Hydraulic composition

Abstract

To provide a hydraulic composition which causes no material separation during pressure feeding, plasticizes quickly after two-component mixing without using sodium aluminate which is a deleterious substance and causes little bleeding.SOLUTION: There is provided a hydraulic composition which is a hydraulic composition for grout comprising two materials of a material A containing a water-soluble hydroxyalkyl alkyl cellulose, a defoaming agent, cement, water and a polyvinyl alcohol or borax and a material B containing one of a polyvinyl alcohol and borax which is not contained in the material A and water, wherein the degree of substitution (DS) of alkoxy groups in the water-soluble hydroxyalkyl alkyl cellulose is 1.2 or more, the saponification degree of the polyvinyl alcohol is 70 to 90 mol%, the 4 mass% aqueous solution viscosity of the polyvinyl alcohol at 20°C is 15 to 300 mPa s and the total amount added of the water is more than 70 pts.mass and 300 pts.mass or less based on the 100 pts.mass of the cement.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a hydraulic composition used for filling and injecting various voids, in particular for filling various voids, such as backfilling of tunnels, filling voids in the ground, filling voids in existing structures, and filling voids caused by disasters. [Background technology]

[0002] The cavity behind the tunnel lining concrete can be a structural problem because if the tunnel is subjected to some kind of pressure, the reaction force from the ground cannot be expected. The backfill injection grouting method, in which grout is injected through a thin tube, is used to fill the cavity.

[0003] Cementitious backfill grouts can be divided into "one-component grout" and "two-component grout" depending on their application method. In one-component grout, cement reacts with water over a very slow time, eventually hardening. This can lead to uneven strength and bleeding due to material separation during pumping and pouring. Separation from contact with water during and after pouring is unavoidable. Furthermore, limited injection to specific, limited areas is difficult to avoid waste. In contrast, two-component grout consists of two components, component A (main component) and component B (plasticizer), which are pumped separately and then combined near the injection point. While this method can overcome some of the drawbacks of one-component grout, it is not perfect.

[0004] Here, "plasticizer" is a general term for a substance that imparts plasticity. Plasticity refers to a state between a liquid and a solid, where the material has poor fluidity as it is but easily becomes fluid when slightly pressurized. In other words, it is a thixotropic state. Challenges with two-component plastic grout include controlling the gelation time, achieving plasticity during filling, and preventing material separation during pumping.

[0005] To solve this problem, Japanese Patent Application Laid-Open No. 2010-112024 (Patent Document 1) proposes using sodium aluminate as a hydration reaction accelerator and water-soluble cellulose to prevent material separation. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-112024 Summary of the Invention [Problem to be solved by the invention]

[0007] However, plasticity and segregation resistance are generally contradictory properties, and it has been difficult to achieve both of these properties in two-component plastic grout. Furthermore, the method of Patent Document 1 uses sodium aluminate, which is designated as a deleterious substance, as a hydration reaction accelerator, making it difficult to handle.Furthermore, because the hydraulic substance and the water-soluble cellulose ether are pumped as separate liquids and mixed, there is a problem that the hydraulic substance settles during pumping, causing material separation.

[0008] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hydraulic composition which does not undergo material separation during pumping, which plasticizes quickly after mixing two components, and which exhibits little bleeding, without using sodium aluminate, which is a deleterious substance. [Means for solving the problem]

[0009] As a result of intensive research conducted by the present inventors to achieve the above-mentioned object, they discovered that by using a hydraulic composition in which grout material A (material A) contains a specific water-soluble hydroxyalkyl alkyl cellulose, an antifoaming agent, cement, and water, and grout material B (material B) contains water, and further in which one grout material contains a specific polyvinyl alcohol and the other grout material contains borax, the two components plasticize quickly after mixing, and no material separation occurs either before or after mixing, which led to the completion of the present invention.

