JP2002332798A - Continuous manufacturing device for accelerator slurry, and spraying construction method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuous manufacturing device for accelerator slurry, and a spraying construction method using the device that can reduce the produced quantity of dust to improve work environment and can expect the initial and long-term manifestation of strength. SOLUTION: This continuous manufacturing device for the accelerator slurry comprises a supply pipe for a powder accelerator force-fed with air, a feed water pipe, and an accelerator slurry discharge pipe facing the supply pipe through a clearance. The diameter of the supply pipe is smaller than that of the discharge pipe, and the feed water pipe connects the supply pipe and the discharge pipe. Water is pressed in from the clearance to manufacture the accelerator slurry, The supply pipe diameter/discharge pipe diameter is 0.3-0.95, a water supply angle to the axis of the supply pipe is 10-90 deg., the clearance/ supply pipe diameter is 0.05-0.2, a feed water pressure is higher by 0.1-3 MPa than the force-feeding air pressure of the powder accelerator, and the powder accelerator contains calcium aluminate. In the spraying construction method, the accelerator slurry manufactured by the continuous manufacturing device is added and mixed in cement concrete and sprayed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for continuously producing a quick-setting slurry which is sprayed on a ground surface or the like exposed in tunnels such as roads, railways and headraces, and a spraying method using the same. . The parts and percentages used in the present invention are based on mass unless otherwise specified. Further, the cement concrete of the present invention is a general term for cement paste, mortar, and concrete.

[0002]

2. Description of the Related Art Conventionally, a method of spraying quick-setting concrete in which a quick-setting agent is blended with concrete to prevent the collapse of exposed ground, such as tunnel excavation, has been performed (Japanese Patent Publication No. 60-1985). No. 4149). In this method, normally, a shotcrete is prepared 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 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.

[0003] Conventionally used quick setting agents include calcium aluminate and / or alkali metal aluminate, or a mixture of these with alkali metal carbonate, or calcium aluminate and 3CaO.SiO _2. And the like are known (JP-A-64-051351, JP-B-56-027457, JP-A-61-026538, JP-A-63-210050, etc.). These quick-setting agents are powder quick-setting agents, and their addition is poor in mixability with concrete due to powder mixing by pneumatic transport, and the unset quick-setting agent is scattered as dust. There was a problem that the working environment such as a tunnel deteriorated.

[0004] Since the influence of pneumoconiosis and the like is feared due to the deterioration of the working environment, eyeglasses and dust masks are required at the time of spraying, which causes a problem that the workability is reduced. For this reason, there has been a demand for a construction method with a smaller amount of dust.

[0005] In order to solve such a problem of the powder quick-setting agent, a strongly alkaline or acidic liquid quick-setting agent has been proposed (Japanese Patent Application Laid-Open No. Sho 6 (1994)).
1-178454, JP-A-2000-219553). However, even if these liquid quick-setting agents are used, at present, satisfactory properties in terms of construction and physical properties have not been obtained.

Therefore, as a method of producing a small amount of dust,
A method was proposed in which a powder quick-setting agent was used in combination with a setting retarder to form a slurry, which was added to and mixed with cement concrete, and then a solution of an alkali metal aluminate was separately pumped, mixed, and sprayed. (Japanese Unexamined Patent Publication No. 05-139804).

Further, a quick setting method has been proposed which improves the working environment by forming a slurry by using a powder quick setting agent in combination with a setting retarder and blending alum with cement concrete (Japanese Patent Application Laid-Open No. HEI 9-205,878). 05-097491).

However, this application method is a method in which an alkali metal aluminate solution is separately pumped and sprayed, and since this method uses a highly alkaline liquid, glasses and gloves are used at the time of spraying. Is required, and there is a problem that it is difficult to handle and workability is reduced. In any of the methods, there is a problem that the operation becomes complicated because the quick-setting agent slurry is once batch-kneaded with a mixer, pump-fed and added to concrete, in combination with a setting retarder. In addition, the commonly used powder quick-setting agent for shotcrete is gelled and hardened in a few seconds to several tens of seconds, so water cannot be added and kneaded with a mixer. Therefore, a method of making a slurry has been required.

[0009] In recent years, from the viewpoint of safety and health, a quick-setting agent has been required which has improved workability and improved work environment such as dust.

