aluminate, in terms of quick-setting property and the initial strength development, preferably 3000 cm ² / g or more in Blaine value, 4000 cm ² / g or more is more preferable. If it is less than 3000 cm ² / g, the quick setting property and the initial strength development property may be reduced. The amount of calcium aluminate used is based on 100 parts by weight of cement.
The amount is preferably 1 to 20 parts by weight, more preferably 5 to 15 parts by weight. If it is less than 1 part by weight, initial setting does not occur, and if it exceeds 20 parts by weight, the long-term strength development may be impaired.

The sulfites used in the present invention have the effect of suppressing a decrease in the slump of sprayed concrete over time and increasing the strength of the concrete. Examples of the sulfites include sodium sulfite, potassium sulfite, and sulfites such as calcium sulfite, bisulfites such as sodium bisulfite and potassium bisulfite, and pyrosulfites such as sodium pyrosulfite and potassium pyrosulfite. One or more of these can be used. Among these, sodium sulfite and potassium sulfite are preferable in terms of strength development. The amount of the sulfite used is preferably 0.05 to 2 parts by weight, more preferably 0.07 to 1 part by weight, based on 100 parts by weight of cement. If the amount is less than 0.05 part by weight, it is impossible to suppress the slump reduction with time or to expect an increase in strength. If the amount exceeds 2 parts by weight, the retardation is large and the strength expression may be impaired. .

The method for mixing sulfites of the present invention can be mixed on either the cement mortar side or the quick setting agent side, and can be used on only one side or on both sides. It is preferable to add to the cement mortar side from the viewpoint that the slump drop with time can be suppressed.

In the present invention, it is preferable that an alkali aluminate or an alkali carbonate is used in combination with a quick setting agent containing calcium aluminate as a main component, in that the initial setting and the initial strength are improved.

The alkali aluminate used in the present invention promotes initial coagulation, and includes lithium aluminate,
Examples thereof include sodium aluminate and potassium aluminate, and one or more of these can be used.
The amount of the alkali aluminate to be 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 the amount is less than 0.1 part by weight, there is no effect, and if it exceeds 50 parts by weight, the long-term strength development may be impaired.

The alkali carbonate used in the present invention improves the initial strength, and includes sodium carbonate, potassium carbonate, sodium bicarbonate, etc., and one or more of these can be used. It is. The amount of the alkali carbonate to be used is preferably 0.1 to 200 parts by weight, preferably 0.5 to 5 parts by weight, per 100 parts by weight of calcium aluminate.
0 parts by weight is more preferred. If it is less than 0.1 part by weight, there is no effect, and if it exceeds 200 parts by weight, the long-term strength may be reduced.

The amount of the quick setting agent used in the present invention is preferably 1 to 20 parts by weight, more preferably 5 to 15 parts by weight, based on 100 parts by weight of cement. If the amount is less than 1 part by weight, initial coagulation hardly occurs, and if it exceeds 20 parts by weight, the long-term strength development may be impaired.

In the present invention, one or more kinds selected from the group consisting of a water reducing agent, a setting retarder, a setting accelerator, an ultrafine powder, and a fibrous substance are further provided in terms of improving the properties of the sprayed material. It is preferable to use an admixture together.

The water reducing agent is used to improve the fluidity of the cement mortar, and any of a liquid or a powder can be used. Examples of the water reducing agent include polyol derivatives, lignin sulfonates and derivatives thereof, and high-performance water reducing agents. A high-performance water reducing agent is preferred from the viewpoint of imparting high strength. With high performance water reducing agent,
The amount of water used can be reduced, and the sprayed thickness can be reduced in order to improve the strength development. Furthermore, since the amount of generated dust and the rebound rate can be reduced, the spraying operation can be performed efficiently. Examples of the high performance water reducing agent include a formalin condensate of an alkyl allyl sulfonate, a naphthalene sulfonate, and a melamine sulfonate, and a polycarboxylic acid polymer compound. Can be used, and either liquid or powder can be used. The use amount of the high-performance water reducing agent is preferably 0.05 to 5 parts by weight, more preferably 0.1 to 3 parts by weight, based on 100 parts by weight of cement as solids. 0.
If the amount is less than 05 parts by weight, there is no effect. If the amount exceeds 5 parts by weight, the viscosity of the cement mortar is too strong, the workability is reduced, and there is a possibility that the strength development may be impaired.

