WO2013088542A1

WO2013088542A1 - Spray material and spray method using same

Info

Publication number: WO2013088542A1
Application number: PCT/JP2011/078975
Authority: WO
Inventors: 寺島　勲; 荒木　昭俊; 三島　俊一
Original assignee: 電気化学工業株式会社
Priority date: 2011-12-14
Filing date: 2011-12-14
Publication date: 2013-06-20

Abstract

Provided are a spray material and spray method using same that are highly safe for people, have favorable material pumping properties, yield excellent physical properties, and result in little rebound. A spray material having a setting onset time of no more than 5 min and a setting end time of no more than 30 min at 20°C, and comprising a mortar that has a flow value of 170-250 mm and is obtained by mixing 18-22 mass parts water relative a dry mortar containing 100 mass parts cement, 2-8 mass parts calcium aluminosilicate, 1-12 mass parts plaster, 4-8 mass parts calcium hydroxide, 0.05-0.3 mass parts water-soluble polymer, 0.2-1 volume parts fiber relative to 100 volume parts of the dry mortar, and 50-70 mass parts aggregate having a maximum grain size 1.2 mm or smaller in 100 mass parts dry mortar, and also comprising an acidic, liquid quick setting agent comprising an alkali metal element and/or fluorine. Also provided is a spray method using the spray material.

Description

Spraying material and spraying method using the same

The present invention relates to a cement-based spraying material and a spraying method using the same.

A small-sized waterway tunnel with a diameter of 2 to 5 m is often excavated by a tunnel boring machine (TBM), and shotcrete is used to stabilize the bedrock after excavation. However, in the conventional spraying, a large construction machine is used and the concrete to be used must be carried from the outside of the mine, so that there is a problem that the working space and the concrete working time are restricted.

As a means for solving this problem, a spraying method (refer to Patent Document 1) that shortens the working time and improves the working environment by using a batch kneaded mortar and a quick hard material slurry containing calcium aluminate in combination. As a spray material with improved workability in a small section tunnel that can be excavated by TBM, a spray material containing cement, aggregate with a maximum particle size of 2.5 mm, slaked lime-containing material, and alkali metal aluminate (patent) Document 2) has been proposed.
However, when a quick-hard material slurry containing calcium aluminate was used, it was necessary to improve the setting properties immediately after spraying. In addition, spray materials containing cement, aggregates with a maximum particle size of 2.5 mm, slaked lime-containing substances, and alkali metal aluminates use alkali metal aluminates, which can cause chemical injury to workers. It was necessary to give sufficient consideration to countermeasures. For this reason, workers have to wear full protective equipment when spraying, and there is a problem that workability is inferior. Furthermore, it was necessary to improve long-term strength development and durability.

A spraying material (see Patent Document 3) was developed with measures against chemical injury to workers and improvement in durability of long-term strength, but this material uses calcium aluminate with high hydration activity, In order to secure the material pumpability after kneading with water, hydration of calcium aluminate is suppressed by using a large amount of organic acid. However, in a low temperature environment, the influence of delay due to the organic acid is large, and it is impossible to spray thickly without obtaining excellent condensation properties, and the sprayed surface may peel off after spraying.

Moreover, although development is performed to reduce the rebound of the spray material (see Non-Patent Document 1), further reduction in the construction cost is necessary from the viewpoint of reducing the construction cost and improving the construction speed.
Further, a spray material (see Patent Document 4) containing an acid liquid quick-setting agent having improved performance and alkali metal carbonate and / or alkali metal phosphate-containing cement concrete, and an acid liquid quick-setting agent A spray material (see Patent Document 5) containing calcium aluminosilicate and calcium hydroxide quick-setting aid has been developed, but there are problems with workability and rebound rate, and workability is high. There is a need for high technology related to spray materials that reduce the rebound rate.

As a means to solve these problems, dry cement mortar made by mixing aggregate and cement is combined with a liquid quick-setting agent in the course of pumping wet mortar by a continuous mixing mixer, mixed and blown. Although the spraying method to attach is proposed, there is no description about the composition of a calcium aluminosilicate and the composition of a liquid quick setting agent (refer patent document 6). In addition, dry mortar containing calcium aluminosilicate, calcium sulfate, early strong cement, and aggregate having a maximum particle size of 1.2 mm or less was kneaded with a continuous mixer and pumped by adding an acidic liquid setting agent to the mortar. Although the spraying method to attach is proposed, there is no description about the proper setting time of the mortar which added the quick setting agent, and the continuous supply system of material (refer patent document 7).

Japanese Patent Laid-Open No. 3-122040 Japanese Unexamined Patent Publication No. 9-227198 Japanese Unexamined Patent Publication No. 2000-1355 Japanese Unexamined Patent Publication No. 2005-35856 WO 01/60760 A1 WO 2005/019131 Japanese Unexamined Patent Publication No. 2008-254973

An object of the present invention is to provide a spray material having high safety to the human body, good material pumpability and less rebound, and a spray method using the same.

