JP4920232B2 - Concrete production method - Google Patents

Description

  The present invention relates to a method for producing concrete with high fluidity and a method for constructing concrete.

  In recent years, reinforced concrete construction sites have been concerned about ensuring the quality of concrete structures due to overcrowding due to restrictions on the cross-section of members and lack of skilled engineers. In order to ensure the construction quality of concrete structures, there are many cases where concrete with high fluidity and filling properties is desired at the construction site.

  On the other hand, in the construction of concrete structures, it is common to produce concrete in a ready-mixed concrete factory (so-called ready-mixed concrete), transport to a construction site with a mixer car, and place it. When concrete with high fluidity is produced in a ready-mixed concrete factory and placed on site, physical property management is more stringent than ordinary concrete in order to cope with material separation and change in fluidity over time after production. Need to do. Also, since the factory manufactures concrete with special specifications, it affects the productivity of the factory as a whole.

  However, if a fluidizing agent is added to ready-mixed concrete to simply increase the fluidity, it becomes difficult to separate the material and use it as concrete. In Patent Document 1, a ready-mixed concrete (ordinary concrete) described in JIS A-5308 is mixed with a cement dispersant and a non-separable admixture so that the material separation resistance is extremely high without changing the concrete mix. Discloses a method for producing a high-fluidity concrete having a slump flow of 35 cm or more.

Patent Document 2 discloses a hydraulic composition having a slump flow value of 50 to 70 cm obtained by adding a specific polysaccharide derivative and a high-performance water reducing agent.
JP-A-8-52730 Japanese Patent No. 3260100

  If it is possible to increase the fluidity of the concrete at the construction site using ordinary concrete, it will be possible to improve the workability and ensure the quality without changing the specifications of the raw concrete, so it will be adopted at many sites is expected. However, the technology of Patent Document 1 has not yet been widely spread, and further improvement in performance is desired. That is, in order to obtain a concrete having high fluidity and excellent material separation resistance by using hydroxyethyl cellulose described as the non-separable admixture of Patent Document 1, it is necessary to add a large amount of hydroxyethyl cellulose and the like. is there. However, when a large amount of hydroxyethyl cellulose is blended, the hydration reaction of hydraulic powder such as cement may be suppressed, and curing delay may occur. Moreover, performance improvement is desired also in terms of breathing properties and fluidity retention.

  An object of the present invention is to provide a method for producing concrete having excellent fluidity from ordinary concrete with less delay in curing, excellent breathing resistance and fluid retention.

The present invention relates to a method for producing concrete having the following steps (I) and (II).
Step (I): Water (W), hydraulic powder (C), fine aggregate (S), coarse aggregate (G) and admixture (P) are kneaded so that W / C (weight ratio) is Step of preparing hydraulic composition (I) that is 40 to 65% Step (II): In hydraulic composition (I), some or all of the hydroxyl groups of the polysaccharide or its alkylated or hydroxyalkylated derivative 1 selected from the group consisting of a hydrophobic substituent (A) having a hydrocarbon chain having 8 to 40 carbon atoms, a sulfonic acid group, a carboxyl group, a phosphoric acid group, a sulfuric acid ester group, and salts thereof Slump flow value defined in JIS A 1150, which is a step of adding a polysaccharide derivative (Q) substituted with an ionic hydrophilic substituent (B) having a group of at least species and a water reducing agent (R). For preparing a hydraulic composition (II) having a diameter of 35 to 70 cm

  Further, the present invention performs the steps (I) and (II) of the production method of the present invention, and after the step (II), starts placing the hydraulic composition (II) within 90 minutes. It relates to a concrete construction method.

  ADVANTAGE OF THE INVENTION According to this invention, the concrete which is less hardened | cured delay, excellent in breathing property and fluid retainability, and excellent in fluidity | liquidity can be manufactured from normal concrete.

<Process (I)>
In the step (I) of the present invention, water (W), hydraulic powder (C), fine aggregate (S), coarse aggregate (G) and admixture (P) are kneaded, and W / C (weight) This is a step of preparing a hydraulic composition (I) having a ratio of 40 to 65%. Examples of the hydraulic composition (I) include ordinary cement described in JIS A-5308. W / C is calculated by [weight of water (W) / weight of hydraulic powder (C)] × 100 (% by weight).

