JP3483117B2 - Quick setting material, spray material, and quick setting spray concrete - 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 spray material, and a quick-setting spray-cement concrete used for spraying on an exposed natural surface in a tunnel such as a road, a railroad, and a headrace. Regarding

[0002]

2. Description of the Related Art Conventionally, in order to prevent collapse of exposed ground such as tunnel excavation, a method of spraying quick-setting shotcrete in which a quick-setting agent is mixed with concrete has been performed (Japanese Patent Publication No. 62-4149). ).

This method is usually a metering and mixing plant installed on the site of excavation work, in which cement, aggregate and water are mixed to prepare sprayed concrete, which is transported by an agitator vehicle and pumped by a concrete pump. It is a method of mixing with a quick-setting material sent from the other side with a confluent pipe provided on the way and spraying it as quick-setting sprayed concrete on the ground surface to a predetermined thickness. As the quick-setting material used in this spraying method, a mixture of calcium aluminate with alkali metal aluminate, alkali metal carbonate or the like was used.

[0004] This quick-setting sprayed concrete is quick to set, and the concrete hardens quickly, so that it is possible to protect the ground surface at the risk of collapse, but the long-term strength after 28 days of age is the addition of quick-setting materials. There was a problem that it was reduced by about 20 to 30% compared to sprayed concrete that was not sprayed.

As described above, although the strength is lowered by the addition of the quick-setting material, the strength is sufficient to protect the ground in the relatively stable ground, and the spraying is applied in the considerably unstable ground. It has been dealt with by increasing the thickness.

[0006]

However, there is a problem that thickening the spray thickness is economically unfavorable because the amount of spray material used is large and the working time is long. In recent years, in the construction of large cross-section tunnels, the exposed area of the ground becomes large and a large amount of spray material is required. Therefore, a quick-setting material that can be expected to exhibit higher strength and a spray material using the same. The demand for reinforced concrete is increasing, and high-strength shotcrete that does not cause long-term deterioration in strength is required.

As a result of extensive studies, the present inventor has completed the present invention by obtaining knowledge that the above problems can be solved by performing spraying using a specific quick-setting material for a spraying method. It was

[0008]

[Means for Solving the Problems] That is, the present invention relates to calcium aluminate, 100 weight parts of calcium aluminate.
100-200 parts by weight of anhydrous gypsum relative parts and <br/> calcium aluminate and 2 parts by weight or more per 100 parts by weight of anhydrous gypsum, in an amount of less than 10 parts by weight
Mol of M ₂ O / Al ₂ O ₃ (M is Na, K or Li)
Alkali metal aluminate with a ratio of 1.02-1.30 ,
And, calcium aluminate, anhydrous gypsum, the total of alkali metal aluminate Shio及 beauty alkali metal carbonate 1
This is a quick-setting material for spraying materials, which contains 0 to 5 parts by weight of an alkali metal carbonate in 100 parts by weight . Its to a spray material comprising a cement, a the sudden formation material. Further, it is a quick-setting spray-concreting cement concrete containing the spray material.

[0009]

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

The spray material used in the present invention contains cement and a quick-setting material.

As the cement used in the present invention, various portland cements which are usually commercially available, such as ordinary, early strength, moderate heat, and super early strength, and various kinds of these portland cements mixed with fly ash, blast furnace slag, etc. Examples include mixed cement, fluorocement containing fluorocalcium aluminate, and the like, which may be used in the form of fine powder. A suitable cement can be selected according to performance such as rebound rate and dust reduction required for spraying, pumpability, strength development, and workability, but ordinary Portland cement and early-strength Portland cement are preferred, and ordinary Portland cement Is more preferable.

The quick-setting material used in the present invention contains calcium aluminate, sulfate, aluminate, and, if necessary, carbonate.

The calcium aluminate used in the present invention is obtained by mixing a raw material containing calcia with a raw material containing alumina, followed by heat treatment such as firing in a kiln or melting in an electric furnace. CaO and Al ₂ O ₃ are main components, and is a general term for substances having hydration activity.
Or, a part of Al ₂ O ₃ is an alkali metal oxide, an alkaline earth metal oxide, silicon oxide, titanium oxide, iron oxide, an alkali metal halide, an alkali metal earth halide, an alkali metal sulfate, and an alkali. It is a substance in which a small amount of these are dissolved in a compound substituted with an 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, from the viewpoint of reaction activity, amorphous is preferable, and amorphous calcium aluminate obtained by rapidly cooling a heat-treated product corresponding to the composition of C ₁₂ A ₇ is more preferable.

