JP5646818B2 - Spraying material and spraying method using the same - Google Patents

Description

The present invention relates to, for example, a quick setting agent, a quick setting slurry, a spraying material, and a spraying method using the same, which are sprayed onto a ground surface exposed in a tunnel or a slope such as a road, a railway, and a waterway. .

Conventionally, in order to prevent collapse of exposed ground such as tunnel excavation, a spraying method of quick setting concrete in which a quick setting agent is mixed with concrete has been performed (Patent Document 1). In this method, spray concrete is usually prepared at a cement, aggregate, and water metering plant installed at the excavation site, transported by an agitator car, pumped by a concrete pump, and a merging pipe provided in the middle Then, it is mixed with the rapid setting agent fed from the other side and sprayed to the ground surface as a quick setting sprayed concrete until a predetermined thickness is reached. In addition, as a quick-setting agent that has been conventionally used, calcium aluminate, a mixture of alkali metal aluminate and alkali carbonate, and the like, and a mixture of calcium aluminate, alkali metal aluminate, and alkali carbonate, etc. In addition, a mixture of calcium aluminate and 3CaO · SiO ₂ is known (Patent Documents 2, 3, 4, and 5). These quick setting agents have a function of promoting the setting of cement, and all of them are mixed with cement concrete and sprayed on the ground surface. The method of adding the quick setting agent is usually a method in which the amount of dust is increased due to powder mixing by pneumatic transportation. Therefore, the work environment may be deteriorated, and it is necessary to wear protective glasses, a dust mask, etc. during the spraying, and a construction method with less dust is required.

As a method of generating less dust, a method is proposed in which a quick setting agent is slurried and added to cement concrete, and then an alkali metal aluminate solution is separately pumped, mixed, and sprayed. (Patent Document 6). Since this method uses a highly alkaline liquid, it is difficult to handle, and when spraying, protective glasses or gloves are required, and there is a problem that workability is reduced.

On the other hand, the quick setting construction method which improves a working environment by making a quick setting agent into a slurry and mix | blending alum with cement concrete is proposed (patent document 7). In recent years, a quick setting method has been proposed that improves workability and dust reduction effect and improves quick setting in terms of shortening the work period (Patent Document 8).

However, the demand for the quick setting agent has increased more and more under the circumstances where the spring water and the ground surface have deteriorated, and the required performance of the conventional quick setting slurry, which is to secure the initial setting time and reduce the dust, is further increased. There is a need for improvement.

As a result of various studies on the problems and requirements, the inventor has obtained knowledge that the problems and requirements can be solved by performing spraying construction using a specific quick setting agent, thereby completing the present invention. It came to.

Japanese Patent Publication No. 60-4149 Japanese Patent Laid-Open No. 64-051351 Japanese Examined Patent Publication No. 56-27457 JP-A-61-026538 JP 63-2105050 A Japanese Patent Laid-Open No. 5-139804 JP-A-5-097491 Japanese Patent Laid-Open No. 2003-81664

The present invention includes cement concrete, calcium aluminate, sulfate, alkali metal aluminate, alkali metal carbonate, oxycarboxylic acid, water retention material, and aluminum powder, carbon material, percarbonate, persulfate, It contains 100 parts of a quick-setting agent quick-setting agent containing 15 or 80 parts of slurry water containing a gas foaming substance that is one or two or more of the group consisting of perborate and permanganate. the quick-setting admixture slurry of Te, based on 100 parts of cement, Ri Na contain 3 to 10 parts in terms of solid content, and quick-setting admixture is, 100 parts of calcium aluminate, 10-50 parts of sulfuric acid salt , 3 to 30 parts of alkali metal aluminate, 10 to 60 parts of alkali metal carbonate, 0.01 to 2 parts of oxycarboxylic acid, 0.001 to 0.02 part of water retaining material, and 100 parts of quick setting agent In contrast, 0.0 A spraying material ing contain gas foaming material 1 to 0.1 parts of a該吹with material gas foaming agent is aluminum powder, the density of the solid material Kyuyuizai slurry 2.00g Spraying method of the spraying material which is a spraying material which is / cm ³ or less, is prepared by rapidly adding water to the quick setting agent, and is then mixed and mixed with cement concrete and sprayed. It is.

