JP2002283336A - Continuous manufacturing device for quick setting agent slurry and spray technique using this device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuous manufacturing device for a quick setting agent slurry having such advantages that the generation of dust can be reduced to a low level, the operating environments are ameliorated, the display of the same initial or long-term strength as seen in a conventional powdered quick setting agent can be expected and the spraying of the agent slurry to an exposed mountainous terrain or the like is achieved as well as a spray technique using this device. SOLUTION: The continuous manufacturing device for a quick setting agent slurry is structured of a supply pipe for a pressure-fed powdered quick setting agent, a water supply pipe and a discharge pipe for the quick setting agent slurry arranged opposite to the supply pipe through a gap, the inside diameter of the supply pipe being the same as that of the discharge pipe and the water supply pipe being connected to the supply pipe and the discharge pipe. Water is forced into the supply pipe and the discharge pipe through the gap to manufacture the quick setting agent slurry. This device is characterized in that the water supply angel is 10 to 90 deg. with a supply pipe axis and the gap and the inside diameter of the supply pipe is 0.05 to 0.2 and further, that the water supply pressure is 0.05 to 3 MPa higher than the pressure at which the powdered quick setting agent is fed under pressure and the powdered quick setting agent contains a calcium aluminate. In addition, the spray technique is provided that the quick setting agent slurry manufactured by the continuous manufacturing device is added to and mixed with a cement concrete and the mixture is 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. . Incidentally, used in the present invention (part)
And (%) are based on mass unless otherwise specified. Further, the cement concrete of the present invention is a general term for paste, mortar, or 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 has been carried out to prevent collapse of exposed ground such as tunnel excavation (Japanese Patent Publication No. 60-4149). No.). 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.). The method of adding these quick-setting agents is poor in mixability with concrete due to powder mixing by pneumatic transportation, and the unsetting quick-setting agent is liable to be scattered as dust, deteriorating the working environment such as a tunnel. There were issues such as.

[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 Laid-Open Publication No.
61-178454, 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 has been proposed in which a quick setting agent is used in combination with a setting retarder to form a slurry, which is added to and mixed with cement concrete, and then a solution of an alkali metal aluminate is separately pumped, mixed, and sprayed. JP-A-05-139804).

[0007] A quick-setting method has been proposed which improves the working environment by slurrying a quick-setting agent together with a setting retarder and adding alum to cement concrete (Japanese Patent Laid-Open No. 05-2005). No. 097491).

However, the method of spraying by separately pumping the alkali metal aluminate solution requires the use of a highly alkaline liquid, so that eyeglasses and gloves are required at the time of spraying, making it difficult to handle and workability. There was a problem of lowering. In any of these methods, the setting agent slurry is batch-kneaded with a mixer once in combination with a setting retarder, and is pumped and added to concrete, so that the operation is complicated. In addition, the commonly used powder quick-setting agents for shotcrete are gelled and hardened in a few seconds to tens of seconds, so water cannot be added and kneaded with a mixer. There was a need for a method of making a slurry.

[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 provides a supply pipe, a water supply pipe, and a powder quick-setting agent and a water which are opposed to each other via a gap between the supply pipe and the water supply pipe of the pneumatically fed powder quick-setting agent. Comprising a discharge pipe of a quick-setting slurry containing the same, the inside diameter of the supply pipe and the inside diameter of the discharge pipe are the same, and the water supply pipe is connected to the supply pipe and the discharge pipe,
This is a continuous manufacturing apparatus for quick-setting slurry by injecting water from a gap between a supply pipe and a discharge pipe to produce a quick-setting slurry.
An apparatus for continuously producing the quick-setting agent slurry having a temperature of ~ 90 degrees,
A device for continuously producing the quick-setting agent slurry in which the inside diameter of the gap / supply pipe is 0.05 to 0.2, wherein the water supply pressure of water injected into the gap is 0.05 to 3 MPa higher than the pressure-feeding pressure of the powder quick-setting agent. A slurry continuous production device, wherein the powder quick-setting agent is a continuous production device for the quick-setting agent slurry containing calcium aluminate, and the quick-setting agent slurry produced by the rapid-setting agent slurry continuous production device is cemented. This is a spraying method in which concrete is added and mixed and sprayed.

