JP3566371B2 - Concrete admixture exposed to low temperatures - Google Patents
Concrete admixture exposed to low temperatures Download PDFInfo
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- JP3566371B2 JP3566371B2 JP33827594A JP33827594A JP3566371B2 JP 3566371 B2 JP3566371 B2 JP 3566371B2 JP 33827594 A JP33827594 A JP 33827594A JP 33827594 A JP33827594 A JP 33827594A JP 3566371 B2 JP3566371 B2 JP 3566371B2
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
- C04B40/0028—Aspects relating to the mixing step of the mortar preparation
- C04B40/0039—Premixtures of ingredients
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/46—Water-loss or fluid-loss reducers, hygroscopic or hydrophilic agents, water retention agents
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/46—Water-loss or fluid-loss reducers, hygroscopic or hydrophilic agents, water retention agents
- C04B2103/465—Water-sorbing agents, hygroscopic or hydrophilic agents
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/60—Agents for protection against chemical, physical or biological attack
- C04B2103/601—Agents for increasing frost resistance
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/60—Agents for protection against chemical, physical or biological attack
- C04B2103/65—Water proofers or repellants
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Description
【０００１】
【産業上の利用分野】
本発明は氷点以下の低温にさらされるコンクリート用混和剤に関する。
【０００２】
【従来の技術】
本発明者の１人竹田は特公平５−８５５９１号公報に記載されているように、道路の凍結を防止するために、アスファルト舗装材中に凍結防止剤を配合することを提供した。
この道路凍結防止剤は疎水性のアスファルト中に配合したときに効果を奏するが他の物に配合したときに効果を奏するかどうかは全く不明であった。アスファルトと異なり親水性を有するコンクリート構造物は浸透した水分が凍ることによりクラックを発生するため問題が大きかった。凍結と融解を繰り返すことにより破壊が発生するが、その前に強度が低下し構造物が所定の強度を維持できなくなる危険がある。水を浸透せず、表面の凍結が問題となるアルファルトの舗装面の凍結とは状況が全く異なるからである。
アスファルト舗装面の凍結を防止する方法として従来知られていた方法は、氷点降下剤を散布するか、凍結防止成分（氷点降下剤など）を外被で覆ってカプセル化し、この粒子を舗装層に数％の割合で混入するものである。舗装層の摩耗に伴い逐次新しいカプセルが表面に露出・摩耗し、内部の氷点降下剤などが侵出するので、舗装層自身の寿命がある間、効果が持続する方法がとられていた。前者は薬剤が流失するため長期間の効果の持続性がなく、後者は構造物の摩耗を必要とする。コンクリート構造物はその親水性、透水性の性質から明らかなように長期間の凍結防止効果の持続が必要であり、また構造物の摩耗は生じてはならない。したがって従来の方法は採用出来ない。
【０００３】
【発明が解決しようとする課題】