  As the water (W), those usually used can be used, and examples thereof include tap water.

  The hydraulic powder (C) is a powder having physical properties that hardens by a hydration reaction, and examples thereof include cement and gypsum. Cement is preferable, and blast furnace slag, fly ash, silica fume and the like may be added thereto.

  Examples of the fine aggregate (S) include those defined in JIS A0203-2302. Fine aggregates include rivers, land, mountains, sea, lime sand, quartz sand and crushed sand, blast furnace slag fine aggregates, ferronickel slag fine aggregates, lightweight fine aggregates (artificial and natural) and recycled fine aggregates. Etc.

  Examples of the coarse aggregate (G) include those defined in JIS A0203-2303. For example, as coarse aggregate, river, land, mountain, sea, lime gravel, crushed stone, blast furnace slag coarse aggregate, ferronickel slag coarse aggregate, lightweight coarse aggregate (artificial and natural), recycled coarse aggregate, etc. Is mentioned.

  Examples of the admixture (P) include water reducing agents, and specific examples include lignin sulfonate and derivatives thereof, oxycarboxylates, polyol derivatives, and water reducing agents (R) described later. The admixture (P) is preferably used in an amount of 0.01 to 1.0 part by weight, more preferably 0.05 to 0.5 part by weight, based on 100 parts by weight of the hydraulic powder (C).

  In step (I), these materials are blended so that W / C (weight ratio) is 40 to 65%, more preferably 50 to 60%, and kneaded to prepare hydraulic composition (I). To do. In this case, the blending ratio of each material is preferably a blend obtained in accordance with the Japan Society of Civil Engineers Concrete Standard Specification and Building Construction Standard Specification or JIS A5308 “Ready Mixed Concrete”.

  For the kneading, a kneader such as a twin screw mixer can be used. For example, after kneading hydraulic powder (C), fine aggregate (S), and coarse aggregate (G), kneading water is added in which water (W) and admixture (P) are mixed in advance. And kneading.

  The hydraulic composition (I) obtained by kneading preferably has a slump (JIS A 1101) of 8 to 18 cm, preferably a slump flow (JIS A1150) of 20 to 30 cm, and has an air volume (JIS A 1128) is preferably 3.5 to 6.0%.

<Process (II)>
In the step (II), the hydraulic composition (I) obtained in the step (I) includes a polysaccharide or an alkylated or hydroxyalkylated derivative thereof in which some or all of the hydroxyl atoms have 8 to 8 carbon atoms. Ionicity having a hydrophobic substituent (A) having 40 hydrocarbon chains and one or more groups selected from the group consisting of sulfonic acid groups, carboxyl groups, phosphoric acid groups, sulfuric acid ester groups and salts thereof A hydraulic property in which a polysaccharide derivative (Q) substituted with a hydrophilic substituent (B) and a water reducing agent (R) are added, and the slump flow value specified in JIS A 1150 is 35 to 70 cm. This is a step for preparing the composition (II).

  In the polysaccharide derivative (Q) used in the present invention, a part or all of the hydroxyl groups of the polysaccharide or its alkylated or hydroxyalkylated derivative have a hydrophobic substituent (A) and an ionic hydrophilic substituent. Substituted with (B). The hydrophobic substituent (A) has a hydrocarbon chain having 8 to 40 carbon atoms, more specifically, this is a straight chain having 8 to 40 carbon atoms, preferably 12 to 36 carbon atoms, more preferably 16 to 24 carbon atoms. An alkyl glyceryl ether group having a chain or branched chain alkyl group, or an alkenyl glyceryl ether group having a straight chain or branched chain alkenyl group having the same carbon number, or a hydroxyl group may be substituted; A linear or branched alkyl group, alkenyl group or acyl group having 8 to 40 carbon atoms, preferably 12 to 36 carbon atoms, more preferably 16 to 24 carbon atoms, which may be inserted. From the viewpoint of ease of production and other points, an alkyl glyceryl ether group, a long-chain alkyl group, and a 2-hydroxy long-chain alkyl group are preferable, and an alkyl glyceryl ether group is particularly preferable. Here, the alkyl glyceryl ether group refers to the structure of the remaining portion excluding one hydroxyl group of the alkyl glyceryl ether. More specific examples of the alkyl glyceryl ether group include 2-hydroxy-3-alkoxypropyl group, 2-alkoxy-1- (hydroxymethyl) ethyl group, 2-hydroxy-3-alkenyloxypropyl group, 2-alkenyloxy- A 1- (hydroxymethyl) ethyl group may be mentioned. These hydrophobic substituents (A) may be substituted with a hydroxyl atom of a hydroxyethyl group or a hydroxypropyl group bonded to a polysaccharide molecule.