The setting retarder is one that delays the setting time of cement mortar, and examples thereof include organic acids and alkali carbonates.

As organic acids, gluconic acid, tartaric acid,
Examples thereof include citric acid, malic acid, lactic acid, and salts thereof, and one or more of these can be used. Among these, citric acid is preferred in that the strength expression is good.
The amount of organic acids used is based on 100 parts by weight of cement.
0.01 to 3 parts by weight is preferable, and 0.05 to 2 parts by weight is more preferable. Less than 0.01 parts by weight has no effect and 3
If the amount is more than 100 parts by weight, curing may be excessively delayed, resulting in poor curing.

Examples of the alkali carbonate include sodium carbonate, potassium carbonate, and sodium bicarbonate, and one or more of these can be used. The use amount of the alkali carbonate is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of cement. If the amount is less than 0.01 part by weight, the effect is not obtained. If the amount is more than 10 parts by weight, curing is excessively delayed, which may result in poor curing.

From the viewpoint of increasing the retardation of setting, it is preferable to use a setting retarder using an organic acid and an alkali carbonate in combination. In this case, the amount of the alkali carbonate used is preferably from 10 to 1,000 parts by weight, more preferably from 50 to 700 parts by weight, based on 100 parts by weight of the organic acid. If the amount is less than 10 parts by weight, there is no effect. If the amount is more than 1000 parts by weight, the curing is excessively delayed, which may result in poor curing. The amount of the setting retarder using the organic acid and the alkali carbonate in combination is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts 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 10 parts by weight, curing is excessively delayed, which may result in poor curing.

The setting accelerator refers to an agent which promotes initial setting, and includes an alkali metal hydroxide such as sodium hydroxide,
Slaked lime, alum, etc., and one or two of these
More than species are available. The amount of the setting accelerator used is preferably 0.05 to 20 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of cement. 0.05
If the amount is less than 20 parts by weight, the effect may not be improved.

The ultrafine powder refers to a powder having an average particle diameter of 10 μm or less, which can reduce the amount of cement and dust and improve the pumpability of concrete. Ultra fine powder includes fine slag, fly ash, bentonite, kaolin,
And silica fume and the like.
More than species are available. Among these, silica fume is preferable in terms of strength development. The amount of the ultrafine powder to be used is preferably 1 to 100 parts by weight, more preferably 2 to 30 parts by weight, based on 100 parts by weight of cement. If the amount is less than 1 part by weight, there is no effect, and if it exceeds 100 parts by weight, the setting and curing may be delayed.

As the fibrous substance, any of inorganic and organic substances can be used, which improves the impact resistance and elasticity of the shotcrete. Examples of the inorganic fiber include glass fiber, carbon fiber, rock wool, asbestos, ceramic fiber, and metal fiber, and examples of the organic fiber include vinylon fiber, polyethylene fiber, polypropylene fiber, polyacryl fiber, and cellulose fiber. Polyvinyl alcohol fiber, polyamide fiber, pulp, hemp, wood wool,
And wood chips, and one or more of these can be used. Among these, metal fibers and vinylon fibers are preferable in terms of economy. The length of the fibrous material is 1
00 mm or less is appropriate, and 0.5 to 60 mm is preferable in consideration of pumpability, mixing properties, and the like. If it is less than 0.5 mm, there is no effect, and if it exceeds 100 mm, the sprayed concrete may be blocked during pumping. The amount of the fibrous substance used is preferably 0.5 to 7 parts by weight, more preferably 1 to 5 parts by weight, based on 100 parts by weight of the cement. If the amount is less than 0.5 part by weight, there is no effect, and if it exceeds 7 parts by weight, the strength development may be impaired.

