JP2003081668A - Quick setting agent, quick setting agent slurry, spraying material, and spraying method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a quick setting agent which can reduce the amount of dust to be produced, can achieve high strength at the initial stage of spraying, and therefore has improved stability, and is sprayed, e.g. on exposed natural ground surfaces in the tunnels, surfaces of slopes or the like of roads, railroads, aqueduct channels or the like, and to provide a quick setting agent slurry, a spraying material, and a spraying method using the same. SOLUTION: The quick setting agent contains calcium aluminates, alkali metal aluminate, slaked lime and oxycarboxylic acids. The quick setting agent slurry contains the quick setting agent and water. The spraying material contains cement concrete and the quick setting agent slurry. In the spraying method, water is added to the quick setting agent to continuously prepare the quick setting agent slurry, and the slurry is flowingly mixed with cement concrete, and this mixture is sprayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quick-setting agent, quick-setting agent slurry, spraying material, and the like, which are sprayed onto exposed ground surfaces in tunnels, slopes, etc., such as roads, railways, and water conduits. It relates to a spraying method using it. Incidentally, the cement concrete of the present invention, paste, mortar,
And is a generic term for concrete. In addition, parts and% in the present invention are based on mass unless otherwise specified.

[0002]

2. Description of the Related Art Conventionally, in order to prevent collapse of exposed ground such as tunnel excavation, a quick-setting concrete spraying method in which a quick-setting agent is mixed with concrete has been performed.
(Japanese Patent Publication No. 60-4149). This method is usually used to prepare sprayed concrete at a cement, aggregate, and water metering and mixing plant installed at an excavation site, transport it with an agitator car, and pump it with a concrete pump. A method of mixing with a quick-setting agent that has been pressure-fed from the other side and spraying it as quick-setting sprayed concrete on the ground surface to a predetermined thickness.

Further, as the quick-setting agent which has been conventionally used, calcium aluminate, a mixture of alkali metal aluminate and alkali carbonate, and calcium aluminate, alkali metal aluminate and alkali carbonate. Mixtures such as salt, calcium aluminate and 3C
A mixture of aO and SiO ₂ is known (Japanese Patent Laid-Open No. 64-051351).
JP-B-56-27457, JP-A-61-026538, and JP-A-63-210050).

These quick-setting agents have the function of promoting the setting of cement, and both are mixed with cement concrete and sprayed onto the ground surface. The method of adding the quick-setting agent was usually a method of increasing the amount of dust 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, or the like when performing the spraying work, and a construction method with a smaller amount of dust has been required.

As a method for producing a small amount of dust, a method is proposed in which a quick-setting admixture is slurried and mixed with cement concrete, and then a solution of an alkali metal aluminate is separately pressure-fed, mixed and sprayed. Has been
(See JP-A-5-139804). However, since this method uses a highly alkaline liquid, it is difficult to handle, and protective glasses, gloves, etc. are required at the time of spraying, and there is a problem that workability deteriorates.

On the other hand, there has been proposed a quick-setting construction method for improving the working environment by slurrying a quick-setting agent and mixing alum with cement concrete (Japanese Patent Laid-Open No. 5-097491). reference). However,
In recent years, in order to improve workability and shorten the construction period, it has been required to further improve quick connection.

As a result of various studies on the above problems and requirements, the present inventor has found that the problems and requirements can be solved by spraying with a specific quick-setting agent. Has been completed.

[0008]

Means for Solving the Problems That is, the present invention is a quick-setting agent containing calcium aluminate, alkali metal aluminate, slaked lime, and oxycarboxylic acid. Is a quick-setting admixture containing, and a spraying material containing cement concrete and the quick-setting admixture, by adding water to the quick-setting admixture, the quick-setting admixture slurry is continuously formed. This is a spraying method in which it is prepared, mixed and mixed with cement concrete, and then sprayed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

The calcium aluminates used in the present invention are obtained by mixing a raw material containing calcia and a raw material containing alumina, and subjecting the mixture to firing in a kiln or heat treatment such as melting in an electric furnace. , CaO and Al ₂ O ₃ as main components,
It is a general term for substances having hydration activity, and CaO and Al ₂ O ₃ are partially alkali metal oxides, alkaline earth metal oxides, silicon oxides, titanium oxides, iron oxides, alkali metal halides, alkaline earths. A compound in which a small amount of these are solid-dissolved in a compound substituted with a metal halide, an alkali metal sulfate, an alkaline earth metal sulfate, or the like, or a compound containing CaO and Al ₂ O ₃ as main components. The mineral form may be crystalline or amorphous. Among these, in terms of reaction activity, amorphous calcium aluminates are preferable, and the amorphous material obtained by quenching the heat-treated product corresponding to the composition of 12CaO · 7Al ₂ O ₃ (hereinafter, C ₁₂ A ₇ ) is amorphous. Calcium aluminate is more preferred. The particle size of the calcium aluminates is 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. 3,000 cm ²
When it is less than / g, the quick-setting property and the initial strength development of the quick-setting spray-cement concrete in which the quick-setting agent and the spray-cement concrete are mixed may decrease.