[0010] Accordingly, the present invention provides the following hydraulic composition. 1. A hydraulic composition for grout is comprised of two materials: Material A containing water-soluble hydroxyalkyl alkyl cellulose, an antifoaming agent, cement, water, and polyvinyl alcohol or borax; and Material B containing a material not contained in Material A among polyvinyl alcohol and borax, one or more inorganic powders selected from fly ash, ground granulated blast furnace slag, ground limestone, and ground calcium carbonate, and water, wherein the degree of substitution (DS) of the alkoxy group of the water-soluble hydroxyalkyl alkyl cellulose is 1.2 or more, the degree of saponification of the polyvinyl alcohol is 70 to 90 mol %, and the viscosity of a 4% by mass aqueous solution of the polyvinyl alcohol at 20°C is 15 to 300 mPa·s, and the amount of the polyvinyl alcohol added is 1 / m of the hydraulic composition. 3 0.1~ 8 kg, and the amount of borax added is 3 0.1~ 8 kg, and the total amount of water added is more than 70 parts by mass and 300 parts by mass or less per 100 parts by mass of the cement. 2. 2. The hydraulic composition according to item 1, wherein material B further contains one or more inorganic compounds selected from sodium bicarbonate, potassium bicarbonate, potassium chloride, aluminum chloride, calcium sulfate, and aluminum sulfate. 3. 3. The hydraulic composition according to 1 or 2, wherein material B further contains a water-soluble hydroxyalkyl alkyl cellulose and an antifoaming agent. 4. 3. The hydraulic composition according to 1 or 2, characterized in that the ratio (A / B) of the flow value B immediately after filling a cylinder container with the mixed A and B materials and measured according to the cylinder method of NEXCO Test Method 313-1999 to the flow value A 10 minutes after filling is 0.50 or less. 5. The amount of polyvinyl alcohol added is 3 0.5~ per 8 3. The hydraulic composition according to 1 or 2, characterized in that the amount of the hydraulic composition is kg. 6. 3. The hydraulic composition according to 1 or 2, wherein the water-soluble hydroxyalkyl alkyl cellulose is hydroxypropyl methyl cellulose and / or hydroxyethyl methyl cellulose. 7. The amount of polyvinyl alcohol added is 3 3. The hydraulic composition according to 1 or 2, characterized in that the weight is 1 to 8 kg per unit area. 8. The amount of borax added is 1 / m of hydraulic composition 3 0.3~ 8 3. The hydraulic composition according to 1 or 2, characterized in that the amount of the hydraulic composition is kg. 9. The amount of borax added is 1 / m of hydraulic composition 3 3. The hydraulic composition according to 1 or 2, characterized in that the amount of the hydraulic composition is 0.5 to 8 kg per unit area. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a hydraulic composition that can be pumped long distances, plasticizes relatively quickly after mixing two components, and has little bleeding so that it can be cast even in areas where water or spring water is present. DETAILED DESCRIPTION OF THE INVENTION

[0012] The hydraulic composition according to the present invention will be described below. The hydraulic composition according to the present invention is a hydraulic composition for grout comprising two materials: material A (hereinafter referred to as grout material A) containing water-soluble hydroxyalkyl alkyl cellulose, an antifoaming agent, cement, water, and polyvinyl alcohol or borax; and material B (hereinafter referred to as grout material B) containing water and a material not contained in material A, selected from polyvinyl alcohol and borax; wherein the degree of substitution (DS) of the alkoxy group of the water-soluble hydroxyalkyl alkyl cellulose is 1.2 or more; the degree of saponification of the polyvinyl alcohol is 70 to 90 mol %; the viscosity of a 4% by mass aqueous solution of the polyvinyl alcohol at 20°C is 15 to 300 mPa·s; and the total amount of water added is more than 70 parts by mass and not more than 300 parts by mass per 100 parts by mass of the cement. The hydraulic composition according to the present invention is a two-component plastic grafting agent comprising the above-mentioned grout material A and grout material B, and by mixing the grout material A and the grout material B, a hydraulic composition containing at least water-soluble hydroxyalkyl alkyl cellulose, an antifoaming agent, polyvinyl alcohol, borax, cement, and water is obtained.

[0013] The water-soluble hydroxyalkyl alkyl cellulose used in the present invention is preferably hydroxypropyl methyl cellulose (HPMC) and / or hydroxyethyl methyl cellulose (HEMC) from the viewpoint of the material separation resistance of the hydraulic composition or the plasticity after mixing of the two components.

