JPH09268048A - Spraying material and spraying by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a spraying material, free from the clogging of a nozzle and the loss of the function of an accelerating agent, and capable of improving the strength generation in the initial and intermediate periods and after a long time and reducing a rebounding ratio. SOLUTION: This spraying material is obtained by compounding a cement mortal mainly consisting of a fluorocalciumaluminate-containing cement and gypsum with an accelerating agent mainly consisting of calciumalminate directly before spraying. Preferably, the cement mortal is compounded with at least one kind selected from a water-reducing agent, a setting retarder, a setting accelerator and ultrafine powder, and the accelerating agent is compounded with alkali aluminate and/or alkali carbonate. Further, an accelerating agent mainly consisting of calciumaluminate is joined to a cement mortal mainly consisting of a fluorocalciumalminate-containing cement and gypsum just before spraying and they are directly sprayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a large initial, mid-term and long-term strength for spraying on exposed ground surfaces in tunnels such as roads, railways, headraces, etc., and also prevents clogging of spray nozzles. The present invention relates to a spray material having good workability and a small rebound amount, and a spraying method using the spray material. The cement mortar in the present invention is a general term for cement paste, cement mortar and cement concrete.

[0002]

2. Description of the Related Art In construction work such as tunnel excavation, a construction method of spraying quick-setting concrete containing a quick-setting admixture on concrete is constructed in order to prevent collapse of the exposed ground due to excavation. (Japanese Patent Publication No. 52-4149). In this method, generally, cement, aggregate and water installed at the excavation site are measured, and sprayed concrete is made in a mixing plant, which is transported by an agitator vehicle and pressure-fed by a concrete pump. This is a method of mixing with a quick-setting agent that has been pressure-fed from, and spraying it as quick-setting sprayed concrete onto the ground surface to a predetermined thickness. With this construction method, the rebound (rebound) rate, which is the ratio of the amount of drop without adhering to the ground and the amount of spray, is 15 to 30%.
And many. In addition, since there is a lot of dust and the work environment is bad, there is concern about the effects of pneumoconiosis.

[0003] Conventionally used concrete containing a quick-setting admixture has a better initial strength rise than concrete containing no quick-setting admixture, but long-term strength does not contain a quick-setting admixture. 30-50 than concrete
%, The long-term strength developability tends to decrease. This tendency has been dealt with by increasing the spray thickness, especially in unstable ground. However, increasing the spray thickness is not preferable in terms of economy and work efficiency. Particularly in the excavation of a large-section tunnel, it is particularly desired to improve the strength of shotcrete, reduce the shot thickness, and shorten the construction time and excavation cycle.

As a method for achieving high strength of shotcrete, there has been a method of making shotcrete from finely powdered cement, and mixing it with a conventional quick-setting admixture (Japanese Patent Laid-Open Publication No. Sho. 50-16717). In addition, a method has been proposed in which gypsum and calcium aluminate are mixed in advance, mixed with spray concrete and sprayed (Japanese Patent Laid-Open No. 50-17718).

[0005]

However, in the former method, the decrease in long-term strength when compared with plain concrete when cement that is not pulverized is used is somewhat reduced, or at the same level. It was difficult to obtain sufficient strength development that greatly exceeds that of concrete. If quick-setting shotcrete can be made significantly stronger than plain concrete, it is possible to make it considerably thinner than the conventional shotthickness.
Work time can also be reduced.

In the latter method of using a quick-setting agent which is a mixture of calcium aluminate and gypsum, when the gypsum and calcium aluminate are brought into contact with each other, there is a phenomenon that the quick-setting property of calcium aluminate is lowered. Therefore, when the amount of the quick-setting admixture increases, it becomes necessary to interrupt the work during spraying to add the quick-setting admixture, the amount of dust generated increases, or the quick-setting admixture disappears during the spraying work. There was a problem in terms of workability, safety and hygiene, such as concrete falling into danger.