本発明は、効果が長期的に持続し、しかも特別な凍結防止装置を必要としない、コンクリート構造物の凍結を防止する、低温にさらされるコンクリート用混和剤を提供する。
【０００４】
【課題を解決する手段】
本発明は、
「１． Ａ．氷点降下剤６０〜９０重量％と、Ｂ．疎水性多孔粒子５〜２０重量％と、Ｃ．非潮解性で非吸水性の親水性粒子５〜２０重量％、とからなる低温にさらされるコンクリート用混和剤。
２． 氷点降下剤が、酢酸カリウムと酢酸カルシウムから選んだ１または２を主成物とするものである、１項に記載された低温にさらされるコンクリート用混和剤。
３． 氷点降下剤が、酢酸カルシウムと酢酸カルシウムから選んだ１または２に、硫酸鉄水和物、マグネシウム塩を添加した混合物である、１項に記載された低温にさらされるコンクリート用混和剤。
４． 氷点降下剤がドロマイトに酢酸と燐酸を反応させて得た酢酸カルシウムを主成分とし、マグネシウム塩等が混合した混合物である、１項に記載された低温にさらされるコンクリート用混和剤。
５． 疎水性多孔粒子がパーライト、膨張雲母、シラスバルーン粒子、発泡ポリウレタン粒子から選んだ１または２以上である、１項ないし４項のいずれか１項に記載された低温にさらされるコンクリート用混和剤。
６． 非潮解性で非吸水性の親水性粒子が、溶岩粉末、石英粉末、軽石粉末、発泡ガラス粉末から選んだ１または２以上である、１項ないし５項のいずれか１項に記載された低温にさらされるコンクリート用混和剤。
７． コンクリートの固形分中１〜１５重量％使用する、１項ないし６項のいずれか１項に記載された低温にさらされるコンクリート用混和剤。」
に関する。
【０００５】
【作用】
本発明の特徴はコンクリート用混和剤が多孔中に氷点降下剤を含有させた疎水性粒子と、非潮解性で非吸水性の親水性粒子とからなることにある。
コンクリート構造物の凍結を防止するためには、コンクリート構造物には付着ないし浸透した水に氷点降下剤を徐々に溶出させるのが最も効果的であるが、氷点降下剤はいずれも水溶性であり、吸湿性に富むため保存中に空気中の水分により溶解したり、吸湿して凝集したりするのでこれを防ぐ必要があること、種々の防湿手段を検討した結果、疎水性の多孔粒子の孔中に収納含有させることが非常に有効であることがわかった。
しかしながら、疎水性多孔粒子は水を撥く性質があるので多孔中に含まれる氷点降下剤の溶出速度が小さいため多量の疎水性粒子を必要としコンクリートの強度などの性質に影響を与える危険があることと、氷点降下剤の大量の配合は水の浸透を助長する傾向があるのでこの点の改善が必要である。
【０００６】
本発明者らはさらに研究を進めた結果親水性粒子を混合すると、氷点降下剤を孔中に収納含有した疎水性の多孔粒子の周沿に分布した親水性粒子が水を引き付けるので、氷点降下剤が良好に溶出するので疎水性多孔体中の氷点降下剤は持続的に効果を発揮する。しかしながら親水性粒子が潮解性であると、コンクリートは透水性を有するので浸透した水により凍結防止を行う以前に溶けてしまい、効果がない。またそれ自身が吸水性があると水を吸水し疎水性粒子に供給しないので効果がない。そのため親水性粒子は非潮解性で非親水性でなければならない。氷点降下剤の配合量をさらに増加する必要のある場合は親水性粒子として多孔性のものを使用しその孔中に氷点降下剤を含有させればよい。
【０００７】
本発明の混和剤は、氷点降下剤が６０〜９０重量％、疎水性多孔粒子が５〜２０重量％、非潮解性で非吸水性の親水性粒子が５〜２０重量％であり、氷点降下剤の量が６０重量％以下であるとこれを含有する疎水性多孔粒子の偏在の傾向があらわれる。９０重量％以上であること、多重の氷点降下剤を含む疎水性多孔粒子の強度が小さくなりコンクリート混和時に破壊される危険がある。
【０００８】
親水性粒子は５重量％以下では水を引きつける効果が小さすぎ、２０重量％以上ではコンクリート構造物に多くの水を浸透させる傾向が大きくなる。
【０００９】
本発明の混和剤はコンクリートの固形分中１〜１５重量％配合することが好ましい。
本発明の他の特徴は氷点降下剤と、疎水性粒子と、非潮解性で非吸水性の親水性粒子からなる組成物をコンクリート中に混和することである。コンクリート構造物の表面に塗布ないし塗工したのでは長期間の効果の持続が得られない。
コンクリート中に混和することにより氷点降下剤が浸透し凍る水分中に徐々に溶出して凍結を防止するからである。
【００１０】
このようにコンクリート構造物の凍結防止が特殊であることは、種々の道路凍結防止剤をコンクリートに混合して凍結防止に使用したテストで、短期間は有効であっても長期間の効果の持続は得られなかったことからも理解される。
【００１１】
次に本発明で使用する材料について説明する。