  The ionic hydrophilic substituent (B) is a substituent having one or more groups selected from the group consisting of a sulfonic acid group, a carboxyl group, a phosphoric acid group, and a sulfate group, and these form a salt. It may be. Specifically, a C1-C5 sulfoalkyl group or a salt thereof, which may be substituted by a hydroxyl group, a carboxyalkyl group or a salt thereof, an alkyl phosphate group or a salt thereof, a sulfate ester alkyl group or a salt thereof, etc. Is mentioned. Preferably, it is a C1-C5 sulfoalkyl group which the hydroxyl group may substitute. More specifically, a 2-sulfoethyl group, a 3-sulfopropyl group, a 3-sulfo-2-hydroxypropyl group, a 2-sulfo-1- (hydroxymethyl) ethyl group, and the like can be mentioned. It may be a salt with alkali metals such as Na and K, alkaline earth metals such as Ca and Mg, organic cation groups such as amines, ammonium ions and the like.

These polysaccharide derivatives (Q) according to the present invention vary in solubility and viscosity increase in kneaded water depending on the degree of substitution with the hydrophobic substituent (A) and the ionic hydrophilic substituent (B). That is, by making the substitution degree of the hydrophobic substituent (A) and the ionic hydrophilic substituent (B) within a preferable range, appropriate solubility and thickening in the kneaded water can be obtained, and therefore The hydraulic composition (I) can be given fluidity as well as excellent separation resistance. From this point of view, the degree of substitution with the hydrophobic substituent (A) is 0.0001 to 1 and more preferably 0.0005 to 0.01 per unit of the constituent monosaccharide residue. The degree of substitution with the ionic polar substituent (B) is 0.001-2 per unit of constituent monosaccharide residue, and more preferably 0.01-1. Particularly preferred substitution degrees are 0.0007 to 0.005 for the hydrophobic substituent (A) and 0.02 to 0.15 for the ionic hydrophilic substituent (B).
In the present invention, the polysaccharides are cellulose; starch; rhizome polysaccharides such as konjac mannan and troloioi sticks; sap polysaccharides such as gum arabic, tragacanth and karaya gum; seed polysaccharides such as locust bean gum, guar gum and tamarind gum; agar And seaweed polysaccharides such as carrageenan and algin; animal polysaccharides such as chitin, chitosan heparin and chondroitin sulfate; and microbial polysaccharides such as dextran and xanthan gum. Examples of the substituted ionic group include anionic group-substituted products such as carboxymethylcellulose, cellulose sulfate, cellulose phosphate, and cellulose phosphite. Examples of the alkylated or hydroxyalkylated derivatives of polysaccharides include hydroxyethyl cellulose, hydroxyethyl guar gum, hydroxyethyl starch, methyl cellulose, methyl guar gum, methyl starch, ethyl cellulose, ethyl guar gum, ethyl starch, hydroxypropyl cellulose, hydroxypropyl guar gum, hydroxypropyl Starch, hydroxyethyl methyl cellulose, hydroxyethyl methyl guar gum, hydroxyethyl methyl starch, hydroxypropyl methyl cellulose, hydroxypropyl methyl guar gum, hydroxypropyl methyl starch, etc., among others, cellulose, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose Cellulose and its derivatives are preferable. Further, the substituents such as methyl group, ethyl group, hydroxyethyl group, hydroxypropyl group and the like of these polysaccharides may be substituted with a single substituent or may be substituted with a plurality of substituents. The substitution degree per constituent monosaccharide residue is preferably 0.1 to 5, particularly 0.5 to 3. When the substituent is an alkyleneoxy group, the degree of substitution, that is, the number of moles added per constituent monosaccharide residue is preferably 0.1 to 10, particularly 0.5 to 5. Further, these polysaccharides or derivatives thereof have a weight average molecular weight of 10,000 to 10,000,000, particularly preferably 100,000 to 5,000,000.