As a result of various studies to solve the above-mentioned problems, the present inventor produced a quick-setting agent slurry using a specific quick-setting agent slurry continuous manufacturing apparatus, and added to and mixed with concrete to spray. By performing the construction, the inventor has found that the above problem can be solved, and has completed the present invention.

[0011]

That is, the present invention confronts the supply pipe 1, the water supply pipe 2, and the supply pipe 1 of the powder quick-setting agent fed by air through the gap b. And a discharge pipe 3 for a quick-setting agent slurry containing a powder quick-setting agent and water. Water supply pipe 2 is connected to the powder quick-setting agent supply pipe 1 and the quick-setting agent slurry discharge pipe 3;
A rapid-setting binder slurry by injecting more water to produce a quick-setting slurry, wherein the inner diameter d of the supply pipe 1 / the inner diameter D of the discharge pipe is 0.3 to 0.95. A device for continuously producing a quick-setting agent slurry, wherein the water-supply angle press-fitted from a gap b between the supply tube 1 and the discharge tube 3 is 10 to 90 degrees with respect to the axis of the supply tube 1. This is a continuous production apparatus for the slurry, and is a continuous production apparatus for the quick-setting slurry in which the gap b between the supply pipe 1 and the discharge pipe 3 / the inner diameter D of the supply pipe 1 is 0.05 to 0.2. An apparatus for continuously producing the quick-setting agent slurry which is 0.1 to 3 MPa higher than the compressed air pressure of the quick-setting agent, wherein the powder quick-setting agent is a continuous manufacturing apparatus for the quick-setting agent slurry containing calcium aluminate. The quick-setting agent slurry produced by the continuous setting device slurry manufacturing equipment is added to and mixed with cement concrete. , A spraying method of spraying construction.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings.

An apparatus for continuously producing a quick setting slurry according to the present invention comprises a powder quick setting agent fed by air, a supply pipe (hereinafter simply referred to as a supply pipe) 1 for the powder quick setting agent, and a quick setting slurry. And a water-pressurized water from a circumferential direction of a gap b with a discharge pipe (hereinafter simply referred to as a discharge pipe) 3 to continuously produce a quick-setting agent slurry. is there. That is, the powder quick setting agent fed by air is passed through the supply pipe 1 and mixed with water press-in from the water supply pipe 2 through the gap b.
It becomes a quick-setting agent slurry, is discharged from the discharge pipe 3, is mixed with separately pumped cement concrete, and is sprayed.

In the present invention, the discharge pipe 3 faces the supply pipe 1 via the gap b, and the water supply pipe 2 is connected to the supply pipe 1 and the discharge pipe 3 so that the discharge pipe 3 is located around the flow of the powder quick-setting agent. Water is injected through the gap b to continuously produce a quick-setting agent slurry containing a powder quick-setting agent and water.

For stable and continuous production of the quick-setting agent slurry, the inner diameter D of the discharge pipe 3 (hereinafter referred to as discharge pipe diameter) must be larger than the inner diameter d of the supply pipe 1 (hereinafter referred to as supply pipe diameter) d. The ratio of supply pipe diameter d / discharge pipe diameter D is preferably 0.3 to 0.95, and more preferably 0.5 to 0.9. If it is less than 0.3, the quick-setting agent may stay in the gap b between the supply pipe 1 and the discharge pipe 3 to be hardened and closed. If it exceeds 0.95, it is difficult to uniformly inject water, so that the quick-setting slurry is stable. May be hardened and clogged without being able to be produced.

The water supply angle of the water press-fitted from the gap b between the supply pipe 1 and the discharge pipe 3, which is the mixing angle of the water-pulverized powder quick-setting agent and water, is set with respect to the axis of the supply pipe 1. , Preferably 10 to 90 degrees, more preferably 20 to 40 degrees. If the water supply angle is less than 10 degrees, the mixture with the powder quick-setting agent is poor, so that the slurry may not be easily formed. If the water supply angle exceeds 90 degrees, the powder quick-setting agent may be hardly pumped and hardened in the supply pipe 1. May be blocked.

