Powder quick-setting admixture, slurry quick-setting admixture, spraying material, spraying method

Abstract

This powder accelerating agent includes: at least 40 mass% calcium aluminate having a CaO / Al2O3 molar ratio of 1.7-3.0, a vitrification rate of at least 50%, and a Blaine's value of 4,500 cm2 / g or more; 3-12.5 mass% aluminum sulfate having a hydration number of 14-18; and 0.1-1.5 mass% citric acid. The powder accelerating agent substantially does not include sodium aluminate.

Description

[Technical Field]

[0001] The present invention relates to a powder quick-setting admixture, a slurry quick-setting admixture, a spraying material, and a spraying method. [Background technology]

[0002] Conventionally, to prevent the collapse of exposed ground during tunnel excavation, a primary lining is applied using a sprayed material such as shotcrete or sprayed mortar, and once the ground has stabilized, a secondary lining is applied using regular concrete. On the other hand, in relatively solid ground with few cracks in the rock mass, a permanent lining is sometimes applied using only the shotcrete material without a secondary lining. Both types of lining require a certain level of high strength development in the very early stages, 10 minutes after spraying.

[0003] For example, Patent Document 1 discloses an accelerator containing predetermined amounts of calcium aluminates, anhydrous calcium sulfate, aluminum sulfate, anhydrous citric acid, and sodium aluminate as an accelerator for providing a mortar or concrete composition having excellent quick-setting properties and strength development. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-203800 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the quick-setting admixture described in Patent Document 1 contains sodium aluminate, which may make spraying work on site complicated.

[0006] Furthermore, if a design is made to increase the development of very early strength, the concrete tends to harden before it adheres to the structure after being sprayed from the nozzle. Therefore, taking into account the decrease in adhesion strength, it is necessary to control the slump of the concrete to a high level before adding the accelerator. This means that adhesion control becomes even more difficult as the temperature conditions increase, which increases the frequency of concrete quality control.

[0007] In other words, the conventional mix design is not necessarily effective in increasing the very early strength development and obtaining high adhesive strength without including sodium aluminate.

[0008] Based on the above, the present invention aims to provide a powder quick-setting admixture that has good workability in spraying treatment, exhibits good strength development in the very early stages after spraying (after 10 minutes of material age), and can also achieve high adhesive strength. [Means for solving the problem]

[0009] As a result of intensive research to solve the above problems, the present inventors have come up with the following invention and found that the above problems can be solved.

[0010] [1] The CaO / Al2O3 molar ratio is 1.7 to 3.0, the vitrification rate is 50% or more, and the Blaine value is 4,500 cm 2 / g or more, 3 to 12.5 mass% of aluminum sulfate having a hydration number of 14 to 18, and 0.1 to 1.5 mass% of citric acid, and is substantially free of sodium aluminate. [2] The powder quick-setting admixture according to [1], wherein the mass ratio of the calcium aluminate to the citric acid (calcium aluminate / citric acid) is 25 to 500, and the mass ratio of the aluminum sulfate to the citric acid (calcium aluminate / citric acid) is 5 to 150. [3] The powder quick-setting admixture according to [1] or [2], further containing 20% ​​by mass or more of calcium sulfate. [4] The Blaine value of the calcium sulfate is 4000 cm 2 / g or more. [5] The powder quick-setting admixture according to any one of [1] to [4], which is used together with an acidic liquid quick-setting admixture. [6] A slurry quick-setting admixture comprising a liquid quick-setting admixture containing aluminum sulfate as a main component and exhibiting a pH of 1 to 4, in combination with the powder quick-setting admixture according to any one of [1] to [5]. [7] The slurry quick-setting admixture according to [6], which is alkali-free. [8] A spraying material comprising cement and the slurry quick-setting admixture described in [6] or [7], wherein the liquid quick-setting admixture is used in an amount of 4 parts by mass or more per 100 parts by mass of the cement. [9] A spraying material comprising cement and the slurry quick-setting admixture described in [6] or [7], wherein the powder quick-setting admixture is used in an amount of 4 parts by mass or more per 100 parts by mass of the cement.

[10] The spraying material according to [9], wherein the powder quick-setting admixture is contained in an amount of 10 parts by mass or more per 100 parts by mass of the cement.