As a result of various studies to solve the above problems, the present inventor has obtained knowledge that can solve the above problems, and has completed the present invention.
The present invention has the following features.
1. 100 parts by weight of cement, 2-8 parts by weight of calcium aluminosilicate, 1-12 parts by weight of gypsum, 4-8 parts by weight of calcium hydroxide, 0.05-0.3 parts by weight of water-soluble polymer, 100 parts by weight of dry mortar On the other hand, 0.2 to 1 part by volume of fibers and 100 to 10 parts by mass of dry mortar containing 100 to 10 parts by mass of aggregate having a maximum particle size of 1.2 mm or less in 100 parts by mass of dry mortar, 18 to 22 water. Containing mortar with a flow value of 170 to 250 mm kneaded in parts by mass and an acidic liquid accelerating agent containing an alkali metal element and / or fluorine, the initial setting time at 20 ° C. is within 5 minutes A spraying material characterized in that the closing time is within 30 minutes.
2. _{2. The} spray material according to 1 above, wherein the calcium aluminosilicate contains 8 to 17 parts by mass of SiO ₂ and has a fineness of 4000 cm ² / g or more.
3. The spraying material according to 1 above, wherein the gypsum is made of anhydrous gypsum and has a fineness of 4000 cm ² / g or more.
4). The aggregate has a maximum particle size of 1.2 mm or less, and the ratio of the aggregate particle size (0.6 to 1.2 mm) / (less than 0.6 mm) is 20/80 to 70/30 in mass ratio. The spraying material according to 1 above, wherein
5. 5. The spray according to any one of 1 to 4 above, wherein the acidic liquid accelerating agent contains 1 to 5 parts by mass of an alkali metal element in terms of R ₂ O (R is an alkali metal) in 100 parts by mass. material.
6). 6. The spray material according to any one of 1 to 5 above, wherein the acidic liquid accelerating agent contains 1 to 5 parts by mass as fluorine (F) in 100 parts by mass.
7). 7. The spray material according to any one of the above 1 to 6, comprising 0.005 to 0.3 parts by mass of a hydroxyl acid salt with respect to 100 parts by mass of the cement.
8). The dry mortar and water are kneaded using a continuous kneading mixer that continuously supplies water, and the kneaded mortar is pumped with a pump and then mixed with an acidic liquid quick-setting agent and sprayed just before spraying. A spraying method using the spraying material according to any one of 1 to 7 above.
9. 9. A spraying method using the spraying material according to 8 above, wherein the dry mortar is supplied from a hopper tank to a hopper upper portion of a continuous kneader by a screw conveyor.
10. 10. A spraying method using the spraying material according to 8 or 9 above, wherein the kneaded mortar is pumped with a pumping hose having an inner diameter of 25 to 32 mm.
11. The spraying method using the spraying material according to any one of the above 8 to 10, wherein the acidic liquid quick setting agent is pressed into air flowing into a hose having an inner diameter of 15 to 20 mm to be misted and mixed with kneaded mortar. .
12 12. A spraying method using the spray material according to any one of the above 8 to 11, wherein the acidic liquid quick setting agent is misted at a spray air amount of 0.5 to 2 m ³ / min.
13. The spraying method using the spraying material according to any one of 8 to 11 above, wherein the dry mortar is supplied to a hopper tank by a screw conveyor or pneumatic transportation.

By using the spraying material and the spraying method of the present invention, it is possible to ensure a highly safe environment for workers even in spraying work in a narrow work space such as a small section tunnel. In addition, since the initial strength and long-term strength after spraying are high, the ground and rock after drilling can be stabilized even when the spraying thickness is 2 to 3 cm. Further, the use of a continuous mixer pump increases the work efficiency of spraying.

It is a model diagram which shows the system which knead | mixes and feeds mortar, adds an acidic liquid quick setting agent, and sprays. It is a model diagram which shows the system which supplies dry mortar with a screw conveyor. It is a model diagram which shows the system which supplies dry mortar by pneumatic feeding.

Hereinafter, the present invention will be described in detail. In the present invention, “part” and “%” are based on mass unless otherwise specified.
In the present invention, mortar means a mixture of cement-based materials such as cement, calcium aluminosilicate, gypsum, calcium hydroxide, water-soluble polymer, fiber, and aggregate with water. Mortar usually does not contain a quick set.
Moreover, in this invention, dry mortar means the mortar which does not contain water.

The calcium aluminosilicate used in the present invention is a component that reacts with the acidic liquid quick-setting agent of the present invention and imparts quick setting properties in the initial stage. Calcium aluminosilicate is obtained by mixing a raw material containing calcia, a raw material containing alumina, and a raw material containing silica, followed by heat treatment such as firing in a kiln or melting in an electric furnace, the main components of which are CaO—Al ₂ O ₃ —SiO ₂ is a general term for substances having hydration activity. Part of this component is alkali metal oxide, alkaline earth metal oxide, titanium oxide, iron oxide, alkali metal halide, alkaline earth metal halide, alkali metal sulfate, alkaline earth metal sulfate, etc. Substituted compounds can also be used. The crystal structure may be either crystalline or amorphous, but it is preferable to use an amorphous one because high crystallinity is imparted.

The proportion of each component in 100 parts by mass of calcium aluminosilicate is preferably 40 to 50 parts by mass of CaO, more preferably 42 to 47 parts by mass, and preferably 35 to 45 parts by mass of Al ₂ O ₃ and more preferably 37. 42 parts by mass and SiO ₂ are preferably 8-17 parts by mass, more preferably 10-15 parts by mass. If the proportion of each component is outside this range, when good coagulation properties are not obtained, hydration activity is increased, and the pot life of mortar after kneading with water is shortened, so the flow value of the mortar becomes low, The pumpability may deteriorate. The calcium aluminosilicate may contain components other than CaO, Al ₂ O ₃ , and SiO _{2 in} 100 parts by mass of calcium aluminosilicate in an amount of 7 parts by mass or less, and may further contain 6 parts by mass or less.
The particle size of the calcium aluminosilicate, preferably 4000 cm ² / g or more in Blaine value, more preferably 4500 ~ 6500cm ² / g. When the brain value is less than 4000 cm ² / g, rapid setting and initial strength development may be deteriorated.
The amount of calcium aluminosilicate used is preferably 2 to 8 parts by mass and more preferably 3 to 6 parts by mass with respect to 100 parts by mass of cement in terms of workability, initial strength development, and durability. If it is less than 2 parts by mass, the cohesive strength and strength development may be reduced, and if it exceeds 8 parts by mass, it is difficult to ensure the pot life of the mortar and durability may not be obtained.