Although it is possible to improve initial strength and long-term strength as compared with conventional sprayed concrete by adding gypsum and a quick-setting agent to cement, this method tends to block the spray nozzle. Moreover, no significant improvement in the mid-term strength was observed around the age of 7 days. A significant improvement in the medium-term strength can suppress the loosening of the ground at an early stage, and can further enhance safety. Therefore, there has been a demand for a spraying material and a spraying method in which the initial, middle and long-term strengths are all improved, and the spray nozzle is not clogged, and the rebound rate is small.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and the constitution thereof is such that cement containing fluorocalcium aluminate and cement mortar containing gypsum as a main component are mainly composed of calcium aluminate. A quick-setting agent as a component is blended immediately before spraying, and more preferably, cement mortar is blended with at least one selected from the group consisting of a water-reducing agent, a setting retarder, a setting accelerator, and an ultrafine powder. Characterized in that alkali aluminate salt and / or alkali carbonate is added to the cement, and further cement containing fluorocalcium aluminate and cement mortar containing gypsum as a main component, and calcium aluminate as a main component immediately before spraying It is characterized by merging quick-setting agents and spraying.

The spray material of the present invention is a system of cement containing fluorocalcium aluminate, gypsum and a quick-setting agent containing calcium aluminate as a main component. It caused a blockage and was not actually implemented. The inventors of the present invention have studied the reason for this, and have achieved a spray material capable of exhibiting high strength in the initial, middle and long term by preventing nozzle clogging by changing the compounding order. That is, using ordinary cement, the strength is improved by adding fluorocalcium aluminate, the strength is further improved by adding gypsum, and the deterioration of long-term strength due to the addition of the conventional quick-setting agent is improved. It has succeeded in obtaining mid-term and long-term strength far exceeding that of plain concrete.

Based on the finding that when gypsum is mixed with calcium aluminate, its activity is reduced and the effect of improving strength is reduced, the present inventors have added a quick-setting agent just before spraying to make The present invention has been completed, which prevents clogging and deterioration of the performance of the quick-setting admixture, and provides a quick-setting effect and an effect of improving the mid-term and long-term strength. Further, the rebound rate is remarkably reduced by blending the ultrafine powder into the cement containing fluorocalcium aluminate.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The cement mortar in the present invention means that cement containing fluorocalcium aluminate and gypsum are mixed, dry cement mortar in a dry state containing no water, and cement mortar mixed with water. It is a concept that includes both. That is, dry cement mortar made of cement and gypsum containing fluorocalcium aluminate, dry cement mortar using dry aggregate paste with fine aggregate, dry cement concrete using dry aggregate paste with fine aggregate and coarse aggregate, These are cement paste, cement mortar and cement concrete in which these are mixed with water.

The amount of water used is 60% or less, preferably 45% or less, in the cement ratio containing water / fluorocalcium aluminate (hereinafter referred to as water cement ratio).
If it exceeds 60%, sufficient strength may not be exhibited and the amount of the quick-setting agent used may increase. In the present invention, an admixture such as a water reducing agent, a setting retarder, a setting accelerator and ultrafine powder can be used in combination with the cement mortar and the quick-setting agent.

Cement containing fluorocalcium aluminate used in the present invention (hereinafter referred to as fluorocement) means various commercially available portland cements such as normal strength, early strength, moderate heat, and super early strength and fly ash. ,
Various mixed cements mixed with blast furnace slag or the like or commercially available fine particle cements to which fluorocalcium aluminate is added and mixed are used. Furthermore, at the time of cement production, in addition to the cement raw material, a fluorine-containing substance such as fluorite is added,
Cement obtained by firing in a kiln can also be used.

