JP2003306370A - Spray material and spraying method using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spray material for repair with which the repairing of a deep part to be repaired can be accomplished with one spray operation instead of several operations, which can prevent the development of corrosion of a reinforcing bar and maintain the long-term durability of a building even if located near the sea, and which has good pumpability due to the improved fluidity of mixed mortar and the reduced flowdown even when the transfer distance of the mortar by a pump is long. <P>SOLUTION: The spray material comprises cement mortar, a polymer, a nitrite salt, a quick setting agent, an inorganic powder, hydroxides, hydroxycarboxylic acids and gypsum. The spraying method characteristically comprises adding water to the spray material, mixing the same with a mixing machine, transferring the mixed mortar with the pump, adding and mixing the quick setting agent and compressed air with the mixed mortar during the transfer, and spraying it. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a spray material used for repairing a deteriorated concrete structure and a spraying method using the spray material.

[0002]

2. Description of the Related Art Concrete structures are subject to salt damage, neutralization,
Deterioration may progress due to the effects of freeze-thawing and chemical corrosion, and cracks and floats may occur on the surface. As a countermeasure, the deteriorated part is confirmed by hitting inspection, etc., removed by an electric pick, an air pick, a water jet, etc., and filled with a repair member for repair work. Conventionally, a polymer cement mortar in which a polymer is mixed with a cement mortar has been used as a repair material for backfilling a cross-section that has been taken off, and a work for spraying and repairing this has been performed.

[0003]

However, when repairing with polymer cement mortar without using a quick-setting agent, if the repairing depth is, for example, 10 cm, it is necessary to carry out spraying in two or three times. there were. This has a problem that it takes time to restore one cross section because the first layer is sprayed and the hardening of the mortar proceeds to some extent and then the next spraying is not performed so that the mortar falls by its own weight. In addition, rust often occurs on the reinforcing bars near the surface of concrete structures that have deteriorated due to salt damage and neutralization.In the case of concrete structures near the coastline, salt permeation occurs even if repaired with new polymer cement mortar. However, there were problems such as being unable to expect long-term durability quickly. Furthermore, in order to pressure-feed the mortar over a long distance (50 m or more), it is required that the kneaded and mixed mortar has good fluidity and a small flow down. In particular, under environmental conditions such as in summer when the temperature exceeds 25 ° C., there is a problem in that there are many opportunities for troubles such as quick flowdown and blockage of the pump.
Therefore, even if the repair depth is deep like the conventional spraying, the repair is completed in one time instead of spraying several times, and long-term durability can be maintained even for structures near the coastline, and pumping Even if the distance is long, the flow-down of the mixed mortar is small, so that a repair spraying material with good pumpability has been demanded. As a result of earnest studies to solve the problem, the present inventor can complete the repair in one time instead of spraying it several times even if the repair depth is deep, and can suppress the progress of reinforcing bar corrosion. To develop a repair spray material that can maintain long-term durability even for structures near the coastline, and has good fluidity of kneaded mortar even with a long pumping distance and a small flowdown so that pumping pumpability is good. succeeded in.

[0004]

That is, the present invention is a spraying material comprising cement mortar, polymer, nitrite and a quick-setting agent, and further inorganic fine powder, hydroxides, oxycarboxylic acids and gypsum. A mortar obtained by adding water to the spraying material and kneading with a mixer, and pumping the mortar together, and then spraying by mixing and mixing the quick-setting agent and compressed air during the pumping. Is a spraying method.

[0005]

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

The cement used in the present invention is Portland cements specified in JIS. For example, ordinary Portland cement, early-strength cement, moderate heat cement, low heat Portland cement, blast furnace cement, fly ash cement and the like can be used. It is preferable to use ordinary Portland cement because of its small flow-down and strength development.

The aggregate used in the present invention is not particularly limited, but river sand, mountain sand, river gravel, silica sand, lime sand, general lightweight sand and lime gravel can be used. The amount of aggregate used is 100 to 4 with respect to 100 parts by mass of cement.
00 parts by mass is preferable, and 150 to 300 parts by mass is more preferable. If the amount is less than 100 parts by mass, cracks may occur after the mortar is hardened, and if the amount exceeds 400 parts by mass, pumpability may be impaired.