  The present invention, for example, improves the workability by suppressing the generation of dust generated in a spraying operation such as a tunnel, and the effect that high quick setting is obtained even in a situation where spring water or natural ground surface deteriorates. Play.

  The cement concrete of the present invention is a generic term for paste, mortar, and concrete. Further, parts and% in the present invention are based on mass unless otherwise specified.

The calcium aluminate used in the present invention is obtained, for example, by mixing a raw material containing calcia and a raw material containing alumina, and performing a heat treatment such as baking in a kiln or melting in an electric furnace. Is. Calcium aluminate is a general term for substances having CaO and Al ₂ O ₃ as main components and having hydration activity. Further, some of CaO and Al ₂ O ₃ are alkali metal oxides, alkaline earth metal oxides, silicon oxides, titanium oxides, iron oxides, alkali metal halides, alkaline earth metal halides, alkali metal sulfates. And compounds obtained by substituting alkaline earth metal sulfates or the like, or substances containing CaO and Al ₂ O ₃ as main components, and substances in which these are dissolved in a small amount. As the mineral form, either crystalline or amorphous can be used. Among these, amorphous calcium aluminate is preferable in terms of reaction activity, and amorphous calcium obtained by quenching a heat-treated product corresponding to a composition of 12CaO · 7Al ₂ O ₃ (hereinafter referred to as C ₁₂ A ₇ ). More preferred is aluminate.

The particle size of the calcium aluminate, in terms of quick-setting property and the initial strength development, Blaine specific surface area (hereinafter, referred to as Blaine) 3,000 cm ² / g or more is preferable, 5,000 cm ² / g or more is more preferable. If it is less than 3,000 cm < ² > / g, the quick setting property and initial strength expression property of the quick setting spray cement concrete which mixed the quick setting agent and the spray cement concrete may fall.

The sulfate used in the present invention is to improve the setting properties and strength development properties of the quick setting sprayed cement concrete, for example, quick setting in which a quick setting agent and water (hereinafter referred to as slurry water) are mixed. It mixes in order to delay the curing time of the agent slurry. Examples of sulfates include sodium sulfate, potassium sulfate, aluminum sulfate, alum, and gypsum of anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum, and one or more of these may be used depending on the purpose of use. It is possible to use together. Among these, sodium sulfate and gypsum are preferable, gypsum is more preferable, and anhydrous gypsum is most preferable from the viewpoint that sufficient quick setting can be obtained, initial strength development and suitable for on-site construction.

The particle size of the sulfate in terms of quick-setting property and the initial strength development, Blaine specific surface area (hereinafter, referred to as Blaine) 2,500 cm ² / g or more is preferable, 3,000 cm ² / g or more is more preferable. If it is less than 2,500 cm < ² > / g, the quick setting property and initial strength development property of the quick setting spray cement concrete which mixed the quick setting agent and the spray cement concrete may fall.

The amount of sulfate used is preferably 10 to 50 parts and more preferably 25 to 45 parts with respect to 100 parts of calcium aluminate. If the amount is less than 10 parts, the viscosity of the quick setting agent slurry increases, so the workability and setting property of the quick setting spray cement concrete may decrease, and it may be difficult to promote long-term strength development. The initial setting may be delayed, and the initial strength development may be reduced.

Alkali metal aluminate (hereinafter referred to as aluminate) used in the present invention is to promote the initial setting of cement. Aluminum hydroxide and alkali metal hydroxide are mixed and dissolved, dried, and powdered. It is obtained as a shape. Examples of the aluminate include sodium aluminate, potassium aluminate, and lithium aluminate, and one or more of these can be used. Among these, sodium aluminate is preferable in terms of the setting property and initial strength development property of the quick setting sprayed cement concrete.

The amount of aluminate used is preferably 3 to 30 parts, more preferably 5 to 15 parts, per 100 parts of calcium aluminate. If it is less than 3 parts, the initial setting may be delayed, and the initial strength development may be reduced. If it exceeds 30 parts, the viscosity of the quick setting slurry increases, and the workability and long-term strength development of the quick setting sprayed cement concrete are increased. May decrease.

