JP5308279B2 - Spraying material and spraying method using the same - Google Patents

Description

  The present invention mainly relates to a spraying material used in the civil engineering and construction industry and a spraying method using the same.

  In order to prevent collapse of exposed ground such as tunnel excavation, a rapid setting concrete spraying method in which a quick setting agent is mixed with concrete is performed (see Patent Document 1). 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.

Accelerating agents include calcium aluminate, a mixture of alkali metal aluminate and alkali metal carbonate, etc., and a mixture of calcium aluminate, alkali metal aluminate, alkali metal carbonate, and calcium aluminate. And 3CaO · SiO ₂ are known (see Patent Documents 2 to 5).

In recent years, spraying techniques that can suppress the generation amount of dust have been developed, and the amount of use has increased (see Patent Documents 6 to 8). This spraying technique is characterized by using a liquid quick-setting agent, and is characterized by containing a water-soluble aluminum salt such as aluminum sulfate as the main component of the liquid quick-setting agent. Liquid quick-setting agents containing water-soluble aluminum salts have poor setting properties compared to powder quick-setting agents, especially when the water-cement ratio is large (eg 60%) or when the amount of cement is small (eg 450 kg / m ³ or less) ) May cause peeling even when sprayed on natural ground, and there is a problem that it cannot be thickened. In addition, there is also a problem that the strength development property at the level of several hours is smaller than that of the conventional powder quick-setting agent.

  An aqueous solution of an alkali metal silicate salt that can be used in addition to aluminum sulfate as a liquid setting agent (see Patent Document 9). Alkali metal silicates exhibit rapid setting action even when used alone. Compared to a powder quick-set agent, the momentary strength immediately after mixing is weak and can be sprayed with concrete, but it is suitable for mortar spraying that does not require thickening of 10 cm or more. Moreover, the hardened | cured body which added the alkali metal silicate salt has a big shrinkage | contraction, and there also exists a subject that it is easy to elute from a hardened | cured material as a metal ion under the influence of spring water etc.

  As a conventional technique related to an alkali silicate salt and a quaternary ammonium salt, one relating to utilization as a material having antibacterial properties is known (see Patent Document 10). This document discloses a technique in which a product obtained by mixing and reacting an alkali silicate salt and a quaternary ammonium salt in advance is mixed with a cement material and used.

Japanese Patent Publication No. 60-4149 Japanese Patent Laid-Open No. 64-051351 Japanese Examined Patent Publication No. 56-27457 JP-A-61-026538 JP 63-2105050 A Japanese Patent Laying-Open No. 2005-60201 JP 2005-89276 A JP 2008-30999 A JP 2002-249360 A JP 2002-235008 A

  In the present invention, a quaternary ammonium salt compound is added to the cement concrete side, and a specific alkali silicate aqueous solution is applied to the cement concrete as a rapid setting agent. A spraying material that can exhibit strength development, can suppress the amount of shrinkage of a cured body and the amount of ions eluted, and has a small amount of dust generation, and a spraying method using the same.

That is, the present invention is (1) a cement concrete containing cement, aggregate, quaternary ammonium salt compound, and a molar ratio in terms of oxides of alkali metal (R: Li, Na, K) and silicon (Si). A spray material comprising a rapid setting agent containing an alkali metal silicate having a SiO ₂ / R ₂ O of 3.3 to 4.5, and (2) the weight average molecular weight of the quaternary ammonium salt compound is (1) spray material of 3000 to 500,000 polymer, (3) (1) or (2) spray material in which the alkali metal silicate is an aqueous solution, (4) (1) It is a spraying construction method using the spraying material in any one of-(3).

  By using the spray material of the present invention, it is possible to obtain a coagulation property and initial strength expression comparable to a powder accelerating agent, it is possible to suppress the amount of shrinkage of the cured body and the amount of ion elution, and also the amount of dust generated Less spray construction is possible.

  The parts and% used in the present invention are based on mass unless otherwise specified.

The cement used in the present invention is usually various Portland cements such as early strength, super early strength, low heat, and moderate heat, and various mixed cements obtained by mixing these Portland cements with blast furnace slag, fly ash, or silica, Eco-cement (eco-cement) made from filler cement mixed with limestone powder with a Blaine specific surface area exceeding 2000 cm ² / g, blast furnace chilled slag fine powder, etc., and municipal waste incineration ash and sewage sludge incineration ash Portland cement such as), and one or more of these can be used.