[0014] The degree of substitution (DS) of alkoxy groups in the water-soluble hydroxyalkyl alkyl cellulose is 1.2 or more, preferably 1.2 to 2.5, more preferably 1.3 to 2.3, and even more preferably 1.4 to 2.0, from the viewpoint of plasticization. The molar substitution (MS) of hydroxyalkoxy groups in the water-soluble hydroxyalkyl alkyl cellulose is preferably 0.05 to 0.6, more preferably 0.1 to 0.5, and even more preferably 0.15 to 0.4, from the viewpoint of solubility during summer use.

[0015] The DS of the alkoxy groups in the water-soluble hydroxyalkyl alkyl cellulose represents the degree of substitution, and refers to the average number of alkoxy groups per unit of anhydroglucose. The MS of the hydroxyalkoxy groups in the water-soluble hydroxyalkyl alkyl cellulose represents the molar substitution, and refers to the average number of moles of hydroxyalkoxy groups per mole of anhydroglucose. The DS of the alkoxy groups and the MS of the hydroxyalkoxy groups in the water-soluble hydroxyalkyl alkyl cellulose can be determined by converting values ​​measured by the substitution degree analysis method for hypromellose (hydroxypropyl methylcellulose) described in the 18th Edition of the Japanese Pharmacopoeia.

[0016] The viscosity of a 1% by mass aqueous solution of the water-soluble hydroxyalkyl alkyl cellulose used in the present invention at 20°C is preferably 5 to 30,000 mPa·s, more preferably 10 to 25,000 mPa·s, and even more preferably 15 to 23,000 mPa·s, from the viewpoint of imparting a predetermined material separation resistance to the hydraulic composition and plasticity after two-part mixing. The viscosity of a 1% by mass aqueous solution of the water-soluble hydroxyalkyl alkyl cellulose at 20°C can be measured using a B-type rotational viscometer.

[0017] The amount of water-soluble hydroxyalkyl alkyl cellulose added is determined based on the pumpability of the hydraulic composition and the resistance to material separation during pumping. In grout material A, the amount of water-soluble hydroxyalkyl alkyl cellulose added is determined based on the pumpability of the hydraulic composition and the resistance to material separation during pumping. 3 The water content is preferably 0.05 to 1.5 mass %, more preferably 0.08 to 1.0 mass %, and even more preferably 0.10 to 0.5 mass %, relative to the unit water content per unit mass.

[0018] The antifoaming agent has the function of suppressing bubbles caused by the water-soluble hydroxyalkyl alkyl cellulose. If there are too many bubbles, there are problems such as a decrease in strength and poor pumpability. As the defoaming agent, an oxyalkylene-based, silicone-based, alcohol-based, mineral oil-based, fatty acid-based, fatty acid ester-based, etc., can be used.

[0019] Examples of oxyalkylene antifoaming agents include polyoxyalkylenes such as (poly)oxyethylene (poly)oxypropylene adducts; (poly)oxyalkylene alkyl ethers such as diethylene glycol heptyl ether, polyoxyethylene oleyl ether, polyoxypropylene butyl ether, polyoxyethylene polyoxypropylene 2-ethylhexyl ether, and oxyethylene oxypropylene adducts to higher alcohols having 8 or more carbon atoms or secondary alcohols having 12 to 14 carbon atoms; (poly)oxyalkylene (alkyl)aryl ethers such as polyoxypropylene phenyl ether and polyoxyethylene nonylphenyl ether; alkylene aryl ethers to acetylene alcohols such as 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,5-dimethyl-3-hexyne-2,5-diol, and 3-methyl-1-butyn-3-ol; (poly)oxyalkylene fatty acid esters such as diethylene glycol oleate, diethylene glycol laurate, and ethylene glycol distearate; (poly)oxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate and polyoxyethylene sorbitan trioleate; (poly)oxyalkylene alkyl (aryl) ether sulfate salts such as polyoxypropylene methyl ether sodium sulfate and polyoxyethylene dodecylphenol ether sodium sulfate; (poly)oxyalkylene alkyl phosphates such as (poly)oxyethylene stearyl phosphate; (poly)oxyalkylene alkyl amines such as polyoxyethylene laurylamine; and polyoxyalkylene amides.