The polymer used in the present invention includes a powder polymer, an emulsion in which a polymer is dispersed in water, and a latex (hereinafter referred to as polymer dispersion). The polymer is a substance used for the purpose of improving the tensile strength of the cured mortar, improving the adhesion strength with the adhered concrete structure, and improving the durability. As the powder polymer, a re-emulsifying resin powder for cement admixture defined in JIS can be used. For example,
Examples thereof include vinyl acetate vinyl acetate, polyacrylic acid ester, ethylene-vinyl acetate copolymer, styrene-acrylic acid ester copolymer, and acrylic copolymer represented by acrylonitrile-acrylic acid ester copolymer. The amount of powdered polymer used is 100
1 to 15 parts by weight is preferable, and 2 to 10 parts by weight.
The mass part is more preferable. If it is less than 1 part by mass, the effect of improving the strength characteristics and durability shown above is small, and if it exceeds 15 parts by mass, the fluidity of the mortar may be adversely affected. The polymer dispersion defined in JIS includes, for example, styrene-butadiene copolymer latex, natural rubber latex, chloroprene latex, ethylene-vinyl acetate copolymer emulsion, polyacrylic acid ester emulsion, styrene-acrylic acid ester copolymer. Examples thereof include acrylic acid ester copolymers represented by polymer emulsions and acrylonitrile-acrylic acid ester copolymer emulsions, and mixed polymer dispersions thereof. When mixing with mortar,
The powdered polymer or polymer dispersion may be used alone or in combination. The total polymer solid content may be within the range of 1 to 15 parts by mass with respect to 100 parts by mass of cement. Polymers classified as polymer dispersion may be mixed when kneading on site, and powdered polymers classified as re-emulsified powder resin may be mixed in advance with premix dry mortar and kneaded on site. You may mix when mixing.

The nitrite used in the present invention is a substance that suppresses rusting of reinforcing bars. For example, lithium nitrite, sodium nitrite, potassium nitrite, calcium nitrite,
Examples thereof include magnesium nitrite and barium nitrite.
Of these, the use of lithium nitrite, which improves the fluidity of the mortar, is preferred. The amount of nitrite used is preferably 0.5 to 20 parts by mass and more preferably 1 to 10 parts by mass with respect to 100 parts by mass of cement. If it is less than 0.5 part by mass, the anticorrosive effect of the reinforcing bar is small, and if it exceeds 20 parts by mass, long-term strength development may be deteriorated.

The quick-setting admixture used in the present invention is used by being mixed and mixed with the polymer cement mortar during transportation in order to improve the initial strength development property. It can be used. For example, calcium aluminate-based quick-setting agent (powder), calcium sulfaluminate-based quick-setting agent (powder), aluminate-based quick-setting agent (powder or liquid), aluminum sulfate-based quick-setting Examples include agents (powder or liquid), quick-setting agents containing silicate as a main component (powder or liquid), and the like. Considering workability, it is preferable to use a liquid quick-setting agent. The amount of quick-setting agent used is
With respect to 100 parts by mass of cement mortar, 0.5 to 7 parts by mass in terms of solid content is preferable, and 2 to 5 parts by mass is more preferable. If it is less than 0.5 parts by mass, sufficient short-time strength may not be exhibited, and if it exceeds 7 parts by mass, long-term strength development may be impaired.

In consideration of fluidity, strength properties, durability and the like, the spraying material of the present invention comprises ordinary cement as cement mortar, lithium nitrite as nitrite, and styrene-butadiene copolymer as polymer. A material composition containing a combination of a latex or an acrylic ester copolymer and a liquid quick-setting agent with less dust generation as a quick-setting agent is more preferable.

The inorganic fine powder used in the present invention is a substance which prevents rebounding and falling off when sprayed. For example, silica fume, blast furnace slag, limestone fine powder, fly ash, clay mineral and the like can be mentioned. Among these, it is preferable to use silica fume, which also improves strength development. The amount of the inorganic fine powder used is preferably 0.5 to 10 parts by mass, and more preferably 1 to 5 parts by mass with respect to 100 parts by mass of cement. If it is less than 0.5 parts by mass, the effect of reducing the rebound is small, and if it exceeds 10 parts by mass, the fluidity of the mortar may be excessively reduced, and pumping performance may be impaired.

