JP6207010B2 - Concrete strength improvement method - Google Patents
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- JP6207010B2 JP6207010B2 JP2013128212A JP2013128212A JP6207010B2 JP 6207010 B2 JP6207010 B2 JP 6207010B2 JP 2013128212 A JP2013128212 A JP 2013128212A JP 2013128212 A JP2013128212 A JP 2013128212A JP 6207010 B2 JP6207010 B2 JP 6207010B2
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- 239000004567 concrete Substances 0.000 title claims description 110
- 238000000034 method Methods 0.000 title claims description 29
- 230000006872 improvement Effects 0.000 title description 9
- 238000001035 drying Methods 0.000 claims description 33
- 238000012360 testing method Methods 0.000 claims description 18
- 239000000203 mixture Substances 0.000 claims description 9
- 230000008859 change Effects 0.000 claims description 7
- 238000002156 mixing Methods 0.000 claims description 6
- 230000008569 process Effects 0.000 claims description 6
- 125000000217 alkyl group Chemical group 0.000 claims description 3
- 125000000816 ethylene group Chemical group [H]C([H])([*:1])C([H])([H])[*:2] 0.000 claims description 3
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 claims description 3
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 claims description 3
- 125000004432 carbon atom Chemical group C* 0.000 claims description 2
- 238000001723 curing Methods 0.000 description 30
- 239000003795 chemical substances by application Substances 0.000 description 12
- -1 2-pentyl group Chemical group 0.000 description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 8
- 239000004568 cement Substances 0.000 description 8
- 239000011398 Portland cement Substances 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 238000005259 measurement Methods 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 230000002708 enhancing effect Effects 0.000 description 6
- 239000004576 sand Substances 0.000 description 5
- 239000003638 chemical reducing agent Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000004570 mortar (masonry) Substances 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 230000008602 contraction Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 2
- 239000002893 slag Substances 0.000 description 2
- 125000004169 (C1-C6) alkyl group Chemical group 0.000 description 1
- 125000004493 2-methylbut-1-yl group Chemical group CC(C*)CC 0.000 description 1
- 239000004129 EU approved improving agent Substances 0.000 description 1
- 229920001732 Lignosulfonate Polymers 0.000 description 1
- 239000004113 Sepiolite Substances 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 239000002313 adhesive film Substances 0.000 description 1
- 239000002518 antifoaming agent Substances 0.000 description 1
- 239000000440 bentonite Substances 0.000 description 1
- 229910000278 bentonite Inorganic materials 0.000 description 1
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 1
- 239000011400 blast furnace cement Substances 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000002734 clay mineral Substances 0.000 description 1
- 239000010883 coal ash Substances 0.000 description 1
- 125000000113 cyclohexyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])(*)C([H])([H])C1([H])[H] 0.000 description 1
- 125000001511 cyclopentyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])(*)C1([H])[H] 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 239000011210 fiber-reinforced concrete Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000010881 fly ash Substances 0.000 description 1
- 238000009415 formwork Methods 0.000 description 1
- 239000011372 high-strength concrete Substances 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 125000001972 isopentyl group Chemical group [H]C([H])([H])C([H])(C([H])([H])[H])C([H])([H])C([H])([H])* 0.000 description 1
- 125000001449 isopropyl group Chemical group [H]C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 125000004108 n-butyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 125000001280 n-hexyl group Chemical group C(CCCCC)* 0.000 description 1
- 125000000740 n-pentyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- 125000004123 n-propyl group Chemical group [H]C([H])([H])C([H])([H])C([H])([H])* 0.000 description 1
- PSZYNBSKGUBXEH-UHFFFAOYSA-M naphthalene-1-sulfonate Chemical compound C1=CC=C2C(S(=O)(=O)[O-])=CC=CC2=C1 PSZYNBSKGUBXEH-UHFFFAOYSA-M 0.000 description 1
- 125000003538 pentan-3-yl group Chemical group [H]C([H])([H])C([H])([H])C([H])(*)C([H])([H])C([H])([H])[H] 0.000 description 1
- 229920005646 polycarboxylate Polymers 0.000 description 1
- 239000002986 polymer concrete Substances 0.000 description 1
- 239000011513 prestressed concrete Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 125000002914 sec-butyl group Chemical group [H]C([H])([H])C([H])([H])C([H])(*)C([H])([H])[H] 0.000 description 1
- 229910052624 sepiolite Inorganic materials 0.000 description 1
- 235000019355 sepiolite Nutrition 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 125000000999 tert-butyl group Chemical group [H]C([H])([H])C(*)(C([H])([H])[H])C([H])([H])[H] 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 230000036962 time dependent Effects 0.000 description 1
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- Preparation Of Clay, And Manufacture Of Mixtures Containing Clay Or Cement (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Description
本発明は、乾燥下に置かれたコンクリートの強度を向上させるコンクリート強度向上剤、該向上剤を含むコンクリート、該コンクリートの製造方法、および該向上剤を用いたコンクリートの強度向上方法に関する。なお、本発明でいうコンクリートは、コンクリートのほかに、モルタルおよびセメントペースト硬化体を含む概念である。 The present invention relates to a concrete strength improver for improving the strength of concrete placed under drying, a concrete containing the improver, a method for producing the concrete, and a method for improving the strength of concrete using the improver. In addition, concrete as used in the field of this invention is the concept containing mortar and a cement paste hardening body other than concrete.
