TW201904909A - Hydraulic composition - Google Patents

Abstract

With respect to hydraulic compositions prepared using black particles for a portion of the binder, provided is such a hydraulic composition that, even when having a high flowability, exhibits a thorough suppression of darkening at the surface of the cured article obtained from the hydraulic composition and can provide a cured article having an excellent surface appearance. The hydraulic composition is prepared using water-soluble cellulose ether containing at least one type selected from hydroxyalkyl alkyl cellulose and hydroxyalkyl cellulose.

Description

   Hydraulic composition   

The present invention relates to a hydraulic composition, and more specifically to a case where black particles contained in a binding material can sufficiently suppress black stains on the surface of a hardened body obtained from the hydraulic composition containing the binding material. On the other hand, it is possible to obtain a hydraulic composition having a hardened body which is excellent in surface appearance.

Recently, in order to reduce the environmental burden, fly ash, blast furnace slag powder, silicon powder, limestone powder and the like are often used as a binding material of hydraulic composition together with cement to achieve the purpose of using industrial by-products or reducing carbon dioxide emissions. On the other hand, the hydraulic composition may be made of natural materials or lignite. The substances used together with cement as part of the binding material contain black particles, mainly carbon particles. In particular, fly ash contains many unburned carbon black particles. In the JIS standard (JIS A6201) for fly ash for concrete, the ignition loss of the recommended amount of unburned carbon is maintained at 8.0% or less. The black particles contained in these substances will appear as black stains on the surface of the hardened body obtained from the hydraulic composition using these substances as a part of the binding material, thereby destroying the appearance. In particular, when a polycarboxylic acid-based water reducing agent is used as a dispersant for a binding material, the occurrence of black stains is very obvious. Furthermore, when the fluidity of the hydraulic composition is increased, the material flow resistance is reduced, and black stains are more likely to occur. It is also possible to reduce black particles by these substances through the treatment process, but not only cause an increase in energy consumption, but also require the introduction of treatment equipment, which is not efficient. Conventionally, there have been proposals for suppressing black stains generated on the surface of a hardened body obtained from a hydraulic composition: a copolymer of a monoolefin having 6 to 10 carbon atoms and a maleic acid or a salt thereof (for example, refer to Patent Documents) 1); and an olefin-maleic acid copolymer having a weight average molecular weight of 1,000 to 20,000 having a structural unit formed of a divalent hydrocarbon group having 6 to 14 carbon atoms, and a polycarboxylic acid polymer other than that Substance (for example, refer to Patent Document 2). However, none of the related conventional methods can sufficiently suppress the black stains generated on the surface of the obtained hardened body, especially in the case of a hydraulic composition having a high fluidity. Problems with the surface of the hardened body obtained from the composition.

    [Previous Technical Literature]         Patent literature    

Patent Document 1: Japanese Patent Publication No. 2004-83303; Patent Document 2: Japanese Patent Publication No. 2004-175651.

The problem to be solved by the present invention is to provide a hydraulic composition in a hydraulic composition prepared by using a substance containing black particles as a part of a binding material, even if it is A hydraulic composition having a high fluidity can sufficiently suppress black stains generated on the surface of a hardened body obtained from the hydraulic composition, and a hardened body having an excellent and beautiful surface can be obtained.

Therefore, as a result of intensive research in order to solve the aforementioned problems, the present inventors have found that a hydraulic composition prepared using a water-soluble cellulose ether containing at least one selected from the group consisting of hydroxyalkyl alkyl cellulose and hydroxy alkyl cellulose is Most correct and appropriate.

That is, the present invention relates to a hydraulic composition formed by containing a binding material, a water-soluble cellulose ether, a polycarboxylic acid-based water reducing agent, and water. The bonding material contains cement and at least one selected from the group consisting of fly ash, blast furnace slag powder, silicon powder, limestone powder, and lignite. The water-soluble cellulose ether contains at least one substance selected from the group consisting of hydroxyalkylalkyl cellulose and hydroxyalkyl cellulose.

The binding material used in the hydraulic composition of the present invention contains cement and at least one black particle selected from the group consisting of fly ash, blast furnace slag powder, silicon powder, limestone powder, and lignite.

