JP2014005183A - Quick-setting cement concrete and spraying method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide liquid quick-setting cement concrete excellent in dispersion stability.SOLUTION: Quick-setting cement concrete contains (1) cement concrete and (2) a liquid quick-setting agent containing aluminum sulfate and phosphate esters. The phosphate esters are preferably phosphate esters of polyoxyalkylene alkyl ethers. The liquid quick-setting agent may contain a fluorine compound, alkanolamines, a compound containing a hydroxyl group, and carboxylic acids. In a spraying method, the cement concrete and the liquid quick-setting agent are mixed and sprayed.

Description

  The present invention mainly relates to a quick setting cement concrete used in the civil engineering and construction industries, and a spraying method using the same. The cement concrete of the present invention is a general term for cement paste, mortar, and concrete.

  In order to prevent the collapse of exposed ground such as tunnel excavation, spraying method of quick setting concrete in which quick setting agent is mixed with concrete is performed. This method usually involves preparing sprayed concrete at a cement, aggregate and water metering and mixing plant installed at the excavation site, transporting it with an agitator car, pumping it with a concrete pump, and using a confluence pipe installed in the middle. This is a method of mixing with a rapid setting agent fed from the other side and spraying it to the ground surface as a quick setting sprayed concrete until a predetermined thickness is reached. As a spraying method, a method using a liquid quick-setting agent mainly composed of aluminum sulfate is known. Patent documents include the following.

JP 2005-89276 A JP 2006-193388 A JP 2009-256201 A JP-A-60-131855 Japanese Patent Laid-Open No. 52-19721

  As a method for improving the rapid setting power of the liquid quick setting agent, there is a method of adding an alkali metal salt (Patent Document 1). In the addition of the alkali metal salt, the amount that can be added is limited in terms of the stability of the liquid, and there is a possibility that it is difficult to impart a sufficient rapid setting force.

  As a method for ensuring the stability of the liquid, there is a method of blending phosphorous acid and / or an organic acid salt thereof (Patent Document 2).

  The phosphoric acid esters of the present invention are different from phosphorous acid and / or its organic acid salt. Patent Document 2 does not describe that the storage stability and rapid setting force are improved by the addition of the stabilizer of the present invention.

  There is a method of blending phosphate ester into cement concrete and using it as an early strengthening agent (Patent Document 3). In Patent Document 3, cement concrete is driven into a mold and the compressive strength after 20 hours is measured. Patent document 3 has no description about containing a phosphate ester in a liquid quick-setting agent beforehand. Since Patent Document 3 is a technique for imparting early strength to cement concrete while ensuring working time, it is different from the technical idea of the present invention.

  Phosphate ester is added to the cement concrete side and used for the purpose of improving workability (Patent Documents 4 and 5). Therefore, it does not itself have the effect of dramatically promoting the hardening of the cement, and many have the effect of delaying the hydration of the cement. In the present invention, by adding a phosphate ester to the liquid quick-setting agent side in advance, the liquid quick-setting agent is stabilized in a suspended state, and quick setting power and strength development are improved. The effect of the present invention is manifested by a combination of aluminum sulfate and phosphate esters, and cannot be expected from Patent Documents 4 to 5.

  That is, the present invention is (1) cement concrete, and (2) a rapid setting cement concrete containing a liquid quick setting agent containing aluminum sulfate and phosphates, and (1) cement concrete, (2) Quick setting cement concrete containing 25 to 50 parts of aluminum sulfate and 0.02 to 5 parts of phosphate ester in 100 parts of liquid quick setting agent, and phosphoric acid The quick setting cement concrete in which the ester is a phosphate ester and / or a phosphate ester salt, and the phosphate ester is a phosphate ester of a polyoxyalkylene alkyl ether and / or a phosphorus ester of a polyoxyalkylene alkyl ether. The quick setting cement concrete which is an acid ester salt, and the liquid quick setting agent contains a fluorine compound. Cement concrete, and further, the quick setting cement concrete in which the liquid quick setting agent contains alkanolamines, and the liquid quick setting agent further contains a compound having a hydroxyl group and / or a compound having carboxylic acids. The quick setting cement concrete, wherein the quick setting cement concrete is a suspended liquid in which a liquid quick setting agent is dispersed in a temperature range of −10 ° C. to 45 ° C., (1) cement concrete (2) ) The rapid setting cement concrete spraying method in which the liquid quick setting agent is mixed and sprayed, and the quick setting property using the liquid quick setting agent stored in a temperature range of −10 ° C. to 45 ° C. It is a spray method of cement concrete.