[0012]

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

The continuous production apparatus for quick-setting agent slurry according to the present invention is characterized in that a gap (b) between the supply pipe (1) and the discharge pipe (3) of the quick-setting agent slurry is supplied by pneumatically fed powder. Is mixed with water which is press-fitted from the circumferential direction to continuously produce a quick-setting agent slurry. That is, the powder quick-setting agent fed by air is passed through the supply pipe (1), mixed with water press-in from the water supply pipe (2) through the gap (b), becomes a quick-setting agent slurry, and is discharged. It is discharged from the pipe (3) and mixed with separately pumped cement concrete to be 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), and presses water from around the flow of the powder quick-setting agent through the gap (b) to contain the powder quick-setting agent and water. Continuous production of quick setting slurry.

In the present invention, the inner diameter of the discharge pipe (3) (hereinafter referred to as the discharge pipe diameter) (D) is the same as the inner diameter of the supply pipe (1) (hereinafter referred to as the supply pipe diameter) (d). .

The angle of water supply, which is the mixing angle of the powder quick-setting admixture and the water fed by air pressure, which is press-fitted from the gap between the supply pipe and the discharge pipe, is 10 to 90 degrees with respect to the axis of the supply pipe. Preferably, it is 20 to 40 degrees. If the water supply angle is less than 10 degrees, the mixture with the powder quick-setting admixture is poor, so it may be difficult to form a slurry.If the water supply angle exceeds 90 degrees, the powder quick-adhesive agent is disturbed by pressure and hardens and blocks in the supply pipe. There are cases.

The ratio of the gap (b) to the supply pipe diameter (d), ie, the gap (b) / supply pipe diameter (d), is preferably 0.05 to 0.2, more preferably 0.07 to 0.15. If it is less than 0.05, water is hard to be uniformly injected 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 and harden and block. . Here, the interval (b) is an axial gap between the supply pipe (1) and the discharge pipe (3).

The water supply pressure is 0.1 to more than the pressure of the powder quick-setting agent.
It is preferably higher by 3 MPa, more preferably higher by 1 to 3 MPa. If it is less than 0.1 MPa, the quick-setting agent may stay in the gap and harden and close. If it exceeds 3 MPa, excessive water pressure may be applied to the production equipment.

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.
CaO and Al ₂ O ₃ as the main components, is a general term for substances having hydration activity, CaO and / or part of Al ₂ O ₃ is an alkali metal oxide, alkaline earth metal oxide, 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 reactivity, calcium aluminate amorphous are preferred, 12CaO · 7Al ₂ O ₃ (hereinafter, C ₁₂ of A ₇₎ and more preferably calcium aluminate amorphous quenched with corresponding heat-treated product of the composition . The particle size of the calcium aluminate is preferably 3,000 cm ² / g or more in terms of Blaine value 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 time of cement concrete is extended, it is possible to use oxycarboxylic acids in combination with calcium aluminate, and it is also possible to dissolve it in water to be slurried before use. .

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.

In the present invention, the quick-setting agent slurry manufactured by the continuous manufacturing apparatus for quick-setting agent slurry 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 the wet spraying method, for example, cement, fine aggregate, coarse aggregate, and water are added, kneaded, and air-kneaded, and a quick-setting agent supply device is supplied from one of the Y-tubes provided on the way. And a method of spraying a quick-setting wet-sprayed concrete by merging and mixing the quick-setting agent slurry produced by the quick-setting agent slurry continuous production apparatus.

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 0.01 to 0.01 to the pressure of the cement concrete pumped so that the inside of the pumping pipe is not blocked when the cement concrete is mixed into the quick-setting slurry. It is preferably 0.3 MPa higher.

In the spraying method of the present invention, the spraying equipment is not particularly limited as long as spraying is sufficiently performed, and a conventional spraying equipment can be used. For example, Ariver's trade name "Aliver 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 quick-setting agent.

[0035]

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

Experimental Example 1 Various powder quick-setting agents containing calcium aluminate were pneumatically fed by a quick-setting additive adding device "NATOM CLEAT".
Under the conditions shown in (1) and (2), the scaling state when the slurry was slurried in the continuous production apparatus for the quick setting slurry was measured.
Table 1 shows the results.

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

<Measurement method> Scaling state: discharge amount 3
Under the conditions of kg / min and a pumping pressure of 0.35 MPa, the powder quick-setting admixture is pneumatically fed using a quick-setting additive adding device `` NAT Cleat '',
70 parts of water was added to 100 parts of the powder quick-setting agent to a quick-setting agent slurry provided at the entrance of the Y-tube to make a quick-setting agent slurry, and the mixture was pressure-fed for 10 minutes. After the end of the pumping, the state of the scaling of the pumping tube was checked, and the case where there was no scaling was evaluated as ○, the case where there was a little scaling was evaluated as △, and the case where the scaling was large was evaluated as x.