The cement may be, for example, ordinary Portland cement, medium-temperature Portland cement, low-temperature Portland cement, early-strength Portland cement, ultra-early-strength Portland cement, or sulfate-resistant Portland cement. Transland Cement. Materials containing black particles such as fly ash, blast furnace slag powder, silica powder, limestone powder, and lignite can be prepared as mixed cement, can be prepared in a hydraulic composition manufacturing plant, or can be contained as a JIS Part of Portland cement prepared by mixing a small amount of ingredients in 0 ~ 5% of R5210. Among the bonding materials used in hydraulic cement compositions, the ratio of cement to black particles contains no particular limitation, but as the bonding material, it is preferable to contain cement in a proportion of 10 to 95% by mass and to contain 5 to 90% by mass. The ratio contains a black particle-containing substance, and the total of both is 100% by mass. The black particles are preferably fly ash, blast furnace slag powder and silicon powder, and blast furnace slag powder and fly ash are particularly preferred.

The water-soluble cellulose ether used in the hydraulic composition of the present invention is a hydroxyalkyl alkyl group such as (1) hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, or hydroxyethyl ethyl cellulose. Among cellulose, and (2) hydroxyalkyl celluloses such as hydroxypropyl cellulose and hydroxyethyl cellulose, at least one selected from (1) and (2).

The MS of the hydroxyalkylalkyl cellulose (the number of substituted mols of the alkyl hydroxyalkyl group, the same applies hereinafter) is preferably 0.1 to 3.0, and the DS (the degree of substitution of the alkyl group, the same applies hereinafter) is preferably 1.0 to 2.2, The MS is preferably 0.1 to 1.0 and the DS is 1.0 to 2.0, and the MS is 0.1 to 0.3 and DS is 1.1 to 1.7. Among them, hydroxypropyl methyl cellulose and hydroxyethyl methyl cellulose are preferred. The MS of the hydroxyalkyl cellulose is preferably 2.0 to 3.3, and the MS is preferably 2.0 to 2.8, and the MS is preferably 2.0 to 2.4. Among them, hydroxyethyl cellulose is particularly preferred.

In addition, MS is a molar substitution of an alkylhydroxyalkyl group, and is an average molar number of a hydroxyalkoxy group added per glucose ring unit of cellulose. DS is the degree of substitution of the alkyl group, and is the number of alkoxy groups present in the glucose ring unit of each cellulose. This measurement method of MS or DS can be obtained by converting a value measured by a method for analyzing the degree of substitution of hypromellose (hydroxypropylmethyl cellulose) described in the 17th edition of the revised Japanese Pharmacopoeia.

In the hydraulic composition of the present invention, the viscosity of the 2% by mass aqueous solution of the water-soluble cellulose ether at 20 ° C (hereinafter referred to simply as 2% viscosity) should preferably be 5000 mPa or more. s, and the viscosity of its 1% by mass aqueous solution at 20 ° C (hereinafter referred to as only 1% viscosity) should be less than or equal to 30,000mPa. s and 2% viscosity is 5000mPa or more. s and 1% viscosity is less than or equal to 20000mPa. s is better, and 2% viscosity is 10000mPa or more. s and 1% viscosity is less than or equal to 15000mPa. s especially good. The above viscosities are all values of 20 rpm of a B-H viscometer.

The method for adding water-soluble cellulose may be adding water-soluble cellulose ether powder, adding water-soluble cellulose ether aqueous solution, adding water-soluble cellulose ether in a state of being dispersed or dissolved in a polycarboxylic acid-based water reducing agent, Alternatively, it is added in a state of being dispersed or dissolved in a liquid shrinkage reducing agent or a liquid defoaming agent. From the viewpoint of the fluidity of the hydraulic composition, the amount of the water-soluble cellulose ether to be added is preferably 0.01 to 0.20 parts by mass, more preferably 0.01 to 0.15 parts by mass, and 0.02 parts by mass. ~ 0.10 parts by mass is particularly preferred. When the added amount of water-soluble cellulose ether is less than 0.01 parts by mass with respect to 100 parts by mass of the binding material, sufficient black stain pressing effect and material flow resistance cannot be obtained, and when it exceeds 0.20 parts by mass, black stains may appear. Squeezing effect, but will cause the fluidity of hydraulic materials to decrease.

From the viewpoint of the effect of suppressing black stains, the water-soluble cellulose ether of the present invention preferably has an average particle diameter of 20 to 500 μm, particularly preferably 20 to 120 μm, and particularly preferably 40 to 100 μm. The average particle diameter is a volume-converted particle diameter, and is a value generated by a powder particle diameter measurement method using laser diffraction. The average particle diameter can be measured using, for example, HELOS & RODOS (product name of Japan Laser Corporation).