[0020] Examples of silicone-based antifoaming agents include dimethyl silicone oil, silicone paste, silicone emulsion, organically modified polysiloxane (polyorganosiloxane such as dimethylpolysiloxane), fluorosilicone oil, and the like. Examples of alcohol-based antifoaming agents include octyl alcohol, 2-ethylhexyl alcohol, hexadecyl alcohol, acetylene alcohol, glycols, and the like. Examples of mineral oil-based defoaming agents include kerosene and liquid paraffin. Examples of fatty acid antifoaming agents include oleic acid, stearic acid, and alkylene oxide adducts thereof. Examples of fatty acid ester-based antifoaming agents include glycerin monoricinoleate, alkenyl succinic acid derivatives, sorbitol monolaurate, sorbitol trioleate, and natural waxes. In the present invention, it is preferable to use an oxyalkylene-based defoaming agent from the viewpoint of defoaming performance.

[0021] The amount of antifoaming agent added is preferably 5 to 100 parts by mass, more preferably 10 to 80 parts by mass, and even more preferably 20 to 60 parts by mass relative to 100 parts by mass of water-soluble hydroxyalkyl alkyl cellulose, from the viewpoints of preventing a decrease in pumpability due to bubbles entrained during stirring of the hydraulic composition and the strength of the hydraulic composition after mixing the two components.

[0022] The cement that can be used in the present invention includes various types of cement, such as ordinary Portland cement, high-early-strength Portland cement, moderate-heat Portland cement, blast-furnace cement, silica cement, fly ash cement, alumina cement, and ultra-high-early-strength Portland cement.

[0023] The total amount of water added in the hydraulic composition is more than 70 parts by mass and not more than 300 parts by mass, preferably more than 70 parts by mass and not more than 280 parts by mass, more preferably more than 70 parts by mass and not more than 260 parts by mass, per 100 parts by mass of the cement.

[0024] The water / cement ratio in the grout material A is preferably 30 to 200 mass %, more preferably 50 to 150 mass %, and even more preferably 70 to 120 mass %.

[0025] Examples of water include tap water and seawater, but tap water is preferred from the viewpoint of preventing salt damage.

[0026] The amount of water used in grout A is an amount that ensures a water / hydraulic substance ratio within a predetermined range. The amount of water used in grout B must take into consideration the plasticity after mixing the two components, and from the viewpoint of obtaining sufficient plasticity after mixing the two components, the amount of water used in grout B is preferably 5 to 200 mass %, more preferably 10 to 180 mass %, and even more preferably 20 to 150 mass % of the amount of water in grout A.

[0027] The saponification degree of the polyvinyl alcohol used in the present invention is 70.0 to 90.0 mol%, preferably 70.0 to 89.0 mol%, more preferably 70.0 to 85.0 mol%, and even more preferably 70.0 to 84.0 mol%, from the viewpoint of imparting plasticity and material separation resistance. The saponification degree of polyvinyl alcohol can be measured by the method for measuring saponification degree described in JIS K 6726 (1994).

[0028] The viscosity of a 4% by mass aqueous solution of polyvinyl alcohol used in the present invention at 20°C is 15 to 300 mPa·s, preferably 20 to 300 mPa·s, more preferably 30 to 290 mPa·s, and even more preferably 70 to 280 mPa·s, from the viewpoint of imparting plasticity and / or material separation resistance. The viscosity of a 4% by mass aqueous solution of polyvinyl alcohol at 20°C can be measured by the viscosity measurement method described in JIS K 6726 (1994).

[0029] The combination of the degree of saponification of the polyvinyl alcohol used in the present invention and the viscosity of a 4% by mass aqueous solution at 20°C is 70 to 90 mol % and 15 to 300 mPa·s, preferably 70.0 to 90.0 mol % and 20 to 300 mPa·s, more preferably 70.0 to 90.0 mol % and 30 to 290 mPa·s, even more preferably 70.0 to 89.0 mol % and 70 to 280 mPa·s, and particularly preferably 70.0 to 85.0 mol % and 70 to 280 mPa·s.

[0030] The amount of polyvinyl alcohol added is determined based on the amount of the hydraulic composition after mixing the two components, from the viewpoint of imparting plasticity. 3 The weight is preferably 0.1 to 10 kg, more preferably 0.5 to 9 kg, and even more preferably 1 to 8 kg per unit area.