  According to the present invention, it is possible to obtain an effect that the liquid quick-setting agent is excellent in dispersion stability in a wide temperature range.

  Hereinafter, the present invention will be described in detail. In the present invention, unless otherwise specified, parts and% refer to values in mass units.

  The liquid quick-setting agent of the present invention contains aluminum sulfate, phosphate esters, and water.

  The aluminum sulfate of the present invention can be used without particular limitation as long as it is commercially available. Examples of aluminum sulfate include aluminum sulfate having crystal water such as anhydrous aluminum sulfate and aluminum sulfate 12 hydrate, and liquid aluminum sulfate that can be purchased in the form of an aqueous solution.

  In the liquid quick setting agent, the solid content concentration of aluminum sulfate is preferably 25 to 50%, more preferably 30 to 40% in terms of the quick setting power and strength development of the quick setting cement concrete. If it is less than 25%, the stability at low temperatures may be lowered, and if it exceeds 50%, the storage stability may be lowered.

  The phosphate esters of the present invention refer to phosphate esters and / or phosphate ester salts. Phosphate esters improve the dispersion stability of the liquid quick-set agent when the liquid quick-set agent is in a suspended state, and give rapid setting power when the liquid quick-set agent is added to cement concrete. It is a compound that improves.

  As the phosphate esters, phosphate esters of polyoxyalkylene alkyl ether are preferable. Examples of the alkylene group include an ethylene group, a propylene group, and a butylene group. In these, an ethylene group is preferable. The alkyl group is preferably a hydrocarbon group having 8 to 20 carbon atoms, and more preferably a hydrocarbon group having 8 to 12 carbon atoms. The phosphoric acid ester of polyoxyalkylene glycol ether may be a monoester or a diester. The production method of the polyoxyalkylene alkyl ether phosphate ester is not particularly limited. Usually, it is obtained by esterifying a compound by reaction of a phosphorylating agent such as phosphoric acid, polyphosphoric acid, phosphorus pentoxide, phosphorus oxychloride and the like with a polyoxyalkylene alkyl ether. In this phosphoric acid esterification reaction, a monoester and a diester are produced and may be obtained as a mixture thereof. Even such a mixture can be used. When the phosphoric acid ester of the polyoxyalkylene alkyl monoether is a phosphoric acid diester, the polyoxyalkylene alkyl ether groups may have the same structure or different structures.

  The phosphoric acid ester salt of polyoxyalkylene alkyl ether may be used in the present invention. Examples of the alkylene group include an ethylene group, a propylene group, and a butylene group. In these, an ethylene group is preferable. The alkyl group is preferably a hydrocarbon group having 8 to 20 carbon atoms, and more preferably a hydrocarbon group having 8 to 12 carbon atoms. Phosphate ester salts include phosphate ester alkali metal salts (K, Na, etc.), phosphate ester alkaline earth metal salts (Mg, Ca, Ba, etc.), phosphate ester ammonium salts, phosphate ester Examples include alkanolamine salts and alkylamine salts of phosphate esters. Examples of the amine include primary to tertiary alkylamines or alkanolamines, alkylene oxide adducts of primary alkylamines or secondary alkylamines, and diamines. The alkyl group is preferably a hydrocarbon group having 1 to 10 carbon atoms. One kind of salt may be used, or two or more different salts may be used in combination.

  The amount of phosphate esters used is preferably 0.02 to 5 parts, more preferably 0.05 to 3 parts, per 100 parts of aluminum sulfate. If it is less than 0.02 part, the effect of improving dispersibility may be small, and if it exceeds 5 parts, strength development may be reduced.

