CONCRETE COMPOSITION AND METHOD FOR PREPARING THE SAME

Abstract

A concrete composition made up of a binder, water, a fine aggregate, a coarse aggregate, and a one-component, in which a water/binder ratio is 30 to 70% by mass, a slump flow value is 35 to 75 cm, and a one-component admixture using four specific components and water is contained in a proportion of 0.5 to 3.0 parts by mass relative to 100 parts by mass of the binder.

Claims

1. A concrete composition comprising: a binder; water; fine aggregate; coarse aggregate; and a one-component admixture, wherein a water/binder ratio is 30 to 70% by mass, a slump flow value is 35 to 75 cm, and a one-component admixture is contained in a proportion of 0.5 to 3.0 parts by mass relative to 100 parts by mass of a binder, wherein the one-component admixture being a one-component admixture that contains a component A, a component B, a component C, and a component D and has an ionic strength, derived from the component A, of 0.02 to 0.8, and wherein the component A being a polycarboxylic acid-based water reducing agent made up of a copolymer of an unsaturated monocarboxylic acid monomer and/or an unsaturated dicarboxylic acid monomer and/or salts of these monomers and an unsaturated monomer that is copolymerizable with these monomers and salts and has a polyoxyalkylene group composed of 1 to 300 oxyalkylene units having 2 to 4 carbon atoms in a molecule and/or a salt of the copolymer, the component B being water-soluble cellulose ether, the component C being gums, and the component D being a defoamer.

2. The concrete composition according to claim 1, wherein the one-component admixture contains the component A in a proportion of 15 to 50% by mass.

3. The concrete composition according to claim 1, wherein the one-component admixture has an ionic strength, derived from the component A, of 0.05 to less than 0.5.

4. The concrete composition according to claim 1, wherein the component B is at least one selected from alkyl cellulose, hydroxyalkyl cellulose, and hydroxyalkyl alkyl cellulose.

5. The concrete composition according to claim 1, wherein the component C is at least one selected from diutan gum, welan gum, xanthan gum, and gellan gum.

6. A method for preparing the concrete composition according to claim 1, using a binder, water, fine aggregate, coarse aggregate, and a one-component admixture, wherein a one-component admixture prepared by adding powdered gums and/or an aqueous solution of the gums as the component C is used when the ionic strength derived from the component A is less than 0.02 to 0.5, and wherein the one-component admixture prepared by adding the aqueous solution of the gums as the component C is used when the ionic strength derived from the component A is 0.5 to 0.8.

Description

EXAMPLE

Test Division 1 (Synthesis of Component a as Polycarboxylic Acid-Based Water Reducing Agent)

[0066] Synthesis of Polycarboxylic Acid-Based Water Reducing Agent (a-4)

[0067] A reaction vessel was charged with 1400 g of water, 1100 g of methoxypoly (45 mol) ethylene glycol monomethacrylate, 104 g of methacrylic acid, 24 g of thioglycerol as a chain transfer agent, and 50 g of a 30% aqueous solution of sodium hydroxide, the atmosphere in the reaction vessel is replaced with nitrogen, and thereafter the mixture was gradually warmed while stirring. The temperature of the reaction system was kept at 60 C. in a warm water bath, and 240 g of a 0.025% aqueous solution of hydrogen peroxide was added to initiate radical polymerization reaction. After the lapse of 2 hours, 60 g of a 0.025% aqueous solution of hydrogen peroxide was further added, and the radical polymerization reaction was continued for 6 hours. To the obtained copolymer, 3,182 g of water and 121 g of a 30% aqueous solution of sodium hydroxide were added to obtain a 20% aqueous solution of the component A (a-4). The component A (a-4) was analyzed to find that its mass average molecular weight was 41,400 (GPC method, calculated as pullulan).

[0068] Synthesis of Component a (a-6), (a-8), and (a-9)

[0069] The component A (a-6), (a-8), and (a-9) listed in Table 1 are synthesized in the same manner as the component A (a-4) to obtain aqueous solutions of (a-6), (a-8), and (a-9).