In the present invention, it is possible to improve strength development by using gypsum. Examples of gypsum include anhydrous gypsum, hemihydrate gypsum, dihydrate gypsum, and the like, and one or more selected from these can be used. Anhydrite includes hydrofluoric acid by-product anhydrous gypsum and natural anhydrous gypsum. Of these, anhydrous gypsum is preferably used because of its excellent strength development.
The particle size of gypsum is preferably 4000 cm ² / g or more and more preferably 4500 to 6500 cm ² / g in terms of brain value from the viewpoint of initial strength development. Outside this range, there may be cases where excellent quick setting properties and strength development properties cannot be obtained.
The amount of gypsum used is not particularly limited, but is preferably 1 to 12 parts by weight, more preferably 2 to 8 parts by weight, based on 100 parts by weight of cement. If the amount is less than 1 part by mass, excellent strength developability may not be obtained. If the amount exceeds 12 parts by mass, it may expand excessively and the strength may decrease.

The cement used in the present invention is not particularly limited, and various portland cements such as normal, early strength, very early strength, moderate heat, or low heat, and blast furnace slag, fly ash, and / or these portland cements. Alternatively, any of various mixed cements mixed with limestone fine powder can be used. The amount of cement used is not particularly limited, but is preferably 30 to 50 parts by mass, more preferably 30 to 40 parts by mass in 100 parts by mass of dry mortar from the viewpoint of initial strength development and mortar pumpability.

The aggregate used in the present invention is used to improve the durability of the sprayed mortar and the mortar pumpability. The kind of aggregate is not particularly limited, and any of natural sand, quartz sand, and / or lime sand can be used. Among the aggregates, it is preferable to use lime sand from the viewpoint of durability of the cured body.
The amount of aggregate used is preferably 50 to 70 parts by mass, more preferably 55 to 65 parts by mass in 100 parts by mass of dry mortar. Outside this range, the mortar pumpability and the durability of the cured product may be reduced.
The maximum particle size of the aggregate is 1.2 mm or less, preferably 0.005 to 1.0 mm, from the viewpoint of improving the pumpability of the mortar and reducing the rebound of the sprayed mortar.
The particle size constitution of the aggregate is not particularly limited, but the ratio of the aggregate particle size (0.6 to 1.2 mm) / (less than 0.6 mm) is 20/80 to 70 / in mass ratio. 30 is preferable, and 25/75 to 40/60 is more preferable. Outside this range, excellent mortar pumpability may not be obtained.

The acidic liquid accelerator used in the present invention reacts with cement or calcium aluminosilicate, and is used for promoting initial setting and improving strength development.
The acidic liquid accelerating agent contains an aluminum component and a sulfur component as main components and contains an alkali metal element or fluorine as an essential component. The acidic liquid quencher may contain both alkali metal elements and fluorine.

The feedstock of the aluminum component is not particularly limited, but there are amorphous or crystalline aluminum hydroxide, inorganic aluminum compounds such as aluminum sulfate, aluminate, organic aluminum compounds, aluminum complexes, and the like. One or two or more selected from these can be used. In the present invention, the use of aluminum sulfate, which is also a sulfur component feedstock, is preferred.
The feedstock of the sulfur component is not particularly limited, but in addition to elemental sulfur such as sulfur and sulfur white, sulfide, sulfuric acid or sulfate, sulfite or sulfite, thiosulfuric acid or thiosulfate, An organic sulfur compound etc. are mentioned, The 1 type (s) or 2 or more types selected from these can be used. Of these, sulfuric acid or sulfate is preferred from the viewpoints of high solubility in water, low production cost, and excellent quick setting properties. As the sulfate, alum and aluminum sulfate are preferred.

The feedstock of the alkali metal element is not particularly limited, but is not particularly limited as long as it is a water-soluble compound containing an alkali metal element, that is, lithium, sodium or potassium. For example, oxides, peroxides, chlorides, hydroxides, nitrates, nitrites, phosphates, silicates, aluminates, sulfates, thiosulfates, persulfates, sulfides of alkali metal elements Salt, carbonate, bicarbonate, oxalate, borate, fluoride, silicate, silicofluoride, alum, metal alkoxide, etc. can be used, one or more selected from these Can be used. Among these, sulfates, bicarbonates, oxalates, fluorides, silicofluorides, and alums of alkali metal elements are preferable.

The raw material for supplying elemental fluorine is not particularly limited as long as it is a compound that dissolves or disperses in water. Fluorine compounds such as fluoride, silicofluoride, boron fluoride salt, organic fluorine compound, and hydrofluoric acid One or two or more selected from these can be used.
In the present invention, fluoride and silicofluoride are preferable from the viewpoints of high safety, low production cost, and excellent coagulation properties.
The amount of the alkali metal element used is preferably 1 to 5 parts by mass and more preferably 2 to 4 parts by mass in terms of R ₂ O (R represents an alkali metal) in 100 parts by mass of the acidic liquid accelerating agent. If it is less than 1 part by mass, excellent quick setting may not be obtained, and if it exceeds 5 parts by mass, strength development may be inhibited.
The content of fluorine is preferably 1 to 5 parts by mass, and more preferably 2 to 4 parts by mass as fluorine (F) in 100 parts by mass of the acidic liquid accelerating agent. If it is less than 1 part by mass, excellent quick setting may not be obtained, and if it exceeds 5 parts by mass, strength development may be inhibited.