The ratio of the gap b between the supply pipe 1 and the discharge pipe 3 to the diameter d of the supply pipe is preferably 0.05 to 0.2, and more preferably 0.07 to 0.15. If it is less than 0.05, it is difficult to uniformly inject water from the circumference, and it may not be possible to stably produce a quick-setting agent slurry.If it exceeds 0.2, the quick-setting agent may stay in gaps, harden, and block. is there. Here, the gap b is an axial gap between the supply pipe 1 and the discharge pipe 3.

The feed water pressure is set at 0.
It is preferably 1-3 MPa higher, more preferably 1-3 MPa higher. If it is less than 0.1 MPa, the quick-setting agent may stay in the gap b and be hardened and closed, and if it is 3 MPa or more, excessive water pressure may be applied to the manufacturing apparatus.

The powder quick-setting admixture is one which causes the setting of cement concrete at an early stage, and specific examples thereof include calcium aluminate, alkali metal aluminate, and a mixture thereof with an alkali metal carbonate. It is also possible to use generally available powder quick setting agents for spraying.
Among these, use of calcium aluminate is preferred from the viewpoint of initial setting and strength development.

Calcium aluminate is obtained by mixing a raw material containing calcia and a raw material containing alumina and subjecting them to a heat treatment such as firing in a kiln or melting in an electric furnace.
With CaO and Al ₂ O ₃ as the main components, it is a general term for substances having hydration activity, and a small amount of CaO and / or Al ₂ O ₃ contains alkali metal oxides, alkaline earth metal oxides, silicon oxide,
Compounds substituted with titanium oxide, iron oxide, alkali metal halides, alkaline earth metal halides, alkali metal sulfates, alkaline earth metal sulfates, etc., or mainly containing CaO and Al ₂ O ₃ These are substances in which a small amount of these are dissolved. As the mineral form, either crystalline or amorphous can be used. Among these,
In terms of reaction activity, amorphous calcium aluminate is preferable, and amorphous calcium aluminate obtained by quenching a heat-treated product corresponding to 12CaO.7Al ₂ O ₃ (hereinafter, referred to as C ₁₂ A ₇ ) composition is more preferable. . The particle size of calcium aluminate
A Blaine value of 3,000 cm ² / g or more is preferable in terms of quick setting and initial strength. If it is less than 3,000 cm ² / g, quick setting and initial strength expression may be reduced.

In the powder quick setting agent of the present invention, it is preferable to use a setting accelerator in combination with the viewpoint of improving initial setting and strength development. Examples of the setting accelerator include sulfates and hydroxides.

Further, in the present invention, when the gelation hardening time of cement concrete is extended, it is also possible to use oxycarboxylic acids in combination with calcium aluminate, and it is also possible to use the oxycarboxylic acids dissolved in water to be slurried. is there.

The amount of water in the quick-setting agent slurry used in the present invention is preferably 50 to 130 parts with respect to 100 parts of the powder quick-setting agent.
70-100 parts are more preferable. If the amount is less than 50 parts, the gelling time of the quick-setting slurry is shortened, the viscosity of the quick-setting slurry is increased, scaling occurs in the pressure-feeding pipe, the pressure-feeding pipe is closed, and the quick-setting slurry is pumped and sprayed. Mixing with cement concrete may be reduced or the setting may be poor, the rebound rate may increase, and the amount of dust may increase.
If it exceeds 130 parts, the coagulability and the strength development may be reduced.

The quick-setting agent slurry manufactured by the continuous manufacturing apparatus for quick-setting agent slurry of the present invention is mixed with cement concrete and sprayed.

The amount of the quick-setting slurry used is 100 cement.
Parts by weight, preferably 2 to 25 parts in terms of solid content, 5 to 20 parts
Parts are more preferred, and 7 to 15 parts is most preferred. If it is less than 2 parts, the initial setting may not be easily promoted, and if it exceeds 25 parts, the long-term strength development may be impaired.

Here, as the cement, various kinds of Portland cement which are usually commercially available, such as ordinary, fast, moderate heat, and super fast, and various kinds of mixed Portland cement mixed with fly ash or blast furnace slag, etc. Cement and the like can be mentioned, and these can be used in the form of fine powder.

In the present invention, if necessary, a water reducing agent, a thickening agent and the like can be used.

The amount of water used in cement concrete is
From the viewpoint of workability and strength development, the water / cement ratio is preferably 35% or more, more preferably 40 to 55%.

