JP3483105B2 - Quick setting material, spraying material, and spraying method - Google Patents

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 for spraying on an exposed ground surface in a tunnel such as a road, a railroad, and a headrace.

[0002]

2. Description of the Related Art Conventionally, in order to prevent collapse of exposed ground such as in tunnel excavation, a spraying method of quick-setting sprayed concrete in which a quick-setting material is mixed with concrete has been carried out (Japanese Patent Publication No. 60-4149). ). This spraying method is usually used in cement mixing,
Aggregate and water are mixed to prepare sprayed concrete, which is transported by an agitator car, pumped by a concrete pump, mixed with a quick-setting material pumped from the other side by a confluent pipe provided in the middle, and quick-setting property. This is a method of spraying concrete onto the ground surface to a predetermined thickness.

The quick-setting materials currently on the market are water glass,
Alkali metal aluminate, combination of alkali metal aluminate and alkali metal carbonate, combination of alkali metal aluminate or combination of alkali metal aluminate and alkali metal carbonate with calcinated albite,
Also known are those containing calcium aluminate as a main component. However, water glass, alkali metal aluminates, alkali metal alkali carbonates, and combinations of alkali metal aluminates or alkali metal aluminates with alkali metal carbonates combined with calcined albite are quick set. However, since the property is small, there was a problem that it was difficult to carry out spraying at the spring location. Further, the range of the optimum addition amount of the quick-setting material to the cement is narrow, and there is a problem that it is difficult to manage it at the actual construction site.

Conventionally, as a quick-setting material containing sodium aluminate, a two-component system using sodium aluminate and calcium aluminate, a two-component system using sodium aluminate and sodium carbonate, and calcium Examples thereof include a three-component system in which aluminate is mixed (see Japanese Examined Patent Publication No. 56-27457).

Conventionally, sodium aluminate has been used as a quick-setting material.
When using um, its Na ₂O / Al₂O₃of
Generally, the molar ratio is as low as less than 1.0.
It was.

[0006]

However, sodium aluminate having a low molar ratio has problems that its long-term storage property is very poor and its quick-setting property is significantly lowered.

Therefore, the present inventor has conducted various studies to solve the above-mentioned problems, and as a result, obtained the finding that the above-mentioned problems can be solved by using a specific sodium aluminate, The invention was completed.

[0008]

That is, according to the present invention, the molar ratio of calcium aluminate and Na ₂ O / Al ₂ O ₃ is 1.05 to 1.20, and its 90% particle size is 0. total 1 to 70 parts by weight in 100 parts by weight of sodium aluminate anhydride calcium aluminate and sodium aluminate anhydride is .05～0.2Mm, and comprising anhydrous cell <br/> Tsu co U It is a quick-setting material for spray material. And cement , water reducing agent, thickening agent, ultra fine powder and fibrous material
A spraying material containing one or more admixtures selected from the group consisting of quality and a quick-setting material, and the spraying method is characterized in that the spraying material is used. .

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. In the present invention, cement mortar and concrete are generically called cement concrete.

As the cement used in the present invention, various portland cements such as ordinary, early strength, moderate heat, and super early strength which are usually commercially available, and fly ash, blast furnace slag and the like are mixed with these portland cements. Various mixed cements and the like mentioned above can be mentioned, and these may be used in the form of fine powder. You can select a suitable cement depending on the performance such as rebound rate and dust reduction required for spraying, pumpability, strength development, and construction conditions, but ordinary portland cement and early strength portland cement that can be generally used are preferable.

Fluorocement containing fluorocalcium aluminate can also be used. Furthermore, CaO
Is C, Al ₂ O ₃ is A, SiO ₂ is S, and Fe ₂ O ₃ is F, the mineral composition of the cement in the cements is shown as C ₂ S, C ₃ S, C ₃ A, and C ₄ AF. It is also possible to use special cement in which calcium sulfate, potassium sulfate, sodium sulfate, and other sulfates are used in combination with a clinker whose content has been changed and fired.