The acidic liquid quick-setting agent of the present invention can further contain an alkanolamine or a stabilizer.
An alkanolamine is an organic compound having an N—C—OH structure in the structural formula. Here, C is an atomic group called an alkyl group or an allyl group, for example, a linear alkyl group such as a methylene group, an ethylene group or an N-propylene group, an alkyl group having a branched structure such as an isopropyl group, a phenyl group, And an allyl group having an aromatic ring such as a benzyl group and the like.
C may be bonded to the nitrogen atom at two or more locations, and a part or all of C may have a cyclic structure.
Furthermore, C may be bonded to a plurality of hydroxyl groups, and an element other than carbon or hydrogen, for example, sulfur, fluorine, chlorine, oxygen, or the like may be included in a part of the alkyl group.
In the present invention, diethanolamine and / or N, N-dimethylethanolamine is preferably used.

The acidic liquid quick-setting agent of the present invention can contain an organic acid as a stabilizer for the purpose of improving storage stability.
Examples of the stabilizer include oxalic acid, malonic acid, succinic acid, formic acid, citric acid, phosphoric acids, or salts thereof, and one or more selected from these can be used.

The acidic liquid accelerating agent can be used from a completely solution to a suspension of each component.
The acidic liquid accelerating agent may have an acidic pH, preferably 2 to 4, and more preferably 2 to 3. If the pH is less than 2, excellent strength developability may not be obtained, and if the pH exceeds 4, the stability of the liquid quick-setting agent may be deteriorated.

The solid content concentration of the acidic liquid accelerator is preferably 25 to 70%, more preferably 30 to 60%. If it is less than 25%, an excellent setting property may not be obtained, and if it exceeds 70%, the stability of the liquid may be deteriorated.
The Al ₂ O ₃ / SO ₃ molar ratio in the acidic liquid quenching agent is not particularly limited, but is preferably 0.2 to 0.6, more preferably 0.3 to 0.5. If the molar ratio is out of this range, an excellent setting property may not be obtained.
The use amount of the acidic liquid accelerating agent is preferably 2 to 8 parts by mass and more preferably 4 to 6 parts by mass with respect to 100 parts by mass of the dry mortar. If the amount is less than 2 parts by mass, an excellent quick setting property may not be obtained. If the amount exceeds 8 parts by mass, the durability of the cured body may decrease.

In the present invention, fibers can be used to improve durability. Examples of the fiber include inorganic fibers such as ceramic fibers, alkali-resistant glass fibers, and carbon fibers; organic fibers such as polyethylene fibers, vinylon fibers, aramid fibers, and polyacryl fibers; and steel fibers such as steel fibers. . Among these, it is selected from the group consisting of alkali-resistant glass fiber, carbon fiber, polyethylene fiber, vinylon fiber and polyacrylic fiber in terms of the mixability and workability of dry mortar in which cement and aggregate are mixed by a dry method. The use of one or more fibers is preferred.
The length of the fiber is preferably 6 to 12 mm, and more preferably 6 to 10 mm, from the inner diameter of the mortar pressure hose. The fiber thickness is preferably 0.05 to 0.5 mm, more preferably 0.1 to 0.3 mm.
The amount of fiber used is preferably 0.2 to 1 part by volume, more preferably 0.3 to 0.8 part by volume with respect to 100 parts by volume of dry mortar. If the amount is less than 0.2 part by volume, the intended strength may not be obtained. If the amount exceeds 1 part by volume, the mixing and dispersibility during mortar mixing may be deteriorated, or the strength may be deteriorated.

The spraying material of the present invention can further improve initial adhesion by further containing calcium hydroxide. The calcium hydroxide used in the present invention includes slaked lime generated when quick lime and carbide are hydrated. Due to the property that concrete uses water, it reacts with water to generate a large amount of calcium hydroxide. Etc. can be used.
The amount of calcium hydroxide used is preferably 4 to 8 parts by mass and more preferably 5 to 7 parts by mass with respect to 100 parts by mass of cement. If the amount used is less than 4 parts by mass, good adhesion may not be obtained, and if it exceeds 8 parts by mass, excellent strength development may not be obtained.

The spray material of the present invention can further contain a water-soluble polymer. The water-soluble polymer refers to a polymer that gives viscosity to mortar, prevents dripping immediately after spraying, reduces the rebound rate, and suppresses dust generation. Examples of water-soluble polymers include celluloses such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl ethyl cellulose; alginic acid, sodium alginate, β-1,3 glucan, pullulan, guar gum, Polysaccharides such as casein and welan gum; vinyl polymers such as vinyl acetate, vinyl chloride, methacrylic acid, acrylic acid, sodium acrylate, unsaturated carboxylic acids, and copolymers thereof; vinyl acetate polymers and copolymers thereof Emulsions such as those saponified and modified into a polyvinyl alcohol skeleton; and the like can be used, and one or more selected from these can be used. Among these, celluloses are preferable in that initial aggregation is difficult to inhibit.
The amount of the water-soluble polymer used is preferably 0.05 to 0.3 parts by mass, more preferably 0.1 to 0.2 parts by mass with respect to 100 parts by mass of cement. If it is less than 0.05 parts by mass, the pumpability of the mortar may decrease and the pumping pressure may increase, and if it exceeds 0.3 parts by mass, the viscosity of the mortar will increase. May increase and strength development may decrease.

The spray material of the present invention further suppresses the reaction of calcium aluminosilicate, and in order to ensure material pumpability after kneading with water, a hydroxylate containing a Group 1 element of the periodic table (hereinafter referred to as hydroxyl group). Acid salt)). In particular, when the environmental temperature is high, it is possible to maintain both the pumpability and the strength development after spraying by using a material containing a Group 1 element in the periodic table. Examples of the hydroxyl acid salt used in the present invention include citrate, gluconate, tartrate, malate and the like, and one or more selected from these can be used. Of these, sodium citrate, sodium gluconate, sodium tartrate and the like are particularly preferable.
The amount of the hydroxyl acid salt used is preferably 0.005 to 0.3 parts by mass, more preferably 0.01 to 0.2 parts by mass with respect to 100 parts by mass of cement. If the amount is less than 0.005 parts by mass, the fluidity of the target material may not be obtained. If the amount exceeds 0.3 parts by mass, the setting properties may be reduced and the initial strength may be reduced. .