The amount of water used is preferably 35 to 60 parts by weight, more preferably 40 to 50 parts by weight, based on 100 parts by weight of cement. If the amount is less than 35 parts by weight, mixing cannot be sufficiently performed, and if it exceeds 60 parts by weight, strength cannot be obtained.

Aggregates such as coarse aggregate and fine aggregate used in the present invention preferably have low water absorption and high aggregate strength, but are not particularly limited. The coarse aggregate preferably has a maximum diameter of 20 mm or less, and more preferably has a maximum diameter of 5 to 15 mm in consideration of pumpability. Fine aggregates having a maximum diameter of 5 mm or less are preferable.
Mountain sand, lime sand, silica sand, and the like.

In the present invention, the method of mixing gypsum is not particularly limited as long as cement and gypsum are mixed before the quick setting agent is mixed. Examples of the mixing method include a method in which a specific amount of gypsum is previously mixed with cement, a method in which gypsum is added at the time of concrete kneading, and the like. Further, the content of sulfur trioxide (SO ₃ ) in cement specified by JIS is 3.0 to 3.0.
Since it is about 4.5% by weight, a method of mixing gypsum in an amount exceeding this JIS specified value at the time of cement production at a cement production plant can also be mentioned.

In the spraying method of the present invention, required physical properties,
From the economic point of view, workability, etc., it is possible to spray as dry cement mortar containing cement, cement mortar containing cement and water, or paste or concrete thereof, either dry spray method or wet spray method Can be used. In the dry spraying method, cement, gypsum, quick-setting agent, and, if necessary, an aggregate are mixed, air-fed, and, for example, water is added from one side of a Y-tube and sprayed in a wet state. And a method in which cement and, if necessary, an aggregate are mixed and pneumatically fed, and a spraying material is added in the order of gypsum, a quick setting agent, and water, and sprayed in a wet state. As a wet spraying method, cement, gypsum, water, and, if necessary, an aggregate are mixed and kneaded, air-fed and, for example, a quick-setting agent is added from one of the Y-shaped pipes and sprayed. Method and the like.

The water reducing agent, setting retarder, setting accelerator, ultrafine powder, and fibrous substance can be mixed with either the cement mortar side or the quick setting side, and may be used on only one side.
It may be used on both sides, but it will improve strength, prevent rebound,
It is preferable to add the cement mortar to the cement mortar from the viewpoint of setting and setting. There is no problem if the shotcrete mixed with these materials is finally sprayed. In the spraying method of the present invention, conventionally used spraying equipment and the like can be used. Usually, the spray pressure is 3-5 kg / cm ² and the spray speed is 4-20 m ³ / h. The spraying equipment is not particularly limited as long as the spraying is sufficiently performed. For example, Aliver Co., Ltd. product name “Aliver 280” or the like is used for concrete pumping, and a quick-setting agent pumping device “ Nattom Cleat "or the like can be used.

[0032]

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

(Example 1) Calcium aluminate 10
0 parts by weight, 100 parts by weight of gypsum, and sulfites A
2.5 parts by weight were mixed to obtain a cement admixture. 15 parts by weight of this cement admixture, 100 parts by weight of cement, and 200 parts by weight of water were mixed to obtain a ground injection material. Compressive strength of the resulting ground grout age of 1 hour and 28 days of was measured, respectively 0.2 N / mm ^2, was 5.6 N / mm ^2. For comparison, when the same procedure as in Example 1 was carried out except that no sulfites were used, the compressive strength at 1 hour and 28 days of age was 0.1 N / mm ² , respectively. 1N /
mm ² , and the strength was better when sulfites were used.

(Materials used) Calcium aluminate: Main component C ₁₂ A ₇ , Blaine value: 6000 cm ² / g, specific gravity: 2.90 Gypsum: Pulverized anhydrous gypsum commercially available, Blaine value: 5
400 cm ² / g Sulfite A: Potassium sulfite, commercial product Cement: Commercial ordinary Portland cement, specific gravity 3.
16

(Measurement method) Compressive strength: A test piece molded by pouring the prepared ground injection material into a mold having a width of 4 cm, a length of 4 cm and a thickness of 16 cm was molded.
100 kg pressure machine for 1 hour old, 20 for 28 days old
It measured using each ton pressure machine, and calculated compressive strength.