[0070] Synthesis of Component A (a-7)

[0071] The reaction vessel was charged with -allyl--methoxy-poly (100 mol) ethylene glycol poly (3 mol) propylene glycol and maleic anhydride, the atmosphere in a reaction vessel is replaced with nitrogen, and thereafter the mixture was gradually warmed while stirring, to be dissolved uniformly. The temperature of the reaction system was kept at 80 C. in a warm water bath, and azobisisobutyronitrile was added to initiate radical polymerization reaction. After the lapse of 2 hours, azobisisobutyronitrile was further added, and the radical polymerization reaction was continued for 2 hours. To the obtained copolymer, water and a 30% aqueous solution of sodium hydroxide were added to obtain an aqueous solution of the component A (a-7). The component A (a-7) was analyzed to find that its mass average molecular weight was 69,200 (GPC method, calculated as pullulan).

[0072] Synthesis of Component A (a-10)

[0073] The reaction vessel was charged with water and 3-methyl-3-buten-1-ol poly (80 mol) ethylene glycol adduct, the atmosphere in the reaction vessel was replaced with nitrogen, and thereafter, the mixture was gradually warmed while stirred. The temperature of the reaction system was kept at 70 C. in a warm water bath to stabilize the temperature. Thereafter, acrylic acid was dropped over 3 hours. Simultaneously, an aqueous solution, in which thioglycollic acid and L-ascorbic acid were dissolved in water, and a 5% hydrogen peroxide solution were each dropped over 3 hours to initiate radical polymerization reaction After the lapse of 1 hour from the end of the dropping, water and a 30% aqueous solution of sodium hydroxide were added to the obtained copolymer to obtain an aqueous solution of the component A (a-10). The component A (a-10) was analyzed to find that its mass average molecular weight was 71,300 (GPC method, in terms of pullulan).

[0074] Synthesis of Component A (ar-1) and (ar-2)

[0075] In the same manner as in the component A (a-4), aqueous solutions of the components A (ar-1) and (ar-2) listed in Table 1 were obtained.

[0076] The contents of the components A (a-1) to (a-10) and (ar-1) to (ar-3) synthesized above were summarized in Table 1. Each of the aqueous solutions of the components A (a-1) to (a-3) and (a-5) was prepared by diluting the aqueous solution of the component A (a-6) with water, and the aqueous solution of the component A (ar-3) was prepared by diluting the aqueous solution of the component A (ar-2) with water.

TABLE-US-00001 TABLE 1 Type of Type of monomer Mass average component A Monomer 1 Monomer 2 molecular weight a-1 methacrylic acid, methoxy-poly (9 mol) ethylene 31000 sodium methacrylate glycol monomethacrylate a-2 methacrylic acid, methoxy-poly (9 mol) ethylene 31000 sodium methacrylate glycol monomethacrylate a-3 methacrylic acid, methoxy-poly (9 mol) ethylene 31000 sodium methacrylate glycol monomethacrylate a-4 sodium methacrylate methoxy-poly (45 mol) ethylene 41400 glycol monomethacrylate a-5 methacrylic acid, methoxy-poly (9 mol) ethylene 31000 sodium methacrylate glycol monomethacrylate a-6 methacrylic acid, methoxy-poly (9 mol) ethylene 31000 sodium methacrylate glycol monomethacrylate a-7 maleic acid, -allyl--methoxy-poly (100 mol) ethylene glycol poly (3 mol) 69200 sodium maleate propylene glycol a-8 methacrylic acid methoxy-poly (23 mol) ethylene 38200 glycol monomethacrylate a-9 methacrylic acid, methoxy-poly (23 mol) ethylene 36800 sodium methacrylate glycol monomethacrylate a-10 acrylic acid, 3-methyl-3-buten-1-ol poly (80 mol) ethylene glycol adduct 71300 sodium acrylate ar-1 acrylic acid methoxy-poly (23 mol) ethylene 49900 glycol monomethacrylate, hydroxyethyl acrylate ar-2 sodium methacrylate methoxy-poly (23 mol) ethylene 32100 glycol monomethacrylate ar-3 sodium methacrylate methoxy-poly (23 mol) ethylene 32100 glycol monomethacrylate In Table 1, Aqueous solutions of a-1 to a-3 and a-5: The aqueous solution of a-6 was diluted with water. Aqueous solution of ar-3: The aqueous solution of ar-2 was diluted with water. Mass average molecular weight: GPC method, calculated as pullulan

Test Division 2 (Other Materials Used)

[0077] Component B used: The contents of the water-soluble cellulose ether were summarized in Table 2.