  Dispersion stability is an important performance when pumping a liquid quick-set agent from a tank during spraying. If the liquid quick-set agent is separated and there is a large amount of sediment in the liquid quick-set agent, the pump may not be discharged from the tank. Even if the liquid quick-setting agent can be delivered, the concentration of the active ingredient of the liquid quick-setting agent may not be uniform, which may affect the quality of the sprayed cement concrete. When the separation stability is evaluated by the degree of separation (the ratio of the supernatant liquid formed by the suspension of particles suspended in a suspended liquid accelerator), it is preferably 10% or less, more preferably 5% or less.

  The liquid quick setting agent of the present invention may contain a fluorine compound. The fluorine compound is used for the purpose of improving the setting property. The fluorine compound is not particularly limited as long as it is a compound that dissolves or decomposes in water. Examples of the fluorine compound include fluoride salts, silicofluoride salts, boron fluoride salts, organic fluorine compounds, and hydrofluoric acid. One or two or more of these can be used.

  Examples of the fluoride salt include lithium fluoride, sodium fluoride, potassium fluoride, calcium fluoride, aluminum fluoride, and cryolite. Cryolite contains sodium hexafluoroaluminate as a component, and any natural product or synthesized product can be used.

  Examples of the silicofluoride include ammonium silicofluoride, sodium silicofluoride, potassium silicofluoride, and magnesium silicofluoride.

  Boron fluoride salts include boron fluoride, boron trifluoride, boron trifluoride monoethylamine complex, boron trifluoride acetic acid complex, boron trifluoride triethanolamine, ammonium borofluoride, sodium borofluoride, potassium borofluoride , And ferrous borofluoride.

  Among the fluorine compounds, cryolite is preferred because it is highly safe, has a low production cost, and has excellent setting properties.

  The amount of the fluorine compound used is preferably 0.2 to 10 parts, more preferably 0.7 to 7 parts, relative to 100 parts of aluminum sulfate. If the amount is less than 0.2 part, the effect of improving the coagulation force may be small. If the amount exceeds 10 parts, strength development may be inhibited.

  The liquid accelerator of the present invention may contain alkanolamines. Alkanolamines are used for the purpose of improving instantaneous cohesion when mixed with cement. The alkanolamines are not particularly limited, but can be used as long as they can be dissolved in the liquid accelerator. Alkanolamines are organic compounds having a> N—R—OH structure in the structural formula. Here, R is an atomic group usually called an alkyl group or an allyl group, a linear alkylene group such as a methylene group, an ethylene group or an n-propylene group, an alkylene group having a branched structure such as an isopropylene group, and the like. And an allyl group having an aromatic ring such as a phenyl group and a benzyl group. R may be bonded to the nitrogen atom at two or more positions, and a part or all of R may have a cyclic structure. R may be bonded to a plurality of hydroxyl groups. R may have an element other than carbon and an element other than hydrogen, such as sulfur, fluorine, chlorine, and oxygen, in part of the alkyl group. R may have a plurality of hydroxyl groups bonded thereto.

  Examples of alkanolamines include ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N, N-dimethylethanolamine, N, N-dibutylethanolamine, N- (2-aminoethyl) ethanolamine, and trifluoride. Examples thereof include boron triethanolamine and derivatives thereof. One or two or more of these can be used.

  Of the alkanolamines, diethanolamine is preferred in terms of stability during dissolution and coagulation properties.

  The amount of alkanolamines used is preferably 0.2 to 10 parts, more preferably 0.7 to 7 parts, per 100 parts of aluminum sulfate. If it is less than 0.2 part, the improvement of instantaneous cohesive force may be small, and if it exceeds 10 parts, strength development may be reduced.

The liquid accelerator of the present invention may contain a compound having a hydroxyl group and / or a carboxylic acid.
The compound having a hydroxyl group and / or carboxylic acid contributes somewhat to the dispersion stabilization of the liquid, but is used for the purpose of improving the strength after one day.