In the hydraulic composition of the present invention, the polycarboxylic acid-based water reducing agent is a (co) polymer having a unit formed of an unsaturated carboxylic acid monomer and / or a salt thereof, although it is used as a binding material. As the dispersant, a commercially available product can be used. The unsaturated carboxylic acid monomer and / or its salt forming the structural unit of the (co) polymer of the polycarboxylic acid-based water reducing agent may be, for example, (meth) acrylic acid, crotonic acid, (anhydrous) malay, (anhydrous) ) Itaconic acid, fumaric acid, and / or salts thereof, and the like, unsaturated dicarboxylic acid monomers having two or more carboxyl groups in one molecule may have one kind of carboxylic acid or its salt, and may also have an ester bond, Amine bond and so on. The kind of the salt is not particularly limited and may be, for example, alkali metal salts such as sodium and potassium salts, alkaline earth metal salts such as calcium and magnesium salts, ammonium salts, or amine salts such as diethanolamine salt and triethanolamine salt.

The monomer other than the carboxylic acid and / or its salt as a structural unit forming the (co) polymer may be, for example, a polyoxyalkylene group composed of an alkylene oxide unit having 1 to 300 carbon atoms and 2 to 4 in the molecule. Group of unsaturated monomers. For example, α-vinyl-ω-hydroxy (poly) butylene oxide (poly) oxyethylene, α-allyl-ω-methoxy- (poly) oxyethylene, α-allyl-ω -Methoxy- (poly) oxyethylene (poly) oxypropylene, α-allyl-ω-hydroxy- (poly) oxyethylene, α-allyl-ω-hydroxy- (poly) oxyethylene (poly) Oxypropylene, α-methylallyl-ω-hydroxy- (poly) oxyethylene, α-methylallyl-ω-methoxy- (poly) oxyethylene, α-methylallyl-ω -Hydroxy- (poly) oxyethylene (poly) oxypropylene, α-methylallyl-ω-ethenyl- (poly) oxyethylene, α- (3-methyl-3-butenyl) -ω -Hydroxy- (poly) oxyethylene, α- (3-methyl-3-butenyl) -ω-butoxy- (poly) oxyethylene, α- (3-methyl-3-butenyl) -ω-hydroxy- (poly) oxyethylene (poly) oxypropylene, α- (3-methyl-3-butenyl) -ω-ethenyl- (poly) oxyethylene (poly) oxypropylene, α- Propylenefluorenyl-ω-hydroxy- (poly) oxyethylene, α-propylenefluorenyl-ω-methoxy- (poly) oxyethylene, α-propylenefluorenyl-ω-butoxy- (poly) are particularly preferred, 40 ~ 100μm is particularly good. The average particle diameter is a volume-converted particle diameter, and is a value generated by a powder particle diameter measurement method using laser diffraction. The average particle diameter can be measured using, for example, HELOS & RODOS (product name of Japan Laser Corporation).

In the hydraulic composition of the present invention, the polycarboxylic acid-based water reducing agent is a (co) polymer having a unit formed of an unsaturated carboxylic acid monomer and / or a salt thereof, although it is used as a binding material. As the dispersant, a commercially available product can be used. The unsaturated carboxylic acid monomer and / or its salt forming the structural unit of the (co) polymer of the polycarboxylic acid-based water reducing agent may be, for example, (meth) acrylic acid, crotonic acid, (anhydrous) malay, (anhydrous) ) Itaconic acid, fumaric acid, and / or salts thereof, and the like, unsaturated dicarboxylic acid monomers having two or more carboxyl groups in one molecule may have one kind of carboxylic acid or its salt, and may also have an ester bond, Amine bond and so on. The kind of the salt is not particularly limited and may be, for example, alkali metal salts such as sodium and potassium salts, alkaline earth metal salts such as calcium and magnesium salts, ammonium salts, or amine salts such as diethanolamine salt and triethanolamine salt, and the like.