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.

The sulfate used in the present invention is used to improve the strength development. As the sulfate,
Examples thereof 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 these may be used in combination. Of these, gypsum is preferable from the viewpoint of strength development.

Gypsum is used to improve strength development. Examples of the gypsum include anhydrous gypsum, hemi-water gypsum, and dihydrate gypsum, and one or more of these may be used in combination. Of these, anhydrous gypsum is preferable from the viewpoint of strength development.

The grain size of gypsum is preferably 2500 cm ² / g or more in terms of Blaine value, from the viewpoint of strength development.
0 cm ² / g or more is more preferable. 2500 cm ² / g
If it is less than the range, strength development may be deteriorated.

The amount of sulfate used is preferably 20 to 200 parts by weight, more preferably 50 to 150 parts by weight, based on 100 parts by weight of calcium aluminate. If it is less than 20 parts by weight, the strength development is low, and if it exceeds 200 parts by weight, the initial setting may be delayed and the adhesion to the ground may be reduced.

The alkali metal aluminate used in the present invention (hereinafter referred to as "aluminate") accelerates the initial setting of cement, and aluminum hydroxide and alkali metal hydroxide are mixed and dissolved, dried and powdered. It is obtained as a state.

Alkali metal aluminates are M2O and A
12O3 (M is Na, K, or Li) as a main component, and there are two types, an aqueous solution and a powder. The molar ratio of M ₂ O / Al ₂ O ₃ of the alkali metal <br/> aluminate 1.02
1.30 is preferable and 1.05 to 1.20 is more preferable. If it is less than 1.02, the quick-setting property may be small,
If it exceeds 1.30, it may absorb moisture and the storage stability may decrease.

Examples of the aluminate include sodium aluminate, potassium aluminate, and lithium aluminate, and one or more of these may be used. Among these, sodium aluminate is preferable from the viewpoint of coagulation.

The maximum particle size of the aluminate is preferably 0.3 mm or less, more preferably 0.05 to 0.2 mm.
If it exceeds 0.3 mm, the quick-setting property may be deteriorated.

These aluminates can be prepared as anhydrous ones or those containing water of crystallization depending on the production conditions, and any of them can be used. However, in view of improving the storage stability when mixed with calcium aluminate, an aluminate can be used. The ignition loss of the acid salt is preferably 10% by weight or less, more preferably 5% by weight or less. If it exceeds 10% by weight, the storage stability may be deteriorated when mixed with calcium aluminate, and the quality may be deteriorated.

The amount of aluminate used is less than 10 parts by weight, preferably 2 to 8 parts by weight, based on 100 parts by weight of calcium aluminate and sulfate. If it is 10 parts by weight or more, long-term strength development may be deteriorated.

Further, in the present invention, an alkali metal carbonate (hereinafter referred to as carbonate) can be used if necessary. Examples of the carbonate used in the present invention include sodium carbonate, potassium carbonate, sodium bicarbonate and the like, and one or more of these can be used.

When a large amount of carbonate is used, setting is delayed at the time of spraying and sagging is observed. Therefore, the amount of carbonate used is calcium aluminate, sulfate, aluminate,
And 0 to 5 parts by weight in total 100 parts by weight of carbonate.

The amount of the quick-setting material used is preferably 5 to 30 parts by weight, more preferably 7 to 20 parts by weight, based on 100 parts by weight of cement. If it is less than 5 parts by weight, initial setting may not be sufficiently obtained, and if it exceeds 30 parts by weight, long-term strength development may be deteriorated or piping or the like may be blocked, which may be economically disadvantageous. is there.

The quick-setting spray-cement concrete used in the present invention contains a spray material.

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

The water-reducing agent used in the present invention is one used to improve 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. These water reducing agents may be used alone or in combination of two or more.
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 extremely reduce the amount of dust generated and the rebound rate. As the high-performance water reducing agent, formalin condensates of alkylallyl sulfonates, formalin condensates of naphthalene sulfonates, formalin condensates of melamine sulfonates, polycarboxylic acid-based polymer compounds, and the like can be mentioned. Any of powdery substances can be used, and one kind or two or more kinds thereof may be used in combination. Among these, a formalin condensate of naphthalene sulfonate, a formalin condensate of melamine sulfonate, and a polycarboxylic acid-based polymer compound are preferable because the amount of dust generated and the rebound rate are small.