The aggregate preferably has a low water absorption and a high aggregate strength. The maximum size of the aggregate is not particularly limited as long as it can be sprayed. As fine aggregate, river sand, mountain sand,
Lime sand, silica sand, and the like can be used, and as coarse aggregate, river gravel, mountain gravel, lime gravel, and the like can be used.

As the spraying method of the present invention, various spraying methods according to the required physical properties, economy, workability and the like are possible. In the present invention, a dry spraying method is also possible, but since there is a possibility that the amount of dust increases, a wet spraying method in which water is previously added to the cement concrete side and kneaded before using the quick-setting agent is preferable.

As a wet spraying method, for example, cement, fine aggregate, coarse aggregate, and water are added and kneaded, air-pneumatically fed, a Y-shaped pipe is provided in the middle, and a quick-setting agent supply device is provided from one of them. The powder quick-setting admixture is pressure-fed, and the quick-setting admixture slurry is manufactured by a quick-setting admixture slurry continuous manufacturing apparatus attached to the Y-tube inlet.
There is a method of spraying what is combined with the fed concrete and mixed to form a quick-setting wet-sprayed concrete.

In the spraying method of the present invention, usually, the spraying pressure is preferably 0.2 to 0.5 MPa, and the spraying speed is 4 to 2 MPa.
0 m ³ / h is preferred.

Further, the pressure of the compressed air for pumping the powder quick-setting admixture is set to be 0.01 to less than the pressure of the cement concrete pumping air so that the inside of the pumping tube is not blocked when the cement concrete is mixed into the quick-setting slurry. It is preferably higher by 0.3 MPa.

In the spraying method of the present invention, the spraying equipment is not particularly limited as long as the spraying is sufficiently performed, and a conventional spraying equipment can be used. For example, Alibar's trade name “Alibar 280” or the like can be used for pumping of sprayed cement concrete, and a quick-setting agent pumping device “Natom Cleat” or the like can be used for pumping of powder quick-setting agent.

[0035]

The present invention will be described below in detail based on experimental examples.

EXPERIMENTAL EXAMPLE 1 Under the conditions of a discharge rate of 3 kg / min and a pressure air pressure of 0.35 MPa, a powder quick-setting agent was air-fed using a quick-setting agent adding device "NATOM CLEAT". Under the conditions, the powder quick-setting agent 100
To this part, 70 parts of water was added to form a quick-setting slurry, and the mixture was pumped for 10 minutes. When scaling, the pumping pipe and the like may be blocked, and stable construction may not be performed. Therefore, after the pumping, the scaling state of the pumping pipe was checked. The results are also shown in Table 1.

<Materials> Powder quick-setting agent A: Commercial product, main component calcium aluminate, alkali metal salt Powder quick-setting agent B: Commercial product, main component calcium aluminate, sulfate

<Measurement Method> Scaling state: 、: visual, no scaling, Δ: slight scaling, x: large scaling.

[0039]

[Table 1]

Experimental Example 2 The unit amount of each material was 450 kg / m ^{3 of} cement and 1,115 kg of fine aggregate.
/ m ³ , coarse aggregate 605 kg / m ³ , and water 203 kg / m ³ to prepare shotcrete. The prepared shotcrete was pneumatically fed by a concrete pump "Aliver 280" under a spraying pressure of 0.3 MPa and a spraying speed of 4 m ³ / h. On the other hand, the powder quick setting agent shown in Table 2 was blended so as to be 10 parts with respect to 100 parts of cement, and the air pressure was 0.35 MPa
Under the conditions described above, air pressure is supplied using a quick-setting additive adding device "Natom Cleat", and to the continuous device of the quick-setting slurry provided at the entrance of the Y-tube provided on the way, to 100 parts of the powder quick-setting agent On the other hand, 70 parts of water was added to obtain a quick-setting binder slurry. This quick-setting agent slurry was mixed with the sprayed concrete fed from the other end of the Y-tube to obtain a quick-setting sprayed concrete. The compressive strength,
The rebound rate and the amount of dust were measured. The results are also shown in Table 2. The results of spraying with a powder quick-setting admixture are also shown as comparative examples.