The alkali metal aluminate used in the present invention (hereinafter referred to as "aluminate") promotes the initial setting of cement, and aluminum hydroxide and alkali metal hydroxide are mixed and dissolved and dried. And obtained as a powder. Examples of the aluminate include sodium aluminate, potassium aluminate, lithium aluminate and the like, and it is possible to use one kind or two or more kinds thereof. Among these, it is preferable to use sodium aluminate in terms of the setting property and the initial strength development property of the quick-setting spray-cement concrete. The amount of the aluminate used is preferably 10 to 70 parts, and more preferably 20 to 50 parts, per 100 parts of calcium aluminate.
If it is less than 10 parts, the initial setting may be delayed and the initial strength development may be deteriorated, and if it exceeds 70 parts, the viscosity of the quick-setting admixture slurry may increase, and the workability and long-term strength development of quick-setting spray-cement concrete may increase. It may decrease.

The slaked lime used in the present invention promotes the initial setting of cement, and examples thereof include calcium hydroxide produced by the reaction of quick lime with water. The amount of slaked lime used is 20 to 1 for 100 parts of calcium aluminate.
50 parts is preferable, and 50 to 100 parts is more preferable. If it is less than 20 parts, the initial setting of the quick-setting spray-cement concrete may be delayed and the initial strength developability may decrease.If it exceeds 150 parts, the viscosity of the quick-setting admixture slurry may increase, resulting in poor workability and long-term strength development. It may decrease.

Examples of the oxycarboxylic acids used in the present invention (hereinafter referred to as oxyacids) 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 from the viewpoint of developing the initial strength. The amount of oxyacids used is preferably 0.3 to 3 parts, and 0.5 to 3 parts per 100 parts of calcium aluminate.
2 parts is more preferred. If it is less than 0.3 part, it inhibits the setting property and the initial strength development of the quick-setting shotcrete concrete,
The viscosity of the quick-setting admixture slurry may increase and the workability of the quick-setting spray-cement concrete may decrease, and if it exceeds 3 parts, the cohesiveness and strength development may be impaired.

The amount of slurry water used in the quick-setting admixture slurry used in the present invention is 100% of the quick-setting admixture containing calcium aluminate, aluminate, slaked lime, and oxyacids.
The amount is preferably 50 to 200 parts, more preferably 70 to 150 parts. If it is less than 50 parts, the viscosity of the quick-setting adhesive slurry increases,
In some cases, the pumpability of the quick-setting admixture slurry and the mixing properties with the spray-cement concrete decrease, the coagulability of the quick-setting spray-cement concrete deteriorates, the rebound rate increases, and the amount of dust increases. If it exceeds 200 parts, the coagulability and strength development may decrease.

The amount of the quick-setting agent used is preferably 3 to 20 parts, more preferably 5 to 15 parts, and most preferably 7 to 10 parts in terms of solid content, based on 100 parts of cement. If it is less than 3 parts, it may be difficult to accelerate the initial setting of the quick-setting shotcrete concrete, and if it exceeds 20 parts, the long-term strength development may be impaired.

Here, the cement means various portland cements such as ordinary, early strength, moderate heat, and super early strength which are usually commercially available, and various mixed cements obtained by mixing fly ash, blast furnace slag and the like with these various portland cements. And the like, and it is also possible to use these in the form of fine powder.

In the quick-setting admixture slurry of the present invention, a water reducing agent, a thickening agent and the like can be further used, if necessary.

The cement concrete used in the present invention contains cement and aggregate. Here, as the aggregate, one having a low water absorption rate and a high aggregate strength is preferable. 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,
And silica sand can be used, and as coarse aggregate, river gravel, mountain gravel, lime gravel, and the like can be used.

From the viewpoint of strength development, the amount of water used for cement concrete is preferably 35% or more, and 40 to 55%.
Is more preferable. If it is less than 35%, cement concrete may not be mixed sufficiently.