The hydroxides used in the present invention are substances used for the purpose of improving the coagulation property when a quick-setting agent is added. For example, calcium hydroxide, magnesium hydroxide, barium hydroxide and the like can be mentioned. The use of inexpensive and readily available calcium hydroxide is preferred. The amount of hydroxides used is 0.5 to 1 with respect to 100 parts by mass of cement.
0 parts by mass is preferable, and 1 to 5 parts by mass is more preferable.
If it is less than 0.5 part by mass, it is difficult to improve the coagulation property when the quick-setting agent is added, and if it exceeds 10 parts by mass, the fluidity may be adversely affected.

The oxycarboxylic acids used in the present invention are substances that improve the fluidity retention of the mortar. Examples thereof include citric acid, tartaric acid, malic acid, gluconic acid, and alkali metal salts thereof. Among these,
It is preferable to use an alkali metal salt that can easily control the setting time. The amount of the oxycarboxylic acid used is preferably 1 to 400 parts by mass and more preferably 4 to 200 parts by mass with respect to 100 parts by mass of the hydroxides. If it is less than 1 part by mass, the effect of retaining the fluidity is small, and if it exceeds 400 parts by mass, the strength development may be hindered.

The gypsum used in the present invention is a substance used for the purpose of improving long-term strength development. For example,
Anhydrous gypsum, dihydrate gypsum, hemihydrate gypsum and the like can be mentioned. Among these, anhydrous gypsum, which has a large effect of improving strength development, is preferably used. The amount of gypsum used is preferably 10 to 500 parts by mass and more preferably 20 to 200 parts by mass with respect to 100 parts by mass of the hydroxides. 1
If it is less than 0 parts by mass, the effect of strength development is small, and if it exceeds 500 parts by mass, fluidity may be adversely affected.

In the present invention, a thickener can be used in combination. The thickener is a substance that gives tackiness to the kneaded mortar and prevents the mortar from bouncing and falling off when sprayed. Examples thereof include methyl cellulose, methyl ethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, guar gum, alginate, polyvinyl alcohol, polyacrylic acid, polyethylene oxide and the like. Among these, it is preferable to use methyl cellulose, which has a large thickening effect in an alkaline environment. The amount of the thickener used is preferably 0.05 to 1 part by mass, and more preferably 0.08 to 0.5 part by mass, relative to 100 parts by mass of cement. If the amount is less than 0.05 parts by mass, it may be insufficient to impart the adhesive effect, and if the amount exceeds 1 part by mass, the adhesiveness may be excessively increased to impair the pumpability.

In the present invention, an expansive material can be used in combination. The expansive material is a substance used for the purpose of preventing cracking that occurs after the mortar hardens. For example, a substance containing calcium sulphoaluminate as a main component, a substance containing lime as a main component and the like can be mentioned. The amount of expansive material used is
Cement 100 parts by mass 1-8 parts by mass is preferred, 2-6
The mass part is more preferable. If it is less than 1 part by mass, the effect of preventing cracking is small, and if it exceeds 8 parts by mass, the fluidity of the mortar may be lowered.

Fibers may be used in combination in the present invention.
The fiber is a substance used for the purpose of preventing the adhered cured mortar from coming off and improving bending toughness. Examples thereof include polymer fibers such as vinylon fibers, polypropylene fibers and aramid fibers, and inorganic fibers such as glass fibers, carbon fibers and steel fibers. Of these, vinylon fibers are preferably used in consideration of cost and durability. The amount of fiber used is
0.2-2 mass parts is preferable with respect to 100 mass parts of cement, and 0.3-1 mass part is more preferable. If it is less than 0.2 parts by mass, the effect of improving bending toughness is small, and if it exceeds 2 parts by mass, the fluidity of the mortar may be adversely affected.

In the present invention, a fluidizing agent can be used in combination. The fluidizing agent is a substance that improves the fluidity of the mortar. For example, generally commercially available naphthalene sulfonate, melamine, lignin sulfonate,
Examples include water reducing agents such as polycarboxylic acid salts. The amount of the fluidizing agent used is 0.05 to 100 parts by mass of cement.
1 mass part is preferable, and 0.1-0.7 mass part is more preferable. If it is less than 0.05 parts by mass, the effect of improving the fluidity is small, and if it exceeds 1 part by mass, the fluidity becomes too large, and rebound or dropout may occur when sprayed.

When water is kneaded, cement, aggregate and water may be separately added and kneaded at the site of use, and premix dry mortar in which a hydraulic substance and aggregate are mixed in advance and water are mixed at the site. You may use it by kneading.