コンクリートの強度発現性はセメントの水和に依存する。したがって、コンクリートの強度発現性を高めるためには、水分に富む環境下でコンクリートを養生するのが望ましい。かかる養生方法には、水中養生、蒸気養生、封緘養生、湿潤養生、膜養生、およびシート養生等がある。これらの中で、水中養生から膜養生までの方法は小型のコンクリートに適用できても、大型のコンクリート構造物に適用するのは難しい。一方、シート養生は、前記方法と比べ養生効果は劣るものの、大型のコンクリート構造物に適用できる。そこで、コンクリート構造物の養生方法として、シート養生がいくつか提案されている。 The strength development of concrete depends on the hydration of cement. Therefore, in order to increase the strength development of the concrete, it is desirable to cure the concrete in an environment rich in moisture. Such curing methods include underwater curing, steam curing, sealing curing, wet curing, film curing, and sheet curing. Among these, the method from underwater curing to film curing can be applied to small concrete, but is difficult to apply to large concrete structures. On the other hand, sheet curing can be applied to large concrete structures, although the curing effect is inferior to the above method. Therefore, several sheet curing methods have been proposed as a curing method for concrete structures.
例えば、特許文献１の方法は、コンクリートの打設直後に、型枠を含む打設箇所の側方全周を囲むように養生シートを配置し、前記打設箇所の上部から散水して前記養生シート内の湿度を維持して養生を行い、前記養生シート内にて脱型作業を行う。そして脱型後に、コンクリートの側面全周にエアシートを巻き付け、前記散水を引き続き行いながら養生を継続する方法である。
また、特許文献２の方法は、型枠の取り外し後、湿潤状態にあるコンクリート打設面に散水し、その上に、ベントナイトやセピオライト等の粘土鉱物の層の下側に吸水性の養生マット層を設けた養生シートを敷設する方法である。
さらに、特許文献３の方法は、型枠の内面に養生シートを貼付してコンクリートを打設し、該コンクリートの硬化後に前記型枠を除去した後も、前記養生シートを前記コンクリートの表面に接着した状態で残置する方法である。そして、前記養生シートは、中心に配置された断熱部材と、この断熱部材を挟むようにその両面に配置された一対の不透水性の接着フィルムからなるものである。
しかし、いずれの養生方法も、コンクリート構造物へ養生シートを適用したり除去するための手間がかかるほか、散水する場合はその手間も加わり、簡単な方法とはいえない。また、コンクリートの養生範囲は養生シートの広さに制限されるというシート養生特有の課題も残る。
For example, in the method of Patent Document 1, a curing sheet is arranged so as to surround the entire circumference of the side of the placement site including the mold immediately after the concrete is placed, and water is sprayed from the upper part of the placement site to within the curing sheet. Curing is performed while maintaining the humidity, and demolding is performed in the curing sheet. Then, after demolding, an air sheet is wound around the entire side surface of the concrete, and curing is continued while continuing the watering.
Moreover, the method of patent document 2 sprinkles water on the concrete casting surface in a wet state after removing a formwork, and also has a water-absorbing curing mat layer on the lower side of a clay mineral layer such as bentonite or sepiolite. It is a method of laying a curing sheet provided with.
Furthermore, in the method of Patent Document 3, a curing sheet is attached to the inner surface of a mold, and concrete is placed. After the concrete is cured, the curing sheet is adhered to the surface of the concrete. It is a method of leaving it in the state that has been. And the said curing sheet consists of a heat insulating member arrange | positioned in the center, and a pair of water-impermeable adhesive film arrange | positioned on both surfaces so that this heat insulating member may be pinched | interposed.