  The quaternary ammonium salt compound used in the present invention is a quaternary ammonium ion in which R1, R2, R3, and R4 are alkyl groups having 1 to 30 carbon atoms (benzene ring, carbonyl group, hydroxyl group, alkenyl having an unsaturated bond). For example, methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, octadecyl, phenyl, benzyl Acetyl, vinyl, allyl, hydroxyethyl, hydroxypropyl and the like.

As quaternary ammonium ion polymers, monomers such as quaternized dimethylaminoethyl (meth) acrylate, diallyldimethylammonium chloride, 4-vinylbenzyltrimethylammonium chloride, 4-vinyl-1-methylpyridinium bromide are polymerized. Or a copolymer of these with the following monomers.
For example, monomers used for copolymerization include vinyl alcohol, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, glycerol mono (meth) acrylate, ( (Meth) acrylic acid and its alkali metal salt, itaconic acid and its alkali metal salt, 2- (meth) acryloyloxyethyl succinic acid and its alkali metal salt, 2- (meth) acryloyloxyethylphthalic acid and its alkali metal salt, 2- (meth) acryloyloxyethyl hexahydrophthalic acid and its alkali metal salt, 2- (meth) acrylamido-2-methylpropanesulfonic acid and its salt, styrenesulfonic acid and its salt, vinylsulfonic acid and its salt, 2 -Su Phoethyl (meth) acrylate and salts thereof, 2- (meth) acryloyloxyethyl phosphoric acid and salts thereof, (meth) acrylamide, (meth) acryloylmorpholine, vinylpyridine, N-methyl (meth) acrylamide, N, N′-dimethyl (Meth) acrylamide, N, N′-dimethylaminopropyl (meth) acrylamide, N, N′-dimethylaminoethyl (meth) acrylate, N, N′-diethylaminoethyl (meth) acrylate, N, N′-dimethylamino Neopentyl (meth) acrylate, N-vinyl-2pyrrolidone, diacetone acrylamide, N-methylol (meth) acrylimide, methoxytriethylene glycol (meth) acrylate, methoxytetraethylene glycol (meth) acrylate, methoxy Liethylene glycol (meth) acrylate (polyethylene glycol number average molecular weight 400), methoxypolyethylene glycol (meth) acrylate (polyethylene glycol number average molecular weight 1000), butoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol ( (Meth) acrylate, phenoxyethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, nonylphenoxyethyl (meth) acrylate, isobornyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) Acrylate, isodecyl (meth) acrylate, cyclohexyl (meth) acrylate, tetraf Examples include rufuryl (meth) acrylate, benzyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, and styrene.
Examples of anions that form pairs of quaternary ammonium ions include chlorine ions, bromine ions, fluorine ions, iodine ions, nitrate ions, hydroxy ions, acetate ions, sulfate ions, carbonate ions, and bicarbonate ions.
Among these, the use of a polymer of a quaternary ammonium compound is preferable in that it is strong when mixed with an alkali metal silicate.
As for the weight average molecular weight of the polymer of a quaternary ammonium compound, 3000-500000 are preferable. When it is less than 3000, the amount of cure shrinkage increases, and when it exceeds 500,000, the gelation reactivity may decrease.

The quaternary ammonium compound is added to the cement concrete side, but a pure product may be added as it is or may be added as an aqueous solution.
The amount of the quaternary ammonium compound used is preferably 0.001 to 50 parts and more preferably 0.01 to 35 parts with respect to 100 parts of cement. If it is less than 0.001 part, it may be difficult to obtain an instantaneous strong flash, and if it exceeds 50 parts, the strong flash may be weakened.