  Examples of the compound having a hydroxyl group include low molecular compounds such as glycerin, ethylene glycol, and propylene glycol, polyoxyethylene alkyl ethers or derivatives thereof. Among the compounds having a hydroxyl group, glycerin is preferable.

  Carboxylic acids refer to carboxylic acids and / or carboxylates. Examples of carboxylic acids include monocarboxylic acids such as formic acid, acetic acid, and propionic acid, dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, fumaric acid, and phthalic acid, Tricarboxylic acids such as trimellitic acid and tricarballylic acid, oxymonocarboxylic acids such as hydroxybutyric acid, lactic acid, and salicylic acid, oxydicarboxylic acids of malic acid, aminocarboxylic acids such as aspartic acid and glutamic acid, ethylenediaminetetraacetic acid (EDTA) and Examples include aminopolycarboxylic acids such as trans-1,2-diaminocyclohexanetetraacetic acid (CyDTA). Examples of the salt constituting the carboxylate include alkali metals and alkaline earth metals. These 1 type, or 2 or more types can be used. Among the carboxylic acids, oxalic acid is preferable because it is easily available and inexpensive.

  The amount of the hydroxyl group-containing compound and / or carboxylic acid used is preferably 0.2 to 5 parts, more preferably 0.5 to 3 parts, relative to 100 parts of aluminum sulfate. If it is less than 0.2 part, it may be difficult to obtain the intended effect, and if it exceeds 5 parts, the coagulation force may be reduced.

  The liquid quick setting agent of the present invention is preferably stably dissolved or suspended in the temperature range of -10 ° C to 45 ° C in terms of excellent workability and storage stability from summer to winter. .

  The amount of the liquid setting agent of the present invention is preferably 0.5 to 15 parts, more preferably 3 to 10 parts in terms of solid content with respect to 100 parts of cement. If the amount is less than 0.5 part, it may be difficult to obtain a sufficient rapid setting force. If the amount exceeds 15 parts, the amount of water in the cement concrete may increase and the strength development may decrease.

  The cement of the present invention is not particularly limited, and a commercially available cement can be used. As cement, various portland cements such as normal, early strength, super early strength, moderate heat, and low heat, various mixed cements mixed with blast furnace slag, fly ash, silica fume, blast furnace chilled slag and limestone fine powder. Examples include filler cement mixed with powder, and environmentally friendly cement (eco-cement) manufactured using municipal waste incineration ash and sewage sludge incineration ash as raw materials. A fine cement obtained by pulverizing these can also be used. The ratio of the mixture and cement in the mixed cement is not particularly limited.

  In the present invention, an aggregate such as fine aggregate such as sand or coarse aggregate such as gravel is blended in cement and used as mortar or concrete. The aggregate is not particularly limited, and natural aggregate, artificially produced aggregate, heavy aggregate, recycled aggregate, or the like can be used.

  The present invention may use water reducing agents. Examples of water reducing agents include water reducing agents, AE water reducing agents, high performance water reducing agents, and high performance AE water reducing agents. Examples of water reducing agents include alkylallyl sulfonic acid, naphthalene sulfonic acid, melamine sulfonic acid, lignin sulfonic acid, polycarboxylic acid, and polyethylene glycol. The water reducing agent can be either liquid or powdery. In these, a high performance water reducing agent is preferable.

  The amount of the water reducing agent used is preferably 0.05 to 5 parts, more preferably 0.1 to 3 parts in terms of solid content with respect to 100 parts of cement.

  As long as the object of the present invention is not substantially inhibited, fluidity retention agent, fiber, antifreeze agent, shrinkage reducing agent, rust preventive agent, clay mineral, retarder, polymer dispersion, expansion material, high strength admixture, coloring Cement admixtures such as an agent, an AE agent, a dust reducing agent, a thickener, a waterproofing agent, and an efflorescence inhibitor can be used in combination.

The amount of cement used in the cement concrete used in the present invention is preferably 330 to 500 kg / m ³ , and the water cement ratio is preferably 40 to 65%.