The water reducing agent is generally used to improve the fluidity of cement concrete and the dispersion stability of the quick setting material, and the water reducing agent can also be used in the spray material of the present invention.
As the water reducing agent, either liquid or powdery can be used. Examples of the water reducing agent include polyol derivatives, lignin sulfonates or derivatives thereof, and high performance water reducing agents, and one or more selected from these can be used. Among these, a high-performance water reducing agent is preferable in terms of high strength expression and dispersion stability. By using a high-performance water reducing agent, the amount of the acidic liquid quick-setting agent can be reduced, and the amount of dust generated and / or the rebound rate can be extremely reduced.
Examples of high-performance water reducing agents include formalin condensates of alkyl allyl sulfonates, formalin condensates of naphthalene sulfonates, formalin condensates of melamine sulfonates, polycarboxylic acid polymer compounds, and the like. Any one of these states can be used, and one or more selected from these can be used. In these, the formalin condensate of naphthalene sulfonate, the formalin condensate of melamine sulfonate, or a polycarboxylic acid polymer compound is preferable in that the above effect is great.

In the present invention, a setting retarder such as phosphate, boric acid or a salt thereof, or alcohols may be used. You may use ultrafine powder with an average particle diameter of 10 micrometers or less, such as fine powder slag, fine powder fly ash, bentonite, metakaorion, and silica fume. Alkali metal carbonates may be used to improve the setting properties of the acidic liquid quenching agent.

In the present invention, water is added to the above-mentioned dry mortar containing cement, calcium aluminosilicate, gypsum, calcium hydroxide, water-soluble polymer, fiber, aggregate and the like, kneaded, and the obtained mortar It is preferable from the viewpoint of workability that the acidic liquid quick setting agent is individually pumped and mixed and sprayed immediately before spraying. In this case, the term “immediately before spraying” is preferably 30 cm or less, more preferably 20 to 30 cm from the tip of the spray nozzle. In the present invention, in particular, a continuous kneading mixer that continuously supplies water to dry mortar is kneaded, the kneaded mortar is pumped, and the acidic liquid quick setting agent is hose at the joint between the spray nozzle and the pumping hose. It is desirable to add and spray from the periphery, especially from the entire periphery.

The amount of water used for kneading is 170 to 250 mm in flow value (measured by a method according to JIS R5201-1998) so as to obtain fluidity that can be pumped with a pump, more preferably 180 to 250 mm. It is preferable to add 18 to 22 parts by weight, preferably 19 to 21 parts by weight of water with respect to 100 parts by weight of dry mortar so as to be 220 mm. If the flow value is 170 mm or less, the pumping pressure may increase and the hose may be blocked. If the flow value is 250 mm or more, the condensation property may be weak and rebound may increase.

As the pump for pumping the kneaded mortar, for example, a pump such as a piston pump, a squeeze pump, or a snake pump can be used. Among these, in terms of workability, for example, the supplied spray material is kneaded with water press-fitted with a blade at the tip of the mixer and continuously pumped with a snake pump connected thereto. A method of kneading and pumping with a kneading and pumping device is preferable in terms of workability.

As a method for supplying dry mortar, a method in which the dry mortar is manually supplied to the upper part of the hopper of the continuous kneading and feeding apparatus (included in the continuous kneading mixer pump 3 in the figure) is generally used. In the case of a large amount of construction, a method of supplying dry mortar to the hopper tank 1 and supplying the dry mortar from the hopper tank 1 to the hopper of the continuous kneading and pressure feeding device with the screw conveyor 2 is preferable from the viewpoint of workability (FIG. 1). Fall under). For further construction, dry mortar is separately supplied to the primary hopper tank 8, and the upper hopper of the continuous kneading and pressure feeding device is passed from the primary hopper tank 8 via the screw conveyor 2 ′, the hopper tank 1, and the screw conveyor 2. Is preferable from the viewpoint of workability (corresponding to FIG. 2).

As a method of supplying dry mortar to the hopper tank, a method of supplying from a flexible container bag is generally used, but a method of supplying from another primary hopper tank 8 by a screw conveyor 2 ′ is preferable in terms of workability. A method of supplying dry mortar from another primary hopper tank 8 to the hopper tank 1 by pneumatic transportation is also preferable in terms of workability. In this case, the pneumatic transport hose 9 is used (corresponding to FIG. 3).
As the primary hopper tank, a stationary silo or a mobile tank can be cited, and it is preferable to select the primary hopper tank according to construction conditions.

The inner diameter of the mortar pressure hose is preferably 25 to 32 mm, more preferably 32 mm. If it is less than 25 mm, the pumping pressure becomes high, so the pumping distance may not be 10 m or more. If it exceeds 32 mm, a lot of mortar is discarded when the hose is washed. It is not preferable also from a point. If the inner diameter of the pressure hose is 25 to 32 mm, it can be fed by 50 m.

The pump for pumping the acidic liquid quick setting agent is not particularly limited, and a piston pump, a squeeze pump, a snake pump, a plunger pump, or the like can be used.