[11] A spraying method for carrying out a spray treatment using the spraying material according to any one of [8] to

[10] . [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a powder quick-setting admixture that has good workability in the spraying process, exhibits good strength development in the very early stages after spraying (after 10 minutes of material age), and can also achieve high adhesive strength. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of the present invention (hereinafter, sometimes referred to as "the present embodiment") will be described below. [Powder Accelerator] (Calcium Aluminate) In this embodiment, the CaO / Al2O3 molar ratio is 1.7 to 3.0, the vitrification rate is 50% or more, and the Blaine value is 4,500 cm 2 / g or more of calcium aluminate is contained in an amount of 40 mass % or more.

[0013] If the CaO / Al2O3 molar ratio is less than 1.7, the initial strength will decrease, and if it exceeds 3.0, the one-day compressive strength value and adhesive strength will decrease. The CaO / Al2O3 molar ratio is preferably 2.3 to 2.8, and more preferably 2.4 to 2.7. The CaO / Al2O3 molar ratio can be determined, for example, by fluorescent X-ray analysis.

[0014] The vitrification rate of calcium aluminate is 50% or more, preferably 70% or more, and more preferably 80% or more. A vitrification rate of less than 50% results in reduced very early strength development and reduced adhesive strength. The vitrification rate is determined by measuring the main peak area S of the crystalline mineral by powder X-ray diffraction of a sample before heating, heating it to 1000°C for 2 hours, followed by slow cooling at a cooling rate of 1 to 10°C / min, and then determining the main peak area S of the crystalline mineral after heating by powder X-ray diffraction. Furthermore, using these S0 and S values, the vitrification rate χ is calculated using the following formula: Vitrification rate χ (%) = 100 × (1-S / S0). The vitrification rate can be adjusted by controlling the cooling rate during heat treatment, melting, and rapid cooling.

[0015] The Blaine value of calcium aluminate is 4,500 cm 2 / g or more and 5,000 to 8,000 cm 2 / g, and 5,500 to 7,500 cm 2 / g. The Blaine value is 4,500 cm 2 If it is less than 1 / g, the initial compressive strength will decrease. In this specification, the Blaine value is measured based on the specific surface area test described in JIS R 5201 "Physical Testing Methods for Cement."

[0016] An example of calcium aluminate is a compound that has a chemical composition consisting mainly of CaO and Al2O3 and exhibits hydraulic properties, but it may also be a compound in which part of the CaO and / or Al2O3 is replaced with a substance such as an alkali metal oxide, alkaline earth metal oxide, silicon oxide, titanium oxide, iron oxide, alkali metal halide, alkaline earth metal halide, alkali metal sulfate, or alkaline earth metal sulfate, or a compound in which a small amount of the above components are dissolved.

[0017] The powder quick-setting admixture contains 40% by mass or more of the calcium aluminate, preferably 50% by mass or more, and more preferably 60% by mass or more. If the calcium aluminate content is less than 40% by mass, the adhesive strength will decrease. The calcium aluminate content in the powder quick-setting admixture is preferably 80% by mass or less.

[0018] (aluminum sulfate) In this embodiment, the powder quick-setting admixture contains 3 to 12.5 mass % of aluminum sulfate having a hydration number of 14 to 18. If the hydration number of the aluminum sulfate is less than 14, the strength development after one day of age will decrease, and if it exceeds 18, the storage stability of the powder quick-setting admixture will decrease.

[0019] The powder quick-setting admixture contains 3 to 12.5% ​​by mass of aluminum sulfate, preferably 4 to 10% by mass, and more preferably 5 to 10% by mass. If the aluminum sulfate content is less than 3% by mass, the initial strength will decrease, and if it exceeds 12.5%, the strength will decrease after one day of use and the adhesive strength will decrease.

[0020] (citric acid) In this embodiment, the powder quick-setting admixture contains 0.1 to 1.5 mass% of citric acid. If the citric acid content is less than 0.1 mass%, the 10-minute strength will decrease, and if it exceeds 1.5 mass%, it will tend to delay setting. The citric acid content is preferably 0.2 to 1.2 mass%, and more preferably 0.3 to 1.0 mass%. From the viewpoint of storage stability, anhydrous citric acid is preferred as the citric acid.

[0021] In this embodiment, the mass ratio of calcium aluminate to citric acid (calcium aluminate / citric acid) is preferably 25 to 500, more preferably 40 to 400, from the viewpoint of enhancing the very early strength development and adhesive strength.

[0022] The mass ratio of aluminum sulfate to citric acid (calcium aluminate / citric acid) is preferably 5 to 150, and more preferably 7 to 80, from the viewpoint of very early strength development.