<Materials Used> Cement: ordinary Portland cement, specific gravity 3.16 Fine aggregate: Himekawa sand from Himekawa, Niigata prefecture, surface dry, specific gravity 2.62 Coarse aggregate: Himekawa gravel from Himekawa, Niigata prefecture, surface dry,
Specific gravity 2.64, maximum dimension 10mm

<Measurement method> Compressive strength: The compressive strength for one hour of age is 25 cm wide by 25 cm long. A pin installed on a pull-out mold is covered with quick-setting sprayable concrete from the surface of the pull-out mold. Pull out the pin from the back side of the frame, find the pullout strength at that time,
The compressive strength was calculated from the formula of (compressive strength) = (pull-out strength) × 4 / (sample contact area). For compressive strength after 1 day of age, quick-setting shotcrete is sprayed on a 50cm wide x 50cm long x 20cm thick formwork, and a sample of 5cm in diameter x 10cm in length is sampled with a 20-ton pressure machine. Measurement Rebound rate: Rapid setting shotcrete at a pumping speed of 4 m ³ / h for 10 minutes, height 3.5 in an arched form made of iron plate
m, simulated 2.5m wide tunnel, (rebound rate)
Calculated as = (mass of quick-setting sprayed concrete that has fallen without adhering to the simulated tunnel) / (mass of quick-setting sprayed concrete blasted on the simulated tunnel) x 100 (%) Dust amount: quick-setting Shotcrete is sprayed at a pumping speed of 4m ³ / h for 10 minutes into a simulated tunnel, and the dust amount is measured at a fixed position 3m from the spraying location and 1.5m from the floor.

[0043]

[Table 2]

[0044]

The use of the apparatus for continuously producing a quick-setting agent slurry of the present invention makes it possible to reduce the amount of dust generated.
The working environment is improved. In addition, there is an effect that, at an initial stage or a long period, the same strength as that of the conventional powder quick-setting agent can be expected.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an example of a continuous production apparatus for a quick-setting agent slurry of the present invention.

[Description of Signs] 1 supply pipe 2 water supply pipe 3 discharge pipe b gap between supply pipe and discharge pipe d inner diameter of supply pipe D inner diameter of discharge pipe

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2D044 DC05 2D055 DB01 2E172 AA05 AA13 DC02 DC06 4G012 MB00 PB05 PC06 PE04

Claims (7)

[Claims] 1. A supply pipe 1 for a powder quick-setting agent fed by air.
It comprises a water supply pipe 2 and a discharge pipe 3 of a quick-setting agent slurry containing a powder quick-setting agent and water, which faces the powder quick-setting agent supply pipe 1 through a gap b. The inner diameter d of the binder supply pipe 1 is smaller than the inner diameter D of the quick-setting agent slurry discharge pipe 3, and the water supply pipe 2 connects the powder quick-setting agent supply pipe 1 and the quick-setting agent slurry discharge pipe 3, A quick-setting agent slurry continuous production apparatus, wherein water is injected from the gap b to produce a quick-setting agent slurry. 2. The method according to claim 1, wherein (inner diameter d of supply pipe 1 of powder quick-setting agent) / (inner diameter D of discharge pipe 3 of quick-setting agent slurry) is 0.3 to 0.95. Continuous production equipment for quick setting slurry. 3. The water supply angle press-fitted from a gap b between the powder quick-setting agent supply pipe 1 and the quick-setting agent slurry discharge pipe 3 is 10 to 10 degrees with respect to the axis of the powder quick-setting agent supply pipe 1. 3. The continuous production apparatus for quick-setting agent slurry according to claim 1, wherein the inclination is 90 degrees. 4. The gap (b) between the powder quick-setting agent supply pipe 1 and the quick-setting agent slurry discharge pipe 3 / (inner diameter d of the powder quick-setting agent supply pipe 1) is 0.05 to 0.2. The apparatus for continuously producing a quick-setting agent slurry according to claim 1, wherein: 5. The feed water pressure is higher than the compressed air pressure of the powder quick-setting agent by 0.5.
The apparatus for continuously producing a quick-setting agent slurry according to any one of claims 1 to 4, wherein the pressure is higher by 1 to 3 MPa. 6. The apparatus for continuously producing a quick-setting agent slurry according to claim 1, wherein the powder quick-setting agent contains calcium aluminate. 7. A quick-setting agent slurry produced by the quick-setting agent slurry continuous production apparatus according to claim 1 is added to and mixed with cement concrete and sprayed. Spraying method.