[0078] Component C used: The contents of the gums were summarized in Table 3.

[0079] Component D used: As a defoamer, SN-DEFOAMER 14-HP (oxyalkylene defoamer, trade name of SAN NOPCO LIMITED), abbreviated as d-1, was used.

TABLE-US-00002 TABLE 2 Name of water-soluble Aqueous solution No. cellulose ether DS MS viscosity (mPa .Math. s) b-1 hydroxypropyl methyl 1.8 0.19 30500 cellulose b-2 hydroxyethyl methyl 1.4 0.18 29800 cellulose b-3 hydroxyethyl cellulose 2.50 31300 In Table 2, Viscosity (mPa .Math. s): viscosity of 2% by mass aqueous solution at 20 C.

TABLE-US-00003 TABLE 3 No. Name of gums c-1 xanthan gum c-2 welan gum c-3 diutan gum c-4 gellan gum In Table 3, c-1: KELZAN (trade name of SANSHO Co., Ltd.) c-2: C P Kelco. K1A96 (trade name of C P Kelco Inc.) c-3: KELCO-CRETE DG-F (trade name of C P Kelco Inc.) c-4: KELCOGEL AFT (trade name of C P Kelco Inc.)

Test Division 3 (Preparation of One-Component Admixture)

[0080] (When Component C is Used in Powder)

[0081] Preparation of One-Component Admixture (e-1)

[0082] The component A, the component B, and the component C, listed in Tables 1 to 3, the component D, and the water were blended in proportions shown in Table 5 and mixed using a homomixer (HM-310, manufactured by AS ONE Corporation) at 5000 rpm for one minute to prepare a one-component admixture (e-1).

[0083] Preparation of One-Component Admixtures (e-2) to (e-7), (e-9) and (e-11)

[0084] One-component admixtures (e-2) to (e-7), (e-9), and (e-1) were prepared in the same manner as the one-component admixture (e-1).

[0085] Preparation of One-Component Admixtures (Er-1) to (Er-3), (Er-5), and (Er-6)

[0086] One-component admixtures (er-1) to (er-3), (er-5), and (er-6) were prepared in the same manner as the one-component admixture (e-1).

[0087] (WHEN component C is used in aqueous solution)

[0088] Preparation of One-Component Admixture (e-8)

[0089] Water and the component C were blended and mixed using the homomixer (HM-310, manufactured by AS ONE Corporation) at 5000 rpm for 1 minute to prepare a 2% aqueous solution of the component C. Thereafter, a one-component admixture (e-8) was prepared in the same manner as the one-component admixture (e-1).

[0090] Preparation of One-Component Admixture (e-10) and (e-12)

[0091] One-component admixtures (e-10) and (e-12) were prepared in the same manner as the one-component admixture (e-8).

[0092] Preparation of One-Component Admixtures (Er-4) and (Er-7)

[0093] One-component admixtures (er-4) and (er-7) were prepared in the same manner as the one-component admixture (e-4).

[0094] The contents of the one-component admixtures (e-1) to (e-12) and (er-1) to (er-7) prepared above were summarized in Table 5.

Test Division 4 (Calculation of Ionic Strength)

[0095] The ionic strength derived from the component A (a-4) in each one-component admixture prepared in Test Division 3 was calculated to be 0.206 according to Formula 1 described above. The calculation process and the like are shown in Table 4.

TABLE-US-00004 TABLE 4 Mass molar Type of ionic Ion species concentration Calculation formula Total of ion substance Type Charge (mol .Math. kg.sup.1) of Formula 1 Ionic strength strengths sodium sulfate sulfate ion 2 0.006 1/2 0.006 2.sup.2 0.012 0.206 sodium ion 1 0.012 1/2 0.012 1.sup.2 0.006 sodium methacrylate carboxylate ion 1 0.188 1/2 0.188 1.sup.2 0.094 sodium ion 1 0.188 1/2 0.188 1.sup.2 0.094

[0096] The ionic strengths derived from the components A (a-1) to (a-3), (a-5) to (a-10), and (ar-1) to (ar-3) were calculated in the same manner as the ionic strength derived from the component A (a-4). The calculation results of the ionic strength derived from the component A in each one-component admixture were summarized in Table 5.