The alkali metal silicate used in the present invention has a function of promoting gelation by reacting a nitrogen atom of a quaternary ammonium compound with a -ONa portion in a silicate molecule to form a crosslinked structure.
For example, No. 1 (SiO ₂ / R ₂ O = 1.9 to 2.3), No. 2 (SiO ₂ / R ₂ O = 2.4 to 2.7), No. 3 specified in JIS K 1408 (SiO ₂ / R ₂ O = 2.9 to 3.4) water glass, one kind of sodium metasilicate (SiO ₂ / R ₂ O = 0.95 to 1.05), two kinds of sodium metasilicate ( SiO ₂ / R ₂ O = 0.9 to 1.1) and sodium orthosilicate (SiO ₂ / R ₂ O = 0.48 to 0.52) are mentioned, but these have the ability to cause gelation instantaneously. Is small.
The ability to cause instantaneous gelation is determined by the molar ratio of oxide of alkali silicate (SiO ₂ / R ₂ O). In particular, the gelation rate when a quaternary ammonium compound is mixed is likely to cause an instantaneous reaction when SiO ₂ / R ₂ O is 3.3 to 4.5, and the range when spraying is performed. Is particularly preferred.
R is sodium because it is easily available and inexpensive, but other alkali metal (lithium and potassium) silicates can also be used.
When SiO ₂ / R ₂ O exceeds 4.5, the composition becomes close to the composition of colloidal silica, so that the solubility is deteriorated, and there is a possibility that the strength is not obtained.
The amount of the alkali metal silicate used is preferably 0.5 to 10 parts, more preferably 1 to 7 parts in terms of solid content with respect to 100 parts of cement. If it is less than 0.5 part, it may be difficult to give sufficient rapid setting force, and if it exceeds 10 parts, long-term intensity | strength may be inhibited.
The alkali metal silicate is preferably used as an aqueous solution for the purpose of reducing dust during spraying.

  The cement concrete of the present invention is not particularly limited as long as spraying is possible. As a general blending, the slump is about 10 cm, W / C = about 60%, s / a = about 60%, the cement amount is about 360 kg / m3, and the maximum gravel dimension is 13 mm, and the strength is high. In the type, the slump is about 20 cm, the slump flow is about 25 to 35 cm, W / C = about 40-50%, s / a = about 60%, the cement amount is about 400-500 kg / m3, and the maximum gravel dimension is 13 mm. There are many cases.

  The aggregate used in the present invention is not particularly limited, and any commercially available aggregate can be used, and there is no problem as long as it does not hinder spray construction.

  In the present invention, a water reducing agent, AE water reducing agent, high performance water reducing agent, high performance AE water reducing agent, cellulose ether, polyethylene oxide, polysaccharide thickener, etc. Various additives such as foaming agents, antirust agents, antifreeze agents, shrinkage reducing agents, polymer emulsions, setting accelerators, setting retarders, polymer flocculants, clay minerals such as bentonite and anion exchangers such as hydrotalcite , Blast furnace granulated slag fine powder or blast furnace slow-cooled slag fine powder, admixtures such as fly ash and silica fume, gypsum such as anhydrous gypsum, one or more of the group consisting of calcium aluminates It is possible.

  The spraying method of the present invention is not particularly limited, but a wet spraying method in which a rapid setting agent is combined and sprayed to cement concrete mixed with water that is pumped and mixed, or in a dry state with concrete. It is possible to use a dry spraying method in which a rapid setting agent is pumped and water is combined and sprayed before the nozzle.

"Experiment 1"
Unit amount of each material, cement 360 kg / ^{m 3,} fine aggregates 1021kg / ^{m 3,} coarse aggregate 691kg / ^{m 3,} water 216 kg / ^{m 3,} a quaternary ammonium salt compound per 100 parts cement (2) 0 Add 5 parts and adjust the shotcrete. The sprayed concrete was pumped by a concrete pumping machine “MKW-25SMT” under conditions of a spraying pressure of 0.4 MPa and a spraying speed of 10 m ³ / h. In the liquid accelerating agent conveying device, the mixture was mixed and sprayed at a position of 1 m from the nozzle tip so as to represent an aqueous solution of alkali metal silicate (adjusted to a solid content of 30%) together with compressed air. Thickness, concrete compressive strength, hardening shrinkage, and silicate ion elution were measured for this quick setting shotcrete. For comparison, the same test was performed using a commercially available liquid accelerator mainly composed of aluminum sulfate and a powder accelerator. The results are shown in Table 1.