  In the polysaccharide derivative (Q) according to the present invention, the hydrogen atom of the hydroxyl group of the polysaccharide or its alkylated or hydroxyalkylated derivative is partially hydrophobized (introduction of a hydrophobic substituent (A)) or hydrophilized (ionic). After the introduction of the hydrophilic substituent (B), it is obtained by hydrophilizing or hydrophobizing part or all of the remaining hydroxyl groups, respectively, or by simultaneously hydrophobizing and hydrophilizing.

  The introduction of substituents can be performed as follows as an example. That is, in the presence of alkali, a polysaccharide or a derivative thereof is an alkyl or alkenyl glycidyl ether having 8 to 40 alkyl carbon atoms, a linear or branched saturated or unsaturated alkyl epoxide having 8 to 40 carbon atoms, Hydrophobic substituent (A) is introduced by reacting with halide, halohydrin, acyl halide, or ester or carboxylic anhydride having an acyl group having 8 to 40 carbon atoms, and vinylsulfonic acid in the presence of alkali. Or it can carry out by making it react with the C1-C5 haloalkanesulfonic acid which the hydroxyl group may substitute, halocarboxylic acid, halophosphoric acid ester, halosulfuric acid ester, or those salts.

  The addition amount of the polysaccharide derivative (Q) in the step (II) may be appropriately determined according to the target degree of thickening. For example, the amount of hydraulic powder (C) 100 used in the hydraulic composition (I) Preferably 0.0001 to 3 parts by weight, more preferably 0.001 to 0.5 parts by weight, particularly preferably 0.01 to 0.1 parts by weight with respect to parts by weight.

  As the water reducing agent (R) used in the step (II), a concrete chemical admixture having a water reduction rate of 18% or more specified in JIS A 6204 is preferably used. Specifically, naphthalene, melamine, phenol, Examples thereof include formaldehyde condensates of one or more compounds selected from the group of methylolated products and sulfonated products of either urea or aniline. For example, naphthalene sulfonic acid metal salt formaldehyde condensate [for example, Mighty 150 manufactured by Kao Corporation], melamine sulfonic acid metal salt formaldehyde condensate [for example, Mighty 150-V2 manufactured by Kao Corporation], phenol sulfonic acid formaldehyde compound (patent no. 1097647), phenol / sulfanilic acid formaldehyde cocondensates (compounds described in JP-A-1-113419, etc.) and the like. As still another example, one or two selected from the group consisting of an ethylenically unsaturated monocarboxylic acid, an alkylene oxide adduct or derivative thereof, and an ethylenically unsaturated dicarboxylic acid, an alkylene oxide adduct or derivative thereof Polymers or copolymers obtained by polymerizing monomers containing at least species (compounds described in JP-B-2-7901, JP-A-3-75252, JP-B-2-8983, etc.) ).

  Furthermore, the water reducing agent (R) used in the present invention is selected from monomers represented by the following general formula (1) and compounds represented by the following general formulas (2) and (3). A water-soluble vinyl copolymer having an oxyalkylene group obtained by polymerizing one or more monomers is particularly preferably used (for example, Mighty 3000 manufactured by Kao Corporation). Such a high-performance water reducing agent is described, for example, in JP-A-7-223852.

[Where:
R ₁ and R ₂ : hydrogen atom or methyl group
m1: Number from 0 to 2
AO: C2-C3 oxyalkylene group n: Average addition mole number, 2-300 number X: Represents a hydrogen atom or C1-C3 alkyl group. ]

[Where:
R ₃ , R ₄ , R ₅ : hydrogen atom, methyl group or (CH ₂ ) _m2 COOM ₂
R ₆ : hydrogen atom or methyl group
M ₁ , M ₂ , Y: hydrogen atom, alkali metal, alkaline earth metal, ammonium, alkylammonium or substituted alkylammonium
m2 represents a number from 0 to 2. ]