The alkali metal carbonate (hereinafter, referred to as alkali carbonate) used in the present invention promotes the initial setting of cement, and examples thereof include sodium carbonate, potassium carbonate, sodium hydrogen carbonate, and potassium hydrogen carbonate. Among these, sodium carbonate is preferable in terms of promoting the initial setting.

The amount of alkali carbonate used is preferably 10 to 60 parts and more preferably 20 to 50 parts with respect to 100 parts of calcium aluminate. If it is less than 10 parts, the initial setting of the rapid setting sprayed cement concrete may be delayed, and the initial strength development may be reduced. If it exceeds 60 parts, the viscosity of the quick setting slurry will increase, and workability and long-term strength development will be improved. May decrease.

Examples of the oxycarboxylic acid (hereinafter referred to as oxyacid) used in the present invention include gluconic acid, tartaric acid, citric acid, malic acid, salicylic acid, lactic acid, and salts thereof. Examples of the salt include alkali metal salts such as sodium and potassium. Among these, sodium gluconate is preferable in terms of initial strength development.

The amount of oxyacid used is preferably 0.01 to 2 parts and more preferably 0.1 to 1 part with respect to 100 parts of calcium aluminate. If it is less than 0.01 part, the setting property and initial strength development of the quick setting sprayed cement concrete may be inhibited, and if it exceeds 2 parts, the setting property and strength development may be inhibited.

The water-retaining substance used in the present invention not only reduces the dust of shotcrete but also enhances the dust reduction effect of the quick setting slurry itself. Examples of water-retaining substances include celluloses such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, and hydroxyethyl ethyl cellulose; alginic acid; sodium alginate; , And polysaccharides such as welan gum, vinyl polymers such as vinyl acetate, ethylene, vinyl chloride, methacrylic acid, acrylic acid, sodium acrylate, and unsaturated carboxylic acids and copolymers thereof, and vinyl acetate polymers Examples include emulsions such as those obtained by saponifying the copolymer and modifying it into a polypinyl alcohol skeleton, bentonite, inorganic substances such as silica gel, water glass and sodium chloride Of water glass of the gelling agent, furthermore, starches, carboxymethyl cellulose, polyvinyl alcohol, polyethylene oxide, polyacrylamide, polyvinyl alcohol - acrylic acid salt copolymer, Poriakuriro nitrile hydrolyzate and the general formula RO (AO) _and a high molecular weight material represented by _n H (wherein R is an alkyl group, A is one or more alkyl groups, and n is an integer). Among these, methyl cellulose, polyethylene oxide, vinyl alcohol-acrylate copolymer, polyacrylonitryl hydrolyzate, and general formula RO (AO) _n H (where R is The alkyl group, A is one or more alkyl groups, and n is an integer) is preferably one or two or more of the group consisting of polymer materials, more preferably polyethylene oxide. The weight average molecular weight of polyethylene oxide is preferably 1 million to 5 million.

0.001-0.02 part is preferable with respect to 100 parts of calcium aluminate, and 0.003-0.01 part is more preferable. If it is less than 0.001 part, a rebound rate and dust amount generate | occur | produce much and workability may fall, and if it exceeds 0.02 part, a rebound rate and dust amount generate | occur | produce much, workability, setting property, Strength development may be inhibited.

Gas foaming agent used in the present invention is preferably prepared from the density of the solidified body of quick-setting slurry 2.00 g / cm ³ or less, and more preferably adjusted to 1.90 g / cm ³ or less. By preparing in this range, the load of a supply apparatus is reduced and workability is improved.

Examples of the gas foaming material include aluminum powder, carbon material, percarbonate, persulfate, perborate, and permanganate such as permanganate. Among these, aluminum powder, carbon material, percarbonate, persulfate, perborate, and one or more of the group consisting of permanganate are preferable in that the density can be reduced, Aluminum powder is more preferable.

0.001-0.1 part is preferable with respect to 100 parts of rapid setting agent, and, as for the usage-amount of a gas foaming substance, 0.01-0.05 part is more preferable. If the amount is less than 0.001 part, the workability may be reduced, and the rapid setting slurry density may not be adjusted to 2.00 g / cm ³ or less. There is a case.