The calcium aluminate used in the present invention is a mixture of CaO raw material and Al ₂ O ₃ raw material.
It is obtained by heat treatment such as firing in a kiln or melting in an electric furnace, which is a quick-setting component that causes the setting of cement concrete in the initial stage.

Calcium aluminate includes C
Examples of the heat-treated calcium aluminate having a mineral composition such as ₃ A, C ₁₂ A ₇ , CA, and CA ₂ may be used, or one or more of these may be used. Further, these may be pulverized, and as other components, calcium aluminate partially containing alkali metals such as sodium, potassium and lithium can be used. Among these, amorphous calcium aluminate is preferable from the viewpoint of reaction activity, and amorphous calcium aluminate obtained by rapidly cooling a heat-treated product corresponding to the composition of C ₁₂ A ₇ is more preferable.

Further, calcium aluminosilicate containing a SiO ₂ component, C ₁₁ A ₇ .CaX ₂ (X is a halogen such as fluorine) in which one CaO of C ₁₂ A ₇ is replaced with a halide such as CaF ₂ , SO C ₄ A ₃ containing ₃ components
SO ₃ can be used as well. Further, alumina cement can be used as well.

The grain size of calcium aluminate is preferably 5000 cm ² / g or more in terms of Blaine value. 5000c
If it is less than m ² / g, the quick-setting property and the initial strength development property may be deteriorated.

Sodium aluminate is composed of Na ₂ O and Al.
_The main component is ₂ O ₃ , and there are two types: aqueous solution and powder. Sodium aluminate is very important as a component of quick-setting materials.

Sodium aluminate has the action of improving the quick-setting property and strength developing property of cement concrete by mixing with calcium aluminate, and promoting the quick-setting of the concrete kneaded product after spraying.

Sodium aluminate is produced by heating and dissolving aluminum hydroxide and sodium hydroxide in water. In this manufacturing process, depending on the synthesis temperature and the drying conditions, it becomes an anhydride or a hydrate, and if the sodium content is high, the anhydride is likely to be produced. Among the anhydrides and the hydrates, the anhydrides are preferable from the viewpoint of quick setting property and storage stability.

Na ₂ O / Al _{2 of} sodium aluminate
The molar ratio of O ₃ is preferably 1.0 to 1.3, and 1.05
1.20 is more preferable. If it is less than 1.0, the quick-setting property may be small, and if it exceeds 1.3, moisture may be absorbed to reduce the storage stability.

The 90% particle size of sodium aluminate is preferably 0.3 mm or less, more preferably 0.05 to 0.2 mm. If it is less than 0.05 mm, it may absorb moisture to reduce the storage stability, and if it exceeds 0.3 mm, the quick-setting property may deteriorate.

The amount of sodium aluminate used is 100 in total of calcium aluminate and sodium aluminate.
In the parts by weight, 1 to 70 parts by weight is preferable, and 5 to 40 parts by weight is more preferable. If it is less than 1 part by weight, the coagulability and strength development may be lowered, and if it exceeds 70 parts by weight, the strength development and storage stability may be lowered.

Sulfate improves strength development.

Examples of the sulfates include alkali metal sulfates such as sodium sulfate and potassium sulfate, alkaline earth metal sulfates such as magnesium sulfate and gypsum, and aluminum sulfate. One or more of them can be used. May be used. Of these, gypsum is preferable from the viewpoint of strength development.

The gypsum used in the present invention is used to improve strength development. Examples of the gypsum include anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum, and one or more of these may be used. Of these, anhydrous gypsum is preferable from the viewpoint of strength development.

The particle size of the sulfate is preferably 2500 cm ² / g or more in terms of Blaine value, from the viewpoint of strength development.
cm ² / g or more is more preferable. If it is less than 2500 cm ² / g, the strength developability may decrease.