Fluorocalcium aluminate is calcium aluminate containing fluorine, and CaO
Is C and Al ₂ O ₃ is A, C ₃ A, C ₁₂ A ₇ , C
Ca of calcium aluminate represented by A, CA _2, etc.
Examples include pulverized products of heat-treated products in which one or more of O is replaced by CaF ₂ . One CaO of C ₄ A ₃ · SO ₃
Was replaced by CaF ₂ , C ₃ A ₃ · SO ₃ · CaF ₂
Fluorauin can also be used. Considering the strength development, one CaO of C ₁₂ A ₇ is replaced with CaF ₂
C ₃ A ₃ · SO replaced with CaF ₂ for one CaO of C ₁₁ A ₇ · CaF ₂ or C ₄ A ₃ · SO ₃ replaced with
The use of fluoroauines such as ₃ · CaF ₂ is preferred.

The content of fluorocalcium aluminate in the fluorocement is 5 to 100 parts by weight based on 100 parts by weight of cement as a fluorine-containing mineral component.
It is more preferably 10 to 60 parts by weight. If it is less than 5 parts by weight, the effect of fluorocement cannot be sufficiently exerted, and 10
If the amount exceeds 0 parts by weight, strength development may be impaired.

The gypsum used in the present invention is a substance mixed with cement for the purpose of increasing the strength of shotcrete, and, for example, anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum can be used. From the viewpoint of, anhydrous gypsum is preferable. The particle size of gypsum may be such that it is usually used for cement, for example, a Blaine value of 3000 cm ² / g,
Further, it is preferable to make fine powder of 4500 cm ² / g or more. The amount of gypsum used is 1 to 25 parts by weight, preferably 5 to 100 parts by weight of the cement in fluorocement.
20 parts by weight. If it is less than 1 part by weight, it is difficult to promote long-term strength development, and if it exceeds 25 parts by weight, the initial setting is delayed and the adhesion to the ground tends to be deteriorated. Further, there is a possibility that the concrete expands due to expansion over a long period of time.

The quick-setting agent used in the present invention contains calcium aluminate as a main component. Calcium aluminate is a quick-setting component that causes the setting of concrete in the initial stage.
It can be obtained by using an aO raw material, an Al ₂ O ₃ raw material, or the like, and firing it in a kiln, or perform heat treatment such as melting in an electric furnace.
As a mineral component of calcium aluminate, if CaO is C and Al ₂ O ₃ is A, C ₃ A, C ₁₂ A ₇ , C
A pulverized product of a heat-treated product of calcium aluminate represented by A, CA ₂ or the like can be used. Calcium aluminate has a Blaine value of 3000 cm ² / g or more, preferably 45
When a particle size of 00 cm ² / g or more is used, preferable quick setting property and initial strength development property can be obtained. The amount of calcium aluminate used is 1-2 with respect to 100 parts by weight of fluorocement.
It is 0 part by weight, preferably 5 to 15 parts by weight. If it is less than 1 part by weight, initial setting is unlikely to occur, and if it exceeds 20 parts by weight, long-term strength development may be impaired.

In the present invention, it is preferable to use calcium aluminate in combination with alkali aluminate and / or alkali carbonate as a quick-setting agent. The alkali aluminate salt has an action of promoting initial setting, and specific examples thereof include lithium aluminate, sodium aluminate, potassium aluminate, and the like, and combinations thereof are also possible. The amount of alkali aluminate used is 0.1 to 50 parts by weight, preferably 1 to 30 parts by weight, based on 100 parts by weight of calcium aluminate. If the amount is less than 0.1 part by weight, the effect is insufficiently expressed, and if it exceeds 50 parts by weight, the long-term strength developability may be impaired.

Alkali carbonate has the effect of improving the initial strength, and when it is used in combination with alkali aluminate, the quick setting force is further improved. The amount of alkali carbonate used is
0.1 to 20 per 100 parts by weight of calcium aluminate
It is 0 part by weight, preferably 0.5 to 100 parts by weight. 0.
If it is less than 1 part by weight, the effect is not sufficiently exhibited, and if it exceeds 200 parts by weight, the long-term strength may decrease.