氷点降下剤としては、塩化ナトリウム、塩化カルシウム、塩化アルミニウム、塩化マグネシウム、酢酸マグネシウム・カルシウム、酢酸カリウム、酢酸カルシウム、酢酸マグネシウム、燐酸カルシウム、燐酸マグネシウム、燐酸−水素カルシウム、燐酸−水素マグネシウム、亜硝酸ナトリウム、硫酸ナトリウム、チオ硫酸カリウムなどが使用される。酢酸カリウムと酢酸カルシウムが特に有効であり、両者の混合物も好ましい。
【００１２】
氷点降下剤としては、酢酸カリウムや酢酸カルシウムの単品やこれを混合して使用してもよいが例えば炭酸カルシウムと炭酸マグネシウムからなるドロマイトを用いてリン酸と酢酸の混酸を反応させて酢酸カルシウムを主成分としマグネシウム塩が混合した混合物として使用することも出来る。
【００１３】
疎水性多孔粒子としては、焼成疎水性パーライト粒子、膨張雲母粒子、シラスバルーン粒子、発泡ポリウレタン、アクリル、シリコーン等の合成樹脂多孔粒子カーボンブラック粒子などが使用される。パーライト、膨張雲母、シラスバルーン、発泡ポリウレタン粒子は好ましい
【００１４】
非潮解性で非吸水性の親水性粒子としては、溶岩粉末、石英粉末、軽石粉末、発泡ガラス粉末、酸化鉄粉、二酸化チタン、炭酸カルシウム、酸化アルミニウム、石膏、酸化マグネシウム、硫酸バリウム、タルク、炭酸バリウムが使用される。溶岩粉末、石英粉末、軽石粉末、発泡ガラスが好ましい。
【００１５】
次に実施例と比較例をあげて本発明を具体的に説明する。
【００１６】
【実施例】
実施例１
ドロマイト９５％と燐酸１％、酢酸４％の反応生成物、すなわち、ドロマイト（粒子径１０〜１５ｍｍのもの）１０００ｇに１５％燐酸７０ｇと１０％酢酸４００ｇを徐々に加えながら混合し、１１０℃〜１５０℃にて３０〜４０分間反応釜で撹拌しながら反応させ、酢酸カルシウムを主成分とする反応生成物を得る。得られた反応生成物６０重量％を、あらかじめ調製して、別々に貯溜しておいた親水性を示し非潮解性の粒子である溶岩粉末２０重量％、石英粉末３重量％並びに疎水性を示す多孔性粒子である焼成疎水性パーライト２重量％、発泡ポリウレタン１５重量％と混合して乾式で混合粉砕に付し、多孔性粒子の空孔ドロマイト反応生成物が充填された粒径０．１ｍｍ以下の微粒子混合物を含有するコンクリート用混和剤を得る。
【００１７】
実施例２
酢酸カリウム４０重量％と、硫酸鉄（ＩＩＩ）九水和物２０重量％の混合物６０重量％を、あらかじめ調整して別々に貯溜しておいた親水性を示し非潮解性の粒子である溶岩粉末２０重量％、石英粉末３重量％並びに疎水性を示す多孔性粒子である焼成疎水性パーライト２重量％、発泡ポリウレタン１５重量％と乾式で混合粉砕に付し、多孔性粒子の空孔に酢酸カリウムと硫酸鉄（ＩＩＩ）九水和物の混合物が充填された粒径０．１ｍｍ以下の微粒子混合物を含有するコンクリート用混和剤を得る。
【００１８】
実施例３
氷点降下剤として塩化マグネシウム３５重量％と、酢酸カルシウム２５重量％の混合物を使用した以外は実施例２と同一にしてコンクリート用混和剤を得た。
【００１９】
比較例１
本発明の混和剤を使用しない。
【００２０】
比較例２
実施例１に示されるドロマイト反応生成物のみを使用し、親水性粒子と疎水性多孔性粒子を使用しない。
【００２１】
比較例３
実施例２に示される酢酸カリウム４０重量％と、硫酸鉄（ＩＩＩ）九水和物２０重量％の混合物のみを使用し、親水性粒子と疎水性多孔性粒子を使用しない。
【００２２】
比較例４
実施例３に示される塩化マグネシウム３５重量％と、酢酸カルシウム２５重量％の混合物のみを使用し、親水性粒子と疎水性多孔性粒子成分を使用しない。
次に性能試験を行った結果を表１に示す。
【００２３】
試験
各例とも水／セメント＝５２％、細骨材／細骨材＋粗骨材＝４１％として、スランプ目標値を５．５ｃｍとして調合を定め４切の可傾式ミキサーにより混練を行った。
ついで、直径１０ｃｍ、高さ２０ｃｍの供試体を成型し、−５℃、−１０℃、２０℃の各温度で所定時間養生した。
養生後供試体は圧縮強度試験を行う前に２０℃の室内に３時間放置して解凍した。
使用したコンクリート材料は次の通りである。
セメント ： 小野田セメント株式会社製、普通ポルトランドセメント
細骨材 ： 川砂 比重２．６０ 粗粒率２．８５
粗骨材 ： 砕石 ＭＳ２０ｍｍ
【００２４】
【表１】
（註） Ｃ：セメント（Ｋｇ） Ｗ：水（Ｋｇ） Ｓ：スランプ（ｃｍ）である。
圧縮強度の欄の７、２８は７日、２８日を表わす。
【００２６】
【発明の効果】
本発明の混和剤を配合したコンクリートは低温にさらされても強度が低下しない優れた効果を奏する。[0001]
[Industrial applications]
The present invention relates to an admixture for concrete exposed to low temperatures below the freezing point.