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, vinyl acetate, ethylene, vinyl chloride, methacrylic acid, acrylic acid, sodium acrylate, and unsaturated carboxylic acid. Examples thereof include polymers and copolymers thereof, and emulsions such as those obtained by saponifying vinyl acetate polymers and their copolymers and modifying them into a polyvinyl alcohol skeleton. Even if one or more of these are used in combination. Good. Among these, it is difficult to inhibit the initial setting,
Celluloses are preferred.

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 sprayed cement concrete of the present invention is preferably 35% or more, more preferably 40 to 55%, in terms of strength development property, in terms of water / cement ratio.
If it is less than 35%, the cement concrete may not be sufficiently mixed, and if it exceeds 55%, the strength development may be impaired.

The aggregate used in the present invention has a low water absorption rate,
A high aggregate strength is preferable, and the fine aggregate ratio and the maximum size of the aggregate are not particularly limited as long as they can be sprayed. As fine aggregate, river sand, mountain sand, lime sand, silica sand, etc. can be used, and as coarse aggregate, river gravel, mountain gravel, lime gravel, etc. can be used.

In the spraying method of the present invention, conventionally used spraying equipment and the like can be used. As the spraying method of the present invention,
Various spraying methods are possible depending on the required physical properties, economical efficiency, workability, and the like.

As the spraying method of the present invention, a dry spraying method can be applied, but since the amount of dust may increase,
It is preferable to use a wet spraying method in which water is previously added to the cement concrete side and kneaded before mixing the quick-setting material.

As the wet spraying method, for example, cement, fine aggregate, coarse aggregate, and water are added and kneaded, pneumatically fed, a Y-shaped pipe is provided on the way, and a quick-setting material supply device is used from one of them. Examples include a method of pneumatically feeding the quick-setting material, confluent mixing, and spraying a quick-setting wet sprayed concrete.

The water-reducing agent and the thickening agent can be added to either the cement concrete side or the quick-setting material side, and may be used on only one side or on both sides, but the strength is improved and the rebound rate is increased. From the viewpoint of reduction and control of setting, it is preferable to add 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 performed. For example, the product name “Aliver 280” of Alibar Co., Ltd. is used for the pressure feeding of sprayed cement concrete, and the quick setting material is used for the pressure feeding of quick setting materials. A pressure feeding device "NATOM CLEAT" or the like can be used.

[0042]

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

[0043] The unit amount of Example 1 each material, cement a450kg / m ^3, fine aggregates 1002kg / m ^3, the spray concrete was prepared as coarse aggregate 671kg / m ^3, and water 225 kg / m ^3,
This was pneumatically fed by a concrete pressure feeder "Aliver 280". From one side of a Y-shaped pipe provided in the middle of pneumatic injection of sprayed concrete, 100 parts by weight of calcium aluminate, the amount of sulfate as shown in Table 1, and 100 parts by weight of calcium aluminate and sulfate are added to aluminate. A quick-setting shotcrete was prepared by adding a quick-setting agent consisting of 5 parts by weight of salt to 10% by weight of 100 parts by weight of cement with a quick-setting agent adding device "NATOM CLEAT". . This quick-setting shotcrete was evaluated. The results are shown in Table 1.

(Material used) Cement: Ordinary Portland cement, commercial product, brae
Value 3200 cm²/ G, specific gravity 3.16 Fine aggregate: Lime sand from Aomi, Niigata, Surface water ratio 3.1%, Specific gravity
2.64 Coarse aggregate: River gravel from Himekawa, Itoigawa City, Niigata Prefecture, surface dry condition, specific gravity
2.65, maximum size 10 mm Calcium aluminate: C₁₂A₇Corresponding to the composition
, Amorphous, Blaine value 6050 cm²/ G Sulfate a: Commercial anhydrous gypsum crushed product, Blaine value 59
00 cm²/ G Sulfate b: Commercially available dihydrate gypsum, Blaine value 52
00 cm²/ G Sulfate c: crushed product of commercial aluminum sulfate, Blaine value
5900 cm²/ G Aluminate: Sodium aluminate, commercial product, high heat
Weight loss 2.1% by weight, Na ₂O / Al₂O₃Molar ratio of 1.
10

(Measurement method) Compressive strength: Compressive strength at a material age of 1 hour is 25 cm in width and 2 in length.
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. Loss on ignition: Aluminate in electric furnace at 1000 ° C, 24
It was heated for a period of time and calculated from the formula of [1- (weight after heating) / (weight before heating)] × 100 (% by weight).