[0039]

[Table 1]

Experimental Example 2 The unit amount of each material was 450 kg / m ^{3 of} cement and 1,080 kg of fine aggregate.
/ m ^3, coarse aggregate 639kg / m ^3, and was the shotcrete was prepared as a water 203kg / m ^3. 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 admixture was pneumatically fed under the condition of a pressure of 0.35 MPa using a quick-setting admixing device "Natom Cleat", and 70 parts of water was added to 100 parts of the powder quick-setting admixture. Then, a quick-setting agent slurry was prepared by a continuous manufacturing apparatus for the quick-setting agent slurry. This quick-setting agent slurry is mixed and mixed from one of the Y-shaped pipes provided in the middle of the pressure-feeding of the shotcrete so as to be 9 parts in terms of solid content with respect to 100 parts of cement. And The concrete compressive strength, rebound rate, and dust amount of the quick setting shotcrete were measured. Table 2 shows the results. Also, for comparison,
A similar experiment was carried out using a powder quick-setting agent without using a quick-setting agent slurry. The results are also shown in Table 2.

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

<Measurement method> Concrete compressive strength: The compressive strength at the age of 1 hour is covered by a pin set on a pull-out mold having a width of 25 cm and a length of 25 cm from the surface of the pull-out mold with quick-setting spray concrete. Pull out the pin from the back side of the mold, determine the pull-out strength at that time, and (compressive strength) =
Compressive strength was calculated from the formula (pull-out strength) × 4 / (sample contact area). Compressive strength after 1 day is 50cm width
A quick-setting shotcrete was sprayed on a mold having a length of 50 cm and a thickness of 20 cm, and a sample having a diameter of 5 cm and a length of 10 cm was measured with a 20-ton pressure machine to determine the compressive strength. Rebound rate: Quick-set shotcrete at a pumping speed of 4 m ³ / h for 10 minutes, height 3.5 in an arched form of iron plate
m, a 2.5m wide mock tunnel. Then, (rebound rate) = (amount of quick-setting sprayed concrete that fell without adhering to the simulated tunnel) / (amount of quick-setting sprayed concrete blasted on the simulated tunnel) x 100 (%) did. Dust amount: Quick-setting sprayed concrete was sprayed at a pumping speed of 4 m ³ / h for 10 minutes into a simulated tunnel. Thereafter, the dust amount was measured at a fixed position 3 m from the spraying location and 1.5 m 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.

[Explanation of symbols]

 Reference Signs List 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) 2D055 DB00 KA08 4G035 AB44 AC19 AE13 4G056 AA07 CC02 CD34 CD36

Claims (6)

[Claims] 1. A supply pipe (1) and a water supply pipe (2) for a pneumatically fed powder quick-setting agent, and a powder quick-setting agent facing the supply pipe (1) via a gap (b). And a discharge pipe (3) for a quick-setting agent slurry containing water, wherein the inner diameter (d) of the supply pipe (1) and the inner diameter (D) of the discharge pipe (3) are the same, and the water supply pipe (2) ) Is connected to the supply pipe (1) and the discharge pipe (3), and water is injected into the gap (b) between the supply pipe (1) and the discharge pipe (3) to produce a quick-setting binder slurry. Continuous production equipment for quick setting slurry. 2. A feed angle of water press-fitted from a gap (b) between the supply pipe (1) and the discharge pipe (3) is 10 to 90 degrees with respect to an axis of the supply pipe (1). The continuous production apparatus for a quick-setting agent slurry according to claim 1. 3. 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.
The continuous production apparatus for a quick-setting agent slurry according to claim 1 or 2, wherein: 4. The water supply pressure of water injected from the gap (b) between the supply pipe (1) and the discharge pipe (3) is 0.05 to 3 MPa higher than the pressure of the powder quick-setting agent. 4. The continuous production apparatus for a quick-setting agent slurry according to any one of the above-mentioned items. 5. The apparatus for continuously producing a quick-setting agent slurry according to claim 1, wherein the powder quick-setting agent contains calcium aluminate. 6. A quick-setting agent slurry produced by the continuous-setting device for continuous setting agent slurry according to claim 1 is added to and mixed with cement concrete and sprayed. Spraying method.