(Materials used)
Coarse aggregate: Himekawa Sakegawa gravel, Itoigawa City, Niigata Prefecture, surface dry condition, specific gravity 2.66, maximum dimension 13mm
Fine aggregate: Himekawa Sakegawa gravel, Itoigawa City, Niigata Prefecture, surface dry condition, specific gravity 2.62, maximum dimension 5mm
Cement: ordinary Portland cement, commercially available quaternary ammonium salt compound (2): 30% aqueous solution of diallyldimethylammonium chloride polymer, weight average molecular weight 200000, commercially available alkaline metal silicate aqueous solution A: No. 2 water glass, SiO ₂ / Na ₂ O molar ratio 2.55, commercial product alkali metal silicate aqueous solution B: No. 3 water glass, SiO ₂ / Na ₂ O molar ratio 3.32, commercial product alkaline metal silicate aqueous solution C: SiO ₂ / Na ₂ O molar ratio 3.72, commercially available alkali metal silicate aqueous solution D: SiO ₂ / Na ₂ O molar ratio 4.48, commercially available liquid accelerator (L): main component aluminum sulfate, solid content 41% concentration, commercially available powder quick-setting agent (P): cement mineral powder quick-setting agent

(Measuring method)
Slump: Measured according to JIS A 1101. The measurement was performed immediately after kneading.
Thickness: Spray concrete was sprayed on the ceiling surface while repeatedly moving the spray nozzle in the range of 1 m, and the thickness until peeling was measured. When the thickness was 30 cm or more, it was judged that the sprayability was good and the test was stopped. In addition, when it peeled within 24 hours after stopping the test, it was judged that the thickness was poor. The sprayed ground is an iron plate.
Concrete compressive strength: The compressive strength of 1 hour and 24 hours of age is to cover the pin placed on the pullout formwork with 25cm width x 25cm length with the quick setting sprayed 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 obtained by spraying quick setting sprayed concrete on a mold of width 50 cm x length 50 cm x thickness 20 cm, and a specimen 5 cm in diameter x 10 cm in length taken with a core drill one day later. The compressive strength was determined by measuring with a 20-ton pressure machine. Curing up to the measurement was water curing at 20 ° C.
Curing shrinkage: A specimen was prepared by spraying on a dedicated formwork (10 × 10 × 36 cm). After 1 day of age, the mold was removed and the base length was determined. After curing in a room at a temperature of 20 ° C. and a humidity of 60% for 28 days, the amount of shrinkage was measured. The measurement was based on JIS R 1129-3 (dial gauge method).
Silicate ion elution amount: A specimen was collected with a core drill in the same manner as the compressive strength, and pulverized with a jaw crusher. 100 g of the pulverized product was added to 1000 g of pure, and stirred for 1 hour using a vibrator. Then, it filtered and the elution amount of the silicate ion was measured about the filtrate using the ion chromatography.

"Experimental example 2"
The test was conducted in the same manner as in Experimental Example 1 except that the alkali metal silicate C was 3.0 parts with respect to 100 parts of cement and various quaternary ammonium salt compounds were added as shown in the table. The results are shown in Tables 2 and 3.

(Materials used)
Quaternary ammonium salt compound (1): Commercially available 50% aqueous solution of tetramethylammonium chloride Quaternary ammonium salt compound (3): 30% aqueous solution of diallyldimethylammonium hydroxide polymer, weight average molecular weight 95,000, commercially available product 4 Quaternary ammonium compound (4): 30% aqueous solution of diallyldimethylammonium chloride polymer, weight average molecular weight 3100, commercially available quaternary ammonium compound (5): 30% aqueous solution of diallyldimethylammonium chloride polymer, weight average molecular weight 485000, commercially available Goods

  The spray material of the present invention has a coagulation property and initial strength expression comparable to those of a powder accelerating agent, can suppress the shrinkage amount of the cured body and the elution amount of ions, and the rapid setting component is liquid. Therefore, since it can be used for spraying with a small amount of dust generation, it is suitable for the civil engineering field.

Claims (4)

Cement, aggregate, cement concrete containing a quaternary ammonium salt compound, and SiO ₂ / R ₂ O which is a molar ratio in terms of oxides of alkali metals (R: Li, Na, K) and silicon (Si) is 3 A spraying material comprising a rapid setting agent containing an alkali metal silicate salt of 3 to 4.5. The spraying material according to claim 1, wherein the quaternary ammonium salt compound is a polymer having a weight average molecular weight of 3000 to 500,000. The spray material according to claim 1 or 2, wherein the alkali metal silicate is an aqueous solution. The spraying method using the spraying material of any one of Claims 1-3.