The amount of sulfate used is preferably 10 to 70 parts by weight, more preferably 30 to 60 parts by weight, based on 100 parts by weight of calcium aluminate, sodium aluminate, and sulfate. If it is less than 10 parts by weight, the strength developability may be reduced, and if it exceeds 70 parts by weight, initial setting may be delayed and the adhesion to the ground may be reduced.

The amount of the quick-setting material used is preferably 3 to 30 parts by weight, more preferably 5 to 20 parts by weight, based on 100 parts by weight of cement. If it is less than 3 parts by weight, the effect may not be obtained, and if it exceeds 30 parts by weight, the pressure-feeding pipe for feeding the quick-setting material may be blocked, or long-term strength development may be reduced.

In the present invention, in order to improve the characteristics such as slump before setting and hardening of cement mortar and the strength characteristics after setting and hardening, etc., it is selected from the group consisting of water reducing agents, thickeners, ultrafine powders, and fibrous substances. Use one or more admixtures. Among these admixtures, a water reducing agent is preferable from the viewpoint of strength development.

The water-reducing agent used in the present invention is one used for improving the fluidity of cement concrete and the dispersion stability of quick-setting materials, and either liquid or powdery can be used. Examples of the water reducing agent include polyol derivatives, lignin sulfonates and their derivatives, and high-performance water reducing agents, and one or more of these may be used.
Among these, a high-performance water reducing agent is preferable in terms of high strength development and dispersion stability.

The high-performance water reducing agent can reduce the amount of the quick-setting material used, and can reduce the amount of dust generation and the rebound rate to an extremely small level.

Examples of the high-performance water reducing agent include formalin condensates of alkylallyl sulfonates, formalin condensates of naphthalene sulfonates, formalin condensates of melamine sulfonates, and polycarboxylic acid polymer compounds. , Liquid or powder may be used, and one or more of these may be used. Among these,
From the point of great effect, formalin condensate of naphthalene sulfonate, formalin condensate of melamine sulfonate,
And polycarboxylic acid type polymer compounds are preferred.

The water reducing agent is preferably used in an amount of 0.05 to 3 parts by weight, preferably 0.1 to 2 parts by weight, based on 100 parts by weight of cement.
More preferably parts by weight. If it is less than 0.05 parts by weight, there is no effect, and if it exceeds 3 parts by weight, the fluidity of the cement concrete increases, but the cement concrete becomes viscous, and the cement concrete adheres to the pressure feed pipe and the rotating blades of the mixer, thus improving workability. May decrease or the strength may decrease.

The thickening agent used in the present invention is one which imparts viscosity to cement concrete, prevents sagging immediately after spraying, reduces rebound rate, and suppresses dust generation. As the thickener, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, and cellulose such as hydroxyethyl ethyl cellulose, alginic acid,
Polysaccharides such as sodium alginate, β-1,3-glucan, pullulan, guar gum, casein, and welan gum, vinyl acetate, ethylene, vinyl chloride, methacrylic acid, acrylic acid, sodium acrylate, and vinyl such as unsaturated carboxylic acid. Polymers and copolymers thereof, and emulsions such as those obtained by saponifying a vinyl acetate polymer or its copolymer to a polyvinyl alcohol skeleton and the like, and using one or more of these Good. Among these, it is difficult to inhibit the initial setting,
Celluloses are preferred.

The amount of the thickener used is preferably 0.001 to 0.5 part by weight, based on 100 parts by weight of cement, and is 0.1.
More preferably 005 to 0.3 parts by weight. If the amount is less than 0.001 part by weight, the viscosity of the cement concrete is small, and when it is sprayed, the sag may occur or the rebound rate may increase. If it exceeds 0.5 parts by weight, the viscosity of the cement concrete may increase and There is a possibility that pumpability may be hindered or strength development may be hindered.

The ultrafine powder is one having an average particle size of 10 μm or less, and has the effect of reducing the amount of cement, the amount of dust, and the rebound rate, and improving the pumpability of cement concrete. Examples of the ultrafine powder include fine slag, fine fly ash, bentonite, metakaolin, and silica fume. Among these, silica fume is preferable from the viewpoint of strength development.