However, any of the curing methods takes time and effort to apply and remove the curing sheet to the concrete structure, and when adding water, it is not easy. Moreover, the problem specific to sheet curing that the curing range of concrete is limited to the size of the curing sheet remains.
したがって、本発明の課題は、乾燥状態でもコンクリートの強度発現性を向上（維持）させるコンクリートの強度向上方法を提供することにある。
Therefore, the subject of this invention is providing the strength improvement method of the concrete which improves (maintains) the strength expression property of concrete also in a dry state.
そこで、本発明者らは、前記課題を解決する手段を種々検討したところ、下記の構成を有するコンクリートの強度向上方法は、前記課題を解決できることを見い出し、本発明を完成させた。
［１］下記（Ａ）工程および（Ｂ）工程を含む、コンクリートの強度向上方法。
（Ａ）複数の種類の配合の試験体を用いて乾燥収縮ひずみを測定し、該測定値と下記（２）式から求めたβ値に基づき、β値が１８以下のコンクリートの配合を選択する、配合選択工程。
εｔ＝εｆ×ｔ／（β＋ｔ） ・・・（２）
（式中、εｔは２０℃、相対湿度６０％の乾燥条件下での、乾燥期間ｔ日におけるコンクリートの乾燥収縮ひずみを表し、εｆは該乾燥条件下での、コンクリートの乾燥収縮ひずみの最終値を表し、βは乾燥収縮ひずみの経時変化を表わす係数を表わす。）
（Ｂ）前記選択した配合のコンクリートに、下記コンクリート強度向上剤（ａ）を複数の添加量添加して試験体を作製し、乾燥状態に置いた該試験体の圧縮強度を測定して、下記コンクリート強度向上剤の最適添加量を決定する、添加量決定工程。
ＲＯ（ＡＯ）ｎＨ・・・・（ａ）
（式中、Ｒは炭素数１〜６のアルキル基またはフェニル基を表し、Ａはエチレン基および／またはプロピレン基を表し、ｎは１〜１０の数を表す。）
The inventors of the present invention have studied various means for solving the above problems, and have found that a method for improving the strength of concrete having the following configuration can solve the above problems, thereby completing the present invention.
[1] A method for improving the strength of concrete, including the following steps ( A) and (B).
(A) Dry shrinkage strain is measured using a plurality of types of test specimens, and based on the measured value and the β value obtained from the following formula (2), a blend of concrete having a β value of 18 or less is selected. , Blending selection process.
εt = εf × t / (β + t) (2)
(In the formula, εt represents the drying shrinkage strain of the concrete at a drying period of t days under a drying condition of 20 ° C. and a relative humidity of 60%, and εf is the final value of the drying shrinkage strain of the concrete under the drying condition. Β represents a coefficient representing a change with time of the drying shrinkage strain.)
(B) A test specimen was prepared by adding a plurality of addition amounts of the following concrete strength improver (a) to the selected blend, and the compressive strength of the specimen placed in a dry state was measured. An addition amount determination step for determining the optimum addition amount of the concrete strength improver.
RO (AO) nH ... (a)
(In the formula, R represents an alkyl group having 1 to 6 carbon atoms or a phenyl group, A represents an ethylene group and / or a propylene group, and n represents a number of 1 to 10).
本発明のコンクリートの強度向上方法は、乾燥状態でもコンクリートの強度を向上させることができる。
Strength improving method of the concrete of the present invention can improve the strength of the concrete in the dry state.