[0031] The amount of borax added is determined based on the amount of the hydraulic composition after mixing the two components, from the viewpoint of imparting plasticity. 3 The weight is preferably 0.1 to 10 kg, more preferably 0.3 to 9 kg, and even more preferably 0.5 to 8 kg per unit area.

[0032] In the present invention, inorganic compounds can be used for the purpose of promoting plasticization, and it is preferable to use one or more compounds selected from sodium bicarbonate, potassium bicarbonate, potassium chloride, aluminum chloride, calcium sulfate, and aluminum sulfate. The amount of these inorganic compounds added is determined based on the amount of the inorganic compound added per 1 ml of the hydraulic composition after mixing the two components, from the viewpoint of promoting plasticization. 3 The weight is preferably 0.5 to 10 kg, more preferably 1 to 8 kg, and even more preferably 2 to 6 kg per unit.

[0033] The hydraulic composition of the present invention is prepared by dividing the above components into two materials (two liquids), grout material A and grout material B, which are pumped separately and then mixed together near the injection point.

[0034] Here, grout material A contains water-soluble hydroxyalkyl alkyl cellulose, an antifoaming agent, cement, and water, and grout material B contains water. Furthermore, one of grout material A and grout material B contains polyvinyl alcohol, and the other contains borax.

[0035] It is also preferable that grout material B contains one or more inorganic compounds selected from the group consisting of sodium bicarbonate, potassium bicarbonate, potassium chloride, aluminum chloride, calcium sulfate, and aluminum sulfate.It is also preferable that grout material B contains the water-soluble hydroxyalkyl alkyl cellulose described above from the viewpoint of the material separation resistance of the hydraulic composition, and the antifoaming agent described above from the viewpoint of adjusting the amount of entrained air.

[0036] The volume ratio of grout material A to grout material B is preferably 1:0.3 to 1:2, more preferably 1:0.5 to 1:1.5, and even more preferably 1:0.8 to 1:1.2. Among these, a 1:1 volume ratio of grout material A to grout material B is most preferred, and an inorganic powder can be added to grout material B as needed. Examples of inorganic powders include fly ash, ground granulated blast furnace slag, ground limestone, and ground calcium carbonate. One or more of these can be mixed and used. Among the inorganic powders, fly ash is particularly preferred from the viewpoint of achieving sufficient plasticization. In this case, the amount of inorganic powder used is 1:0.3 to 1:2 per 1 ml of the hydraulic composition after the two-component mixing. 3 Each weighs 50 to 600 kg.

[0037] In the hydraulic composition of the present invention, the grout materials A and B are mixed and measured according to the cylinder method of NEXCO Test Method 313-1999. The ratio (A / B) of the flow value B immediately after filling a cylinder container to the flow value A 10 minutes after filling is preferably 0.50 or less, and more preferably 0.47 or less, from the viewpoint of changes in plasticity over time. Flow value A is the flow value when the mixed hydraulic composition is filled into a cylinder container, allowed to stand for 10 minutes, and then the cylinder container is removed. Flow value B is the flow value when the mixed hydraulic composition is filled into a cylinder container and then immediately removed. A cylinder container with a height of 80 mm and an inner diameter of 80 mm is used to measure the flow values.

[0038] The hydraulic composition of the present invention does not require as high strength as general mortar or concrete, but in order to obtain high fluidity with a smaller amount of water, a water-reducing agent can be added to both grout material A and grout material B as needed.

[0039] The water reducing agent may be a polycarboxylic acid-based, melamine-based or lignin-based agent. Examples of polycarboxylic acid-based materials include polycarboxylic acid ether-based materials, complexes of polycarboxylic acid ether-based materials and crosslinked polymers, complexes of polycarboxylic acid ether-based materials and oriented polymers, complexes of polycarboxylic acid ether-based materials and highly modified polymers, polyether carboxylic acid-based polymer compounds, maleic acid copolymers, maleic acid ester copolymers, maleic acid derivative copolymers, carboxyl group-containing polyether-based materials, polycarboxylic acid group-containing multicomponent polymers having terminal sulfonic groups, polycarboxylic acid-based graft copolymers, polycarboxylic acid-based compounds, and polycarboxylic acid ether-based polymers. Examples of melamine-based compounds include melamine sulfonic acid formalin condensates, melamine sulfonate condensates, and melamine sulfonate polyol condensates. Examples of lignin-based compounds include lignin sulfonates and derivatives thereof.