The water reducing agent is used for the purpose of improving the fluidity of the cement mortar, and any liquid or powdery water reducing agent can be used. Specific examples include a polyol derivative, a lignin sulfonate, or a derivative thereof. When high strength is required, it is preferable to use a high performance water reducing agent,
Specifically, a formalin condensate of alkylallyl sulfonate, a polycarboxylic acid-based polymer compound, or the like can be used. When a water reducing agent is used, the spray thickness can be reduced, the quick setting force can be improved, and the amount of the quick setting agent added can be reduced. Further, the amount of dust generated is small, the rebound rate is reduced, and the spraying efficiency can be improved. The amount of the water reducing agent used was 100 parts by weight of fluorocement, and the solid content was 0.
It is 1 to 5 parts by weight, preferably 0.5 to 3 parts by weight.
If it is less than 0.1 parts by weight, no effect can be expected, and if it exceeds 5 parts by weight, the viscosity of the cement mortar increases and the workability may deteriorate.

Further, in order to control the setting time of the cement mortar, setting retarders such as organic acids and alkali carbonates, alkali metal hydroxides such as sodium hydroxide, setting accelerators such as slaked lime and light vane are used. It is also possible to use together. As the organic acids, gluconic acid, tartaric acid, citric acid, lactic acid or salts thereof can be used. The amount of organic acids used is 0.1 per 100 parts by weight of fluorocement.
To 3 parts by weight, preferably 0.5 to 2 parts by weight. If it is less than 0.1 part by weight, the effect is not exhibited, and if it exceeds 3 parts by weight, curing may be delayed too much, resulting in poor curing. As the alkali carbonate, sodium carbonate, calcium carbonate, potassium carbonate, sodium bicarbonate or the like can be used. The amount of alkali carbonate used is 0.1 to 10 parts by weight based on 100 parts by weight of fluorocement. The amount of the alkali metal hydroxide such as sodium hydroxide, slaked lime and setting accelerator such as Mingban used is 0.1 to 20 parts by weight, preferably 0.1 to 10 parts by weight based on 100 parts by weight of fluorocement. is there.

The ultrafine powder used in the present invention means an average particle size of 10
The fine particles have a size of μm or less, and have the effects of reducing the amount of cement, reducing the amount of dust generation, and improving the pumpability of concrete, and in particular have the effect of significantly reducing the rebound rate. Specifically, ultrafine powder such as fine powder slag, fly ash, bentonite, kaolin, and silica fume can be used. In the present invention, the average particle size is 10 depending on the case.
Fine powder exceeding μm can also be used. The amount of ultrafine powder used is 1 to 50 parts by weight, preferably 1.5 to 30 parts by weight, based on 100 parts by weight of fluorocement. If it is less than 1 part by weight, no effect can be expected, and if it exceeds 50 parts by weight, setting and curing may be delayed.

The aggregate used in the present invention preferably has low water absorption and high aggregate strength. As the fine aggregate, river sand, mountain sand, lime sand, silica sand, etc. can be used. The coarse aggregate preferably has a G _{max of} 20 mm or less, and a G _{max of} 15 mm or less is preferable in consideration of pumpability.

In the present invention, it is important that the component containing fluorocement, gypsum and the component containing a quick-setting agent are separately stored, and both are mixed immediately before spraying. Immediately before spraying is a few seconds before the spray material is sprayed from the tip of the nozzle in wet spraying, specifically, at most 30 seconds before, and in the case of dry spraying, it is several minutes before and at most 120 minutes before.

In the spraying method of the present invention, a conventionally used spraying device can be used, and either a wet spraying method or a dry spraying method can be used. The spraying material of the present invention can be prepared by mixing a specific amount of gypsum in advance with fluorocement, or by adding gypsum when kneading concrete. Furthermore, since the content of sulfur trioxide in cement specified in JIS is 3.0 to 4.5% by weight or less, at the time of cement production in a cement manufacturing plant, gypsum in an amount exceeding this JIS specified value is mixed. A method is also possible.