以下にコンクリート強度向上剤、コンクリート、コンクリートの製造方法、および本発明のコンクリートの強度向上方法に分けて説明する。
１．コンクリート強度向上剤
該強度向上剤は下記（ａ）式の化学式で示される化合物である。
ＲＯ（ＡＯ）ｎＨ・・・・（ａ）
ただし、式中、Ｒは炭素数１〜６のアルキル基またはフェニル基を表し、Ａはエチレン基および／またはプロピレン基を表し、ｎは１〜１０の数を表す。
前記（ａ）式中のアルキル基は、例えば、メチル基、エチル基、１−プロピル基、２−プロピル基、１−ブチル基、２−ブチル基、ｔｅｒｔ−ブチル基、２−メチル−１−ブチル基、３−メチル−１−ブチル基、１−ペンチル基、２−ペンチル基、３−ペンチル基、２−メチル−１−ペンチル基、３−メチル−１−ペンチル基、４−メチル−１−ペンチル基、シクロペンチル基、１−へキシル基、２−へキシル基、３−へキシル基、１，１−ジメチル−１―ブチル基、１，１−ジメチル−２，２―ジメチル―１−エチル基、１−メチル−２−メチル−１−ブチル基、およびシクロへキシル基等が挙げられる。
また、コンクリート強度向上剤のＨＬＢ値は、好ましくは８以上で２０未満である。該値が該範囲内であれば、コンクリートの強度向上効果はより高い。前記ＨＬＢ値の下限は、より好ましくは１０、さらに好ましくは１２、特に好ましくは１３であり、前記ＨＬＢ値の上限は、より好ましくは１８、さらに好ましくは１６、特に好ましくは１５である。なお、本発明においてＨＬＢ値は、下記（１）式により求めることができる。
ＨＬＢ値＝２０×前記（ａ）式中の［Ｏ（ＡＯ）ｎＨ］部分の式量／前記（ａ）式の分子量 ・・・（１）
また、コンクリート強度向上剤は、前記（ａ）式で示される化合物を２種以上混合したものでもよい。この場合、該混合物のＨＬＢ値は、各化合物のＨＬＢ値の加重平均で表わす。
後掲の図１に示すように、コンクリート強度向上剤を用いると、２０℃、相対湿度６０％の乾燥条件下で、材齢９１日以降におけるコンクリートの圧縮強度が１０〜２０％程度向上する。
The following concrete strength improving agents, concrete, method of producing concrete, and divided into strength improvement process of the concrete of the present invention will be described.
1. Concrete strength improver The strength improver is a compound represented by the following chemical formula (a).
RO (AO) nH ... (a)
However, in formula, R represents a C1-C6 alkyl group or a phenyl group, A represents an ethylene group and / or a propylene group, and n represents the number of 1-10.
The alkyl group in the formula (a) is, for example, methyl group, ethyl group, 1-propyl group, 2-propyl group, 1-butyl group, 2-butyl group, tert-butyl group, 2-methyl-1- Butyl group, 3-methyl-1-butyl group, 1-pentyl group, 2-pentyl group, 3-pentyl group, 2-methyl-1-pentyl group, 3-methyl-1-pentyl group, 4-methyl-1 -Pentyl group, cyclopentyl group, 1-hexyl group, 2-hexyl group, 3-hexyl group, 1,1-dimethyl-1-butyl group, 1,1-dimethyl-2,2-dimethyl-1- Examples thereof include an ethyl group, a 1-methyl-2-methyl-1-butyl group, and a cyclohexyl group.
Moreover, concrete HLB value of strength enhancing agent is preferably less than 20 at 8 or more. When the value is within the range, the concrete strength improvement effect is higher. The lower limit of the HLB value is more preferably 10, still more preferably 12, particularly preferably 13, and the upper limit of the HLB value is more preferably 18, still more preferably 16, particularly preferably 15. In the present invention, the HLB value can be obtained by the following equation (1).
HLB value = 20 × formula weight of [O (AO) nH] part in the formula (a) / molecular weight of the formula (a) (1)
Moreover, concrete strength enhancing agent, said (a) compound of formula may be a mixture of two or more. In this case, the HLB value of the mixture is expressed as a weighted average of the HLB values of each compound.
As shown in Figure 1 of infra, the use of concrete strength improving agent, 20 ° C., under dry conditions of 60% relative humidity, the compressive strength of the concrete at the age of 91 days or later improved by about 10% to 20% .
また、コンクリート強度向上剤は、下記（２）式を用いて求めたβ値が３０以下のコンクリートに用いると強度向上効果が高い。前記β値は好ましくは２６以下、より好ましくは２３以下、さらに好ましくは２０以下、特に好ましくは１８以下である。
εｔ＝εｆ×ｔ／（β＋ｔ） ・・・（２）
ただし、式中、εｔは２０℃、相対湿度６０％の乾燥条件下での、乾燥期間ｔ日におけるコンクリートの乾燥収縮ひずみを表し、εｆは該乾燥条件下での、コンクリートの乾燥収縮ひずみの最終値を表し、βは乾燥収縮ひずみの経時変化を表わす係数を表わす。
前記（２）式は、「２０１２年制定コンクリート標準示方書 設計編」の１０６頁に記載の下記式において、ｔを乾燥期間に、７をゼロ等に置き換えた式である。
Moreover, concrete strength enhancing agent, the following (2) is high is used when the
εt = εf × t / (β + t) (2)
However, in the formula, εt represents the drying shrinkage strain of the concrete in the drying period t days under a drying condition of 20 ° C. and a relative humidity of 60%, and εf represents the final drying shrinkage strain of the concrete under the drying condition. Represents a value, and β represents a coefficient representing a change with time of the drying shrinkage strain.