The amount of the slurry water in the quick setting agent slurry used in the present invention is preferably 15 to 80 parts, more preferably 22 to 70 parts, and most preferably 30 to 60 parts with respect to 100 parts of the quick setting agent. If the amount is less than 22 parts, the rapid setting agent may not be in a slurry state, and the amount of dust may increase.

The amount of the rapid setting agent is preferably 3 to 10 parts, more preferably 5 to 8 parts, and most preferably 6 to 8 parts in terms of solid content with respect to 100 parts of cement. If it is less than 3 parts, it may be difficult to promote initial setting of the rapid setting sprayed cement concrete, and if it exceeds 10 parts, long-term strength development may be inhibited.

Here, the cement includes various portland cements such as normal, early strength, moderate heat, and super early strength, and various mixed cements obtained by mixing fly ash, blast furnace slag, and the like with these various portland cements. These can be used in the form of fine powder.

In the quick setting agent slurry of the present invention, a water reducing agent can be further used as necessary.

The cement concrete used in the present invention contains cement and aggregate. Here, the aggregate preferably has a low water absorption rate and a high aggregate strength. The maximum dimension of the aggregate is not particularly limited as long as it can be sprayed. River sand, mountain sand, sea sand, lime sand, and quartz sand can be used as the fine aggregate, and river gravel, mountain gravel, lime gravel, and the like can be used as the coarse aggregate.

The amount of water used for cement concrete is preferably 35% or more, and more preferably 50 to 65% in terms of strength development. If it is less than 35%, cement concrete may not be sufficiently mixed.

In the spraying method using the quick setting agent slurry of the present invention, conventionally used spraying equipment or the like can be used. For example, the product name “MKW-25SMT” manufactured by Shintech Co., Ltd. can be used for pressure-feeding spray cement concrete, and the quick-setting agent pressure-feeding device “Natom Cleat” can be used for pressure-setting quick-setting agent.

Moreover, as the spraying method using the quick setting agent slurry of the present invention, various spraying methods according to the required physical properties, economical efficiency, workability and the like are possible. As a spraying method using the quick setting agent slurry of the present invention, any of a dry spraying method and a wet spraying method is possible.

As the dry spraying method, for example, cement, fine aggregate, and coarse aggregate are added and mixed to prepare dry cement concrete, the dry cement concrete is conveyed by compressed air, and a Y-shaped tube is provided in the middle. From one of them, a quick setting agent adding device or a water pump is used to join and mix the quick setting agent slurry, dry cement concrete, and water to form a quick setting sprayed concrete, and spray it.

As a wet spraying method, for example, cement, fine aggregate, coarse aggregate, and water are added and kneaded, pumped and pumped, a Y-shaped tube is provided in the middle, and pumped from one side by a rapid setting agent supply device. There is a method of spraying a quick setting wet spray concrete by merging and mixing quick setting agents.

In the spraying method using the quick setting agent slurry of the present invention, the spraying pressure is usually preferably 0.2 to 0.5 MPa, and the spraying speed is preferably 4 to 20 m ³ / h.

In addition, the pressure of the pumping air for pumping the rapid setting agent is 0.01 to 0.3 MPa larger than the pumping pressure of the cement concrete so that the pumping pipe is not blocked when the cement concrete is mixed in the pumping tube of the quick setting agent slurry. It is preferable.

In the spraying method using the quick setting agent slurry of the present invention, in order to reduce dust and rebound, slurry water is added to the powder quick setting agent to continuously slurry the quick setting agent. It is preferable to spray the slurry mixed with spray cement concrete at the discharge port tip. As a method of continuously slurrying the quick setting agent, for example, a hole is made around a pressure feeding pipe for pneumatically feeding the powder quick setting agent, and water, for example, high pressure water is added into the pressure feeding pipe from the hole. A method of slurrying and pneumatic feeding can be used.