  As the spraying method of the present invention, a wet spraying method and a dry spraying method which are generally performed can be applied. Examples of the wet construction method include a method of mixing the liquid quick setting agent with cement concrete mixed with cement, aggregate, and water. Examples of the dry construction method include a method of mixing water and the liquid quick setting agent or only the liquid quick setting agent into cement concrete in which cement and aggregate are mixed.

  As a method of mixing a liquid quick-setting agent into cement concrete and using it as a spray material, use a shower ring tube or Y-shaped tube that can add the liquid quick-set agent in a shower form, and then use a liquid quick-setting agent and cement concrete. A method of mixing just before spraying is preferred. When the liquid quick-setting agent of the present invention is mixed with cement concrete, the liquid quick-setting agent may be added in the form of mist with compressed air in advance.

  The spraying material of the present invention can be used as a support member during construction of an underground structure typified by tunnel construction. The spray material of the present invention can also be used for the stabilization method of the slope that sprays directly on the slope of the natural ground, the stabilization method of the slope that sprays on the place where the frame skeleton is arranged, and the repair of various concrete structures.

  Hereinafter, it demonstrates in detail based on an Example. The gelation shown in the table means a state in which suspended particles are completely settled and remain without falling even when the container is turned upside down.

Phosphate esters of the amount shown in Table 1 were added to 370 g of aluminum sulfate, 630 g of water and 100 parts of aluminum sulfate, and stirred at 20 ° C. for 5 minutes to prepare a liquid quick-setting agent (solid content concentration of aluminum sulfate: 37%). After stirring, the mixture was transferred to a glass container, sealed, and stored for 3 months. The dispersion state was observed, and the degree of separation was evaluated. The results are shown in Table 1.
As a comparative example, a composition not added with phosphate esters was also evaluated. Table 2 shows the composition of the liquid quick setting agent of the comparative example.

(Materials used)
Aluminum sulfate: powder, commercially available 12 hydrate, reagent primary phosphate ester a: polyoxyethylene alkyl ether phosphate ester, product name “Price Surf A208F” manufactured by Daiichi Kogyo Seiyaku Co., Ltd., alkyl having 8 carbon atoms .
Phosphate esters b: Polyoxyethylene lauryl ether phosphate monoethanolamine salt, trade name “Price Surf DB-01” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
Fluorine compound: sodium hexafluoroaluminate, commercial product Reagent primary alkanolamines: diethanolamine, commercial product Reagent primary carboxylic acids A: oxalic acid, commercial product Reagent primary hydroxyl group compound: glycerin, commercial product Reagent primary Carboxylic acids B: Calcium formate, commercial product, reagent grade 1

(Test method)
Dispersion state: After stirring, the liquid quick-setting agent was immediately transferred to a glass bottle with a scale of 100 cc, and the liquid state was observed from the next day. The state of the liquid was observed every week, the ratio of the volume of the liquid surface in the suspended state to the volume of the liquid surface (100 cc) was determined, and the separation state (degree of separation) was evaluated by the following formula. Observation was carried out for up to 3 months. The environmental temperature during storage is 20 ° C. If the degree of separation is 0%, the liquid quenching agent does not settle and maintains a good dispersion state. As the degree of separation increases, the dispersion stability of the liquid accelerator decreases.
(formula)
Degree of separation (%) = 100 − [(volume of liquid surface in suspension (cc) / 100 (cc)) × 100]

  The solid content concentration of aluminum sulfate was adjusted to the amount shown in Table 3, and the same procedure as in Example 1 was performed except that 0.3 part of phosphate ester a was used with respect to 100 parts of aluminum sulfate. The results are shown in Table 3.

  The same procedure as in Example 1 was conducted except that 100 parts of aluminum sulfate, 0.3 part of phosphate ester a, and the amount of fluorine compound shown in Table 4 were added. The results are shown in Table 4.

  The same procedure as in Example 1 was performed except that 100 parts of aluminum sulfate, 0.3 part of phosphate ester a, and alkanolamines in the amounts shown in Table 5 were added. The results are shown in Table 5.