The amount of ultrafine powder used is preferably 1 to 50 parts by weight, more preferably 2 to 30 parts by weight, based on 100 parts by weight of cement. If it is less than 1 part by weight, no effect is obtained, and if it exceeds 50 parts by weight, setting and curing may be delayed.

The fibrous substance improves the impact resistance and elasticity of cement concrete, and either inorganic substances or organic substances can be used.

As the inorganic fibrous substance, glass fiber, carbon fiber, rock wool, asbestos, ceramic fiber,
Examples of the organic fibrous substance include vinylon fiber, polyethylene fiber, polypropylene fiber, polyacrylic fiber, cellulose fiber, polyvinyl alcohol fiber, polyamide fiber, pulp, hemp, and wood wool.
And wood chips and the like. Among these, metal fibers and vinylon fibers are preferable in terms of economy.

The length of the fibrous substance is preferably 50 mm or less, more preferably 30 mm or less, from the viewpoint of pumpability and mixing property. If it exceeds 50 mm, the cement concrete may be clogged during pumping.

The amount of the fibrous substance used is preferably 0.5 to 30 parts by weight, and 2 to 2 parts by weight based on 100 parts by weight of cement.
0 weight part is more preferable. If it is less than 0.5 parts by weight, no effect is obtained, and if it exceeds 30 parts by weight, pumpability may be reduced or the effect may be lost.

Further, in the present invention, in order to delay the setting time of cement concrete, organic acid or its salt,
A set retarder such as an organic acid or a mixture of a salt thereof and a carbonate, a phosphate, a boric acid or a salt thereof, and an alcohol may be used.

The amount of water used in the cement concrete of the present invention is 35 to 6 with respect to 100 parts by weight of cement.
5 parts by weight is preferable, and 40 to 55 parts by weight is more preferable. If it is less than 35 parts by weight, the viscosity may be large and the pumpability may be deteriorated or may not be sufficiently mixed. If it exceeds 65 parts by weight, the strength development is small and a large amount of quick-setting material is required. There is a risk that

The fine aggregate or coarse aggregate to be used preferably has a low water absorption rate and high aggregate strength, but is not particularly limited. The coarse aggregate includes river gravel, mountain gravel, lime gravel, and the like, and the fine aggregate includes river sand, mountain sand, lime sand, silica sand, and the like.

In the present invention, in addition to the above, a dust reducing agent, a setting regulator, an AE agent, an AE water reducing agent, a high-performance AE water reducing agent, a cement expanding agent, a rust preventive agent, an antifreezing agent, a polymer emulsion, and a silica fine powder. One or more of silica fume, calcium carbonate, and the like may be used.

The quick-setting material spraying method of the present invention is a dry spraying method in which a quick-mixing material is added to a dry mixture of mortar and concrete, the inside of the hose is pressure-fed by compressed air, and water is added immediately before the nozzle portion, or mortar or It is possible to use either of the wet spraying methods in which a wet mix of concrete is pressure-fed by compressed air, and a quick-setting material is added and sprayed from one side of the Y-tube. Of these, the wet spraying method is preferable because it produces less dust.

In the spraying method of the present invention, conventionally used spraying equipment can be used.

In the spraying method of the present invention, spraying can be carried out using either mortar or concrete as long as the workability, physical properties and price can be satisfied.

The admixture can be added to either the cement-concrete side or the quick-set side, and may be used on only one side or on both sides, but it is possible to improve strength, prevent rebound, and control setting. Therefore, it is preferable to add it to the cement concrete side. In particular, it is more preferable to add a water reducing agent to the cement concrete side in advance in order to reduce the unit water amount and improve the strength development. There is no problem if finally the quick-setting spray-cement concrete mixed with these materials is sprayed.

In the spraying method of the present invention, conventionally used spraying equipment can be used. Spray pressure is usually 2-5 kg
/ Cm ² , and the spraying speed is 4 to 20 m ³ / h.