Table 1 for 100 parts of calcium aluminate and 100 parts of gypsum, aluminate, alkali carbonate, oxyacid, water-retaining substance, and rapid setting agent in the amounts shown in Table 1 for 100 parts of calcium aluminate A quick-setting agent slurry was prepared by mixing and stirring 100 parts of the quick-setting agent composed of the gas foaming material in the amount shown in the above and 50 parts of slurry water, and the viscosity thereof was measured.
Further, a mortar having a sand / cement ratio = 3 and a water / cement ratio = 57% was prepared, and 6 parts of the quick setting slurry was added to 100 parts of the cement to obtain a quick setting mortar. The setting time and mortar compressive strength were measured. The water / cement ratio of the mortar without adding the quick setting slurry was 60%. The results are also shown in Table 1.

<Materials used>
Cement: Ordinary Portland cement, commercial product, Blaine value 3,200 cm ² / g, specific gravity 3.16
Fine aggregate: Himekawa water system river sand, Itoigawa City, Niigata Prefecture, surface dry state, specific gravity 2.62
Calcium aluminate: Corresponding to C ₁₂ A ₇ composition, amorphous, Blaine value 6,500 cm ² / g
Gypsum: commercially available anhydrous gypsum pulverized product, brain value 5,900 cm ² / g
Aluminate: sodium aluminate, commercial product alkali carbonate: sodium carbonate, commercial product oxyacid: sodium gluconate, commercial product water retention material: polyethylene oxide, commercial product, molecular weight 1 million to 2 million gas foaming material: aluminum powder, Commercial item

<Measurement method>
Viscosity: A quick setting agent slurry was prepared under the conditions of temperature 20 ° C. and humidity 80%, and measured with a B-type viscometer under the condition of a rotation speed of 20 rpm. Setting time: quick setting mortar Measured according to JIS R5201 Measured mortar compressive strength according to JIS R 5201 Measured according to JIS R 5201 Measured according to JIS R 5201

From Table 1, the test results of Experiment Nos. 1-4 were balanced data on the rapid setting agent slurry viscosity, compressive strength, and setting time.

The unit quantity of each material, cement 360 kg / ^{m 3,} fine aggregates 1,058kg / ^{m 3,} coarse aggregate 710 kg / ^{m 3,} and the shotcrete was prepared as a water 216 kg / ^{m 3,} the shotcrete It pumped by concrete pumping machine "MKW-25SMT" on condition of spraying pressure 0.4MPa and spraying speed 10m < ³ > / h. On the other hand, the experiment No. shown in Table 1 performed in Experimental Example 1 was performed. The quick setting agent adding device “NATOM” under the condition of a pressure of 0.5 MPa so that the quick setting agent of 1-4, 27, 28, 29, 30, 31 is 7 parts with respect to 100 parts of cement. It is pneumatically fed using a cleat, and 50 parts of slurry water is added to 100 parts of the quick setting agent from a hole provided around one of the Y-shaped pipes provided in the middle of the quick setting agent. A slurry was obtained. This quick setting slurry was mixed with the shotcrete fed from the other side of the Y-shaped tube to obtain quick setting shotcrete. About this quick setting shotcrete, the amount of dust, rebound rate, concrete compressive strength, and workability evaluation were measured.
Moreover, the density of the solidified body was measured about the quick-setting agent slurry. The results are shown in Table 2.

<Materials used>
Coarse aggregate: Gravel from Himekawa, Itoigawa City, Niigata Prefecture, surface dry condition, specific gravity 2.64, maximum dimension 10mm

<Measurement method>
Concrete compressive strength: The compressive strength at 1 hour of age is that the pin placed in the pullout formwork 25cm wide x 25cm long is covered with the quick setting sprayed concrete from the surface of the pullout formwork, and the pin from the back side of the formwork The pullout strength at that time was determined, and the compressive strength was calculated from the formula of (compressive strength) = (pullout strength) × 4 / (test specimen contact area). The compressive strength after 1 day of age is 20 tons pressure-resistant machine by spraying quick setting sprayed concrete on a form of width 50cm x length 50cm x thickness 20cm, and collecting the specimen 5cm in diameter x 10cm in length. And the compressive strength was determined.
Rebound rate: Quick setting shotcrete was sprayed on a simulated tunnel having a height of 3.5 m and a width of 2.5 m created in an arch shape with an iron plate at a pumping speed of 10 m ³ / h for 10 minutes. After that, (Rebound rate) = (Amount of quick setting sprayed concrete dropped without adhering to the simulated tunnel) / (Amount of quick setting shot concrete sprayed to the simulated tunnel) x 100 (%) did.
Dust amount: Quick setting shot concrete was sprayed to the simulated tunnel at a pumping speed of 10 m ³ / h for 10 minutes. Thereafter, the amount of dust was measured at a fixed position of 3 m from the spraying place.
Density: A quick setting agent and water were mixed to prepare a quick setting agent slurry, which was left to solidify for one day. The density was determined from the volume and mass of the solidified body.
Workability evaluation: The pumping pressure of the rapid setting agent adding device was measured every minute, and after spraying, the number of holes where the Y-shaped tube was blocked was confirmed.