In the spraying method using the quick-setting admixture slurry of the present invention, conventionally used spraying equipment and the like can be used. Specifically, for example, the product name "Alibar 280" manufactured by Aliber Co., Ltd. is used to press-powder cement concrete, and the quick-setting admixture pumping device "NATOM CLEAT" is used to press-feed the quick-setting admixture. It is possible.

As the spraying method using the quick-setting admixture slurry of the present invention, various spraying methods can be used depending on the required physical properties, economy, workability and the like. As a spraying method using the quick-setting admixture slurry of the present invention, a dry-type spraying construction method can also be applied, but since the amount of dust may be large, water is previously applied to the cement concrete side before using the quick-setting admixture. In addition, it is preferable to use a kneaded wet spraying method.

As the wet spraying method, for example, cement, fine aggregate, coarse aggregate, and water are added and kneaded, pneumatically fed, and a Y-shaped pipe is provided on the way, and a quick-setting agent supply device is provided from one of them. There is a method of spraying a quick-setting wet-sprayed concrete by confluently mixing the quick-setting agents that have been pressure-fed.

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

Further, the pressure of the compressed air for pumping the quick-setting admixture is 0.01 to 0.3 MPa from the pressure-feeding pressure of the cement concrete so that the inside of the press-feeding tube is not clogged when the cement-concrete is mixed into the pressure-feeding tube of the quick-setting admixture slurry. It is preferably large.

In the spraying method using the quick-setting admixture slurry of the present invention, in order to reduce dust and rebound, slurry water is added to the powder quick-setting admixture to continuously make the quick-setting admixture into a slurry. It is preferable that the quick-setting admixture slurry is mixed with spray cement concrete at the tip of the discharge port and sprayed. As a method for continuously slurrying the quick-setting admixture, for example, a hole is formed around the pressure-feeding pipe for pneumatically feeding the powder quick-setting admixture, and high-pressure water is slurried into the pressure-feeding pipe through the hole to form a slurry. The method of sending can be used.

[0026]

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

Experimental Example 1 100 parts of calcium aluminate, and 100 parts of calcium aluminate, a quick-setting admixture 100 comprising aluminate A, slaked lime, and oxyacids α in the amounts shown in Table 1.
Parts and 80 parts of slurry water were mixed and stirred to prepare a quick-setting agent slurry, and its viscosity was measured. The results are also shown in Table 1. Also, sand / cement ratio = 3, water / cement ratio = 53%
Was prepared, and 7 parts of the quick-setting admixture slurry in terms of solid content was added to 100 parts of the cement to obtain a quick-setting mortar, and the setting time and the compressive strength thereof were measured. In addition, mortar water /
The cement ratio was 60%. The results are also shown in Table 1.

<Materials used> Cement: Normal Portland cement, commercial product, Blaine value 3,200 cm ² / g, specific gravity 3.16 Fine aggregate: River sand from Himekawa, Itoigawa City, Niigata Prefecture, surface dry condition, specific gravity 2.62 Calcium aluminates: C ₁₂ A ₇ Corresponding to composition, amorphous, Blaine value 6,500 cm ² / g Aluminate A: sodium aluminate, commercial product, loss on ignition 2.1%, 90% particle size 0.2 mm slaked lime: commercial product oxyacids α: Sodium gluconate, commercial product

<Measurement method> Viscosity: The quick-setting admixture slurry is measured with a B-type viscometer. Coagulation time: The quick-setting mortar is compliant with the Japan Society of Civil Engineers standard “Quick-setting admixture quality standard for shotcrete (JSCED-102)” Measurement compressive strength: Measures quick-setting mortar according to JIS R 5201

[0030]

[Table 1]

Experimental Example 2 With respect to 100 parts of calcium aluminate, 100 parts of the quick-setting admixture consisting of 50 parts of aluminate shown in Table 2, 80 parts of slaked lime and 1.0 part of oxyacids, and the amount shown in Table 2 The same procedure as in Experimental Example 1 was performed except that the quick-setting agent slurry was prepared by mixing and stirring slurry water. The results are also shown in Table 2.

<Materials used> Aluminate B: potassium aluminate, a commercial product, ignition loss 2.3%, oxyacids β: sodium citrate, a commercial product

[0033]

[Table 2]

Experimental Example 3 100 parts of calcium aluminate, aluminate A50
Parts, 80 parts of slaked lime, and 100 parts of a quick-setting admixture consisting of 1.0 part of oxyacids and 80 parts of slurry water were mixed and stirred to prepare a quick-setting admixture slurry. A mortar with a sand / cement ratio of 3 and a water / cement ratio of 53% was prepared, and 100 parts of the cement was mixed with the mortar of the quick-setting agent slurry in the amount shown in Table 3 in terms of solid content. Was mixed and mixed to prepare a quick-setting mortar, and the setting time and compressive strength were measured. The results are also shown in Table 3.

[0035]

[Table 3]

Experimental Example 4 Unit amount of each material, cement 400 kg / m ³ , fine aggregate 1,058 kg / m
³ , coarse aggregate 710kg / m ³ , water 200kg / m ³ , and high-performance water reducing agent 4k
Spraying concrete was prepared as g / m ³ , and this spraying concrete was pneumatically fed by a concrete pump “Aliver 280” under the conditions of a spraying pressure of 0.4 MPa and a spraying speed of 4 m ³ / h. On the other hand, calcium aluminates 100
Parts, aluminate A 50 parts, slaked lime 80 parts, oxyacids α1.
A quick-setting admixture consisting of 0 parts was pneumatically fed using a quick-setting admixture adding device "NATOM CLEAT" under the condition of a pressure-feeding pressure of 0.5 MPa so as to be 7 parts with respect to 100 parts of cement. 80 parts of the slurry water was added to 100 parts of the quick-setting admixture through holes provided at several places around one of the provided Y-shaped pipes to form a quick-setting admixture slurry. This quick-setting admixture slurry was mixed with the quick-setting admixture, in which the slurry water was not added, under pressure feed, and was mixed from the other side of the Y-shaped pipe to obtain a quick-setting admixture concrete. Concrete compressive strength, rebound rate, and dust amount were measured for this quick-setting shotcrete. The results are shown in Table 4.

<Materials Used> Coarse Aggregate: River gravel from Himekawa, Itoigawa City, Niigata Prefecture, surface dry state,
Specific gravity 2.64, maximum dimension 10 mm

<Measurement method> Concrete compressive strength: The compressive strength at an age of 1 hour is 25
cm × 25 cm length of the pullout formwork, the pins are covered with quick-setting shotcrete from the surface of the pullout formwork, the pins are pulled out from the backside of the formwork, and the pullout strength at that time is calculated. = Compressive strength was calculated from the formula: (pull-out strength) x 4 / (contact area of specimen). The compressive strength after 1 day of age is 5 cm in diameter, which is obtained by spraying quick-setting shotcrete on a mold of width 50 cm x length 50 cm x thickness 20 cm.
C. A specimen with a length of 10 cm was measured with a 20 ton pressure machine to determine the compressive strength. Rebound rate: Quick-setting shotcrete made of arched steel plate with a pumping speed of 4 m ³ / h for 10 minutes, height 3.5
It was sprayed on a m. tunnel with a width of 2.5 m. After that, (rebound rate) = (amount of quick-setting sprayed concrete that fell without adhering to the simulated tunnel) / (amount of quick-set sprayed concrete sprayed in the simulated tunnel) x 100 (%) did. Dust amount: A quick-setting shotcrete made in an arc shape with an iron plate at a pumping speed of 4 m ³ / h for 10 minutes, height 3.5
It was sprayed on a m. tunnel with a width of 2.5 m. Then, the dust amount was measured at a fixed position 3 m from the spraying place.

[0039]

[Table 4]

[0040]

By using the quick-setting admixture of the present invention, the amount of dust generated can be reduced. Furthermore, since high strength is obtained in the initial stage of spraying, safety is also improved.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) E02D 17/20 104 E02D 17/20 104B E21D 11/10 E21D 11/10 D // C04B 103: 12 C04B 103 : 12 F term (reference) 2D044 DC04 2D055 BA05 DB03 KA08 4G012 PB03 PB05 PC06 PE04 4G056 AA07 CB32

Claims (4)

[Claims] 1. A quick-setting agent containing calcium aluminate, alkali metal aluminate, slaked lime, and oxycarboxylic acid. 2. A quick-setting admixture slurry containing the quick-setting admixture according to claim 1 and water. 3. A spraying material containing cement concrete containing cement and the quick-setting admixture slurry according to claim 2. 4. A spraying method characterized in that a quick-setting agent slurry is continuously prepared by adding water to the quick-setting agent according to claim 1, and is mixed and mixed with cement concrete and sprayed.