Example 2 A unit amount of each material was changed to cement 4
00 kg / m ³ , fine aggregate 1055 kg / m ³ , coarse aggregate 713 kg / m
^3, and the water 200 kg / m ^3, the cement 100 parts by weight,
Shotcrete was prepared by mixing 10 parts by weight of gypsum and the sulfites in the amounts shown in Table 1. About this shotcrete, the time-dependent change of the slump was measured. Further, the sprayed concrete is supplied to a concrete pumping machine "Aliver-28".
0 ", and from one of the Y-tubes provided in the middle,
The quick-setting additive made of calcium aluminate was pumped by a quick-setting additive adding machine “Denkanatomcrete” to 10 parts by weight with respect to 100 parts by weight of cement and mixed and mixed to obtain a quick-setting sprayable concrete. This quick-setting sprayed concrete was sprayed on a formwork at a spraying speed of 4 m ³ / h, and the compressive strength of each material age was measured. Table 1 shows the results.

(Materials used) Fine aggregate: sand from Himekawa, Niigata Prefecture, surface water 5%, maximum diameter 5 mm
Below, specific gravity 2.61 coarse aggregate: gravel from Himekawa, Niigata Prefecture, surface dry state, maximum diameter 15m
m, specific gravity 2.65 Sulfite B: sodium bisulfite, commercial product Sulfite C: sodium pyrosulfite, commercial product

(Measurement Method) Slump: Measured according to JIS A1101. Compressive strength: The prepared shotcrete was sprayed onto a 25 cm wide × 25 cm long pull-out formwork and a 50 cm wide × 50 cm long × 20 cm thick formwork. The material age of 3 hours or less was measured using a pull-out mold specimen. Cover the pin with spray concrete from the surface of the pull-out formwork, pull out the pin from the back side of the formwork, find the pullout strength at that time,
The compressive strength was calculated from the formula (compressive strength) = (pull-out strength) × 4 / (specimen surface area). 5 days old after 1 day
A test piece having a diameter of 5 cm and a length of 10 cm collected from a mold having a size of 0 cm x a length of 50 cm x a thickness of 20 cm was measured with a 20-ton pressure machine,
The compressive strength was determined.

[0039]

[Table 1]

Example 3 100 parts by weight of cement, Table 2
Example 2 except that gypsum in the amount shown in Table 1 and 0.5 parts by weight of sulfite A were mixed to give shotcrete.
The same was done. Table 2 shows the results.

[0041]

[Table 2]

Example 4 100 parts by weight of cement, 10 parts by weight of gypsum, and 0.5 part by weight of sulfite A were mixed to give a shotcrete, and a quick-setting agent consisting of calcium aluminate was added to 100 parts by weight of cement. The procedure was performed in the same manner as in Example 2 except that the quick-setting spray concrete was used using the amounts shown in Table 3. Table 3 shows the results.

[0043]

[Table 3]

Example 5 100 parts by weight of cement, 10 parts by weight of gypsum, and 0.5 parts by weight of sulfite A were mixed to give a shotcrete, and calcium aluminate 1
Except that 00 parts by weight and a quick setting agent obtained by mixing an alkali aluminate and an alkali carbonate in the amounts shown in Table 4 were used in 10 parts by weight with respect to 100 parts by weight of cement to give a quick setting sprayable concrete. Performed in the same manner as in Example 2. Table 4 shows the results.

(Materials used) Alkaline aluminate: commercially available sodium aluminate Alkaline carbonate: commercially available sodium carbonate

[0046]

[Table 4]

(Example 6) 100 parts by weight of cement, 10 parts by weight of gypsum, and 0.5 parts by weight of sulfite A were mixed to give a shotcrete, and calcium aluminate 1
Example 2 was the same as Example 2 except that the quick-setting admixture obtained by mixing 00 parts by weight and 10 parts by weight of the alkali aluminate was used as a quick-setting spray concrete using the amount shown in Table 5 with respect to 100 parts by weight of cement. Performed similarly. Table 5 shows the results.