  The same procedure as in Example 1 was carried out except that 100 parts of aluminum sulfate, 0.3 part of phosphoric acid ester a, and a compound having a hydroxyl group and / or carboxylic acid in the amount shown in Table 6 were added. The results are shown in Table 6.

  100 parts of aluminum sulfate, phosphate ester a in the amount shown in Table 7, fluorine compound in the amount shown in Table 7, alkanolamine in the amount shown in Table 7, compound having hydroxyl group in the amount shown in Table 7, Table 7 The same procedure as in Example 1 was carried out except that the amount of carboxylic acid shown in the above was added. The results are shown in Table 8.

The same procedure as in Example 1 was carried out except that the liquid quick setting agent having the composition shown in Table 9 was used, the temperature condition during storage of the liquid quick setting agent was changed to the temperature shown in Table 9, and the dispersion state after 3 months was confirmed. The results are shown in Table 9.

A high-performance water reducing agent of 1.0 part in terms of solid content was added to 2100 g of sand, 700 g of cement, 315 g of water and 100 parts of cement, and kneaded with a mortar mixer to prepare a sprayed mortar. To this mortar, 8 parts of a liquid quick-setting agent having the composition shown in Table 10 was added in terms of solid content with respect to 100 parts of cement, and stirred at high speed for 10 seconds to prepare a quick-setting mortar. The quick setting mortar was evaluated for setting properties and mortar compressive strength. In the evaluation, a liquid quick-setting agent stored until the next day was used. The results are shown in Table 10.
For comparison, the performance when the phosphate ester a is not added to the liquid quick-setting agent side but is added to the mortar side so as to be 0.3 parts with respect to 100 parts of aluminum sulfate in the liquid quick-setting agent. Were also evaluated (Experiment No. 7-27 to Experiment No. 7-29). The composition of the liquid quick-setting agent is the same as that of Experiment No. 1-1, Experiment No. 1-2, Experiment No. Same as 1-3. Experiment No. 7-27, Experiment No. Since the liquid quick-setting agent 1-1 gelled the next day, the liquid quick-starting agent immediately after preparation was used.

(Materials used)
Sand: Crushed sand from Itoigawa, Niigata density 2.66g / cm ³
Cement: Commercial product, Portland cement Density 3.15 g / cm ³
Water: tap water high-performance water reducing agent: commercial product, polycarboxylic acid water reducing agent

(Test method)
Condensation property: Based on JSCE-D102, the time range to reach the first start and the time range to reach the end were measured in minutes (for example, when the first start time is 10-11, the first start time is 10 to 11 minutes) . The test temperature is 25 ° C. Mortar compressive strength: Based on JISR 5201, the compressive strength was measured. The test temperature is 25 ° C.

  The same procedure as in Example 8 was performed except that the amount of the liquid quick-setting agent shown in Table 11 in terms of solid content was used for 100 parts of cement. The results are shown in Table 11.

The unit quantity of each material cement 400 kg / ^{m 3,} fine aggregates 1058kg / ^{m 3,} the shotcrete was prepared as coarse aggregate 710 kg / ^{m 3,} water 200 kg / ^{m 3,} superplasticizer 4 kg / ^{m 3,} The sprayed concrete was pumped by a concrete pump “MKW-25SMT” (manufactured by Shintech Co., Ltd.) under conditions of a spraying pressure of 0.4 MPa and a spraying speed of 10 m ³ / h. Compressed air was introduced at a position 3 m behind the mixing tube where the liquid quick-setting agent was merged, and the shotcrete was conveyed by air. From one of the mixing tubes, the liquid quick setting agent shown in Table 12 previously misted with compressed air was mixed and mixed with the sprayed concrete. Eight holes (diameter 3 mm) are arranged at equal intervals on the circumference of the pipe that joins the liquid quick-set agent, and the liquid quick-set agent joins and mixes with the cement concrete in a shower-like manner. It is a method. The amount of liquid quenching agent that merged with the compressed air was adjusted to 8 parts in terms of solid content with respect to 100 parts of cement. The concrete compressive strength and rebound rate were measured for this quick setting shot concrete. The results are shown in Table 12.