The formula (2) is a formula in which “t” is replaced with “drying period” and “7” is replaced with zero or the like in the following formula described on page 106 of “2012 Standard Specification for Concrete Design”.
前記（２）式中の乾燥収縮ひずみは、大きさが縦１００ｍｍ、横１００ｍｍ、長さ４００ｍｍの試験体を用いて、ＪＩＳ Ａ １１２９「モルタル及びコンクリートの長さ変化測定方法」に準拠するか、または、該試験体の中心部に設置した埋込型ひずみ計により測定できる。
また、前記（２）式中のβ値は、前記（２）式を用いて最小二乗法によるカーブフィッティングにより求めることができる。
The drying shrinkage strain in the formula (2) conforms to JIS A 1129 “Method for measuring change in length of mortar and concrete” by using a specimen having a size of 100 mm in length, 100 mm in width, and 400 mm in length. Alternatively, it can be measured by an embedded strain gauge installed at the center of the specimen.
The β value in the equation (2) can be obtained by curve fitting by the least square method using the equation (2).
本発明のコンクリート強度向上剤は、ナフタレンスルホン酸塩・ホルマリン縮合物等の高性能減水剤、ポリカルボン酸塩等の高性能ＡＥ減水剤、およびリグニンスルホン酸塩等の減水剤と、空気量調整剤、収縮低減剤、消泡剤、遅延剤、並びに硬化促進剤等から選ばれる１種以上の混和剤と併用できる。 The concrete strength improver of the present invention comprises a high-performance water reducing agent such as naphthalene sulfonate / formalin condensate, a high-performance AE water reducing agent such as polycarboxylate, and a water reducing agent such as lignin sulfonate, and an air amount adjustment. It can be used in combination with one or more admixtures selected from agents, shrinkage reducing agents, antifoaming agents, retarders, curing accelerators and the like.
２．コンクリート
コンクリートは、前記コンクリート強度向上剤をコンクリート１ｍ３あたり１〜１２ｋｇ含んでなるものである。該強度向上剤の含有量が１ｋｇ未満では強度向上効果が低く、１２ｋｇを超えると該効果は飽和する傾向がある。前記含有量の下限は、好ましくは２ｋｇ、より好ましくは３ｋｇ、さらに好ましくは４ｋｇであり、前記含有量の上限は、好ましくは１０ｋｇ、より好ましくは９ｋｇ、さらに好ましくは８ｋｇである。
前記コンクリートは、例えば、普通コンクリート、暑中コンクリート、寒中コンクリート、マスコンクリート、流動化コンクリート、高流動コンクリート、高強度コンクリート、低発熱コンクリート、膨張コンクリート、プレストレストコンクリート、低収縮コンクリート、繊維補強コンクリート、軽量コンクリート、およびポリマーコンクリート等が挙げられる。
また、前記コンクリートに含まれるセメントは、普通ポルトランドセメント、早強ポルトランドセメント、超早強ポルトランドセメント、中庸熱ポルトランドセメント、低熱ポルトランドセメント、および耐硫酸塩ポルトランドセメント等のポルトランドセメント、高炉セメント、フライアッシュセメント、およびシリカセメント等の混合セメント、石炭灰含有セメント、白色セメント、並びにエコセメント等から選ばれる１種以上が挙げられる。
また、前記コンクリートに含まれる粗骨材は、川砂利、山砂利、砕石、スラグ粗骨材、および軽量粗骨材等から選ばれる１種以上が挙げられ、前記コンクリートに含まれる細骨材は、川砂、山砂、陸砂、海砂、砕砂、硅砂、スラグ細骨材、および軽量細骨材等から選ばれる１種以上が挙げられる。また、前記粗骨材や細骨材は天然骨材のほか、人工骨材や再生骨材を用いることができる。
2. concrete
Concrete is the concrete strength improving agent are those which comprise 1~12kg per concrete 1 m 3. If the content of the strength improver is less than 1 kg, the strength improving effect is low, and if it exceeds 12 kg, the effect tends to be saturated. The lower limit of the content is preferably 2 kg, more preferably 3 kg, and even more preferably 4 kg. The upper limit of the content is preferably 10 kg, more preferably 9 kg, and still more preferably 8 kg.