The spraying equipment is not particularly limited as long as the spraying is sufficiently carried out. For example, for the pressure feeding of sprayed cement concrete, the product name “Alibar 28 of the Alibaba company” is used.
0 "and the like, and the quick-bonding material pressure-feeding device" NATOM CLEAT "and the like can be used for pressure-feeding the quick-bonding material.

[0051]

EXAMPLES Next, the present invention will be explained based on examples.

(Example 1) Calcium aluminate 4
2.5 parts by weight, Na shown in Table 1₂O / Al₂O₃The mole
Ratio of sodium aluminate 7.5 parts by weight and sulfate 5
Prepare a quick-setting material consisting of 0 parts by weight and measure the setting time.
It was In addition, the unit amount of each material is 400 kg of cement /
m³, Fine aggregate 1151 kg / m ³Coarse aggregate 629 kg /
m³, And water 190kg / m³And cement 100 weight
0.5 parts by weight of the water reducing agent is mixed with the amount of
Prepare uncrete, pumping speed 4m³/ H, pumping pressure 4
kg / cm²Under the conditions of the concrete pump "Ariva
-280 ". Meanwhile, this shotcrete
The prepared quick-setting material was added to 100 parts by weight of cement.
So that the weight of the Y-tube is 10 parts by weight.
From the other side, using the quick-connect material pump "NATOM CLEAT"
Pressure 4.5kg / cm²Under the conditions of
It was mixed with ncrete to give quick-setting shotcrete.
Measure the setting time and compressive strength of this quick-setting shotcrete.
Decided The results are shown in Table 1.

(Materials used) Cement: ordinary Portland cement, commercial product, Blaine value 3200 cm ² / g, specific gravity 3.16 Fine aggregate: river sand from Himekawa, Niigata prefecture, surface water ratio 4.0%, specific gravity 2.62 rough Aggregate: River gravel from Himekawa, Niigata Prefecture, surface dry condition, specific gravity 2.6
4. Maximum aggregate size 10 mm Calcium aluminate: Corresponding to C ₁₂ A ₇ composition, amorphous, Blaine value 6000 cm ² / g Sodium aluminate: Dissolve aluminum hydroxide and sodium hydroxide in water by heating. By Na ₂ O /
Al was prepared and the molar ratio ₂ O _3, which was crushed after drying, anhydride, 90% particle diameter 0.2mm sulfate a: Anhydrous gypsum, hydrofluoric acid byproduct gypsum, Blaine value 5200 cm ² / g water reducing agent A: Commercially available polycarboxylic acid polymer compounds

(Measurement method) Setting time: 100 parts by weight of cement, 10 parts by weight of quick setting material, 300 parts by weight of fine aggregate, and 60 parts by weight of water were weighed in a constant temperature and humidity room at a temperature of 20 ° C. and a humidity of 80%. did. Cement, quick-setting material, and fine aggregate are kneaded and mixed in a mortar mixer for 10 seconds, then water is added and mixed for another 10 seconds to form a mortar, which is quickly filled into a mold and the proctor penetration resistance method (ASTM). The setting time was measured according to C-403-65T). In addition, the quick-setting material is packed in a bag and the temperature is 20
The same measurement was carried out for a sample stored for 6 months in a constant temperature and constant humidity chamber at a temperature of 80 ° C. and a humidity of 80%. Compressive strength: Compressive strength at age of 1 hour is width 25 cm x length 2
A pin installed on a 5 cm pullout formwork is covered with quick-setting shotcrete from the surface of the pullout formwork, the pin is pulled out from the backside of the formwork, and the pullout strength at that time is calculated. (Compressive strength) = (Pullout strength) The compressive strength was calculated from the formula of × 4 / (contact area of specimen). The compressive strength after 1 day of age was measured by spraying quick-setting concrete onto a mold of width 50 cm × length 50 cm × thickness 20 cm and measuring a sample of diameter 5 cm × length 10 cm with a 20 ton pressure machine. Then, the compressive strength was obtained.