(Materials used)
Coarse aggregate: Gravel from Himekawa, Itoigawa City, Niigata Prefecture, surface dry condition, specific gravity 2.66, maximum dimension 10mm
Fine aggregate: Himekawa Sakegawa gravel, Itoigawa city, Niigata prefecture, surface dry condition, specific gravity 2.62

(Measuring method)
Concrete compressive strength: The compressive strength of 3 hours and 1 day of age is that the pin placed on the pull-out formwork 25cm wide x 25cm long is covered with quick setting spray concrete from the surface of the pullout formwork. The pin was pulled out from the back side, the pulling strength at that time was determined, and the compressive strength was calculated from the formula of (compressive strength) = (pullout strength) × 4 / (test specimen contact area). The compressive strength at the age of 28 days was determined by spraying rapidly setting sprayed concrete onto a formwork of width 50 cm x length 50 cm x thickness 20 cm. Measured and determined compressive strength.
Rebound rate: Quick setting shotcrete was sprayed on a simulated tunnel having a height of 3.5 m and a width of 2.5 m created in an arch shape with an iron plate at a pumping speed of 10 m ³ / h for 10 minutes. After that, (Rebound rate) = (Amount of quick setting sprayed concrete dropped without adhering to the simulated tunnel) / (Amount of quick setting shot concrete sprayed to the simulated tunnel) x 100 (%) did.

  By using the liquid accelerating agent of the present invention, when the liquid accelerating agent is in a suspended state, the dispersion stability is excellent in a wide temperature range. Therefore, there is no blockage trouble during pumping, and it is possible to perform good spraying construction. Since the present invention has an excellent quick setting force, spraying can be performed with little rebound and little flaking. Therefore, the present invention can realize cost reduction by shortening construction time and material loss, and can be applied in a wide range of fields such as tunnel construction, slope construction, repair construction, and the like.

  When the concentration of aluminum sulfate in the liquid accelerating agent is increased in order to give a sufficient rapid setting force, for example, when the solid content concentration of aluminum sulfate exceeds 27%, the solubility decreases and the sediment There was a possibility of generating. Even if the liquid quick-setting agent is dissolved by heating, gelation may occur, and there is a problem in the stability of the liquid. The present invention solves these problems and improves the stability of the liquid. The industrial applicability of the present invention is extremely large.

Claims (10)

Quick setting cement concrete containing (1) cement concrete and (2) liquid quick setting agent containing aluminum sulfate and phosphates. (1) Cement concrete, (2) Quick setting containing liquid quick setting agent containing 25 to 50 parts of aluminum sulfate and 0.02 to 5 parts of phosphate ester in 100 parts of liquid quick setting agent Cement concrete. The rapid setting cement concrete according to claim 1 or 2, wherein the phosphate ester is a phosphate ester and / or a phosphate ester salt. The quick setting cement concrete according to claim 1, wherein the phosphate ester is a phosphate ester of polyoxyalkylene alkyl ether and / or a phosphate ester salt of polyoxyalkylene alkyl ether. Furthermore, the quick setting cement concrete of Claim 1 in which a liquid quick setting agent contains a fluorine compound. Furthermore, the quick setting cement concrete of Claim 1 in which a liquid quick setting agent contains alkanolamines. Furthermore, the quick setting cement concrete of one of Claims 1-6 in which the liquid quick setting agent contains the compound which has a compound which has a hydroxyl group, and / or carboxylic acid. The quick setting cement concrete according to claim 1, wherein the liquid quick setting agent is a suspended liquid dispersed in a temperature range of −10 ° C. to 45 ° C. 9. The rapid setting cement concrete spraying method according to claim 1, wherein (1) cement concrete and (2) liquid quick setting agent are mixed and sprayed. The rapid setting cement concrete spraying method according to claim 9, wherein a liquid quick setting agent stored in a temperature range of −10 ° C. to 45 ° C. is used.