The concrete is, for example, ordinary concrete, summer concrete, cold concrete, mass concrete, fluidized concrete, high fluid concrete, high strength concrete, low heat concrete, expanded concrete, prestressed concrete, low shrinkage concrete, fiber reinforced concrete, lightweight concrete , And polymer concrete.
Further, the cement contained in the concrete includes ordinary Portland cement, early-strength Portland cement, ultra-high-strength Portland cement, moderately hot Portland cement, low heat Portland cement, and sulfate-resistant Portland cement such as Portland cement, blast furnace cement, fly ash. Examples thereof include one or more selected from cement, mixed cement such as silica cement, coal ash-containing cement, white cement, and ecocement.
The coarse aggregate contained in the concrete includes one or more selected from river gravel, mountain gravel, crushed stone, slag coarse aggregate, lightweight coarse aggregate, and the like, and the fine aggregate contained in the concrete is , River sand, mountain sand, land sand, sea sand, crushed sand, dredged sand, slag fine aggregate, lightweight fine aggregate, and the like. The coarse aggregate and fine aggregate may be natural aggregate, artificial aggregate, or regenerated aggregate.
３．コンクリートの製造方法
該コンクリートの製造方法は、前記β値が３０以下のコンクリートを対象として、前記コンクリート強度向上剤をコンクリート１ｍ３あたり１〜１２ｋｇ添加して混練する方法である。
前記β値が３０以下のコンクリートの配合は、大きさが縦１００ｍｍ、横１００ｍｍ、長さ４００ｍｍの、複数の配合の試験体を用いて、ＪＩＳ Ａ １１２９「モルタル及びコンクリートの長さ変化測定方法」に準拠するか、または、該試験体の中心部に設置した埋込型ひずみ計により乾燥収縮ひずみ測定し、該測定値と前記（２）式から求めたβ値に基づき選択できる。
3. Concrete production method The concrete production method is a method in which 1 to 12 kg of the concrete strength improver is added per 1 m 3 of concrete and kneaded for the concrete having a β value of 30 or less.
The blending of concrete having a β value of 30 or less is JIS A 1129 “Method for measuring mortar and concrete length change” by using a plurality of blended specimens having a size of 100 mm in length, 100 mm in width, and 400 mm in length. Or dry shrinkage strain is measured with an embedded strain gauge installed in the center of the test specimen, and can be selected based on the measured value and the β value obtained from the above equation (2).
４．コンクリートの強度向上方法
該強度向上方法は、下記（Ａ）工程および（Ｂ）工程を含む方法である。
（Ａ）複数の種類の配合の試験体を用いて乾燥収縮ひずみを測定し、該測定値と前記（２）式から求めたβ値に基づき、β値が３０以下のコンクリートの配合を選択する、配合選択工程。
（Ｂ）前記選択した配合のコンクリートに、前記コンクリート強度向上剤を複数の添加量添加して試験体を作製し、乾燥状態に置いた該試験体の圧縮強度を測定して、前記コンクリート強度向上剤の最適添加量を決定する、添加量決定工程。
強度向上剤の添加量は、一般に、コンクリート１ｍ３あたり１〜１２ｋｇの範囲を目安にするとよい。
なお、前記（Ａ）工程において、乾燥収縮ひずみの測定は、大きさが縦１００ｍｍ、横１００ｍｍ、長さ４００ｍｍの、複数の配合の試験体を用いて、ＪＩＳ Ａ １１２９「モルタル及びコンクリートの長さ変化測定方法」に準拠するか、または、該試験体の中心部に設置した埋込型ひずみ計により行うことができる。また、前記（Ｂ）工程において、乾燥状態に置いた試験体の圧縮強度の測定は、ＪＩＳ Ａ １１０８「コンクリートの圧縮強度試験方法」に準拠して行う。
前記コンクリートの強度向上方法によれば、β値が３０以下のコンクリートの圧縮強度を向上させることができる。
4). Concrete Strength Improvement Method The strength improvement method is a method including the following steps (A) and (B).
(A) Drying shrinkage strain is measured using a plurality of types of test specimens, and based on the measured value and the β value obtained from the above equation (2), a blend of concrete having a β value of 30 or less is selected. , Blending selection process.