In the case of the wet spraying method, for example, cement, gypsum, fine aggregate, coarse aggregate and water are added and kneaded, and air is pneumatically fed. On the way, for example, a quick-setting agent is added from one of the Y-shaped pipes. There is a method of spraying. In the case of the dry spraying method, for example, cement, gypsum, fine aggregate, coarse aggregate and a quick-setting agent are added and kneaded and pneumatically fed. For example, water is added from one side of the Y-shaped tube in the wet state. There is a method of spraying. in this case,
After mixing the cement mortar and the quick-setting agent, the elapsed time until spraying is preferably 120 minutes or less.

[0027]

EXAMPLES The materials used in the following examples are as follows. Cement: Normal Portland cement Gypsum: Anhydrous gypsum crushed product Fluorocalcium aluminate: Main component C ₁₁ A ₇・ C
aF _2, Blaine 5600cm ² / g Calcium aluminate: principal component C ₁₂ A _7, Blaine value 6000 cm ² / g fine aggregate: sand, Niigata Himekawa produced river sand, surface water of 5%, specific gravity 2.61 crude bone Material: gravel, river gravel from Himekawa, Niigata, dry condition, specific gravity 2.65, crushed stone G _max 15mm or less

Example 1 Fluorocalcium aluminate was added to 100 parts by weight of cement at a ratio shown in Table 1 to obtain fluorocement. This fluorocement 400 kg / m ³ is added to fine aggregate 1055 kg / m ³ , coarse aggregate 713 kg / m ³ , water 20
Gypsum with 0 kg / m ³ and a Blaine value of 5400 cm ² / g was added to obtain a cement mortar. Gypsum was added in an amount of 10 parts by weight based on 100 parts by weight of the cement in the fluorocement. Aliber 280 (manufactured by Aliber) is used as a spraying machine, a Y-shaped mixing tube is provided in front of the spraying nozzle, and the quick-setting agent composed of calcium aluminate is 10 parts by weight with respect to 100 parts by weight of fluorocement. Spraying was carried out under the condition of 4 m ³ / h so as to be mixed, and the compressive strength of each material was measured, and the results are shown in Table 1.

The compressive strength was measured by the following method. (The same applies to the following examples.) The kneaded sprayed concrete is pressure-fed by a spraying machine, and a quick-setting admixture is added and mixed from a mixing pipe in the middle of the press-concrete pressure-feeding to obtain a quick-setting sprayed concrete, which is used as a pull-out formwork. 50 x 5
Spray on a 0 x 20 cm formwork, pull out formwork specimens for 1 hour and 3 hours, 50 x 50 x after 1 day of age
The compressive strength of a core of φ5 × 10 cm sampled from a 20 cm mold was measured at a specified age.

[0030]

[Table 1]

Example 2 Fluorocement 40 prepared by adding 20 parts by weight of fluorocalcium aluminate to 100 parts by weight of cement and mixing.
To 0 kg / m ^3, fine aggregates 1055kg / m ^3, coarse aggregate 7
13 kg / m ³ , water 200 kg / m ³ and Blaine value 5
400 cm ² / g of gypsum was mixed to obtain shotcrete. The amount of gypsum added is the amount shown in Table 2 with respect to 100 parts by weight of cement in the fluorocement. This sprayed concrete was sprayed on the spraying machine (Alibar 28
0) is used to add calcium aluminate as a quick-setting agent from the Y-shaped tube to 100 parts by weight of fluorocement.
While adding the amount shown in, the composition was sprayed on the mold under the condition of 4 m ³ / hr and the compressive strength was measured.

[0032]

[Table 2]

Comparative Example 1 Experiment No. 2 of Example 2 was repeated except that the fluorocement, gypsum and the quick-setting admixture were kneaded at once. Construction was performed in the same manner as 2-11. The compressive strength is expressed in N / mm ² , the 1-hour strength is 4.9, the 3-hour strength is 8.9, and the 1-day strength is 2
The 2.5- and 7-day strengths were 40.6 and the 28-day strength was 57.4. However, in this comparative example, the hardened material adheres to the inner wall of the pressure-feeding pipe within a few minutes after the start of spraying, resulting in the narrowing of the nozzle inner diameter, and when the spraying is continued, the pressure-feeding pipe is blocked in 10 to 20 minutes. occured.