The method of mixing the kneaded and pressure-fed mortar with the acidic liquid accelerating agent is a method of adding just before spraying, and immediately before spraying includes the following methods. That is, using an Y-shaped tube, an acidic liquid quick-setting agent can be press-fitted into the spraying air to form a mist, which can be conveyed and sprayed. The conveyance hose is an inner diameter of 15 to 20 mm, more preferably 20 mm. The position where the acidic liquid quick-setting agent is added is not particularly limited, but the position close to the mortar pressure feeding hose can be shared with the blowing air hose. Therefore, it is preferable.

As an addition method, it is preferable that an inlet piece having several holes around the ring is press-fitted with air containing an acidic liquid quenching agent, mixed with mortar, and sprayed.
In this case, the discharge amount of mortar is preferable to below ^{^{3m 3 / hr, 2m 3 /}} hr or less is more preferable. Furthermore, blowing air volume is preferably 0.5 ^~ 2m 3 / min, more preferably 0.7 ~ 1.0m ³ / min. If it is less than 0.5 m ³ / min, a smooth finish cannot be obtained, and the pumping pressure may increase and may be blocked by the spray nozzle. If it exceeds 2 m ³ / min, dust will increase and rebound (rebound) will also increase. There is a case.
In the mortar of the present invention, the initial setting time at 20 ° C. is within 5 minutes, preferably within 1 minute, and the final time is within 30 minutes, preferably within 10 minutes.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by these.
In any experimental example, the amounts of calcium aluminosilicate, anhydrous gypsum, calcium hydroxide, and water-soluble polymer used are all parts by mass with respect to 100 parts by mass of cement, and unless otherwise noted, in the table. The display of any amount is the same. Further, the mixing ratios and% described in the following examples are based on mass unless otherwise specified.

(Experimental example 1)
100 parts by mass of cement, calcium aluminosilicate (CAS) in the amount shown in Table 1, gypsum in the amount shown in Table 1, calcium hydroxide in the amount shown in Table 1, 0.1 part by mass of water-soluble polymer, dry mortar obtained 100 parts by volume of fiber A or fiber B 0.7 part by volume (multiplying the volume of the fiber by the density of the fiber to make a mass measurement), and 100 parts by weight of the resulting dry mortar, 60 parts by weight of the aggregate Dry mortar was prepared.
Next, 20 parts by mass of water was added to 100 parts by mass of the dry mortar, and kneaded with a mortar mixer according to JIS-R5201, to prepare a mortar, and the flow value was measured. 5 parts by mass of an acidic liquid quenching agent was added to 100 parts by mass of dry mortar in the mortar, and the mixture was kneaded for 10 seconds to measure the start time, the termination time, and the compressive strength. Table 1 shows the composition of the mortar and the measurement results.

<Materials used>
The raw materials used in Experimental Example 1 are as follows.
Cement A: Early strong Portland cement, commercial product.
Cement B: Ordinary Portland cement, commercially available product.
Aggregate: Dry lime sand product from Aomi, Niigata Prefecture, maximum particle size 1.2 mm (particle size 0.6-1.2 mm: mass mixing ratio less than 0.6 mm = 30: 70).
Calcium aluminosilicate (CAS): CaO: 44%, Al ₂ O ₃ : 38%, SiO ₂ : 12%, other components 6%, amorphous, brain value 6000 cm ² / g.
Gypsum A: natural anhydrous gypsum, brain value 5000 cm ² / g.
Gypsum B: hemihydrate gypsum, brain value 4800 cm ² / g.
Calcium hydroxide: commercial product, brain 4000 cm ² / g.
Water-soluble polymer: methyl cellulose, commercially available product.
Fiber A: Vinylon fiber (trade name RF400, manufactured by Kuraray Co., Ltd.), thickness 0.2 μm, length 6 mm, density 1.3 g / cm ³ .
Acidic liquid accelerator: (pH 2.7, solid content is Al ₂ O ₃ : 8.5%, SO ₃ : 18.7%, Na ₂ O: 2.5%, F: 2.8%), commercially available Goods.

<Measurement method>
Mortar flow value: Measured according to JIS-R5201.
Initial time: The time required for the proctor penetration resistance value to reach 3.5 N / mm ² was measured.
Termination time: The time required for the proctor penetration resistance value to reach 28 N / mm ² was measured.
Compressive strength: Measured according to JIS-R5201 at 20 ° C. and a predetermined age.
Mortar pot life: After the dry mortar and water were added to prepare the mortar, the time until the mortar flow value reached 160 mm or less was measured.

(Experimental example 2)
100 parts by mass of cement, the ratio of CaO / Al ₂ O ₃ and the content of other components of 6% are the same, 5 parts by mass of calcium aluminosilicate containing the amount of SiO ₂ shown in Table 2, 5 parts by mass of anhydrous gypsum, hydroxylation 6 parts by mass of calcium, 0.1 part by mass of water-soluble polymer, 0.7 parts by mass of fiber A with respect to 100 parts by mass of dry mortar obtained, and 60 parts by mass of aggregate in 100 parts by mass of dry mortar to be obtained A dry mortar was prepared. The raw material components described above were the same as those used in Examples 1-4. Calcium aluminosilicate is the same as 1-4 in Experimental Example 1 except for the amount of SiO ₂ .
Subsequently, it carried out similarly to Experimental example 1 except having added 20 mass parts of water with respect to 100 mass parts of this dry mortar, and preparing mortar. The results are shown in Table 2.