[0048]

[Table 5]

(Example 7) By changing the unit amount of cement, the amount of water used was changed to 100 parts by weight of cement as shown in Table 6, 100 parts by weight of cement, 10 parts by weight of gypsum, and sulfurous acid. 0.5 parts by weight of salt A is mixed to make shotcrete, and calcium aluminate 1
Except that the quick setting agent using 00 parts by weight and 10 parts by weight of the alkali aluminate was used as a quick setting spray concrete using 10 parts by weight with respect to 100 parts by weight of cement,
Performed in the same manner as in Example 2. Regarding shotcrete, the slump immediately after kneading was measured. Table 6 shows the results.

[0050]

[Table 6]

(Embodiment 8) The unit amount of each material was
Same as above, 100 parts by weight of cement, 10 parts by weight of gypsum
Parts, and 0.5 parts by weight of sulfites A
Concrete and transport it to the spraying machine on a belt conveyor.
Was. On the other hand, 100 parts by weight of calcium aluminate
A quick-setting admixture containing 10 parts by weight of alkali metal citrate is
10 for 100 parts by weight of cement in concrete
Dry condensed on a belt conveyor so that the weight
Added to REIT. Dry concrete with quick-setting additive
Air from the spraying machine and cement the water with a Y-shaped pipe.
Add it to 47 parts per 100 parts by weight and dry
Spray construction was carried out. As a result, troubles such as
It was possible to carry out spraying work without any problems. Wood at that time
The compressive strength of 1 hour and 28 days is 7.0N / mm respectively^Two ,
62.2 N / mm ^TwoMet. For comparison, sulfite
Example 8 was carried out in the same manner as in Example 8 except that
As a result, the compressive strength of 1 hour and 28 days
6.1 N / mm^Two, 57.7 N / mm^TwoUsing sulfites
The strength was better when used.

(Example 9) 100 parts by weight of cement, 10 parts by weight of gypsum, 0.5 parts by weight of sulfite A, and a high-performance water reducing agent in an amount shown in Table 7 were mixed to give a shotcrete, and calcium aluminate 100 Wet spraying was carried out in the same manner as in Example 2 except that 10 parts by weight of a quick-setting admixture of 10 parts by weight of sodium aluminate and 10 parts by weight of cement was mixed to give a quick-setting sprayable concrete. Construction was performed. Table 7 shows the results.

(Materials used) Water reducing agent α: Commercially available high-performance water reducing agent, formalin condensate of main component sodium salt of naphthalenesulfonic acid Water reducing agent β: Commercially available high-performance water reducing agent, main component sodium polycarboxylate

[0054]

[Table 7]

Example 10 100 parts by weight of cement, 10 parts by weight of gypsum, 0.5 parts by weight of sulfite A, and the setting retarders and setting accelerators in the amounts shown in Table 8 were mixed to give shotcrete. Example 2 except that a quick-setting admixture obtained by mixing 100 parts by weight of silicate and 10 parts by weight of sodium aluminate was mixed with 100 parts by weight of cement and 10 parts by weight to obtain a quick-setting sprayable concrete.
Wet spraying was carried out in the same manner as above. Table 8 shows the results.

(Materials used) Set retarder: organic acids, citric acid, set retarder: alkali carbonate, sodium carbonate, set retarder: alkali carbonate, sodium bicarbonate set accelerator a: slaked lime set accelerator b: Alum

[0057]

[Table 8]

(Example 11) 100 parts by weight of cement, 10 parts by weight of gypsum, 0.5 parts by weight of sulfite A, and ultrafine powder in an amount shown in Table 9 were mixed to give a shotcrete.
A quick setting agent obtained by mixing 100 parts by weight of calcium aluminate and 10 parts by weight of sodium aluminate was added to cement 100
The wet spraying was carried out in the same manner as in Example 2, except that 10 parts by weight was mixed with the parts by weight to obtain a quick-setting sprayable concrete. Table 9 shows the results.