[0023] Furthermore, from the viewpoint of better exerting the combined effect of calcium aluminate, aluminum sulfate, and citric acid, the mass ratio thereof (citric acid / (calcium aluminate+aluminum sulfate)) is preferably 0.002 to 0.031, and more preferably 0.004 to 0.021.

[0024] (Calcium sulfate) In this embodiment, it is preferable that calcium sulfate is further contained in an amount of 20 mass% or more, and more preferably 20 to 50 mass%. By containing calcium sulfate in an amount of 20 mass% or more, it is possible to improve long-term strength development. It is preferable that calcium aluminate, aluminum sulfate, and citric acid are contained in the above-mentioned predetermined amounts, with the remainder being calcium sulfate.

[0025] The Blaine value of calcium sulfate is 4000 cm 2 / g or more, and 4,000 to 8,000 cm 2 / g. The Blaine value is more preferably 4000 cm 2 / g or more, it is possible to improve the long-term strength development.

[0026] In this embodiment, the composition is substantially free of sodium aluminate. "Substantially free" means that the presence of sodium aluminate is not confirmed by XRD. By being substantially free of sodium aluminate, workability in the spraying process can be improved.

[0027] It is expressed as NaAlO2 or Na[Al(OH)4]. That is, sodium aluminate refers to sodium aluminum dioxide and sodium aluminate tetrahydroxide.

[0028] The powder quick-setting admixture according to this embodiment is preferably used together with an acidic liquid quick-setting admixture, which is easier to handle than an alkaline liquid quick-setting admixture, and therefore can further improve the workability of the spraying treatment. As the acidic liquid quick-setting admixture, it is preferable to use a liquid quick-setting admixture described below from the viewpoint of obtaining a synergistic effect with the powder quick-setting admixture according to this embodiment.

[0029] [Slurry Accelerator] The slurry quick-setting admixture according to this embodiment is obtained by combining a liquid quick-setting admixture containing aluminum sulfate as a main component and exhibiting a pH of 1 to 4 with the powder quick-setting admixture according to this embodiment described above. Here, since the powder quick-setting admixture of this embodiment does not substantially contain sodium aluminate, even when combined with a liquid quick-setting admixture having a pH of 1 to 4, the pH after combination is stable, eliminating the need to control the time until mixing into concrete, and allowing for stable concrete adhesion properties to be obtained.

[0030] By containing aluminum sulfate as a main component, the liquid quick-setting admixture is less likely to become alkaline, and as a result, it is possible to improve handleability and reduce environmental impact while maintaining good quick-setting properties.

[0031] Here, "containing aluminum sulfate as a main component" means that the content (by mass) of aluminum sulfate is the highest among the quick-setting admixture components of the liquid quick-setting admixture, and it is preferably 50 mass% or more of the quick-setting admixture components, more preferably 80 mass% or more, and even more preferably 90 mass% or more, and it is particularly preferable that the quick-setting admixture component is solely made up of aluminum sulfate.

[0032] The pH of the liquid quick-setting admixture is preferably less than 7, and more preferably not more than 5. A pH of less than 7 can exert an effect of reducing environmental load. The pH is preferably 2 or more.

[0033] The liquid quick-setting admixture preferably contains 20 to 40% by mass of aluminum sulfate, more preferably 25 to 30% by mass. By including 25 to 30% by mass of aluminum sulfate, it is possible to improve handling and reduce environmental impact while maintaining good quick-setting properties. Water can be used as the liquid component that dissolves or disperses aluminum sulfate. Furthermore, a portion of the aluminum sulfate may be present as a solid content.

[0034] From the viewpoint of workability, the slurry quick-setting admixture according to this embodiment is preferably alkali-free. Here, "alkali-free" means that the content of R2O (where R is an alkali metal, and if there is more than one, all of them) in the slurry quick-setting admixture is 1.0 mass% or less, more specifically 0.5 mass% or less.

[0035] By keeping the R2O content at 1.0 mass% or less, it is possible to improve the ease of handling and the reduction of the environmental load, thereby further improving the workability. The R2O content in the powder auxiliary can be measured by atomic absorption spectrometry.

[0036] The powder quick-setting admixture and liquid quick-setting admixture constituting the slurry quick-setting admixture according to this embodiment may contain, in addition to the components already described, various additives, such as pH adjusters, dispersants, stabilizers, antifreeze agents, water-solubility promoters, air-entraining agents, water-reducing agents, air-entraining water-reducing agents, thickeners, fibers, and fine powders, within a range that does not impair the effects of the present invention.