[0055]

[Table 1]

(Example 2) 0.5 parts by weight of a water reducing agent was mixed with 100 parts by weight of cement to prepare sprayed concrete, and Table 2 was used in a total of 100 parts by weight of calcium aluminate and sodium aluminate. In 100 parts by weight of cement, 50 parts by weight of a quick-setting material is added to 100 parts by weight of calcium aluminate, sodium aluminate, and calcium aluminate, sodium aluminate, and a total of 100 parts by weight of sulfate. On the other hand, the same procedure as in Example 1 was carried out except that 10 parts by weight of the quick-setting concrete was used. The results are shown in Table 2.

(Materials used) Sodium aluminate: Anhydrous, Na ₂ O / Al ₂ O ₃
Molar ratio of 1.10, 90% particle diameter 0.2 mm Sodium aluminate: Na ₂ O by heating and dissolving aluminum hydroxide and sodium hydroxide in water.
/ Al ₂ O ₃ molar ratio was adjusted, dried and pulverized, hydrate, Na ₂ O / Al ₂ O ₃ molar ratio 1.10, 90% particle diameter 0.2 mm (Comparative Example) sodium aluminate : Anhydrous, Na ₂ O / Al ₂ O ₃
Molar ratio of 1.10, 90% particle size 0.3 mm (Comparative example)

[0058]

[Table 2]

Example 3 100 parts by weight of cement was mixed with 0.5 part by weight of a water reducing agent to prepare sprayed concrete. 85 parts by weight of calcium aluminate, 15 parts by weight of sodium aluminate, and Total of calcium aluminate, sodium aluminate, and sulfate 1
In the same manner as in Example 1 except that 10 parts by weight of the quick-setting material composed of sulfate in an amount shown in Table 3 was used in 10 parts by weight with respect to 100 parts by weight of cement to make quick-setting sprayed concrete. went. The results are shown in Table 3.

(Materials used) Sulfate b: pulverized gypsum dihydrate, Blaine value 5500c
m ² / g (Comparative example) Sulfate c: crushed aluminum sulfate, Blaine value 590
0 cm ² / g (Comparative example)

[0061]

[Table 3]

Example 4 0.5 parts by weight of a water reducing agent was mixed with 100 parts by weight of cement to prepare sprayed concrete. 42.5 parts by weight of calcium aluminate and 7.5 parts by weight of sodium aluminate were prepared. Parts and sulfate a50
A quick-setting material consisting of parts by weight is used in an amount shown in Table 4 with respect to 100 parts by weight of cement to give a quick-setting shotcrete,
The same procedure as in Example 1 was carried out except that the compressive strength was measured. The results are shown in Table 4.

[0063]

[Table 4]

(Example 5) Calcium aluminate 4
2.5 parts by weight, 7.5 parts by weight of sodium aluminate, and 50 parts by weight of sulfate a were mixed and stored for a period shown in Table 5, and 10 parts by weight of cement was used for 100 parts by weight of cement. The same procedure as in Example 1 was carried out except that quick-setting shotcrete was used and the setting time was measured. The results are shown in Table 5.
Shown in.

(Material used) Sodium aluminate: Anhydrous, Na ₂ O / Al ₂ O
₃ mole ratio 0.90,90% particle size 0.2mm

[0066]

[Table 5]

As is clear from Table 5, Na ₂ O / Al
_When sodium aluminate with a molar ratio of ₂ O ₃ of 0.90 is used, the
Both the termination times tend to be delayed, while Na ₂ O
When sodium aluminate having a molar ratio of / Al ₂ O ₃ of 1.10 was used, the initial and final times hardly changed even after storage for 6 months, and no deterioration in physical properties was observed.

(Example 6) 0.5 parts by weight of a water reducing agent was mixed with 100 parts by weight of cement to prepare sprayed concrete. 42.5 parts by weight of calcium aluminate and 7.5 parts by weight of sodium aluminate were prepared. Parts and 50 parts by weight of sulfate a and stored for a period shown in Table 6 were used as quick-setting shotcrete by using 10 parts by weight with respect to 100 parts by weight of cement to obtain quick-setting shotcrete. The same procedure as in 1 was performed to measure the dust amount, sag, and rebound rate. The results are shown in Table 6.