The monomer other than the carboxylic acid and / or its salt as a structural unit forming the (co) polymer may be, for example, a polyoxyalkylene group composed of an alkylene oxide unit having 1 to 300 carbon atoms and 2 to 4 in the molecule. Group of unsaturated monomers. For example, α-vinyl-ω-hydroxy (poly) butylene oxide (poly) oxyethylene, α-allyl-ω-methoxy- (poly) oxyethylene, α-allyl-ω -Methoxy- (poly) oxyethylene (poly) oxypropylene, α-allyl-ω-hydroxy- (poly) oxyethylene, α-allyl-ω-hydroxy- (poly) oxyethylene (poly) Oxypropylene, α-methylallyl-ω-hydroxy- (poly) oxyethylene, α-methylallyl-ω-methoxy- (poly) oxyethylene, α-methylallyl-ω -Hydroxy- (poly) oxyethylene (poly) oxypropylene, α-methylallyl-ω-ethenyl- (poly) oxyethylene, α- (3-methyl-3-butenyl) -ω -Hydroxy- (poly) oxyethylene, α- (3-methyl-3-butenyl) -ω-butoxy- (poly) oxyethylene, α- (3-methyl-3-butenyl) -ω-hydroxy- (poly) oxyethylene (poly) oxypropylene, α- (3-methyl-3-butenyl) -ω-ethenyl- (poly) oxyethylene (poly) oxypropylene, α- Acrylfluorenyl-ω-hydroxy- (poly) oxyethylene, α-acrylfluorenyl-ω-methoxy- (poly) oxyethylene, α-acrylfluorenyl-ω-butoxy- (poly) oxyethylene, α-polypropylene 醯 -ω-methoxy- (poly) oxyethylene (poly) oxypropylene, α-methacryl 醯 yl-ω-hydroxy- (poly) oxyethylene, α-methacryl 醯 yl-ω -Methoxy- ( ) Oxyethylene, α-methacrylfluorenyl-ω-butoxy- (poly) oxyethylene, α-propylenefluorenyl-ω-methoxy- (poly) oxyethylene (poly) oxypropylene, α-methyl Propylene fluorenyl-ω-hydroxy- (poly) oxyethylene (poly) oxypropylene, α-methacryl fluorenyl-ω-ethylfluorenyl- (poly) oxyethylene (poly) oxypropylene, polyalkylene Polyalkylene polyamine type monomers having an active imino group of an amine, an alkylene oxide added to the active amino group, and an unsaturated bond such as a (meth) acrylfluorenyl group in the molecule; Polyamine polyamine monomers containing polyimide polyamines with reactive imino, amino, and amine residues added to the condensation of amines and having unsaturated bonds such as (meth) acrylfluorenyl groups Wait.

The (co) polymer as a polycarboxylic acid water reducing agent is preferably composed of the following structural units: a structural unit formed of an unsaturated carboxylic acid monomer and / or a salt thereof; and a molecule having 1 to 300 carbons in the molecule A structural unit formed by an unsaturated monomer of a polyoxyalkylene group composed of an oxyalkylene unit having 2 to 4 atoms. The mass average molecular weight should preferably be 2,000 to 500,000 and more preferably 5,000 to 100,000.

In the hydraulic composition of the present invention, the polycarboxylic acid-based water reducing agent can be used as an aqueous solution or a powder. The amount of the polycarboxylic acid-based water reducing agent is preferably 0.01 to 2% by mass of the polycarboxylic acid-based water reducing agent ( (I.e., (co) polymer), and more preferably 0.05 to 0.5% by mass.

Aggregate can be used in the hydraulic composition of the present invention. The aggregate can be, for example, fine aggregates such as river sand, mountain sand, ground sand, silica sand, crushed sand or blast furnace slag fine aggregate, and river sand stones, mountain gravel, gravel, crushed stone, coarse blast furnace slag Etc. coarse aggregate. In order to reduce drying shrinkage and self-shrinkage of the hydraulic composition and thereby suppress the heat generation of the bonding material, it is preferable to include fine aggregates and coarse aggregates.

In the hydraulic composition of the present invention, the mass ratio of the water / binding material is preferably 0.35 to 0.65. When the mass ratio of the water / bond material is less than 0.35, the fluidity of the hydraulic composition is liable to deteriorate, and when the mass ratio of the water / bond material is more than 0.65, it is difficult to obtain sufficient material flow resistance.

As long as the hydraulic composition of the present invention does not impair the effect of the present invention, it can be used in combination with, for example, an AE regulator made of an anionic surfactant, such as an oxyalkylene series defoamer, or an oxycarboxylic Retarders formed from acid salts, for example, curing accelerators formed from alcohol amines, dry shrinkage reducing agents such as polyoxyalkylene alkyl ethers, preservatives composed of isothiazoline-based compounds, such as higher fatty acid derivatives Water-repellent agents, such as rust inhibitors composed of nitrite.