(B) A test specimen is prepared by adding a plurality of addition amounts of the concrete strength improver to the concrete of the selected blend, and the compressive strength of the specimen placed in a dry state is measured to improve the concrete strength. An addition amount determining step for determining an optimum addition amount of the agent.
Amount of strength enhancing agent is generally better to measure the range of 1~12kg per concrete 1 m 3.
In addition, in the said (A) process, the measurement of a drying shrinkage | contraction strain is JIS A 1129 "the length of mortar and concrete using the test body of a some mixing | blending whose magnitude | size is 100 mm long, 100 mm wide, and
According to the concrete strength improving method, the compressive strength of concrete having a β value of 30 or less can be improved.
以下、本発明を実施例により具体的に説明するが、本発明はこれらの実施例に限定されない。
１．使用材料
下記表１に、試験に用いた材料を示す。
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples.
1. Materials used
Table 1 below shows the materials used in the test.
２．圧縮強度試験および乾燥収縮ひずみ試験
表１に示す材料を用い、表２に示す配合に従いコンクリートを混練して型枠に打設し、外気と接するコンクリート面を湿布で覆った状態で、材齢３日および材齢７日まで２０℃で湿潤養生を行った後に脱型して、３種類の普通コンクリートの試験体（ＰＬｌ、ＰＬ２、ＰＬ３）と、コンクリート強度向上剤を含む２種類の試験体（ＳＲｌ、ＳＲ２）の合計５種類の試験体（ただし、それぞれについて、形状は、直径１００ｍｍ、高さ２００ｍｍの圧縮強度測定用の試験体と、縦１００ｍｍ、横１００ｍｍ、長さ４００ｍｍの乾燥収縮ひずみ測定用のひずみ計埋込型試験体の２種類がある。）を作製した。
ＰＬ１はＳＲ１に対する比較例であり、ＰＬ２はＳＲ２に対する比較例である。また、ＰＬ３は乾燥収縮ひずみが比較的小さなコンクリートであるが、それでも、乾燥条件下に置かれると圧縮強度は低くなることを示すための参考例である。
なお、コンクリート強度向上剤は単位水量の一部として添加した。また、混和剤（ＳＰとＡＥ）は、コンクリートのスランプが１８±２．５ｃｍ、コンクリートの空気量が４．５±１．５％になるように添加した。
2. Compressive strength test and drying shrinkage strain test Using the materials shown in Table 1, concrete was kneaded according to the composition shown in Table 2 and placed in a mold, and the concrete surface in contact with the outside air was covered with a poultice. After wet curing at 20 ° C. until day 7 and material age, it is demolded and three types of ordinary concrete specimens (PL1, PL2, PL3) and two specimens containing concrete strength improvers ( SR1 and SR2) in total 5 types of test specimens (however, the shape of each specimen is 100 mm in diameter and 200 mm in height for compressive strength measurement, and 100 mm in length, 100 mm in width and 400 mm in length for measurement of dry shrinkage strain There are two types of strain gauge embedded specimens for use.).
PL1 is a comparative example for SR1, and PL2 is a comparative example for SR2. Moreover, although PL3 is a concrete with a relatively small drying shrinkage strain, it is still a reference example for showing that the compressive strength is lowered when placed under dry conditions.
The concrete strength improver was added as part of the unit water volume. The admixtures (SP and AE) were added so that the concrete slump was 18 ± 2.5 cm and the concrete air amount was 4.5 ± 1.5%.
次に、前記試験体を、２０℃、相対湿度６０％の乾燥条件下に置き、所定の乾燥期間ごとに、圧縮強度をＪＩＳ Ａ １１０８「コンクリートの圧縮強度試験方法」に準拠して測定し、また、乾燥収縮ひずみを、試験体中に埋め込んだひずみ計により測定した。圧縮強度の測定結果を表３と図１に、乾燥収縮ひずみの測定結果を図２に示す。また、乾燥収縮ひずみの測定結果と前記（２）式を用いてカーブフィッティングにより求めたβ値を表３に示す。 Next, the test specimen is placed under a drying condition of 20 ° C. and a relative humidity of 60%, and the compressive strength is measured in accordance with JIS A 1108 “Testing method for compressive strength of concrete” for each predetermined drying period. Further, the drying shrinkage strain was measured with a strain gauge embedded in the test body. The measurement results of compressive strength are shown in Table 3 and FIG. 1, and the measurement results of drying shrinkage strain are shown in FIG. Table 3 shows the measurement results of the drying shrinkage strain and the β value obtained by curve fitting using the above equation (2).