(Measurement method) Dust amount: A quick-setting shotcrete was made into an arch shape from an iron plate at a shot rate of 4 m ³ / h for 30 minutes, and had a height of 3.5.
It was sprayed on a m.m, 2.5 m wide tunnel. The dust amount was measured at a fixed position of 3 m from the spraying place every 10 minutes, and the average value of the obtained measured values was shown. Sagging: Quick-setting shotcrete was made into an arch shape with an iron plate at a spray rate of 4 m ³ / h for 30 minutes, and a height of 3.5 m,
The state after spraying on a simulated tunnel with a width of 2.5 m was observed. The case where no sagging occurred was rated as ⊚, the case where a little sagging occurred was rated as ○, and the case where a large amount of sagging occurred was rated as x. Rebound rate: Quick-setting sprayed concrete was sprayed at a spraying speed of 4 m ³ / h for 30 minutes on a simulated tunnel having a height of 3.5 m and a width of 2.5 m. After spraying, measure the amount of quick-setting sprayed concrete that did not adhere and measure (rebound rate) = (weight of quick-setting sprayed concrete that did not adhere to the simulated tunnel during spraying) / (Weight of quick-setting sprayed concrete used for spraying) × 100 (%).

[0070]

[Table 6]

As is clear from Table 6, the strength of the product of the present invention was not reduced even when compared with that immediately after storage. Moreover, the dust generation rate and rebound rate were low. Further, even after being stored for one year, the product of the present invention had a strong quick setting property, and the amount of the quick setting material used could be reduced.

(Example 7) 100 parts by weight of cement was mixed with the water reducing agent in the amounts shown in Table 7 to prepare sprayed concrete. 42.5 parts by weight of calcium aluminate and 7.5 parts by weight of sodium aluminate. , And slump and compressive strength, except that 10 parts by weight of quick-setting material consisting of 50 parts by weight of sulfate a and 100 parts by weight of cement were used to make quick-setting shotcrete. Was measured. The results are shown in Table 7.

(Materials used) Water reducing agent a: Commercially available naphthalene sulfonate type formalin condensate

(Measurement method) Slump: According to JIS A 1101.

[0075]

[Table 7]

(Example 8) 100 parts by weight of cement was mixed with the thickening agent in the amounts shown in Table 8 to obtain sprayed concrete. 42.5 parts by weight of calcium aluminate, 7.5 parts by weight of sodium aluminate, And 10 parts by weight of cement a 100 parts by weight of cement.
Dust amount, sag, and pumpability were measured in the same manner as in Example 1, except that the weight part was used to obtain quick-setting sprayed concrete. The results are shown in Table 8.

(Material used) Thickener i: methyl cellulose Thickener ii: hydroxypropyl cellulose

(Evaluation Method) Pumpability: Quick-setting sprayed concrete was sprayed at a spraying rate of 4 m ³ / h and a discharge pressure of 4 kg / cm ² for 30 minutes using a pressure-feeding pipe, and the pressure in the pressure-feeding pipe was measured. . Also when the pressure in the pumping tube is 4.0~5.5kg / cm ² ◎, it becomes more than 6.0 kg / cm ^2, which tends to closed pumping tube 4 by impacting the pumping tube. 0-5.5
The case where it became kg / cm ² was marked with ◯, and the case where the pressure-feeding tube was blocked and the pressure-feeding tube did not reach 4.0-5.5 kg / cm ² even when shocked, was marked with x.