The water / cement mortar ratio is preferably 9 to 20%, more preferably 11 to 15%. If it is less than 9%, pumping performance may be impaired, and sufficient strength development exceeding 20% may not be obtained. The water referred to here includes water in the aqueous polymer dispersion.

The mixing of polymer cement mortar is
It uses a mixer. The kind of the mixer is not particularly limited, but the one having a higher kneading efficiency is preferable because a uniform polymer cement mortar can be prepared in a short time. Examples of the mixer include a hand mixer, a pan mixer, and a forced kneading mixer in which the entire blade revolves and a part of the blades rotates to knead and mix.

The spraying method used in the present invention is a method for repairing a concrete structure by scraping off a deteriorated part of the concrete structure and spraying a quick-setting polymer cement mortar on the surface of the cross section of the scraped-out concrete structure. Yes, it is a construction method applied to all concrete structures and brick structures such as viaduct beams, girders, piers, floor plate backs, wall surfaces of dams, tunnel inner surfaces, etc. In addition, in terms of improving the adhesive strength of the scraped concrete structure cross section and the quick-setting polymer cement mortar, spray or apply a commercially available primer solution such as ethylene-vinyl acetate copolymer before the spraying work. Good.

The spraying method used in the present invention is carried out as follows. There is no particular limitation as long as it is a spraying method of a system in which the kneaded polymer cement mortar is pumped through a pumping pipe and the quick-setting agent and compressed air are combined and mixed before the mortar is discharged. . Spraying is performed while controlling the distance from the nozzle tip to the spray surface so that the repaired area is uniformly filled with quick-setting polymer cement mortar. At that time, in order to maximize the adhesive force of the quick-setting polymer cement mortar, it is preferable that the distance from the nozzle tip to the spray surface is within 100 cm, and the amount of compressed air consumed is 0.1 m ³ / min or more. It is preferable to set. Since the quick-setting agent is added, if the cross-sectional depth of the repaired portion is about 100 mm, it can be filled with one spray. When it is necessary to finish the iron in the end, stop the addition of the quick-setting agent, and use mortar alone for 10 mm.
Spray after spraying the surface. In order to suppress the occurrence of cracks on the surface of the repaired portion, it is preferable to spray or apply a primer liquid such as ethylene-vinyl acetate copolymer on the surface finished with the iron after the quick-setting polymer cement mortar is cured.

[0025]

[Experimental Example] Hereinafter, detailed description will be given based on an experimental example.

Experimental Example 1 A dry cement mortar consisting of 100 parts by mass of cement and 200 parts by mass of aggregate was prepared. 5 parts by mass of polymer A and nitrite were added to 100 parts by mass of cement in the dry cement mortar. Was added to the dry cement mortar in 100 parts by weight, and 13 parts by weight of water was added, and the mixture was kneaded with a plaster mixer and pressure-fed with a squeeze pump. During the pressure feeding, the quick-setting admixture was pumped so as to be 3 parts by mass with respect to 100 parts by mass of cement, and was kneaded and mixed with the compressed air to be mixed and mixed with the mortar being pumped, and then sprayed. The flow in the state kneaded by the mixer, the presence or absence of rusting of the reinforcing bar and the compressive strength when the quick-setting agent and the compressed air were mixed and mixed and sprayed were measured. The results are shown in Table 1.

(Materials used) Cement: ordinary Portland cement manufactured by Denki Kagaku Kogyo Co., Ltd., specific gravity 3.15 Aggregate: lime sand, particle diameter 1.5 mm or less, specific gravity 2.65 Polymer A: styrene-butadiene latex, solid Minute 45% Nitrite A: Lithium nitrite aqueous solution, solid content 25% Nitrite B: Sodium nitrite aqueous solution, solid content 25% Accelerator: Denki Kagaku Kogyo KK, aluminate liquid accelerator, solid content 50%

(Measurement method) Flow: conforming to JIS R 5201 Compressive strength: conforming to JIS R 5201 The curing method was air curing in a room at a temperature of 20 ° C. and a humidity of 60%. The measuring material age was 28 days. Presence or absence of rust on reinforcing bar: Width 10 cm, length 20 cm, thickness 10 c with one D13 round steel bar 20 cm long arranged
m sprayed mortar specimen was prepared for 28 days at a temperature of 20
It was cured in air in a room at ℃ and humidity of 60%. The specimen was immersed in seawater at a temperature of 20 ° C. for 3 months, the mortar portion was destroyed, and the reinforcing bar was taken out to confirm the presence or absence of rust.