[0037] [Spraying material and spraying method] The spraying material according to this embodiment is (1) a spraying material made by using the slurry quick-setting admixture of this embodiment together with cement, in which the liquid quick-setting admixture is 4 parts by mass or more per 100 parts by mass of cement, or (2) a spraying material made by using the slurry quick-setting admixture of this embodiment together with cement, in which the powder quick-setting admixture is 4 parts by mass or more per 100 parts by mass of cement. Among these, (3) a spraying material made by using the slurry quick-setting admixture of this embodiment together with cement, in which the liquid quick-setting admixture is 4 parts by mass or more per 100 parts by mass of cement and the powder quick-setting admixture is 4 parts by mass or more per 100 parts by mass of cement, is preferred. By using such a spraying material, the adhesion properties are less likely to vary depending on the addition rate and temperature, and stable adhesion properties can be imparted.

[0038] In the above cases (1) and (3), the amount of liquid quick-setting admixture is more preferably 6 parts by mass or more, and even more preferably 7 to 10 parts by mass, per 100 parts by mass of cement, and in the above cases (2) and (3), the amount of powder quick-setting admixture is more preferably 10 parts by mass or more, and even more preferably 11 to 20 parts by mass, per 100 parts by mass of cement.

[0039] Examples of cement include various types of Portland cement, such as ordinary, early strength, extra early strength, low heat, and medium heat; various mixed cements in which blast furnace slag, fly ash, or silica is mixed with these Portland cements; filler cements in which limestone powder or ground granulated cooled blast furnace slag is mixed; and environmentally friendly cements, so-called ecocements, which are produced using various types of industrial waste as the main raw material. One or more of these can be used in combination.

[0040] In practice, the sprayed material is mixed with aggregate and other materials to produce cement concrete. The type of aggregate is not particularly limited, and it is preferable to use one with low water absorption and high aggregate strength. The maximum size of the aggregate is not particularly limited as long as it can be sprayed. River sand, mountain sand, sea sand, lime sand, and silica sand can be used as fine aggregate, and river gravel, mountain gravel, and lime gravel can be used as coarse aggregate, and crushed sand and crushed stone can also be used. Here, cement concrete refers to mortar, concrete, etc.

[0041] The spraying method according to the present embodiment is a method of performing a spraying treatment using the spraying material according to the present embodiment. According to such a spraying method, either a dry method or a wet method can be used for spraying.

[0042] Specifically, this method involves mixing a liquid quick-setting admixture, a powder quick-setting admixture, and cement concrete, and then spraying the mixture. The powder quick-setting admixture and the liquid quick-setting admixture are preferably mixed together in a mixing pipe just before being added to the cement concrete to form a slurry, in order to improve the mixability with the sprayed cement concrete. The water / cement ratio is preferably 65% ​​or less.

[0043] In the spraying treatment, the spraying pressure is usually preferably 0.2 to 0.5 MPa, and the spraying speed is preferably 4 to 20 m / s. 3 / h is preferred. [Example]

[0044] [Experimental Example 1] (powder quick-setting admixture) Calcium aluminate, calcium sulfate, citric acid, and aluminum sulfate were mixed in the mass ratios shown in Table 2 to prepare powder quick-setting admixtures. The materials used are as follows: The content of sodium aluminate in each powder quick-setting admixture was 0% by mass.

[0045] <Materials used> Calcium aluminate: A heat-treated material with a CaO / Al2O3 molar ratio of 2.5 was quenched to a vitrification rate of 90% and a Blaine value of 5,900 cm 2 / g, containing 3 parts by mass of SiO2 in oxide equivalent Aluminum sulfate: hydration number 14-18, powder, reagent Citric acid: anhydrous, powder Calcium sulfate: anhydrous, Blaine 5,000 cm 2 / g, natural gypsum

[0046] The mortar, excluding the coarse aggregate, was mixed with the concrete mixture conditions listed in Table 1 under pump discharge conditions of 4 m 3 A fixed amount was transported at 1 / Hr to the accelerator mixing section, and liquid accelerator A was pumped from one side at a weight ratio of 7% to the cement and continuously transported by compressed air, and powder accelerator with the formulation shown in Table 2 was pumped at a mass ratio of 10 parts to 100 parts of cement and continuously transported by compressed air.The liquid and powder were combined just before joining the mortar to form a slurry accelerator, and then mixed and combined with the mortar to prepare quick-setting mortar, and the strength development was evaluated when it was sprayed from the spraying section. In all of the slurry quick-setting admixtures, the content of R2O (R is an alkali metal) was 0% by mass.