The present invention does not currently have a detailed mechanism for discovering the effect, but it is estimated by the following methods. It is speculated that water-soluble cellulose ether will adsorb black particles generated from fly ash, blast furnace slag powder, silica powder, limestone powder, and lignite, and in hydraulic compositions, the water-soluble cellulose ether will be used as a thickening material. The flow resistance is also increased, which can simultaneously suppress black stains and inhibit material flow under high fluidity. Such characteristics differ depending on the chemical structure effect, and by using a specific water-soluble cellulose ether, the hydraulic composition of the present invention having both suppression of black stains and material flow resistance can be obtained.

According to the present invention, the following effects can be obtained: In a hydraulic composition prepared by using a substance containing black particles as a part of a binding material, even if the hydraulic composition has high fluidity, the black composition can be sufficiently pressed. The stain is generated on the surface of the hardened body obtained from the hydraulic composition, and a hardened body having an excellent and beautiful surface can be obtained.

In the following, the structure and effects of the present invention will be described more specifically, taking the embodiment and the like as examples, but the invention is not limited to the embodiment. In the following examples, unless otherwise stated, parts are parts by mass and% is mass%.

Test category 1 (preparation of mortar as hydraulic composition)

Using a mortar mixer in accordance with the JIS R 5201 cement physical test method, 100 parts by mass of the bonding material was added at a ratio of 0.005 parts by mass of an antifoaming agent (product name AFK-2 manufactured by Takemoto Oil Co., Ltd.). Under the combined conditions, the contents of Table 2 were kneaded for 240 seconds. This kneading test and the following tests were performed by setting the material temperature to 20 ± 3 ° C, room temperature to 20 ± 3 ° C, and humidity of 60% or more. The mortar flow is an unslurried mortar flow. The goal is to confirm that the water seepage at the edge of the mortar is 295 ± 5 mm without using additives other than polycarboxylic acid-based water reducing agents and defoamers. The determination of the mortar flow, the degree of black stains, and the determination of the flow resistance of the uncured mortar was performed after 3 minutes of pulling up the mortar flow. This mortar was filled into a cylindrical frame (5 cm in diameter and 10 cm in height) and cured in a room at 20 ° C. for 24 hours and demoulded, and the degree of black staining of the cured mortar was determined. The results are collectively shown in Table 2.

in FIG. 1,

OPC: Ordinary Portland Cement

BB: B type of blast furnace cement

FA1: Fly ash (5.3% burning loss)

FA2: fly ash (burning loss 2.1%)

SF: Silicon powder (4.3% burning loss)

Fine aggregate: land sand from the Oigawa water system

In Table 2,

Amount used: Relative to the amount (%) of the binding material (when used as an aqueous solution, it means the solid content in the aqueous solution relative to the amount of the binding material (%))

PC-1: Polycarboxylic acid type high performance AE water reducing agent (product name) HP-11)

PC-2: Polycarboxylic acid type high performance AE water reducing agent (product name made by BASF Japan) SP8SV)

PC-3: Polycarboxylic acid type high performance AE water reducing agent (product name) 1100NT)

CB: Kao Corporation's special polycarboxylic acid type surfactant black stain pressure preparation (product name 21B)

Water-soluble cellulose Water-soluble cellulose ether: Use is described in Table 3.

table 3

In Table 3,

Viscosity: The viscosity (mPa.s) of a 2% by mass aqueous solution at 20 ° C. Only those with a 1% by mass aqueous solution are noted as (1%).

The degree of black stain was determined visually based on the following criteria.

Criteria for determining the degree of black stains

◎: Black stains are very inconspicuous

○: Black stains can be confirmed slightly

×: Black stains can be clearly recognized

The determination of the flow resistance was performed visually based on the following criteria.

Criteria for determining flow resistance

◎: Very good (no drift)

○: Good (although the surface of the hydraulic composition is slightly whitish, although it does not flow away)

△: Water leakage of the hydraulic composition is slightly confirmed

×: Water leakage of hydraulic composition is obvious

Test category 2 (preparation of concrete as hydraulic composition)