[0029]

[Table 1]

It can be seen from Table 1 that in the spray material of the present invention, the nitrite improves the fluidity of the mortar and eliminates the rusting of reinforcing bars.

Experimental Example 2 100 parts by mass of cement, 200 parts by mass of aggregate, 1 part of cement
1.5 parts by weight of hydroxides, 5 parts by weight of polymer A in solid content, 1 part by weight of nitrite A in solid content and 100 parts by weight of inorganic fine powder shown in Table 2, and water. Oxides 1
20 parts by mass of oxycarboxylic acids and 50 parts by mass of gypsum were mixed with 00 parts by mass to prepare dry cement mortar, 12 parts by mass of water was added to 100 parts by mass of this dry cement mortar, and the mixture was kneaded with a plaster mixer to squeeze pump. Sent by pressure. During the pressure feeding, the quick-setting admixture was pumped so as to be 3 parts by mass with respect to 100 parts by mass of cement, and was kneaded and mixed with the compressed air to be mixed and mixed with the mortar being pumped, and then sprayed. The flow rate in the state kneaded with a mixer and the bounce rate when the quick-setting admixture and compressed air were combined and mixed and sprayed were measured. The results are shown in Table 2.

(Material used) Hydroxides: slaked lime, commercial product Inorganic fine powder: Silica fume, commercial product Oxycarboxylic acids: sodium citrate, commercial product Gypsum: anhydrous gypsum, commercial product

(Measurement Method) Flow: According to JIS R 5201 Bounce Rate: The amount of bounce on the ground was measured by spraying onto a concrete slab installed at the top for 3 minutes and calculated by the following formula. Bounce rate (%) = [(bounce amount (kg)) / (mortar discharge rate per hour (kg / min)) x (spraying time (mi
n))] × 100

[0034]

[Table 2]

It can be seen from Table 2 that in the spray material of the present invention, the rebound rate of mortar is reduced by the inorganic fine powder.

Experimental Example 3 Same as Experimental Example 2 except that 2 parts by weight of inorganic fine powder, 1.5 parts by weight of hydroxides and nitrite A were added to 100 parts by weight of cement. Then, the flow in the kneaded state, the quick-setting admixture and the compressed air were combined and mixed and sprayed. The compressive strength of the collected mortar was measured and the presence or absence of rusting of the reinforcing bar was confirmed in the same manner as in Experimental Example 1. The results are shown in Table 3.

[0037]

[Table 3]

From Table 3, it can be seen that in the spray material of the present invention, the nitrite improves the fluidity of the mortar, and the reinforcing bars do not rust.

Experimental Example 4 Experimental Example 2 except that 2 parts by mass of the inorganic fine powder and 100 parts by mass of hydroxides were added to 100 parts by mass of cement.
In the same manner as above, the initial time in the proctor test of the mortar collected by the flow in the kneaded state (immediately after kneading and after 60 minutes), the quick-setting agent and the compressed air were mixed and sprayed and sprayed was measured. The results are shown in Table 4.

(Measurement method) Proctor test: According to ASTM C 403, the time at which the penetration resistance value is 3.55 N / mm ² was taken as the starting time. The test temperature is 20 ° C.

[0041]

[Table 4]

It can be seen from Table 4 that in the spray material of the present invention, the initial time for the setting of mortar is shortened by the hydroxides.

Experimental Example 5 The same as Experimental Example 2 except that 2 parts by mass of inorganic fine powder was added to 100 parts by mass of cement and oxycarboxylic acids were added to 100 parts by mass of hydroxides as shown in Table 5. Then, the flow in the kneaded state, the quick-setting admixture and the compressed air were combined and mixed and sprayed. The compressive strength of the collected mortar was measured in the same manner as in Experimental Example 1. The results are shown in Table 5.

[0044]

[Table 5]

From Table 5, it can be seen that in the spray material of the present invention, the oxycarboxylic acids improve the fluidity of the mortar.

Experimental Example 6 2 parts by weight of inorganic fine powder and 1.5 parts by weight of hydroxides were added to 100 parts by weight of cement, and gypsum was added to 100 parts by weight of hydroxides as shown in Table 6. Except for this, the procedure was the same as in Experimental Example 2, and the kneaded flow, the quick-setting admixture and the compressed air were combined and mixed and sprayed. The compressive strength of the collected mortar was measured in the same manner as in Experimental Example 1. The results are shown in Table 6.