(Experimental example 3)
100 parts by weight of cement, 5 parts by weight of calcium aluminosilicate, 5 parts by weight of anhydrous gypsum, 6 parts by weight of calcium hydroxide, 0.1 part by weight of water-soluble polymer, and 0.7 volume of fiber with respect to 100 parts by weight of the resulting dry mortar The dry mortar was prepared by blending 60 parts by mass of the aggregate with 100 parts by mass of the obtained dry mortar. The raw material components described above were the same as those used in Examples 1-4. Calcium aluminosilicate is the same as 1-4 in Experimental Example 1 except for the amount of SiO ₂ .
Next, 20 parts by mass of water was added to 100 parts by mass of the dry mortar to prepare a mortar. To 100 parts by mass of dry mortar in the mortar, 5 parts by mass of the acidic liquid quick-setting agent shown in Table 3 was added and kneaded for 10 seconds. The results are shown in Table 3.
In Table 3, the amounts of Na ₂ O and F are the contents (parts by mass) in 100 parts by mass of the acidic liquid quick setting agent.

(Experimental example 4)
Table 4 shows 100 parts by mass of cement, 5 parts by mass of calcium aluminosilicate, 5 parts by mass of anhydrous gypsum, 6 parts by mass of calcium hydroxide, and the water-soluble polymer in the amount shown in Table 4, and 100 parts by volume of the resulting dry mortar. An amount of fiber A and 60 parts by mass of aggregate in 100 parts by mass of the obtained dry mortar were mixed using a Nauter mixer to produce a dry mortar.
The produced dry mortar is put into a G4 continuous mixer pump (manufactured by PFT, Germany), 20 parts by mass of water is added to 100 parts by mass of the dry mortar, and the mixture is continuously kneaded with a capacity of 2 m ³ / hr. Pumped. The specifications of the pressure feeding hose were hose inner diameter: 32 mm and hose length 30 m.

In addition, the acidic liquid suddenly used in Experimental Example 1 was used from a Y-shaped tube attached to the rear of the spray nozzle to a hose with an inner diameter of 20 mm that pumps spray air with an air pressure of 0.35 MPa and a spray air amount of 1 m ³ / min. The binder was press-fitted with a plunger pump. A mixture of an acidic liquid quick-setting agent and air was added to a mortar from an inlet piece attached 20 cm before the tip of the spray nozzle to obtain a spray material. The spraying material, the side walls only sprayed to the size of 1 m ² to a thickness of 3cm in (height 3.5 m, the side walls of the simulated tunnel width 2.5 m), was measured pumped pressure and rebound rate . The acidic liquid quick-setting agent was added so as to be 5 parts by mass with respect to 100 parts by mass of dry mortar. The results are shown in Table 4.

<Materials used>
The raw materials used in Experimental Example 4 are as follows.
Cement: Early strong Portland cement, commercial product.
Aggregate A: A dried lime sand product from Aomi, Niigata Prefecture, maximum particle size 2.5 mm (0.6 to 2.5 mm: mixing ratio less than 0.6 mm = 30: 70), for comparative example.
Aggregate B: A dried lime sand product from Aomi, Niigata Prefecture, maximum particle size 1.5 mm (0.6 to 1.5 mm: mixing ratio less than 0.6 mm = 30: 70), for comparative example.
Aggregate C: dried lime sand product from Aomi, Niigata Prefecture, maximum particle size 1.2 mm (mixing ratio of 0.6 to 1.2 mm: less than 0.6 mm = 30: 70).
Fiber A: Vinylon fiber length 6 mm, manufactured by Kuraray.
Water-soluble polymer: methyl cellulose, commercially available product.

<Measurement method>
Pump pressure: The pressure at which the mortar was pumped was measured (upper limit 2 MPa).
Rebound rate: indicated by (amount bounced / amount sprayed) × 100 (unit:%) when sprayed on the side wall for 1 minute.
1 hour strength: Tested and evaluated in accordance with JIS R 5201.
Bending toughness coefficient: sprayed on a mold having a width of 10 cm, a height of 10 cm, and a length of 40 cm, and tested and evaluated according to JSCE-G552-2010 at a material age of 28 days.

(Experimental example 5)
100 parts by weight of cement, 5 parts by weight of calcium aluminosilicate, 5 parts by weight of anhydrous gypsum, 6 parts by weight of calcium hydroxide, 0.1 part by weight of water-soluble polymer, 0.5 volume of fiber to 100 parts by weight of the resulting dry mortar 60 parts by mass of aggregate in 100 parts by mass of dry mortar and the resulting dry mortar were mixed using a Nauta mixer to produce dry mortar. In addition, as said each raw material component, all used the same thing as described in Experimental example 4.
The experiment was performed in the same manner as in Experimental Example 4 except that the mass part of water relative to 100 parts by mass of the dry mortar was changed and the inner diameter of the mortar pumping hose was changed to the values shown in Table 5. The results are shown in Table 5.

(Experimental example 6)
100 parts by weight of cement, 5 parts by weight of calcium aluminosilicate, 5 parts by weight of gypsum, 6 parts by weight of calcium hydroxide, 0.1 part by weight of water-soluble polymer, 0.5 parts by weight of fiber with respect to 100 parts by weight of the resulting dry mortar Then, 60 parts by mass of the aggregate and 100 parts by mass of the obtained dry mortar were mixed with an organic acid (hydroxyl acid) in an amount shown in Table 6 using a Nauta mixer to produce a dry mortar. In addition, as said each raw material component, all used the same thing as described in Experimental example 4.
It carried out similarly to Experimental Example 4 except having used the said dry mortar. The results are shown in Table 6. In Table 6, the amount of organic acid is part by mass with respect to 100 parts by mass of dry mortar.
<Materials used>
Organic acid A: sodium citrate, commercially available product.
Organic acid B: sodium gluconate, commercial product.