TABLE-US-00005 TABLE 5 Concentration Ionic strength Mixed Composition of one-component admixture of component A in derived from Type of form of Component Component Component Component one-component component A in one-component component A B C D Water admixture one-component admixture C Type (g) Type (g) Type (g) Type (g) (g) (%) admixture e-1 powder a-1 160 b-1 5.000 c-2 1.500 d-1 1.500 840 15.9 0.111 e-2 powder a-2 200 b-1 7.500 c-1 0.625 d-1 1.875 800 19.8 0.139 e-3 powder a-3 225 b-1 7.031 c-3 3.094 d-1 1.125 775 22.2 0.156 e-4 powder a-4 200 b-1 12.500 c-2 5.000 d-1 2.500 800 19.6 0.206 e-5 powder a-5 300 b-1 9.375 c-3 2.813 d-1 2.813 700 29.6 0.207 e-6 powder a-6 360 b-1 10.125 c-3 3.375 d-1 4.500 640 35.4 0.248 e-7 powder a-7 200 b-2 12.500 c-1 3.750 d-1 3.750 800 19.6 0.459 e-8 aqueous a-7 200 b-2 14.000 c-1 3.000 d-1 3.000 800 19.6 0.459 solution e-9 powder a-8 200 b-3 7.500 c-4 0.625 d-1 1.875 800 19.8 0.041 e-10 aqueous a-9 200 b-1 18.000 c-1 10.000 d-1 12.000 800 19.2 0.559 solution e-11 powder a-9 200 b-1 14.000 c-1 10.000 d-1 16.000 800 19.2 0.559 e-12 aqueous a-10 200 b-2 5.625 c-3 1.875 d-1 2.500 800 19.8 0.762 solution er-1 powder a-3 225 b-1 12.500 d-1 2.500 775 22.2 0.156 er-2 powder a-3 225 b-1 12.500 c-2 5.000 775 22.1 0.155 er-3 powder ar-1 200 b-1 6.250 c-2 1.875 d-1 1.875 800 19.8 0.012 er-4 aqueous ar-2 200 b-1 11.250 c-1 3.750 d-1 5.000 800 19.6 0.836 solution er-5 powder ar-3 100 b-2 6.250 c-3 1.250 d-1 2.500 900 9.9 0.423 er-6 powder *1 410 b-1 14.000 c-1 10.000 d-1 16.000 590 39.4 er-7 aqueous *2 250 b-1 18.000 c-1 10.000 d-1 12.000 750 24.0 solution In Table 5, *1: alkylallyl sulfonate high condensate (high-performance water reducing agent for concrete, manufactured by TAKEMOTO OIL & FAT Co., Ltd, trade name: Paul Fine 510 AN) *2: nitrogen-containing sulfonate (high-performance water reducing agent for concrete, manufactured by TAKEMOTO OIL & FAT Co., Ltd, trade name: Paul Fine MF)

Test Division 5 (Stability Test of One-Component Admixture)

[0097] After 100 ml of the one-component admixture prepared in the test division 3 is collected in a measuring cylinder equipped with a stopper cock, the mixture was allowed to stand in an environment of 20 C. and 40 C., and the sedimentation volume of the water-soluble cellulose ether was measured. The sedimentation volume was evaluated as follows: the state of uniform dispersion without salting-out was taken as 100%, a transparent portion begins to appear gradually on the top of the measuring cylinder as time passes, and a scale of the measuring cylinder of the boundary between the transparent portion and a dispersed portion is read. For example, when the scale of the measuring cylinder of the boundary between the transparent portion and the dispersed portion after seven days is 90 ml, the sedimentation volume is 90%. The measurement results were summarized in Table 6.