[0047]

[Table 6]

From Table 6, it can be seen that the spray material of the present invention improves the fluidity of the mortar and improves the 28-day compressive strength due to gypsum.

Experimental Example 7 The same procedure as in Experimental Example 2 was carried out except that 2 parts by mass of the inorganic fine powder and 100 parts by mass of the polymer were added to 100 parts by mass of cement, and tensile strength and neutralization resistance were determined. It was measured. The results are shown in Table 7.

(Materials used) Polymer B: ethylene-vinyl acetate copolymer, powder form,
Commercial goods

(Measurement Method) Tensile Strength: According to ASTM C 190. The curing method was air curing in a room at 20 ° C. and a humidity of 60%. The measuring material age was 28 days. Neutralization resistance: 20 × 20 × 4 × 4 × 16 cm
It was aerated in a room at a temperature of 60 ° C. and a humidity of 60% for 28 days. Then, after curing for 28 days in the accelerated neutralization tester, the neutralization depth was measured by the phenolphthalein method. Accelerated neutralization conditions are as follows: carbon dioxide concentration: 5%, temperature: 30 ° C, humidity: 6
It is 0%.

[0052]

[Table 7]

It can be seen from Table 7 that in the spray material of the present invention, the polymer improves the tensile strength of the mortar and reduces the neutralization depth.

Experimental Example 8 The same procedure as in Experimental Example 2 was carried out except that 2 parts by mass of the inorganic fine powder and 100 parts by mass of the quick-setting agent were added to 100 parts by mass of cement, and the thick spraying property was measured. The compressive strength of the collected mortar was measured in the same manner as in Experimental Example 1. The results are shown in Table 8
Shown in.

(Measurement method) Thick blasting property: Mortar was sprayed on a concrete slab installed at the top at a spraying distance of 40 cm and sprayed at a thickness of 10 cm or more, and it adhered without dropping even after 10 minutes. If yes, it is marked as less than 10 cm or if it falls within 10 minutes after adhesion, it is marked as x.

[0056]

[Table 8]

It can be seen from Table 8 that the spray material of the present invention shows good thick sprayability of mortar by the quick-setting agent and the compressive strength is improved for 3 hours.

Experimental Example 9 The same procedure as in Experimental Example 2 was repeated except that 2 parts by mass of the inorganic fine powder and 100 parts by mass of the thickener shown in Table 9 were added to 100 parts by mass of cement, and the flow in the kneaded state was obtained. The rebound rate was measured when the quick-setting admixture and compressed air were mixed together and sprayed. The results are shown in Table 9.

(Material used) Thickener: methyl cellulose, commercial product

[0060]

[Table 9]

From Table 9, it can be seen that in the spray material of the present invention, when a thickener is used in combination, the rebound rate of mortar decreases.

Experimental Example 10 The same procedure as in Experimental Example 2 was carried out except that 2 parts by mass of the inorganic fine powder and 100 parts by mass of the expansive material were added to 100 parts by mass of cement. The presence or absence of cracks when the binder and compressed air were combined and mixed and sprayed was confirmed. The results are shown in Table 10.

(Materials used) Expanding material: Calcium sulfaluminate-based expanding material manufactured by Denki Kagaku Kogyo Co., Ltd.

(Measurement Method) Crack: After spraying on a concrete slab, trowel finishing was performed to adjust the thickness to 20 mm. It was exposed outdoors for 28 days and visually inspected for cracks.

[0065]

[Table 10]

It can be seen from Table 10 that the spray material of the present invention eliminates cracks in the mortar when the expansive material is used together.

Experimental Example 11 The same operation as in Experimental Example 2 was carried out except that 2 parts by mass of the inorganic fine powder and 100 parts by mass of the fibers were added to 100 parts by mass of cement, and the flow in the kneaded state and quick setting were carried out. The bending toughness was measured when the agent and compressed air were mixed together and sprayed. The results are shown in Table 11.

(Material used) Fiber: Vinylon fiber, fiber length 6 mm, commercial product

(Measurement method) Bending toughness: According to JSCE G 552. The curing method was air curing in a room at a temperature of 20 ° C. and a humidity of 60%. The measuring material age was 28 days.