３．試験結果について
表３と図１に示すように、ＳＲ１とＳＲ２の圧縮強度は、それぞれの比較例であるＰＬ１とＰＬ２の圧縮強度と比べ、材齢９１日以降で１０〜２０％程度向上している。また、材齢２８日以降は、材齢とともに、ＰＬ１とＰＬ２の圧縮強度は低下するのに対し、ＳＲ１とＳＲ２の圧縮強度は増加傾向にあるから、コンクリート強度向上剤は極めて特異な効果を有している。
また、ＰＬ３（参考例）の乾燥収縮ひずみは、図２に示すように比較的小さく、長期的にはＳＲ２と同程度にも関わらず、図１に示すように圧縮強度の低下は一番大きい。したがって、この参考例の結果から、コンクリート強度向上剤の強度向上効果は、必ずしもその乾燥収縮低減作用に起因するとはいえず、未知の作用の可能性を示唆しているとも考えられる。
よって、以上のことから、コンクリート強度向上剤は、混和剤分野に新たな領域を開くものと期待される。
3. About a test result As shown in Table 3 and FIG. 1, the compressive strength of SR1 and SR2 has improved about 10 to 20% after the age of 91 days compared with the compressive strength of PL1 and PL2 which are each comparative examples. Yes. Also, age of 28 days later, with the age, whereas decreases compressive strength PL1 and PL2, because the compressive strength of the SR1 and SR2 is increasing, concrete strength enhancing agent a very specific effect Have.
In addition, the drying shrinkage strain of PL3 (reference example) is relatively small as shown in FIG. 2, and the long-term decrease in compressive strength is the largest as shown in FIG. . Therefore, from the result of this reference example, it can be said that the strength improvement effect of the concrete strength improver is not necessarily due to the drying shrinkage reduction action, and suggests the possibility of an unknown action.
Therefore, from the above, concrete strength enhancing agent is expected to open a new area in admixture field.
Claims (1)
（Ａ）複数の種類の配合の試験体を用いて乾燥収縮ひずみを測定し、該測定値と下記（２）式から求めたβ値に基づき、β値が１８以下のコンクリートの配合を選択する、配合選択工程。
εｔ＝εｆ×ｔ／（β＋ｔ） ・・・（２）
（式中、εｔは２０℃、相対湿度６０％の乾燥条件下での、乾燥期間ｔ日におけるコンクリートの乾燥収縮ひずみを表し、εｆは該乾燥条件下での、コンクリートの乾燥収縮ひずみの最終値を表し、βは乾燥収縮ひずみの経時変化を表わす係数を表わす。）
（Ｂ）前記選択した配合のコンクリートに、下記コンクリート強度向上剤（ａ）を複数の添加量添加して試験体を作製し、乾燥状態に置いた該試験体の圧縮強度を測定して、下記コンクリート強度向上剤の最適添加量を決定する、添加量決定工程。
ＲＯ（ＡＯ）ｎＨ・・・・（ａ）
（式中、Ｒは炭素数１〜６のアルキル基またはフェニル基を表し、Ａはエチレン基および／またはプロピレン基を表し、ｎは１〜１０の数を表す。）
A method for improving the strength of concrete, comprising the following steps ( A) and (B).
(A) Dry shrinkage strain is measured using a plurality of types of test specimens, and based on the measured value and the β value obtained from the following formula (2), a blend of concrete having a β value of 18 or less is selected. , Blending selection process.
εt = εf × t / (β + t) (2)
(In the formula, εt represents the drying shrinkage strain of the concrete at a drying period of t days under a drying condition of 20 ° C. and a relative humidity of 60%, and εf is the final value of the drying shrinkage strain of the concrete under the drying condition. Β represents a coefficient representing a change with time of the drying shrinkage strain.)
(B) A test specimen was prepared by adding a plurality of addition amounts of the following concrete strength improver (a) to the selected blend, and the compressive strength of the specimen placed in a dry state was measured. An addition amount determination step for determining the optimum addition amount of the concrete strength improver.
RO (AO) nH ... (a)
(In the formula, R represents an alkyl group having 1 to 6 carbon atoms or a phenyl group, A represents an ethylene group and / or a propylene group, and n represents a number of 1 to 10).
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