TABLE-US-00006 TABLE 6 Type of Sedimentation volume (%) one-component 20 C. 40 C. admixture 7 days 14 days 28 days 7 days 14 days 28 days e-1 100 100 100 100 100 100 e-2 100 100 100 100 100 97 e-3 100 100 99 100 100 98 e-4 100 100 100 100 100 98 e-5 100 99 97 100 98 97 e-6 100 97 96 98 96 95 e-7 100 99 99 99 97 95 e-8 100 100 100 100 100 99 e-9 100 100 99 100 98 98 e-10 99 97 96 97 95 95 e-11 98 93 88 95 87 81 e-12 96 89 86 92 83 80 er-1 88 83 55 72 51 38 er-2 93 85 82 79 62 49 er-4 71 58 30 51 21 21 er-6 44 32 21 19 19 18 er-7 32 32 28 20 20 20

Test Division 6 (Stability Evaluation of One-Component Admixture)

[0098] Based on the measurement results of Table 6, the one-component admixtures of the respective examples were evaluated as follows, and the results were summarized in Table 7.

[0099] Evaluation of Stability

[0100] Evaluation was performed based on the following criteria.

[0101] : sedimentation volume (%) after standing for 28 days is 95 to 100%

[0102] : sedimentation volume (%) after standing for 28 days is 80 or more and less than 95%

[0103] x: sedimentation volume (%) after standing for 28 days is less than 80%

TABLE-US-00007 TABLE 7 Stability of one-component admixture Type of one-component (28 days) admixture 20 C. 40 C. e-1 e-2 e-3 e-4 e-5 e-6 e-7 e-8 e-9 e-10 e-11 e-12 er-1 x x er-2 x er-4 x x er-6 x x er-7 x x

Test Division 7 (Preparation of Concrete Composition)

Examples 1 to 19 and Comparative Examples 1 to 8

[0104] The contents were mixed for 90 seconds according to the contents listed in Table 8 and Table 9 by using a 60-liter forced twin screw mixer to prepare concrete compositions of the respective examples listed in Table 9. Note that the one-component admixture was prepared 10 times the amount used 28 days before the test and allowed to stand at 20 C., and the upper 70% or more supernatant was used unless otherwise stated. In addition, for the concrete composition of each example, the target air content was 4.5+1.0%, using an AE agent (trade name AE-300, manufactured by Takemoto Oil & Fats Co., Ltd.) and a defoamer (trade name AFK-2, manufactured by Takemoto Fat & Oil Co., Ltd.), and the target slump flow value was 605 cm.

TABLE-US-00008 TABLE 8 Unit amount of concrete composition Blend Fine aggregate rate (kg/m.sup.3) No. Water/binder ratio (%) (%) Water Binder 1 40 51 165 413 2 50 54 170 340 3 60 57 175 292 In Table 8, Fine aggregate: land sand from Oi River system (surface dry density 2.57 g/cm.sup.3) Coarse aggregate: crushed stone from Okazaki (surface dry density 2.66 g/cm.sup.3)

Test Division 8 (Physical Property Test of Prepared Concrete Composition)

[0105] The slump flow value immediately after mixing, the air content, and the bleeding rate were measured as follows for the prepared concrete compositions of each example, and the results were summarized in Table 9. [0106] Slump flow (cm): The concrete composition immediately after mixing was measured according to JIS-A1150. [0107] Air content (% by volume): The concrete composition immediately after mixing was measured according to JIS-A1128. [0108] Bleeding rate (%): A concrete composition was collected immediately after mixing and measured in accordance with JIS-A1123.