  In the copolymer used as the preferred high performance water reducing agent, the monomer represented by the general formula (1) includes methoxy polyethylene glycol, methoxy polyethylene polypropylene glycol, ethoxy polyethylene glycol, ethoxy polyethylene polypropylene glycol, propoxy Deesterification (oxidation) of acrylic acid, methacrylic acid or fatty acid, esterification product of one-end alkyl-blocked polyalkylene glycol such as polyethylene glycol and propoxy polyethylene polypropylene glycol and dehydrogenation (oxidation) reaction product of acrylic acid, methacrylic acid or fatty acid ) An ethylene oxide or propylene oxide adduct is used for the reaction product. As the repeating unit of the polyalkylene glycol monomer, any of ethylene oxide alone, propylene oxide alone, random, block, and alternate addition of ethylene oxide and propylene oxide can be used. When the average added mole number of the repeating unit of the polyalkylene glycol monomer is 110 to 300 as described in JP-A-7-223852, the curing delay is shortened, high fluidity, high filling property, This is particularly preferable in terms of high separation reduction.

  As the compound represented by the general formula (2), as an unsaturated monocarboxylic acid monomer, acrylic acid, methacrylic acid, crotonic acid, or an alkali metal salt, alkaline earth metal salt, ammonium salt thereof, Examples thereof include amine salts and substituted amine salts. Further, as unsaturated dicarboxylic acid monomers, maleic anhydride, maleic acid, itaconic anhydride, itaconic acid, citraconic anhydride, citraconic acid, fumaric acid, or alkali metal salts, alkaline earth metal salts, ammonium thereof And salts, amine salts, and substituted amine salts.

  Examples of the compound represented by the general formula (3) include allyl sulfonic acid, methallyl sulfonic acid, or alkali metal salts, alkaline earth metal salts, ammonium salts, amine salts, and substituted amine salts thereof. .

  The amount of the water reducing agent (R) added in the step (II) can be appropriately determined according to the desired fluidity, but is preferably 0.01 to 1 with respect to 100 parts by weight of the hydraulic powder (C). Part by weight, more preferably 0.05 to 0.5 part by weight.

  The polysaccharide derivative (Q) and the water reducing agent (R) in the step (II) can be added to the hydraulic composition (I) in either an aqueous solution or a powder state. Further, the polysaccharide derivative (Q) and the water reducing agent (R) may be mixed in advance and the mixture may be added. Furthermore, either the method of adding each of the polysaccharide derivative (Q) and the water reducing agent (R) or the mixture in a whole amount at a time, or the method of adding in several divided portions can be employed.

  The hydraulic composition (II) is obtained by adding the polysaccharide derivative (Q) and the water reducing agent (R) to the hydraulic composition (I) and then kneading. For kneading, a kneader such as a twin-screw mixer or a kneading device for a mixer truck can be used.

  The hydraulic composition (II) has a slump flow value specified in JIS A 1150 in the range of 35 to 70 cm, more preferably 38 to 50 cm.

  Further, the hydraulic composition (II) preferably has a slump (JIS A 1101) of 22 to 25 cm. Further, the air amount (JIS A 1128) is preferably 3.5 to 6%. The slump (JIS A 1101) after 30 minutes of kneading is preferably 22 to 25 cm. The strength after 28 days (JIS A 1108) is preferably a predetermined strength.

  In the production method of the present invention, it is preferable to perform the step (II) at the concrete construction site using the ready-mixed concrete produced in the ready-mixed concrete factory as the hydraulic composition (I). By using ready-mixed concrete, concrete having stable physical properties can be obtained as the hydraulic composition (I). Even if there is a transportation process using a mixer truck or the like between the process (I) and the process (II), the physical properties of the concrete during transportation may be controlled under the condition of ordinary cement, and no special management is required. Furthermore, by performing the step (II) at the construction site, it is possible to cope with changes in the physical properties of the concrete during transportation by finely adjusting the addition amounts of the polysaccharide derivative (Q) and the water reducing agent (R). Moreover, since the concrete pouring can be started immediately after the step (II), it becomes easy to maintain the fluidity of the highly fluid concrete. From the viewpoint of maintaining fluidity, the placement of the hydraulic composition (II) is preferably started within 90 minutes after the step (II). In addition, although the process (II) can be performed immediately after the completion of the process (I), as described above, after taking an appropriate interval (30 minutes, etc.) in consideration of transportation by a mixer truck, etc. It is preferable to perform step (II) on site. Moreover, it is preferable that the completion | finish of casting is less than 210 minutes after process (II).