Under the combination conditions described in Table 4, the concrete described in Table 5 was prepared as described below. Put ordinary Portland cement (density 3.16g / cm ³ ), fly ash (density 2.29g / cm ³ , burning loss 2.3%), blast furnace slag powder (density 2.88g / cm ³ ), Fine aggregate (land sand produced by the Oigawa water system, density 2.58g / cm ³ ), and coarse aggregate (okazaki crushed stone, density 2.68g / cm ³ ), after kneading for 10 seconds, 100 mass parts of the binding material An antifoaming agent (product name AFK-2 manufactured by Takemoto Oil Co., Ltd.) was added in a proportion of 0.005 parts by mass, and the polycarboxylic acid-based water reducing agent and water-soluble cellulose ether used in Test Category 1 were added together with the mixed water. The mixture was kneaded for 120 seconds so that the slump was 65 ± 2 cm and the air volume was 2% or less. Polycarboxylic acid water reducing agents and defoamers are considered as part of water. For the prepared concrete composition, the slump just after mixing is measured in accordance with JIS-A1150, and the air volume is measured in accordance with JIS-A1128. The determination of the slump of the uncured concrete, the degree of black stains, and the determination of the flow resistance were performed after the slump cone was pulled up for 3 minutes. This uncured concrete was filled into a cylindrical frame (10 cm in diameter and 20 cm in height), and was cured in a room at 20 ° C. for 24 hours, and then demolded to determine the degree of black stain on the cured concrete. The results are shown in Table 5.

In Table 5,

Use amount: used amount (%) relative to the binding material (when used in an aqueous solution, it means the solid content in the aqueous solution relative to the used amount (%) of the binding material)

Polycarboxylic acid water reducer, water-soluble cellulose ether, etc .: Users in Test Category 1

The degree of black stain was determined visually according to the following criteria.

Criteria for determining the degree of black stains

◎: almost no black stains

○: Black stains can be confirmed only slightly

×: Black stains can be clearly confirmed

The determination of the flow resistance was performed visually based on the following criteria.

Criteria for determining flow resistance

◎: Very good (the aggregate and mortar / paste did not flow away)

○: Good (bone material and mortar / paste flow only slightly)

△: Poor (bone and mortar / paste flow away)

×: Very poor (bone material and mortar / paste are clearly separated)

Claims (14)

    A hydraulic composition comprising a binding material, a water-soluble cellulose ether, a polycarboxylic acid-based water reducing agent, and water, wherein the binding material contains cement and is selected from the group consisting of fly ash, blast furnace slag powder, silicon powder, limestone powder, and lignite. And at least one substance selected from the group consisting of hydroxyalkyl alkyl cellulose and hydroxy alkyl cellulose.         For example, the hydraulic composition of claim 1, wherein the molar number of alkylhydroxyalkyl substitutions of hydroxyalkylalkylcellulose is 0.1 to 3.0, and the degree of alkyl substitution is 1.0 to 2.2.         The hydraulic composition according to claim 1, wherein the hydroxyalkylalkyl cellulose is selected from the group consisting of hydroxypropylmethyl cellulose and hydroxyethyl methyl cellulose.         The hydraulic composition according to claim 2, wherein the hydroxyalkylalkyl cellulose is selected from the group consisting of hydroxypropylmethyl cellulose and hydroxyethyl methyl cellulose.         For example, the hydraulic composition of claim 1, wherein the molar number of the alkyl hydroxyalkyl group substituted for the hydroxyalkyl cellulose is 2.0 to 3.3.         For example, the hydraulic composition of claim 2, wherein the molar number of the alkylhydroxyalkyl group substituted by the aforementioned hydroxyalkyl cellulose is 2.0 to 3.3.         For example, the hydraulic composition of claim 3, wherein the molar number of the alkyl hydroxyalkyl group substituted for the hydroxyalkyl cellulose is 2.0 to 3.3.         For example, the hydraulic composition according to claim 4, wherein the molar number of the alkyl hydroxyalkyl group substituted by the aforementioned hydroxyalkyl cellulose is 2.0 to 3.3.         The hydraulic composition according to claim 1, wherein the hydroxyalkyl cellulose is hydroxyethyl cellulose.         For example, the hydraulic composition of claim 1, wherein the 2 mass% aqueous solution of the aforementioned water-soluble cellulose ether has a viscosity at 20 ° C. of 5000 mPa or more. s, and the viscosity of its 1% by mass aqueous solution at 20 ° C is less than or equal to 30,000 mPa. s.         For example, the hydraulic composition of claim 1, wherein the bonding material contains the cement in a proportion of 10 to 95% by mass, and a substance selected from the foregoing fly ash and the blast furnace slag powder in a proportion of 5 to 90% by mass, The total amount of the cement and the material selected from the fly ash and the blast furnace slag powder is 100% by mass.         The hydraulic composition according to claim 1, wherein the water-soluble cellulose ether is contained in a proportion of 0.01 to 0.20 parts by mass with respect to 100 parts by mass of the aforementioned binding material.         For example, the hydraulic composition of claim 1 further contains aggregate.         For example, the hydraulic composition of claim 1, wherein the mass ratio of water / bonding material is 0.35 to 0.65.