[0047] <Materials used> Liquid setting accelerator A: Reagent-grade aluminum sulfate dissolved in pure water, adjusted to a concentration of 27% by mass, pH 2.0 Ordinary cement: Commercially available, Blaine value 3,200 cm 2 / g, density 3.15 Fine aggregate: sand from the Himekawa River system in Itoigawa City, Niigata Prefecture, maximum size 5mm or less, density 2.62 Coarse aggregate: Niigata Prefecture Itoigawa No. 6 crushed stone, maximum size 15 mm, density 2.67 Water: Tap water Water reducing agent: Commercially available, high-performance water reducing agent

[0048] [Table 1]

[0049] <Evaluation> Strength development evaluation: Test specimens were prepared by spraying quick-setting mortar onto a 4x4x16cm triple formwork, and the compressive strength was measured at various ages after spraying: 10 minutes, 3 hours, 1 day, and 28 days. Bond strength: Concrete without powdered setting accelerator according to the mix conditions listed in Table 1 was poured into a formwork measuring 20cm thick x 40cm long x 40cm wide, and left to cure in air for 28 days. Concrete containing each powdered setting accelerator was sprayed onto the surface of the concrete to a thickness of approximately 10cm, and after leaving to cure in air for 28 days, the bond strength was measured using a Construction Research Institute type bond tester. The pullout diameter was 10cm. An adhesive strength of 0.5 N or more is acceptable, preferably 0.7 N or more, and more preferably 1.0 N or more.

[0050] [Table 2]

[0051] The results in Table 2 show that when the amount of citric acid in the powder quick-setting admixture is increased or decreased, strength development up to 1 day is low, especially at 1 day, and strength growth at 1 day is small. When the amount is increased or decreased above 1.5 mass%, strength development up to 10 minutes tends to decrease. Therefore, the citric acid content in the powder quick-setting admixture is preferably 0.1 to 1.5 mass%. When the amount of aluminum sulfate is increased or decreased, strength development at 10 minutes is low at 3 mass% or less, and strength development at 1 day is low at 12.5 mass% or more. Therefore, aluminum sulfate is preferably 3 to 12.5 mass%. When the amount of calcium aluminate is less than 40 mass%, strength development up to 10 minutes tends to decrease. When aluminum sulfate or citric acid is completely omitted, strength development from the very beginning to 28 days tends to decrease. Therefore, a calcium aluminate content of 40 mass% or more is preferred, and the inclusion of aluminum sulfate and citric acid is essential.

[0052] [Experimental Example 2] The mortar, excluding the coarse aggregate, was mixed with the concrete mixture conditions listed in Table 1 under pump discharge conditions of 4 m 3The mixture was pumped at a constant rate of 1 / hr to the quick-setting admixture mixing section. Liquid quick-setting admixtures with pH values ​​shown in Table 3 were pumped from one side at a mass ratio of 7 parts per 100 parts of cement and continuously conveyed by compressed air. Powder quick-setting admixtures with compositions Nos. 1-6 in Table 2 were pumped at a mass ratio of 10% per 100 parts of cement and continuously conveyed by compressed air. The liquid and powder were combined just before the mortar was mixed to prepare a slurry-like quick-setting admixture. This was mixed with the mortar to prepare a quick-setting mortar, which was then sprayed from the spraying section. Strength development was evaluated. Adhesion strength was also evaluated as in Experimental Example 1. The results are shown in Table 3.

[0053] <Materials used> Liquid quick-setting agent A: Dissolve sulfuric acid and aluminum oxide in pure water to a pH of 0.8, and adjust the concentration to 27% by mass. Liquid quick-setting agent C: Dissolve sulfuric acid and aluminum oxide in pure water to a pH of 1.0, and adjust the concentration to 27% by mass. Liquid quick-setting agent D: Dissolve sulfuric acid and aluminum oxide in pure water to a pH of 4.0, and adjust the concentration to 27% by mass. Liquid quick-setting agent E: Dissolve sulfuric acid and aluminum oxide in pure water to a pH of 5.0, and adjust the concentration to 27% by mass.