Comparative Example 2 Experiment No. 2 of Example 2 was repeated except that the fluorocement and the quick-setting admixture were mixed in advance and the gypsum was joined from the Y-shaped tube. 2-11
Construction was carried out in the same manner as. Its compressive strength is N / mm
Expressed as ² , 1 hour intensity is 4.9 and 3 hour intensity is 8.
The 8-day intensity was 23.0, the 7-day intensity was 41.0, and the 28-day intensity was 57.6. However, in this comparative example, since the quick-setting component was added to the fluorocement, it was difficult to adjust the fluidity of the cement, and the pressure feed pipe was blocked in a short time as in the case of the comparative example 2.

Comparative Example 3 Experiment No. 2 of Example 2 was repeated except that the fluorocement was mixed with the gypsum and the quick-setting agent previously mixed from the Y-shaped tube. 2-1
Construction was carried out in the same manner as 1. Its compressive strength is N / m
Expressed in m ² , 1-hour intensity is 4.1 and 3-hour intensity is 7.
The 4-day intensity was 21.5, the 7-day intensity was 38.7, and the 28-day intensity was 54.5. However, in this comparative example, the consumption amount per hour of the mixture of gypsum and the quick-setting agent was increased, and the spraying operation had to be interrupted during the spraying due to the shortage of the quick-setting agent. In the present invention, the amount of the quick-setting agent used was 10 kg, but 20 kg was required.

Example 3 20 parts by weight of fluorocalcium aluminate was added to 100 parts by weight of cement, and 10 parts by weight of gypsum was added to 100 parts by weight of cement in fluorocement. Fluorocement 10 was used as a quick-setting admixture containing 100 parts by weight of calcium aluminate and an amount of alkali aluminate and / or alkali carbonate shown in Table 3.
The same procedure as in Example 1 was performed except that 10 parts by weight was mixed with 0 parts by weight. Table 3 shows the results. Table 3 is all examples. As the alkali aluminate and alkali carbonate, commercially available products were used.

[0037]

[Table 3]

Example 4 Same as Example 1 except that 10 parts by weight of gypsum was mixed with 100 parts by weight of cement in 100 parts by weight of cement, in which 20 parts by weight of fluorocalcium aluminate was added and mixed with 100 parts by weight of cement. Then, dry concrete was obtained. This dry concrete was carried into the spraying machine by a belt conveyor. 10 parts by weight of an aluminate alkali salt was added to 100 parts by weight of calcium aluminate, and 10 parts by weight of a quick-setting agent was added to 10 parts by weight of fluorocement.
It was added on a belt conveyor so that it would be part by weight. Dry concrete containing a quick-setting agent was pneumatically fed from a spraying machine, water was added by a Y-tube so that the water / cement ratio was 47%, and dry spraying was carried out. As a result, it was possible to carry out the spraying work without any trouble such as blockage of the pipe. The compressive strengths after 1 hour, 7 days and 28 days of age were measured and are shown in Table 4. Separately, Table 4 also shows the compressive strength when spraying was carried out in the same manner as in Example 4 except that ordinary Portland cement (having the same specific surface area) was used instead of fluorocement.

[0039]

[Table 4]

Example 5 20 parts by weight of fluorocalcium aluminate was added to 100 parts by weight of cement to obtain fluorocement. The unit amount of this fluorocement is 450 kg / m ³
Then, to 100 parts by weight of cement in fluorocement, 10 parts by weight of gypsum and the amount of sodium naphthalene sulfonate-based water reducing agent shown in Table 5 were added, and water was added so that the concrete slump became 20 ± 2 cm. Example 1
Sprayed concrete was obtained in the same manner as in. Separately, a quick-setting admixture was prepared in which 100 parts by weight of calcium aluminate were mixed with the amounts of alkali aluminate salt and alkali carbonate shown in Table 5. The sprayed concrete was pneumatically fed, the above-mentioned quick-setting admixture was added so as to be 10 parts by weight with respect to 100 parts by weight of fluorocement, and wet spraying was carried out. Material order 1
Table 5 also shows the compressive strength after 7 hours and 28 days.