(Materials used) Ultrafine powder A: Fine powder slag, commercial product, average particle size 10 μm or less Ultrafine powder A: Silica fume, commercial product, average particle size 4 μm Ultrafine powder U: Kaolin, commercial product, average particle size 10 μm or less

(Measurement method) Rebound rate: Quick-setting sprayed concrete was sprayed onto a simulated tunnel having a height of 3.5 m and a width of 2.5 m for 30 minutes at a blowing speed of 4 m ³ / h. After spraying, measure the amount of shotcrete dropped without adhering, and (rebound rate) = (weight of shotcrete dropped without adhering to the simulated tunnel during spraying) / (used for spraying) Weight of sprayed concrete) × 100 (%).

[0061]

[Table 9]

Example 12 100 parts by weight of cement, 10 parts by weight of gypsum, 0.5 parts by weight of sulfite A, and fibrous substances in the amounts shown in Table 10 were mixed to give shotcrete, and 100 parts by weight of calcium aluminate Wet spraying was carried out in the same manner as in Example 2 except that 10 parts by weight of a quick-setting agent obtained by mixing 10 parts by weight of sodium aluminate with 10 parts by weight of cement were mixed to give a quick-setting sprayable concrete. Carried out. Table 10 shows the results.

(Materials used) Fibrous substance i: commercially available steel fiber, fiber length 30 mm Fibrous substance ii: commercially available vinylon fiber, fiber length 10 mm

(Measurement method) Impact resistance: Rapid setting after one hour of age A piece of sprayed concrete cut out to a width of 20 cm x a length of 20 cm x a thickness of 1 cm was placed on flattened standard sand. A sphere weighing 100 g was dropped from a height of 50 cm. When the cut pieces were broken within 5 times, the pieces were broken, the cracks without breaking were marked with ○, and those without cracking without breaking were marked with ◎.

[0065]

[Table 10]

[0066]

By using the spray material of the present invention, the initial and long-term strength developability is better than that of the conventional spray material. Therefore, the spray thickness is reduced, the spray time is shortened, and the spray amount is reduced, so that it is economical. Further, since the amount of the quick-setting agent used is small, it is not necessary to interrupt the spraying operation for replenishing the quick-setting agent. Furthermore, since the slump down with time can be reduced, the workability and the pumping property can be improved.

──────────────────────────────────────────────────続 き Continuing on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C04B 22:08 22:14) 103: 12 111: 20 (72) Inventor Isao Terashima Nishikokujo-gun, Niigata 2209 Aomi, Aomi Town Inside the Aomi Plant of Denki Kagaku Kogyo Co., Ltd. 2209 Aomi, Aomi Town Inside the Aomi Plant of Denki Kagaku Kogyo Co., Ltd.

Claims (7)

[Claims] 1. A cement admixture containing gypsum, a quick setting agent mainly composed of calcium aluminate, and sulfites. 2. The composition of claim 1, further comprising a water reducing agent, a setting retarder, a setting accelerator, an ultrafine powder, and a fibrous substance.
The cement admixture according to claim 1, wherein the cement admixture contains one or more admixtures. 3. A spray material comprising a cement mortar mainly composed of cement and gypsum, a quick setting agent mainly composed of calcium aluminate, and sulfites. 4. The spray material according to claim 3, wherein the quick-setting agent comprises calcium aluminate and an alkali aluminate and / or an alkali carbonate as main components. 5. The method according to claim 3, wherein the sulfites contain at least one member selected from the group consisting of sulfates, bisulfites, and pyrosulfites. Spray material as described. 6. A composition selected from the group consisting of a water reducing agent, a setting retarder, a setting accelerator, an ultrafine powder, and a fibrous substance.
The spray material according to any one of claims 3 to 5, comprising a seed or two or more admixtures. 7. A spraying method using the spraying material according to claim 3. Description: