JPH10251049A - Accelerating agent, spray material and spray process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a curing accelerating agent and a spray material for spraying to the ceiling part or the wall part of a tunnel or the like, free from adverse effect on working environment or ambient environment and having excellent accelerating property. SOLUTION: The accelerating agent contains a CaO-Al2 O3 -LiO2 based material 1-15wt.% in LiO2 content and aluminum sulfate as effective components. And the curing accelerating agent contains the CaO-Al2 O3 -Li2 O based material 1-15wt.% in LiO2 content, aluminum sulfate and a pozzolane material as effective components. The pozzolane material is one or more kinds selected from a group composed of a silica fume, a meta kaoline, a blast furnace slag and a fly ash. The spray material contains cement and the accelerating agent as effective components. A spray concrete contains the spray material as an effective components. The spray process is by spraying the spray concrete.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quick setting material, a spraying material, and a spraying method using the same, and particularly to the adhesiveness and quick setting property of concrete which is sprayed on a ceiling or a wall of a tunnel or a shaft. The present invention relates to a quick-setting material, a spray material, and a spraying method using the same. Note that the sprayed concrete in the present invention is a general term for sprayed cement paste, mortar, and concrete.

[0002]

2. Description of the Related Art Conventionally, a method for spraying concrete or the like at the time of excavating a tunnel and lining the tunnel to prevent collapse of the excavated surface due to falling surface or spring water has been generally implemented. Usually, a quick-setting material is added to such concrete in order to impart quick-setting properties.

[0003] Generally, in tunnel construction, primary spraying of spraying concrete to an excavation surface is often performed, and then secondary lining for constructing a concrete wall on the sprayed surface is often performed. The single shell method, which is completed only by itself, tends to be widely adopted.

[0004] The spraying method of sprayed concrete is roughly classified into two methods, a dry spraying method and a wet spraying method. The dry spraying method is a method of transporting a mixture of cement, aggregate, and quick-setting material that has been pulverized by compressed air, adding and mixing water immediately before spraying, and spraying the work surface from a nozzle by wet spraying. The law is
In this method, concrete mixed with water is transported, a quick-setting material is added and mixed on the way, and sprayed from a nozzle.

[0005] As a quick-setting material used for spraying, a composition comprising calcium aluminate and a carbonate or aluminate of an alkali metal, a composition comprising calcined alunite, lime, and an alkali metal carbonate; Also, compositions comprising alkali metal carbonates, hydroxides, silicates, and aluminates have been proposed (Japanese Patent Publication No. 56-27457,
JP-A-60-260452). These quick-setting materials usually contain sodium and potassium which exhibit strong alkalinity in the form of hydroxides, carbonates, silicates, aluminates and the like in order to obtain rapid setting. Since these sodium and potassium are strongly alkaline, there is a problem that if they are contained in shotcrete, an alkali-aggregate reaction occurs depending on the aggregate used, which adversely affects the concrete structure. In addition, these strongly alkaline substances dissolve in water and have the property of causing severe burns when they come into direct contact with the worker's skin. There were problems such as inviting environmental pollution.

[0006] As a measure to solve these problems, as a quick-setting material for spraying containing little or no sodium or potassium, a setting accelerator consisting of calcium aluminate, calcium sulfoaluminate, and a basic aluminum salt is used. It has been proposed to divert the agent (JP-A-8-48553). However, there is a problem that these quick-setting materials do not have sufficient quick-setting properties and that the sprayed shot concrete rebounds, that is, has a large amount of rebound, so that a large amount of material is lost and dust is easily generated.

As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that by using a specific quick-setting material,
The present invention has been completed based on the finding that a shotcrete exhibiting excellent adhesive properties and quick-setting properties can be obtained without deteriorating the working environment and the surrounding environment.

[0008]

That is, the present invention provides a LiO_TwoIncluding
CaO-Al of 1 to 15% by weight_TwoO_Three-LiO_TwoSystem substances and aluminum sulfate
It is a quick-setting material containing lithium and aluminum as an active ingredient._TwoContent 1
~ 15 wt% CaO-Al_TwoO _Three-LiO_TwoSystem material, aluminum sulfate
And a quick-setting material containing a pozzolanic substance as an active ingredient,
The pozzolanic substance is silica fume, metakaolin,
Furnace slag and fly ash
One or more quick-setting materials, cement and
A spraying material containing a binder as an active ingredient;
Sprayed concrete as an active ingredient;
This is a spraying method characterized by spraying a REET.

Hereinafter, the present invention will be described in detail.

[0010] The present invention provides an active ingredient containing LiO _{2 having a} content of 1
To 15% of CaO-Al ₂ O ₃ -LiO ₂ based material (referred hereinafter CAL) relates quick-material made of aluminum sulfate, alkaline than those using compounds of sodium and potassium as quick-material Are low, and the harmful effects of using them can be reduced. C
AL is obtained by blending a CaO raw material, an Al ₂ O ₃ raw material, and a LiO ₂ raw material and subjecting them to a heat treatment. As a CaO raw material, slaked lime, limestone, calcium carbonate, and the like, Al ₂ O ₃
Raw materials include bauxite, residual aluminum ash, and alumina, and examples of the LiO ₂ raw material include lithium salts such as Li ₂ CO ₃ and LiOH. The heat treatment method in the production of CAL is not particularly limited, and includes, for example, a firing method using a rotary kiln or a melting method using an electric furnace, and the heat treatment time is not particularly limited. The heat treatment temperature is usually preferably about 1,100 to 1,800 ° C,
00 to 1,700 ° C is more preferable. If the temperature is lower than 1,100 ° C., unreacted raw materials may remain. If the temperature exceeds 1,800 ° C., energy loss increases, which is not preferable in terms of cost. The method of cooling the heat-treated product is not particularly limited. For example, any method such as a rapid cooling method using water or high-pressure air or a slow cooling method using standing can be used.

The CAL has a LiO ₂ content of 1 to 15% by weight, preferably 2 to 12% by weight, more preferably 3 to 9% by weight. If the LiO ₂ content is out of this range, the effects of the present invention may not be sufficiently obtained. In addition, CaO and Al _{2 in} CAL
Although the ratio of O ₃ is not particularly limited, CaO / Al ₂ O
_{The 3} molar ratio (hereinafter referred to as C / A molar ratio) is preferably 1.5 to 3.0. If the C / A molar ratio is less than 1.5, quick setting properties may deteriorate, and if it exceeds 3.0, long-term durability may decrease. Further, the presence of other components or impurities is not particularly limited, for example, TiO ₂ , MgO, Fe ₂ O ₃ , Na ₂ O, K ₂ O, SiO _{2 which} is expected to be mixed as other components , B
The presence of ₂ O ₃ , P ₂ O ₅ , F ₂ , SO _3, etc. has the effect of lowering the melting point of the fired material or melt during the heat treatment of each raw material and increasing the activity of the fired material or melt, etc. Therefore, there is no problem as long as the object of the present invention is not substantially inhibited. In the present invention, CAL can be either crystalline or amorphous. The fineness of CAL is preferably about 3,000 to 9,000 cm ² / g in Blaine value. In 3,000cm less than ² / g may not be obtained sufficient quick-setting property, 9,000cm ²
Even if you exceed / g, you may not be able to increase the effect.

The aluminum sulfate used in the present invention is necessary for improving quick-setting properties, and generally commercially available aluminum sulfate can be used, and is not affected by impurities usually contained. In addition, aluminum sulfate includes anhydrous salts and water of crystallization, but any of them can be used as it is, and is not limited by the amount of water of crystallization. The particle size of aluminum sulfate is not particularly limited, but a Blaine value of about 3,000 to 9,000 cm ² / g is preferable. The use amount of aluminum sulfate is preferably 20 to 50 parts by weight based on 100 parts by weight of CAL. If the amount of aluminum sulfate used is outside this range, good quick-setting properties may not be obtained.

The pozzolanic substance used in the present invention is a substance containing a reactive silicic acid, which hardens by reacting with calcium hydroxide, for example, artificial ones such as silica fume, metakaolin, blast furnace slag, and fly ash. There are natural substances such as diatomaceous earth and volcanic ash, and in the present invention, it is possible to use one or more pozzolanic substances selected from the group consisting of silica fume, metakaolin, blast furnace slag, and fly ash, with a quick setting property. This is preferable from the viewpoint of improving the repellency and reducing the rebound of sprayed concrete.

The silica fume used in the present invention is called silica flour, silica dust, micro silica, or the like, and is used as a deoxidizing agent or a desulfurizing agent in producing steel, or an alloy element is added to steel. This is an industrial by-product produced during the production of ferroalloys such as ferrosilicon used for this purpose and metallic silicon as a raw material for various materials. Ferrosilicon and metallic silicon are manufactured from silica stone or high-purity quartz, iron shavings, carbon or coal as a reducing agent, and heated to a high temperature near 2,000 ° C in an electric furnace. Silicon oxide generated as an intermediate product is gasified, a part of which is scattered in the air, oxidized in an exhaust duct, and SiO ₂ collected by a dust collector is silica fume, which is spherical ultrafine particles. The chemical composition of silica fume varies depending on the raw material used, the production method, the type of main product, and the like, but the main component is amorphous SiO ₂ , and the content of SiO ₂ is preferably at least 80% by weight. Further, the specific gravity of the silica fume is about 2.1 to 2.2, a bulk specific gravity of 250~300kg / m ³ approximately, fineness BET specific surface area 1
5,000 to 25,000 m ² / kg or so, and the average particle size is 0.1 to 0.2.mu.
m can be used.

The metakaolin used in the present invention is obtained by baking kaolinite at 500 to 600 ° C. to make amorphous the main components SiO ₂ and Al ₂ O ₃ . The particle size of metakaolin is preferably a Blaine value of 4,000 cm ² / g or more, more preferably 6,000 cm ² / g or more. If it is less than 4,000 cm ² / g, good quick-setting properties may not be obtained.

The blast furnace slag used in the present invention is obtained by crushing or crushing molten slag by-produced when pig iron is produced from iron ore in a blast furnace by quenching with water or air.
It is a fine powder mainly composed of aluminosilicate obtained by classification. Blast furnace slag consists of CaO, SiO ₂ , Al ₂ O ₃ , and M
gO, CaO / SiO ₂ = 1.15-1.25, (CaO + MgO) / (SiO ₂ +
Al ₂ O ₃ ) = 0.90 to 1.05, Al ₂ O ₃ is less than 15% by weight, and MgO
Is preferably less than 5% by weight. The particle size of the blast furnace slag is preferably 4,000 cm ² / g or more, and 6,000 cm ²
/ g or more is more preferable. If it is less than 4,000 cm ² / g, good quick-setting properties may not be obtained.

The fly ash used in the present invention, when the combustion of pulverized coal, which was collected which molten ash becomes cooled by spherical electrostatic precipitator or the like, the SiO ₂ 60
% Or more, and may also contain Al ₂ O ₃ , Fe ₂ O ₃ and carbon. The particle size of fly ash is preferably 3,000 to 6,000 cm ² / g in Blaine value. If it is less than 3,000 cm ² / g, good quick setting may not be obtained, and 6,000 cm ² / g
In some cases, further effects cannot be expected.

The amount of various pozzolanic substances used is CAL 100
50 to 200 parts by weight, preferably 100 to 1 part by weight,
50 parts by weight is more preferred. Outside this range, good quick-setting properties may not be obtained.

According to the present invention, a C content of 1 to 15% by weight of LiO ₂ is used.
It is a quick-setting material containing AL and aluminum sulfate as active ingredients, and uses a quick-setting material containing CAL, aluminum sulfate, and a pozzolan substance as active ingredients. The particle size of the quick-setting material is not particularly limited because it depends on the purpose and method of use, but usually, the Blaine value is 3,000 to 9,
000 cm ² / g is preferred. If it is less than 3,000 cm ² / g, quick-setting properties may decrease, and if it exceeds 9,000 cm ² / g, further effects cannot be achieved. In the case of a two-component system of CAL and aluminum sulfate, the amount of the quick setting material is preferably 3 to 15 parts by weight, more preferably 5 to 10 parts by weight, based on 100 parts by weight of the spraying material composed of cement and the quick setting material.
Parts by weight are more preferred. If the amount is less than 3 parts by weight, the quick-setting property of the spray material is not sufficient, and even if the amount exceeds 15 parts by weight, further effects cannot be achieved. When the quick-setting material is composed of a three-component system of CAL, aluminum sulfate, and pozzolan, the amount of the quick-setting material used is a spray material composed of cement and quick-setting material.
Of the 00 parts by weight, 5 to 20 parts by weight is preferable, and 8 to 15 parts by weight is more preferable. If the amount is less than 5 parts by weight, the quick-setting property of the spray material is not sufficient, and even if the amount exceeds 20 parts by weight, no further effect can be obtained.

Here, the cement used in the present invention is not particularly limited, and various portland cements which are usually used, such as ordinary, fast-strength, ultra-fast-strength and moderate heat, can be used.

Various additives can be used in combination with the quick-setting material and the spray material of the present invention. For example, setting agents, fibrous substances such as glass fibers, carbon fibers, and steel fibers, high molecular polymer emulsions (latex), coloring agents (pigments), AE agents, water reducing agents, AE water reducing agents,
Superplasticizer, rust inhibitor, insoluble admixture in water such as methyl cellulose, thickener, water retention agent, waterproofing agent such as calcium chloride, foaming agent, foaming agent, calcium-containing compounds such as calcium hydroxide, and One or more of antifreezing agents and the like can be used in combination as long as the object of the present invention is not impaired.

In producing the quick setting material and the spray material according to the present invention, it is possible to use existing mixing and stirring devices such as a tilting mixer, an omni mixer, a V-type mixer, a Henschel mixer and a Nauta mixer. It is. The mixing may be performed by mixing the respective materials at the time of construction, or may be performed by partially or entirely mixing the materials in advance. Furthermore, the curing method is not particularly limited, either.
Commonly used curing methods can be applied. In the spraying of the spray material of the present invention, any of a dry spraying method and a wet spraying method can be used.

[0023]

The present invention will be described below in detail with reference to examples.

Example 1 A CaO raw material, an Al ₂ O ₃ raw material and a LiO ₂ raw material were mixed, and 1,600
The clinker obtained by quenching the melt melted in an electric furnace at a temperature of ℃ was pulverized and adjusted to a Blaine value of 6,500 ± 200 cm ² / g to obtain various amorphous CALs as shown in Table 1. The composition ratio of CAL was determined by chemical analysis. 100 parts by weight of the adjusted CAL and 35 parts by weight of aluminum sulfate α were mixed to prepare a quick setting material. Spraying material consisting of cement and quick setting material 7 parts by weight of quick setting material in 100 parts by weight of cement were mixed with cement to produce a spraying material. 700 g of the produced spraying material and 2,100 g of fine aggregate were blended and kneaded at a low speed of a small table-top mortar mixer for 30 seconds, and then 350 g of water was added and kneaded at a high speed for 10 seconds to form a cement mortar. The setting properties were evaluated in terms of the resistance to penetration of the proctor. For comparison, the same operation was performed using a commercially available quick-setting material instead of the quick-setting material of the present invention. The results are also shown in Table 1.

<Materials> CaO raw material: reagent primary calcium carbonate Al ₂ O ₃ raw material: reagent primary aluminum oxide LiO ₂ raw material: reagent primary lithium carbonate aluminum sulfate α: anhydride, chemical reagent, 6,000 cm ² / g
Degree of commercial quick setting material: Main component calcium aluminate, 5,000cm ²
Cement: Made by Denki Kagaku Kogyo Co., Ltd., ordinary Portland cement, Blaine value: 3,300cm ² / g Fine aggregate: Himekawa river sand, Niigata prefecture, specific gravity 2.62 Water: Tap water

<Measurement method> Proctor penetration resistance: Immediately after kneading in a constant temperature room at 20 ° C., divide into two layers in a mold, stuff the mortar quickly with a piercing stick, and after pouring water, at predetermined intervals, ASTMC403- 65
Implemented using needle needle point area 1 / 40in ² according to T

[0027]

[Table 1]

Example 2 Example 2 was repeated except that the melt melted in an electric furnace at 1600 ° C. was gradually cooled. Table 2 shows the results.

[0029]

[Table 2]

Example 3 A sample was prepared in the same manner as in Example 1 except that 100 parts by weight of a quenched CAL having a C / A 2.5 content of 5% by weight of LiO _{2 and} aluminum sulfate shown in Table 3 were used. The results are also shown in Table 3.

<Materials> Aluminum sulfate β: 14-18 hydrate, chemical reagent, 6,000 c
m ² / g approximately

[0032]

[Table 3]

Example 4 A quick setting material prepared by blending 100 parts by weight of a rapidly quenched product CAL having a C / A 2.5 content of 5% by weight of LiO ₂ and 35 parts by weight of aluminum sulfate was used as shown in Table 4. Except for this, the procedure was the same as in Example 1. The results are also shown in Table 4.

[0034]

[Table 4]

Example 5 100 parts by weight of CAL prepared in Example 1, 35 parts by weight of aluminum sulfate α, and 125 parts by weight of a pozzolanic substance were blended to form a quick-setting material.
The same procedure as in Example 1 was carried out except that 10 parts by weight of the quick setting material was mixed. Table 5 shows the results.

<Materials used> Pozzolanic substance: silica fume, ferrosilicon production by-product, specific gravity 2.20, specific surface area 21.9 m ² / g

[0037]

[Table 5]

Example 6 The procedure of Example 5 was repeated except that the CAL prepared in Example 2 was used. Table 6 shows the results.

[0039]

[Table 6]

Example 7 CAL 1 shown in Table 7 with C / A 2.5 and LiO ₂ content of 5 parts by weight
Example 5 was repeated except that 00 parts by weight, 35 parts by weight of aluminum sulfate α, and 125 parts by weight of the pozzolanic substance shown in Table 7 were mixed. The results are also shown in Table 7.

<Materials used> Pozzolanic substance: metakaolin, commercial product, Blaine value 6,
000cm ² / g Pozzolanic substance: Blast furnace slag, commercial product, Blaine value 8,00
0cm ² / g Pozzolan substance: Fly ash, commercial product, Blaine value
4,000cm ² / g

[0042]

[Table 7]

Example 8 Example 7 was repeated except that aluminum sulfate β was used. Table 8 shows the results.

[0044]

[Table 8]

Example 9 Example 5 was repeated except that C / A 2.5, 100 parts by weight of quenched CAL having a LiO ₂ content of 5% by weight, aluminum sulfate α shown in Table 9 and 125 parts by weight of a pozzolanic substance were used. Performed similarly. The results are also shown in Table 9.

[0046]

[Table 9]

Example 10 Same as Example 5 except that C / A 2.5, 100 parts by weight of quenched CAL having a LiO ₂ content of 5% by weight, aluminum sulfate α35 parts by weight, and a pozzolanic substance shown in Table 10 were blended. I went to. The results are shown in Table 10.

[0048]

[Table 10]

Example 11 C / A 2.5, 100 parts by weight of quenched CAL having a LiO ₂ content of 5% by weight, aluminum sulfate α35 parts by weight, and a pozzolanic substance
125 parts by weight were blended to prepare a quick setting material. The procedure was performed in the same manner as in Example 1 except that the prepared quick-setting material was used as shown in Table 11 in 100 parts by weight of the spray material. Table 11 shows the results.
It is described together.

[0050]

[Table 11]

Example 12 A quick-setting material prepared by blending quenched product CAL having a C / A 2.5 and LiO ₂ content of 5% by weight shown in Table 12 with aluminum sulfate α was mixed with 7 parts by weight in 100 parts by weight of spraying material. and parts, the unit quantity of each material, cement 360 kg / m ^3, fine aggregates 1,130kg / m ^3, the coarse aggregate 756kg / m ^3, and water 162 kg / m ^3, the maximum aggregate size 10 mm,
Using concrete with a fine aggregate ratio of 60%, spraying was performed in a simulated tunnel with a height of 3.5m and a width of 3m with a dry spray machine or a wet spray machine, respectively, and the concrete that fell into the tunnel was rebounded. The amount was measured as the rebound rate. Table 12 shows the results.

<Materials> Coarse aggregate: Gravel from Himekawa, Niigata Prefecture, specific gravity 2.66

<Measurement method> Rebound ratio: The ratio of the amount used for spraying to the amount of rebound of concrete that fell without adhering when sprayed

[0054]

[Table 12]

Example 13 A quenched product CAL having a C / A 2.5 and a LiO ₂ content of 5% by weight as shown in Table 13, aluminum sulfate α, and a pozzolanic substance 125
Example 12 was carried out in the same manner as in Example 12 except that the quick-setting material prepared by blending parts by weight was changed to 10 parts by weight in 100 parts by weight of the spray material. The results are shown in Table 13.

[0056]

[Table 13]

[0057]

The quick-setting material of the present invention does not contain a strong alkali component such as sodium or potassium, so that it has no adverse effect on the working environment and the surrounding environment and has excellent quick-setting characteristics.

Claims (6)

[Claims] 1. A CaO-Al ₂ O ₃ -Li having a LiO ₂ content of 1 to 15% by weight.
Quick-setting material containing O ₂ substance and aluminum sulfate as active ingredients. _2. A CaO—Al ₂ O ₃ —Li having a LiO ₂ content of 1 to 15% by weight.
A quick setting material containing O ₂ -based substances, aluminum sulfate, and pozzolanic substances as active ingredients. 3. The quick-setting material according to claim 2, wherein the pozzolanic substance is one or more selected from the group consisting of silica fume, metakaolin, blast furnace slag, and fly ash. 4. A spray material comprising cement and the quick-setting material according to claim 1 as active ingredients. 5. A sprayed concrete comprising the sprayed material according to claim 4 as an active ingredient. 6. A method for spraying shotcrete, comprising spraying the shotcrete according to claim 5.