[0079]

[Table 8]

(Example 9) 100 parts by weight of cement was mixed with the ultrafine powder in the amounts shown in Table 9 to obtain sprayed concrete, 42.5 parts by weight of calcium aluminate, 7.5 parts by weight of sodium aluminate, and A quick-setting material consisting of 50 parts by weight of sulfate a is added to 10 parts by weight of 100 parts by weight of cement
The rebound rate was measured in the same manner as in Example 1 except that parts by weight were mixed to form a quick-setting shotcrete. The results are shown in Table 9.

(Material used) Ultra-fine powder α: commercial silica fume, average particle size 10 μm or less Ultrafine powder β: commercially available metakaolin, average particle size 10 μm or less

(Measuring method) Rebound rate: Quick-setting sprayed concrete was sprayed at a spraying speed of 4 m ³ / h for 30 minutes on a simulated tunnel having a height of 3.5 m and a width of 2.5 m. After spraying, measure the amount of quick-setting sprayed concrete that did not adhere and measure (rebound rate) = (weight of quick-setting sprayed concrete that did not adhere to the simulated tunnel during spraying) / (Weight of quick-setting sprayed concrete used for spraying) × 100 (%).

[0083]

[Table 9]

(Example 10) 100 parts by weight of cement was mixed with the fibrous substance in the amounts shown in Table 10 to obtain sprayed concrete, and 42.5 parts by weight of calcium aluminate,
7.5 parts by weight of sodium aluminate and sulfate a5
Impact resistance was measured in the same manner as in Example 1 except that 10 parts by weight of the quick-setting material consisting of 0 parts by weight was mixed with 100 parts by weight of cement to obtain quick-setting sprayed concrete. The results are shown in Table 10.

(Material used) Fibrous substance A: vinylon fiber, fiber length 10 mm Fibrous substance B: Steel fiber, fiber length 30 mm

(Evaluation method) Impact resistance: Sprayed concrete after 1 hour of age has a width of 20
It was sprayed on a mold having a size of 20 cm, a length of 20 cm, and a thickness of 2 cm, the bottom surface was removed, and it was placed on flattened standard sand, and a sphere weighing 50 g was dropped from a height of 50 cm. When the number of drops was within 5 times, the sample was cracked and destroyed, x, when cracked but not destroyed, ◯, and when not cracked, ◎.

[0087]

[Table 10]

(Example 11) 0.5 parts by weight of a water reducing agent, 100 parts by weight of cement, a thickener i, a fibrous substance A, and an ultrafine powder α were mixed in the amounts shown in Table 11. 10% by weight of 100% by weight of cement was mixed with 10% by weight of quick-setting material consisting of 42.5 parts by weight of calcium aluminate, 7.5 parts by weight of sodium aluminate, and 50 parts by weight of sulfate a, as sprayed concrete. A slump, a rebound rate, and an impact resistance were measured in the same manner as in Example 1 except that the concrete was sprayed. The results are shown in Table 11.

[0089]

[Table 11]

[0090]

EFFECTS OF THE INVENTION By using the quick-setting material using sodium aluminate of the present invention, compared with the conventional one using sodium aluminate, the quick-setting material does not show deterioration in physical properties even during long-term storage. It was possible to obtain a cement sprayed cement concrete.

Continuation of the front page (56) Reference JP-A-8-225351 (JP, A) JP-A-1-294554 (JP, A) JP-A-3-37145 (JP, A) JP-A-61-162666 (JP , A) JP-A-5-105426 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C04B 22 / 00-22 / 16

Claims (3)

(57) [Claims] 1. Calcium aluminate, Na ₂ O / A
The sodium aluminate anhydride having a molar ratio of l ₂ O ₃ of 1.05 to 1.20 and a 90% particle size of 0.05 to 0.2 mm is calcium aluminate and sodium aluminate anhydride. 1 to 70 parts by weight in 100 parts by weight of the total, and the quick-setting material for a spray material comprising a dry Secco c. 2. Cement, water reducing agent, thickening agent, ultrafine powder
And one or more selected from the group consisting of
A spraying material containing the admixture according to claim 1 and the quick-setting material for spraying material according to claim 1. 3. A spraying method comprising using the spraying material according to claim 2.