(Experimental example 7)
100 parts by weight of cement, 5 parts by weight of calcium aluminosilicate, 5 parts by weight of gypsum, 6 parts by weight of calcium hydroxide, 0.1 part by weight of water-soluble polymer, and 0.5 parts by volume of fiber for 100 parts by weight of the resulting dry mortar 60 parts by mass of aggregate in 100 parts by mass of the resulting part and dry mortar were mixed using a Nauta mixer to produce dry mortar. In addition, as said each raw material component, all used the same thing as described in Experimental example 4.
The experiment was performed in the same manner as in Experimental Example 5 except that the amount of air blown into the dry mortar and the inner diameter of the hose for conveying the acidic liquid quick-setting agent were changed to the values shown in Table 7. The results are shown in Table 7.
<Measurement method>
Dust amount: The dust amount 5 m behind the spraying location was measured with a digital dust meter for 1 minute from the start of spraying.

(Experimental example 8)
The same dry mortar as in Experimental Example 7 was performed in the same manner as in Experimental Example 6 except that the test was performed by changing the method of charging the hopper of a P4 G4 continuous mixer pump. A method for supplying dry mortar with a screw conveyor is shown in FIG.
<Input method>
Manual loading: The product bag was opened and loaded.
Screw conveyor charging: A hopper tank 1 and a screw conveyor 2 were used. Dry mortar was put into the continuous kneading mixer pump 3 from the hopper tank 1 with the screw conveyor 2 (FIG. 1).

(Experimental example 9)
The same dry mortar as in Experimental Example 7 was performed in the same manner as in Experimental Example 6 except that the method for supplying the dry mortar to the hopper tank in Experimental Example 8 was changed and tested. FIG. 2 shows the dry mortar supply method, and Table 9 shows the results.
<Supply method>
Flexible container: The flexible container was opened and charged from the upper part of the primary hopper tank 8.
Screw conveyor: Dry mortar was put into the hopper tank 1 from the primary hopper tank 8 by the screw conveyor 2 '. Dry mortar was put into the continuous kneading mixer pump 3 from the hopper tank 1 with the screw conveyor 2 (FIG. 2).
Pneumatic transport: Air having an air pressure of 0.4 MPa is supplied from the pneumatic transport hose 9 to the primary hopper tank 8, and the dry mortar is transported from the primary hopper tank 8 to the hopper tank 1 via the mortar pumping hose 4 ′. (FIG. 3).

The spraying material of the present invention and the spraying method using the same can ensure an environment with high worker safety even in spraying work in a narrow work space such as a small cross-section tunnel. In addition, since the long-term strength is high, the ground and rock after excavation can be stabilized, and a continuous mixer pump can be used to improve work efficiency.

DESCRIPTION OF SYMBOLS 1 Hopper tank 2 2 'Screw conveyor 3 Continuous kneading mixer pump 4 4' Mortar pressure feed hose 5 Inlet piece 6 Spray nozzle 7 Spray air hose 8 Primary hopper tank 9 Air transport hose

Claims

100 parts by weight of cement, 2-8 parts by weight of calcium aluminosilicate, 1-12 parts by weight of gypsum, 4-8 parts by weight of calcium hydroxide, 0.05-0.3 parts by weight of water-soluble polymer, 100 parts by weight of dry mortar On the other hand, 0.2 to 1 part by volume of fibers and 100 to 10 parts by mass of dry mortar containing 100 to 10 parts by mass of aggregate having a maximum particle size of 1.2 mm or less in 100 parts by mass of dry mortar, 18 to 22 water. Containing mortar with a flow value of 170 to 250 mm kneaded in parts by mass and an acidic liquid accelerating agent containing an alkali metal element and / or fluorine, the initial setting time at 20 ° C. is within 5 minutes A spraying material characterized in that the closing time is within 30 minutes.
The spray material according to claim 1, wherein the calcium aluminosilicate contains 8 to 17 parts by mass of SiO 2 and has a fineness of 4000 cm 2 / g or more.
The spray material according to claim 1, wherein the gypsum is made of anhydrous gypsum and has a fineness of 4000 cm 2 / g or more.
The aggregate has a maximum particle size of 1.2 mm or less, and the ratio of the aggregate particle size (0.6 to 1.2 mm) / (less than 0.6 mm) is 20/80 to 70/30 in mass ratio. The spray material according to claim 1, wherein
The spray according to any one of claims 1 to 4, wherein the acidic liquid accelerating agent contains 1 to 5 parts by mass of an alkali metal element in terms of R 2 O (R is an alkali metal) in 100 parts by mass. Attached material.
The spray material according to any one of claims 1 to 5, wherein the acidic liquid quick-setting agent is contained in an amount of 1 to 5 parts by mass as fluorine (F) in 100 parts by mass.
The spray material according to any one of claims 1 to 6, comprising 0.005 to 0.3 parts by mass of a hydroxyl acid salt with respect to 100 parts by mass of the cement.
The dry mortar and water are kneaded using a continuous kneading mixer that continuously supplies water, and the kneaded mortar is pumped with a pump and then mixed with an acidic liquid quick-setting agent and sprayed just before spraying. A spraying method using the spraying material according to any one of claims 1 to 7.
The spraying method using the spraying material according to claim 8, wherein the dry mortar is supplied from a hopper tank to a hopper upper part of a continuous kneader by a screw conveyor.
The spraying method using the spraying material according to claim 8 or 9, wherein the kneaded mortar is pumped by a pumping hose having an inner diameter of 25 to 32 mm.
The spraying using the spraying material according to any one of claims 8 to 10, wherein the acidic liquid quick setting agent is pressed into air flowing into a hose having an inner diameter of 15 to 20 mm to be misted and mixed with the kneaded mortar. Construction method.
The spraying method using the spraying material according to any one of claims 8 to 11, wherein the acidic liquid quick setting agent is misted at a spraying air amount of 0.5 to 2 m 3 / min.
The spraying method using the spraying material according to any one of claims 8 to 11, wherein the dry mortar is supplied to a hopper tank by a screw conveyor or pneumatic transportation.