Examples 1-2 and Comparative Example 1
In Formula 1 of Table 1, cement (C), fine aggregate (S) and coarse aggregate (G) were charged into a 40 liter forced biaxial mixer and then kneaded at 20 ° C. for 10 seconds. Next, kneading water with concrete admixture added to tap water (W) was added and kneaded for 90 seconds to prepare hydraulic composition (I) [step (I)]. The concrete admixture is a lignin sulfonic acid compound polyol composite (product name: Pozoris No. 70, manufactured by Pozzolith Co., Ltd.), and may have a predetermined air amount using Mighty AE-02 as an air amount adjusting agent. Added to.

  The obtained hydraulic composition (I) was discharged into a kneading boat and allowed to stand for 30 minutes assuming a concrete transportation time. Thereafter, the hydraulic composition (I) was transferred to a tilted barrel mixer, the components shown in Table 2 were added in the amounts shown in Table 2, and kneaded for 60 seconds to obtain a hydraulic composition (II) [Step (II)]. .

  For the hydraulic compositions (I) and (II), the slump value, slump flow value, air amount, and concrete temperature were evaluated over time. Moreover, the amount of breathing was measured as separation resistance. Each evaluation was performed based on the following.

・ Slump value: JIS A 1101
・ Slump flow value: JIS A 1150
・ Air volume: JIS A 1128
・ Concrete temperature: Visible with thermometer ・ Breathing amount: JIS A 1123

The materials used in Table 1 are as follows.
-Water (W): Tap water-Cement (C): Ordinary Portland cement (1: 1 mixture of ordinary Portland cement manufactured by Taiheiyo Cement Co., Ltd. and ordinary Portland cement manufactured by Sumitomo Osaka Cement Co., Ltd.), density 3.16 g / cm ³
・ Fine aggregate (S): Kimitsu mountain sand (density 2.60g / cm ³ , coarse grain ratio 2.63)
・ Coarse aggregate (G): Torigatayama lime crushed stone (density 2.70 g / cm ³ , coarse grain ratio 7.03, maximum dimension 20 mm)

The components in Table 2 are as follows.
・ Concrete admixture: AE water reducing agent, lignin sulfonic acid compound polyol composite (Pozoris Co., Ltd., product name: Pozoris No. 70)
・ Comparative water reducing agent: Leopak S100, manufactured by Lion Corporation ・ Comparison thickener: Leopak V2000, manufactured by Lion Corporation ・ Water reducing agent 1: Mighty 3000S, manufactured by Kao Corporation

Polysaccharide derivative 1: obtained by the following synthesis example <Synthesis example>
(1) In a 1000 ml glass separable reaction vessel equipped with a stirrer, thermometer and cooling tube, 50 g of hydroxyethyl cellulose having a weight average molecular weight of about 800,000 and a hydroxyethyl group substitution degree of 1.8 (HEC-QP4400, manufactured by Union Carbide) Then, 400 g of 88% isopropyl alcohol and 3.5 g of 48% aqueous sodium hydroxide solution were added to prepare a slurry, which was stirred at room temperature for 30 minutes in a nitrogen atmosphere. To this, 4.0 g of stearyl glycidyl ether was added and reacted at 80 ° C. for 7 hours for hydrophobization. After completion of the hydrophobic reaction, the reaction solution was neutralized with acetic acid, and the reaction product was filtered off. The reaction product was washed twice with 500 g of 80% acetone and then twice with 500 g of acetone, and dried under reduced pressure at 70 ° C. for one day to obtain 49.4 g of a hydrophobized hydroxyethylcellulose derivative.