TABLE-US-00009 TABLE 9 One-component admixture Physical properties of concrete composition Additive Slump flow Air Bleeding Blend Type of amount value content rate Division No. binder Type (%) (cm) (%) (%) Example 1 1 f-1 e-2 1.20 61.5 4.6 2.1 2 1 f-2 e-3 1.15 60.0 4.4 1.9 3 1 f-1 e-10 1.35 62.0 4.5 2.7 4 2 f-1 e-1 1.60 59.5 4.4 2.9 5 2 f-1 e-2 1.25 58.5 4.2 3.0 6 2 f-1 e-3 1.10 59.0 4.4 2.9 7 2 f-1 e-4 1.25 60.0 4.6 2.5 8 2 f-1 e-5 0.85 59.5 4.4 2.8 9 2 f-1 e-6 0.70 58.5 4.2 2.9 10 2 f-1 e-7 1.30 60.5 4.7 2.4 11 2 f-2 e-7 1.15 60.5 4.7 2.7 12 2 f-1 e-8 1.30 60.0 4.5 2.6 13 2 f-1 e-9 2.30 62.0 4.3 3.2 14 2 f-1 e-10 1.55 59.0 4.5 2.1 15 2 f-1 e-11 1.45 63.5 4.8 2.8 16 2 f-1 e-12 1.15 59.5 4.6 3.8 17 3 f-1 e-8 1.40 59.0 4.4 5.4 18 3 f-2 e-10 1.50 62.0 4.4 5.0 19 3 f-1 e-12 1.25 61.0 4.5 6.2 Comparative 1 f-1 er-1 1.05 60.0 4.5 7.2 Example 1 2 1 f-1 *3 2.05 63.5 4.4 1.6 3 2 f-1 er-2 1.15 58.0 4.3 3.8 4 2 f-1 er-3 5.00 38.0 4.6 5 2 f-1 er-4 1.25 61.0 4.2 10.1 6 2 f-1 er-5 3.20 60.0 4.4 2.5 7 3 f-1 er-6 2.00 58.5 4.4 13.8 8 3 f-1 er-7 3.25 62.0 4.0 14.2 In Table 9, Blend No.: blend No. listed in Table 8 f-1: ordinary Portland cement f-2: blast furnace cement type B One-component admixtures: admixtures listed in Table 5 *3: The one-component admixture (er-1) was extracted from the bottom of the storage container and used. Additive amount: ratio of one-component admixture to 100 parts by mass of binder (parts by mass) Comparative Example 4: Even when 5.0% of the one-component admixture was added, the target fluidity could not be obtained.

Test Division 9 (Evaluation of Dispersion Performance of One-Component Admixture)

[0109] Based on the measurement results of Table 9, the dispersion performance of the one-component admixture was evaluated as follows, and the results were summarized in Table 10.

[0110] Evaluation of Dispersion Performance of One-Component Admixture

[0111] The concrete composition immediately after mixing was evaluated based on the following criteria by the addition ratio of the one-component admixture for obtaining the target slump flow value.

[0112] : The addition ratio of the one-component admixture is less than 2.00 parts by mass relative to 100 parts by mass of the binder

[0113] : The addition ratio of the one-component admixture is 2.00 to 3.00 parts by mass relative to 100 parts by mass of the binder

[0114] x: The addition ratio of the one-component admixture is more than 3.00 parts by mass relative to 100 parts by mass of the binder

Test Division 10 (Physical Property Evaluation of Prepared Concrete Composition)

[0115] Based on the measurement results of Table 9, the material separation resistance of the concrete composition of each example was evaluated as follows using the bleeding ratio and the sense of material integrity as indexes, and the results were summarized in Table 10.

[0116] Evaluation of Bleeding Rate

[0117] (40% Water Binder Ratio)

[0118] : The bleeding rate is 4.0% or less

[0119] x: The bleeding rate exceeds 4.0% (50% water binder ratio)

[0120] : The bleeding rate is 6.0% or less

[0121] x: The bleeding rate exceeds 6.0% (60% water binder ratio)

[0122] : The bleeding rate is 8.0% or less

[0123] x: The bleeding rate exceeds 8.0%

[0124] Evaluation of Sense of Material Integrity of Concrete Composition

[0125] With respect to the concrete composition, the sense of material integrity was visually evaluate based on the following criteria.

[0126] : very good (no separation of aggregate and mortar paste)

[0127] : good (slight separation of aggregate and mortar paste)

[0128] x: bad (apparent separation of aggregate and mortar paste)

TABLE-US-00010 TABLE 10 Material separation resistance of concrete composition Dispersion performance Sense of of one-component Bleeding material Division admixture rate integrity Example 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Comparative x x Example 1 2 3 4 x 5 x x 6 x 7 x x 8 x x x

[0129] As apparent from the results of Tables 6, 7, 9, and 10, according to various embodiments, it is possible to provide a concrete composition which simultaneously satisfies 1) to 3) below: 1) high fluidity; 2) little separation of materials such as aggregate; and 3) using of a one-component admixture with a water-reducing component having a correspondingly high solid content concentration and having high stability.