[0041]

[Table 5]

Example 6 A fluorocement was prepared by adding 20 parts by weight of fluorocalcium aluminate and 10 parts by weight of gypsum to 100 parts by weight of cement. To 100 parts by weight of this fluorocement, the amount of a set retarder and commercially available slaked lime as a set accelerator were mixed, and spray concrete was obtained in the same manner as in Example 1. Separately, calcium aluminate 10
A quick-setting admixture was prepared by mixing 10 parts by weight of sodium aluminate with 0 part by weight. Wet spraying was carried out in the same manner as in Example 5 except that sprayed concrete was pneumatically fed and the above-mentioned quick-setting admixture was added so as to be 7 parts by weight with respect to 100 parts by weight of fluorocement. Age 1 hour, 7 days and 2
The compressive strength after 8 days is also shown in Table 6.

[0043]

[Table 6]

Example 7 A fluorocement was prepared by adding 20 parts by weight of fluorocalcium aluminate to 100 parts by weight of cement. The unit amount of this fluorocement is 450 kg / m ³
Then, water was added so that the concrete slump was 20 ± 2 cm, and 10 parts by weight of gypsum was added to 100 parts by weight of the cement in fluorocement, and 100 parts by weight of the fluorocement was added, and the amount of poly Example 1 with the addition of a water reducing agent consisting of carboxylic acid sodium salt and ultrafine powder
Sprayed concrete was obtained in the same manner as in. Separately, 10 parts by weight of sodium aluminate per 100 parts by weight of calcium aluminate was used as a quick-setting agent in 10 parts of fluorocement.
Wet spraying was carried out in the same manner as in Example 5 except that 10 parts by weight was added to 0 parts by weight. Measure the rebound rate,
The results are shown in Table 7. As is clear from Table 7,
It was confirmed that the rebound rate was reduced by using ultrafine powder.

[0045]

[Table 7]

[0046]

EFFECTS OF THE INVENTION According to the present invention, it is possible to improve the strength development in the early, middle and long term, and to reduce the rebound rate, without the nozzle clogging or the performance of the quick-setting agent decreasing. it can. Therefore, the spraying thickness can be made thinner than the conventional quick-setting concrete, and it is possible to provide the concrete obtained by the spraying method with higher safety.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location // C04B 103: 12 (72) Inventor Mizushima Ai 2209 Aomi, Aomi, Nishikubiki-gun, Niigata Prefecture Electrochemistry Industrial Co., Ltd.Aomi Factory (72) Inventor Isamu Terajima 2209 Aomi, Aomi-cho, Nishikubiki-gun, Niigata Electrochemical Industry Co., Ltd. Aomi Factory (72) Akira Watanabe 2209 Aomi, Aomi-cho, Nishikubiki-gun, Niigata Electrochemical Industrial Co., Ltd. Aomi factory

Claims (5)

[Claims] 1. A spraying material obtained by mixing a cement containing fluorocalcium aluminate and a cement mortar containing gypsum as a main component with a quick-setting agent containing calcium aluminate as a main component. 2. The spray material according to claim 1, wherein the quick-setting agent is mainly composed of calcium aluminate and alkali aluminate and / or alkali carbonate. 3. The spray material according to claim 1, which comprises at least one selected from the group consisting of a water reducing agent, a setting retarder, a setting accelerator and an ultrafine powder. 4. The spray according to any one of claims 1 to 3, wherein 1 to 25 parts by weight of gypsum is mixed with 100 parts by weight of cement in the cement containing fluorocalcium aluminate. material. 5. The cement containing fluorocalcium aluminate and the cement mortar containing gypsum as a main component are mixed and mixed with a quick-setting agent containing calcium aluminate as a main component immediately before spraying, and then sprayed. Spraying method.