[0040] In the present invention, it is preferable to use a polycarboxylic acid-based water-reducing agent in terms of water-reducing effect, fluidity and fluidity retention. The amount of the water reducing agent added is preferably 0 to 5 parts by mass relative to 100 parts by mass of cement. [Example]

[0041] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following examples, the viscosity values ​​were measured at 20°C using a B-type rotational viscometer.

[0042] [Examples 1 to 10, Comparative Examples 1 to 3] <Materials used> The following materials were used as hydraulic compositions. (1) Cement (C): Ordinary Portland cement (manufactured by Taiheiyo Cement Corporation), density 3.16 g / cm 3 (2) Water (W): Tap water (3) Water-soluble hydroxyalkyl alkyl cellulose (CE): Sample details are shown in Table 1 (4) Defoamer: SN Deformer 14HP (manufactured by San Nopco Co., Ltd.) (5) Polyvinyl alcohol (PVA): Sample details are shown in Table 2 (6) Fly ash (FA): J Powder (manufactured by Electric Power Development Co., Ltd.), density 2.20 g / cm 3 ) (7) Sodium bicarbonate (SHC): First-grade reagent (8) Borax: First-class reagent

[0043] [Table 1] HPMC: Hydroxypropyl methylcellulose HEMC: Hydroxyethylmethylcellulose

[0044] [Table 2]

[0045] <Preparation of hydraulic composition> Grout material A (2 liters) and grout material B (2 liters) having the formulations shown in Table 3 were placed in a mortar mixer conforming to JIS R 5201 and mixed for 3 minutes at high speed (rotational motion 290 rpm, planetary motion 120 rpm). Next, while stirring grout material A at low speed (rotational motion 140 rpm, planetary motion 60 rpm) with the mortar mixer, grout material B was added over 15 seconds, and the mixture was further stirred for another 15 seconds to obtain a hydraulic composition. The material temperature was adjusted so that the temperature after mixing would be within 20±3°C.

[0046] [Table 3]

[0047] The hydraulic compositions thus obtained were subjected to the following evaluations, the results of which are shown in Table 4. <Evaluation method> 1. Flow Value The hydraulic composition obtained by mixing grout material A and grout material B was filled into a cylinder container with a height of 80 mm and an inner diameter of 80 mm according to the cylinder method of NEXCO test method 313-1999, and the flow value was measured immediately after filling (B) and 10 minutes after filling (A). 2. Flow ratio (A / B) The ratio of the flow values ​​immediately after filling (B) to those 10 minutes after filling (A) was defined as the flow value ratio (A / B). 3.Breeding rate The hydraulic composition obtained by mixing grout material A and grout material B was evaluated for bleeding rate after 3 hours according to the bleeding rate and expansion rate test method (polyethylene bag method) of JSCE-F 522-2013. The bleeding rate is an index of material separation, and the lower the bleeding rate, the less material separation there is. 4. Material separation The settling state of grout material A and grout material B before mixing was visually observed, and if no settling of material was observed at the bottom of the bowl used in the mortar mixer and the state was uniform, it was marked as ◯, and if settling of material was observed at the bottom, it was marked as ×.

[0048] [Table 4]