From the results in Table 2, when the quick setting agent without adding the gas foaming material is slurried as in Experiment No. 1-27, a lump of quick setting agent slurry is generated in the Y-shaped tube, and the quick setting agent is mixed with the concrete. The concrete being sprayed peeled off and the concrete did not harden. Moreover, in the quick setting agent which put much gas foaming substances like experiment No.1-31, hardening of quick setting sprayed concrete after mixing and mixing with the quick setting agent is delayed, and the rebound amount is 20.0%. As a result, it was difficult to obtain compressive strength.

The unit quantity of each material, cement 360 kg / ^{m 3,} fine aggregates 1,058kg / ^{m 3,} coarse aggregate 710 kg / ^{m 3,} and the shotcrete was prepared as a water 216 kg / ^{m 3,} the shotcrete It pumped by concrete pumping machine "MKW-25SMT" on condition of spraying pressure 0.4MPa and spraying speed 10m < ³ > / h. On the other hand, the experiment No. shown in Table 1 performed in Experimental Example 1 was performed. The quick setting agent adding device “NATOM” under the condition of the pressure of 0.5 MPa so that the quick setting agent of 1-4, 22, 23, 24, 25, 26 becomes 7 parts with respect to 100 parts of cement. It is pneumatically fed using a cleat, and 50 parts of slurry water is added to 100 parts of the quick setting agent from a hole provided around one of the Y-shaped pipes provided in the middle of the quick setting agent. A slurry was obtained. This quick setting slurry was mixed with the shotcrete fed from the other side of the Y-shaped tube to obtain quick setting shotcrete. About this quick setting shotcrete, the amount of dust, rebound rate, concrete compressive strength, and workability evaluation were measured. The results are shown in Table 3.

From Table 3, the test results of Experiment No. 1-4 became balanced data in terms of dust amount, rebound rate, concrete compressive strength, and workability evaluation.

By using the quick setting agent of the present invention, the amount of dust generated can be reduced. Furthermore, since high strength is obtained at the initial stage of spraying, safety is improved. By using the quick setting agent of the present invention, the workability of tunnels and the like, the dust reduction effect is further improved, and the quick setting method that exhibits high quick setting even under conditions where the spring water or the ground surface has deteriorated. Can provide.

Claims (4)

Cement concrete, calcium aluminate, sulfate, alkali metal aluminate, alkali metal carbonate, oxycarboxylic acid, water retention material, and aluminum powder, carbon material, percarbonate, persulfate, perborate And a quick setting agent slurry containing 100 parts of a quick setting agent containing a gas foaming substance which is one or more of the group consisting of permanganate and 15 to 80 parts of slurry water. , relative to 100 parts of cement, Ri Na contain 3 to 10 parts in terms of solid content, and quick-setting admixture is, 100 parts of calcium aluminate, 10-50 parts of sulfuric acid, alkali metal aluminates 3 To 30 parts, 10 to 60 parts of alkali metal carbonate, 0.01 to 2 parts of oxycarboxylic acid, 0.001 to 0.02 parts of water-retaining substance, and 100 parts of quick setting agent. 0.1 part Spraying material ing contain a scan foaming substance. The spray material according to claim 1, wherein the gas foaming material is aluminum powder. The spraying material according to claim 1 or 2, wherein the density of the solidified body of the quick setting agent slurry is 2.00 g / cm ³ or less. The spraying method of the spraying material in any one of Claims 1-3 which prepares a quick-setting agent slurry by continuously hydrating to a quick-setting agent, and mixes and mixes with cement concrete, and sprays. .