[0054] [Table 3]

[0055] The results in Table 3 show that strength development up to 3 hours tends to decrease at pH below 1.0, and strength development from 10 minutes to 3 hours tends to increase at pH above 4.0, but the 1-day strength remains almost unchanged at 3 hours. For this reason, the pH of the liquid quick-setting admixture is preferably 1 to 4.

[0056] [Experimental Example 3] The mortar, excluding the coarse aggregate, was mixed with the concrete mixture conditions listed in Table 1 under pump discharge conditions of 4 m 3The mixture was pumped at a constant rate to the accelerator mixing section at 1000 kJ / hr. Liquid accelerator A was pumped at a constant rate of 7% by mass relative to the cement and continuously conveyed by compressed air. Powder accelerators, each containing calcium aluminate with the CaO / Al2O3 molar ratio, vitrification rate, and Blaine value shown in Table 4, with compositions Nos. 1-6 in Table 2, were pumped at a constant rate of 10% by mass relative to the cement and continuously conveyed by compressed air. The liquid and powder were mixed just before the mortar was introduced to prepare a slurry-like accelerator. This was then mixed with the mortar to prepare a quick-setting mortar, which was then sprayed onto the spraying section and evaluated for strength development. Adhesion strength was also evaluated as in Experimental Example 1.

[0057] <Materials used> Calcium aluminate: Heat-treated material corresponding to the CaO / Al2O3 molar ratio shown in Table 4 was quenched, containing 3 parts SiO2 in oxide equivalent, the vitrification rate shown in Table 4 was calculated by XRD, and the Blaine value shown in Table 4 was adjusted by pulverizing in a disc mill after quenching.

[0058] [Table 4]

[0059] From the results in Table 4, it was confirmed that when the vitrification rate of calcium aluminate is less than 30%, strength development tends to decrease from 10 minutes to 3 hours, and when the vitrification rate is increased, the strength value after 10 minutes tends to increase, so a vitrification rate of 30% or more is essential. When the CaO / Al2O3 molar ratio is less than 1.7, a decrease in strength is confirmed at all ages, and when the molar ratio is increased, the initial strength increases. When the molar ratio exceeds 3.0, a decrease in strength is confirmed after 3 hours or more, so a molar ratio of 1.7 to 3.0 is essential. The Blaine value is 4500 cm 2 / g, the strength development within 3 hours was extremely reduced, and the Blaine value was 4500 cm 2 / g or more is required. [Industrial Applicability]

[0060] The powder quick-setting admixture of the present invention can be suitably used in the fields of civil engineering and construction, particularly as a spraying material for tunnels and the like.

Claims

1. CaO / Al ２ O ３ The molar ratio is 1.7 to 3.0, the vitrification rate is 50% or more, and the Blaine value is 4,500 cm ２ / g or more, 3 to 12.5 mass% of aluminum sulfate having a hydration number of 14 to 18, 0.1 to 1.5 mass% of citric acid, and substantially no sodium aluminate; A powder quick-setting admixture, wherein the mass ratio of the calcium aluminate to the citric acid (calcium aluminate / citric acid) is 25 to 500.

2. 2. The powder quick-setting admixture according to claim 1, wherein a mass ratio of the aluminum sulfate to the citric acid (calcium aluminate / citric acid) is 5 to 150.

3. The powder quick-setting admixture according to claim 1, further comprising 20% ​​by mass or more of calcium sulfate.

4. The Blaine value of the calcium sulfate is 4000 cm ２ The powder quick-setting admixture according to claim 3, wherein the viscosity is 1 / g or more.

5. 2. The powder quick-setting admixture according to claim 1, which is used together with an acidic liquid quick-setting admixture.

6. A slurry quick-setting admixture comprising a liquid quick-setting admixture containing aluminum sulfate as a main component and exhibiting a pH of 1 to 4 in combination with the powder quick-setting admixture according to any one of claims 1 to 5.

7. The slurry quick-setting admixture according to claim 6, which is alkali-free.

8. A spraying material comprising cement and the slurry quick-setting admixture according to claim 6, The spraying material contains 4 parts by mass or more of the liquid quick-setting admixture per 100 parts by mass of the cement.

9. A spraying material comprising cement and the slurry quick-setting admixture according to claim 6, A spraying material in which the powder quick-setting admixture is contained in an amount of 4 parts by mass or more per 100 parts by mass of the cement.

10. The spraying material according to claim 9, wherein the powder quick-setting admixture is contained in an amount of 10 parts by mass or more relative to 100 parts by mass of the cement.

11. A spraying method for carrying out a spray treatment using the spray material according to claim 8.

Images