[0049] As shown in Examples 1 to 15 in Table 4, hydraulic compositions with low flow ratios (A / B) and low bleeding rates were obtained by using a water-soluble hydroxyalkyl alkyl cellulose (CE) with a specific degree of substitution (DS) and a polyvinyl alcohol (PVA) with a specific degree of saponification and aqueous solution viscosity. These results indicate that the hydraulic compositions rapidly plasticize and exhibit little material separation when mixed with grout A and grout B. Furthermore, as shown in Examples 2, 13, and 14, both the flow ratios (A / B) and bleeding rates were low regardless of whether polyvinyl alcohol (PVA) and borax were contained in grout A or grout B (i.e., whether grout A contains PVA and grout B contains borax, or whether grout A contains borax and grout B contains PVA). On the other hand, in the comparative examples, it was not possible to reduce both the flow value ratio (A / B) and the bleeding rate. In comparative example 1, the bleeding rate was equivalent to that of the examples, but the flow value ratio (A / B) was high at 0.89 because the viscosity of the aqueous solution of polyvinyl alcohol was lower than the range of the present invention. In comparative example 2, the saponification degree of polyvinyl alcohol was higher than the range of the present invention, and in comparative example 3, the degree of substitution (DS) of the water-soluble hydroxyalkyl alkyl cellulose was lower than the range of the present invention, so both the flow value ratio (A / B) and the bleeding rate were higher than those of the examples. Furthermore, Example 1 (saponification degree 88.2 mol%), Example 5 (saponification degree 72.3 mol%), and Example 4 (saponification degree 88.3 mol%) and Example 8 (saponification degree 77.2 mol%) showed that as the saponification degree of polyvinyl alcohol approaches 70 mol%, the plasticity and material separation resistance tend to improve. Furthermore, Example 1 (viscosity 24 mPa s), Example 4 (viscosity 280 mPa s), and Example 10 (viscosity 74 mPa s) showed that as the viscosity of polyvinyl alcohol increases, the plasticity in particular (flow value ratio (A / B)) tends to improve.

[0050] Although the present invention has been described using the above-mentioned embodiment, the present invention is not limited to this embodiment, and can be modified within the scope of what a person skilled in the art can conceive, such as other embodiments, additions, changes, deletions, etc., and any aspect is included in the scope of the present invention as long as it achieves the effects of the present invention.

Claims

1. A hydraulic composition for grout is comprised of two materials: Material A containing water-soluble hydroxyalkyl alkyl cellulose, an antifoaming agent, cement, water, and polyvinyl alcohol or borax; and Material B containing a material not contained in Material A among polyvinyl alcohol and borax, one or more inorganic powders selected from fly ash, blast furnace slag ground powder, limestone ground powder, and calcium carbonate ground powder, and water, wherein the degree of substitution (DS) of the alkoxy group of the water-soluble hydroxyalkyl alkyl cellulose is 1.2 or more, the degree of saponification of the polyvinyl alcohol is 70 to 90 mol %, and the viscosity of a 4% by mass aqueous solution of the polyvinyl alcohol at 20°C is 15 to 300 mPa·s, and the amount of the polyvinyl alcohol added is 1.0 to 1.5 mPa·s per 1 m of the hydraulic composition. 3 The amount of borax added is 0.1 to 8 kg per 1 m of hydraulic composition. 3 The hydraulic composition is characterized in that the total amount of water added is more than 70 parts by mass and 300 parts by mass or less per 100 parts by mass of the cement.

2. 2. The hydraulic composition according to claim 1, wherein material B further contains one or more inorganic compounds selected from the group consisting of sodium bicarbonate, potassium bicarbonate, potassium chloride, aluminum chloride, calcium sulfate, and aluminum sulfate.

3. 3. The hydraulic composition according to claim 1, wherein the material B further contains a water-soluble hydroxyalkyl alkyl cellulose and an antifoaming agent.

4. The hydraulic composition according to claim 1 or 2, characterized in that the ratio (A / B) of the flow value B immediately after filling a cylinder container with the mixture of materials A and B and the flow value A 10 minutes after filling, measured according to the cylinder method of NEXCO Test Method 313-1999, is 0.50 or less.

5. The amount of polyvinyl alcohol added is 3 3. The hydraulic composition according to claim 1, wherein the weight of the hydraulic composition is 0.5 to 8 kg per unit area.

6. 3. The hydraulic composition according to claim 1, wherein the water-soluble hydroxyalkyl alkyl cellulose is hydroxypropyl methyl cellulose and / or hydroxyethyl methyl cellulose.

7. The amount of polyvinyl alcohol added is 3 3. The hydraulic composition according to claim 1, wherein the weight of the hydraulic composition is 1 to 8 kg per unit area.

8. The amount of borax added is 1 m of hydraulic composition 3 3. The hydraulic composition according to claim 1, wherein the weight of the hydraulic composition is 0.3 to 8 kg per unit area.

9. The amount of borax added is 1 m of hydraulic composition 3 3. The hydraulic composition according to claim 1, wherein the weight of the hydraulic composition is 0.5 to 8 kg per unit area.

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