[0070]

[Table 11]

It can be seen from Table 11 that the spray material of the present invention tends to improve the bending toughness of the mortar when the fibers are used together.

Experimental Example 12 Experimental Example 2 except that 2 parts by mass of the inorganic fine powder and 100 parts by mass of the superplasticizer were added to 100 parts by mass of cement.
In the same manner as above, the bounce rate was measured when the kneaded flow, the quick-setting admixture and the compressed air were combined and mixed and sprayed. The results are shown in Table 12.

(Material used) Superplasticizer: Melamine type, commercial product

[0074]

[Table 12]

From Table 12, it can be seen that the spray material of the present invention tends to improve the fluidity of the mortar when the fluidizing agent is used together.

Experimental Example 13 2 parts by mass of inorganic fine powder, 100 parts by mass of cement, the thickener of Experimental Example 9, the expansive material of Experimental Example 10, the fibers of Experimental Example 11, and the fluidizing agent of Experimental Example 12 were shown. The experiment was performed in the same manner as in Experimental Example 2 except that the mass part shown in 13 was added, and the rebound rate when the flow in the kneaded state, the quick-setting admixture and the compressed air were mixed and sprayed was measured. The compressive strength of the collected mortar was measured in the same manner as in Experimental Example 1. The results are shown in Table 13.

[0077]

[Table 13]

From Table 13, it can be seen that the spray material of the present invention exhibits excellent mortar fluidity, 28-day compressive strength, and rebound rate when a thickening agent, an expanding material, a fiber and a fluidizing agent are used in combination.

Experimental Example 14 2 parts by mass of the inorganic fine powder, 0.1 part by mass of the thickener of Experimental Example 9, 3 parts by mass of the expansive material of Experimental Example 10, and 0.1 part of the fiber of Experimental Example 11 with respect to 100 parts by mass of cement. Dry cement mortar was prepared in the same manner as in Experimental Example 2 except that 3 parts by mass and 0.1 part by mass of the fluidizing agent of Experimental Example 12 were added, and water was added in Table 13 to 100 parts by mass of the dry cement mortar. In addition to the mass parts shown, the rebound rate when the quick-setting admixture and compressed air were combined and mixed and sprayed was measured as in Experimental Example 2. The compressive strength of the collected mortar was measured in the same manner as in Experimental Example 1.
The results are shown in Table 14.

[0080]

[Table 14]

From Table 14, it can be seen that the spraying material of the present invention has a rebound rate of mortar and 2 by changing the amount of water used.
It can be seen that the 8 day compressive strength can be varied.

[0082]

By using the spraying material of the present invention, the fluidity of the mortar kneaded and mixed is improved, the flow down is small, and the setting time is short. Also, the repaired section is 10 cm
Even if it has the above thickness, it can be repaired by one spraying, and the construction time can be shortened. Furthermore, since it has a great rustproofing effect on the reinforcing bars, it is useful as a repair material for concrete structures near the coast.

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) C04B 22/14 C04B 22/14 A B D 24/06 24/06 A 24/26 24/26 C F G Z // C04B 103: 12 103: 12 103: 14 103: 14 103: 22 103: 22 103: 30 103: 30 103: 44 103: 44 103: 61 103: 61 (72) Inventor Seiichi Terasaki Nishi Niigata Prefecture 2209 Aomi, Aomi-machi, Aki-machi, Kubiki-gun Inside Aomi Plant, Electric Chemical Industry Co., Ltd. (72) Kushibashi Takumi, 2209, Aomi, Aomi-cho, Nishi-Kibun-gun, Niigata Prefecture F-term inside Aomi Plant (reference) 4G012 MA00 MA02 MB04 MB12 MB13 MB23 MB33 MC01 MC02 MC11 MC12 PB03 PB04 PB05 PB07 PB11 PB12 PB17 PB27 PB30 PB31 PC01 PC03 PC04 PC05 PC06 PC08 PC11 PD02 PD03 PE04

Claims (3)

[Claims] 1. A spray material comprising cement mortar, a polymer, nitrite and a setting agent. 2. The spray material according to claim 1, further comprising inorganic fine powder, hydroxides, oxycarboxylic acids, and gypsum. 3. Mortar obtained by adding water to the spraying material according to claim 1 or 2 and kneading with a mixer is pumped, and the quick-setting admixture and compressed air are combined and sprayed during the pumping. A spraying method characterized by that.