(2) In a 500 ml glass separable reaction vessel equipped with a stirrer, thermometer and cooling tube, 10.0 g of the hydrophobized hydroxyethylcellulose derivative obtained in (1), 80.0 g of isopropyl alcohol and 0.33 g of 48% sodium hydroxide aqueous solution Was prepared to prepare a slurry, and the mixture was stirred at room temperature for 30 minutes under a nitrogen stream. A mixture of 6.4 g of sodium 3-chloro-2-hydroxypropanesulfonate, 2.7 g of 48% aqueous sodium hydroxide and 20.0 g of water was added to the reaction solution, and sulfonation was performed at 50 ° C. for 9 hours. After completion of the reaction, the reaction solution was neutralized with acetic acid and the product was filtered off. The product was washed three times with 500 g of 80% acetone (20% water) and then twice with 500 g of acetone, and then dried at 70 ° C. for one day under reduced pressure to obtain stearyl glyceryl ether groups and 3-sulfo-2-hydroxypropyl groups. 7.2 g of a substituted hydroxyethylcellulose derivative (polysaccharide derivative 1) was obtained.

  The degree of substitution of the stearyl glyceryl ether group of the obtained hydroxyethyl cellulose derivative was 0.008, and the degree of substitution of the 3-sulfo-2-hydroxypropyl group was 0.15.

  The degree of substitution of the hydrophobic substituent (A) of the polysaccharide derivative (Q) is as follows when the substituent (A) as in the above synthesis does not have an oxo group at the 1-position (when ether is formed): Quantified by the Zeisel method (DGAnderson, Anal. Chem., 43, 894 (1971)), when the substituent (A) has an oxo group at the 1-position (when an ester is formed), After being hydrolyzed with acid and neutralized, it was esterified with diazomethane and quantified by gas chromatography. The degree of substitution of the substituent (B) was determined by colloid titration method. In other words, a thickener solution with a known concentration was prepared, and an N / 200 methyl glycol chitosan solution with a known weight (manufactured by Wako Pure Chemical Industries, Ltd., for colloid titration) was added to the solution while stirring, and a toluidine blue indicator solution (Japanese sum) A few drops of Koyo Pure Chemical Co., Ltd. (for colloid titration) were added. This was back titrated with an N / 400 potassium potassium sulfate solution (manufactured by Wako Pure Chemical Industries, Ltd., for colloid titration), and the degree of substitution was calculated from the titration amount. The “degree of substitution” indicates the average number of substituents per constituent monosaccharide residue.

  Moreover, when the setting time was measured in accordance with JIS A 1147, the first time in Example 1 was +54 minutes and the last time was +59 minutes, and in Comparative Example 1, the first time was +179 minutes and the last time was +201 minutes. It was confirmed that the concrete obtained by the production method of the present invention has less curing delay.

Claims (6)

The manufacturing method of the concrete which has the following process (I) and process (II).
Step (I): Water (W), hydraulic powder (C), fine aggregate (S), coarse aggregate (G) and admixture (P) are kneaded so that W / C (weight ratio) is Process for preparing ready-mixed concrete (I) having a slump flow value of 20 to 30 cm as specified in JIS A 1150 at 40 to 65% . Process (II): Ready-mixed concrete (I) with polysaccharides at the concrete construction site. Or a hydrophobic substituent (A) in which part or all of the hydroxyl groups of the alkylated or hydroxyalkylated derivative have a hydrocarbon chain having 8 to 40 carbon atoms, a sulfonic acid group, a carboxyl group, and phosphoric acid A polysaccharide derivative (Q) substituted with an ionic hydrophilic substituent (B) having at least one group selected from the group consisting of a group, a sulfate ester group and a salt thereof; and a water reducing agent (R); And add slan as specified in JIS A 1150 Process flow value to prepare concrete (II) is a. 35 to 50 cm The method for producing concrete according to claim 1, wherein the admixture (P) is a water reducing agent comprising lignin sulfonate or a derivative thereof . The method for producing concrete according to claim 1 or 2, wherein the placing of concrete (II) is started within 90 minutes after step (II). Furthermore, the manufacturing method of concrete in any one of Claims 1-3 which has the process of transferring ready mixed concrete (I) with a mixer truck between process (I) and process (II). A polysaccharide derivative (Q) and water reducing agent (R), in their sum, hydraulic powder (C) 100 parts by weight of either one of claims 1-4 is added 0.001 to 0.5 parts by weight The manufacturing method of the concrete as described. A concrete construction method, wherein the steps (I) and (II) of the production method according to any one of claims 1 to 5 are performed, and after the step (II), the placement of the concrete (II) is started within 90 minutes. .