[0046]

[Table 1]

Example 2 100 parts by weight of calcium aluminate and sulfate a100
1 part by weight and total of calcium aluminate and sulfate
Example 1 except that quick-setting concrete was prepared by using 10 parts by weight of the quick-setting material composed of aluminate in an amount shown in Table 2 with respect to 100 parts by weight of the cement, and 100 parts by weight of the cement. I went the same way. The results are shown in Table 2.

(Materials used) Aluminate: potassium aluminate, commercial product, loss on ignition 2.1%, molar ratio of K ₂ O / Al ₂ O ₃ 1.10

[0049]

[Table 2]

Example 3 100 parts by weight of calcium aluminate and sulfate a100
5 parts by weight and 5 parts by weight of the aluminate having a loss on ignition shown in Table 3 prepared by changing the drying time of the aluminate based on 100 parts by weight of calcium aluminate and sulfate in total. To 1 part by weight of cement
The storage stability was measured in the same manner as in Example 1 except that 0 part by weight was used for quick-setting shotcrete.
The results are shown in Table 3.

(Measurement method) Storage stability: Immediately after preparing the quick-set material, the temperature was 20 ° C. and the humidity was 80.
% Constant temperature and humidity chamber. Immediately after being loaded into the constant temperature and humidity chamber, one month, three months, and six months later, the quick-setting material was taken out and sprayed as quick-setting sprayed concrete, and the compressive strength after 1 hour was obtained.

[0052]

[Table 3]

Example 4 100 parts by weight of calcium aluminate and sulfate a100
100 parts by weight of calcium aluminate and sulfate
5 parts by weight of aluminate to 100 parts by weight of calcium aluminate, sulfate, aluminate, and carbonate based on 100 parts by weight of aluminate, and a quick-setting material composed of the amount of carbonate shown in Table 4 were prepared. The setting time was measured. Also, the sag was measured in the same manner as in Example 1 except that 10 parts by weight of the prepared quick-setting material was used with respect to 100 parts by weight of cement to make a quick-setting shotcrete. The results are shown in Table 4.

(Material used) Carbonate: Commercial sodium carbonate

(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 are weighed in a constant temperature and humidity room at a temperature of 20 ° C. and a humidity of 80%. did. In a mortar mixer, cement, quick setting material, and fine aggregate are kneaded and mixed for 10 seconds, then water is added and further mixed for 10 seconds,
Quickly fill the formwork and use the proctor penetration resistance method (ASTM
The setting time was measured according to C-403-65T). 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 sagging did not occur was marked with ◯, and the case where sagging occurred was marked with x.

[0056]

[Table 4]

Example 5 100 parts by weight of calcium aluminate and sulfate a100
1 part by weight and total of calcium aluminate and sulfate
Same as Example 1 except that the quick-setting material consisting of 5 parts by weight of aluminate with respect to 00 parts by weight was used as the quick-setting shotcrete using the amount shown in Table 5 with respect to 100 parts by weight of cement. Went to. The results are shown in Table 5.

[0058]

[Table 5]

[0059]

By using the quick-setting material of the present invention,
It is possible to obtain a sprayed material in which the strength after 28 days of age does not easily decrease, and the strength can be increased. Therefore, it is optimal as a spraying material for unstable ground, and the spraying thickness can be reduced, which is economical.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C04B 103: 12 C04B 103: 12 (56) References JP-A-6-48794 (JP, A) JP-A-8-225351 (JP , A) JP 60-108352 (JP, A) JP 7-196352 (JP, A) JP 7-196351 (JP, A) JP 8-253354 (JP, A) JP 5-330875 (JP, A) JP 5-24893 (JP, A) JP 7-89755 (JP, A) JP 3-37145 (JP, A) JP 61-162666 (JP, A) JP 5-105426 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C04B 22/00-22/16 C04B 28/00-28/36

Claims (3)

(57) [Claims] 1. Calcium aluminate, calcium acetate
100-200 parts by weight per 100 parts by weight of luminate
Anhydrous gypsum, and calcium aluminate and anhydrous
2 parts by weight or more based on 100 parts by weight of gypsum , 10
M ₂ O / Al ₂ O ₃ (M is N
a, alkali metal aluminates molar ratio is from 1.02 to 1.30 K or Li), and calcium aluminate, anhydrous gypsum, in total 100 parts by weight of an alkali metal aluminate Shio及 beauty alkali metal carbonate , A quick-setting material for spraying materials, which contains 0 to 5 parts by weight of an alkali metal carbonate. 2. A cement, spray material comprising a spray material for <br/> quick-material according to claim 1 Symbol placement. 3. A quick-setting spray-cement concrete which uses the spray material according to claim 2 . "