[0002]
[Prior art]
As described in Japanese Patent Publication No. 5-85591, one of the inventors of the present invention has provided the incorporation of an antifreezing agent into asphalt pavement to prevent the road from freezing.
This road deicing agent is effective when incorporated in hydrophobic asphalt, but it is completely unknown whether it is effective when incorporated in other products. Concrete structure having a parent aqueous Unlike asphalt was greater problem for cracks by moisture that has penetrated freezes. Destruction occurs due to repeated freezing and thawing, but before that, there is a risk that the strength is reduced and the structure cannot maintain the predetermined strength. This is because the situation is completely different from the freezing of the pavement surface of Alfalt, which does not penetrate water and the freezing of the surface is a problem.
Conventionally known methods for preventing the asphalt pavement surface from freezing include spraying a deicing agent or encapsulating the deicing component (such as a deicing agent) with a jacket and encapsulating the particles in the pavement layer. It is mixed at a rate of several percent. With the wear of the pavement layer, new capsules are successively exposed and worn on the surface, and the internal freezing point depressant and the like are leached out. Therefore, a method has been used in which the effect is maintained for the life of the pavement layer itself. The former does not have a long-lasting effect because the drug is washed away, and the latter requires abrasion of the structure. Concrete structures require a long-term antifreeze effect, as is evident from their hydrophilic and water-permeable properties, and the structures must not wear. Therefore, the conventional method cannot be adopted.
[0003]
[Problems to be solved by the invention]
The present invention provides an admixture for concrete exposed to low temperatures, which prevents the freezing of concrete structures and has a long-lasting effect and does not require a special anti-freezing device.
[0004]
[Means to solve the problem]
The present invention
Consisting "1. A. 60 to 90 wt% freezing point depressant, B. And hydrophobic porous particles 5 to 20 wt%, C. Non-deliquescent in non-water-absorbing hydrophilic particles 5 to 20 wt%, city An additive for concrete exposed to low temperatures.
2 . 2. The concrete admixture according to claim 1, wherein the freezing point depressant is mainly composed of 1 or 2 selected from potassium acetate and calcium acetate.
3 . 2. The concrete admixture according to claim 1, wherein the freezing point depressant is a mixture obtained by adding iron sulfate hydrate and magnesium salt to 1 or 2 selected from calcium acetate and calcium acetate.
4 . 2. The concrete admixture according to item 1, wherein the freezing point depressant is a mixture containing calcium acetate as a main component obtained by reacting dolomite with acetic acid and phosphoric acid, and a magnesium salt or the like.
5 . 5. The concrete admixture according to any one of items 1 to 4 , wherein the hydrophobic porous particles are one or more selected from pearlite, expanded mica, shirasu balloon particles, and expanded polyurethane particles.
6 . The low temperature according to any one of Items 1 to 5 , wherein the non-deliquescent, non-water-absorbing hydrophilic particles are one or more selected from lava powder, quartz powder, pumice powder, and foamed glass powder. Admixture for concrete exposed to water.
7 . Item 7. The concrete admixture according to any one of Items 1 to 6 , which is used in an amount of 1 to 15% by weight based on the solid content of the concrete. "
About.
[0005]
[Action]
The feature of the present invention resides in that the concrete admixture is composed of hydrophobic particles containing a freezing point depressant in the pores and non-deliquescent, non-water-absorbing hydrophilic particles.
In order to prevent concrete structures from freezing, it is most effective to gradually elute the freezing point depressants into the water that has adhered to or penetrated the concrete structures, but all freezing point depressants are water-soluble. Because of its high hygroscopicity, it is dissolved by the moisture in the air during storage or it is necessary to prevent it from absorbing and aggregating. It has been found that it is very effective to contain and contain them.
However, since hydrophobic porous particles have a water-repellent property, the elution rate of the freezing point depressant contained in the pores is low, so a large amount of hydrophobic particles is required, and there is a risk of affecting properties such as strength of concrete. It is necessary to improve this point because large amounts of the freezing point depressant tend to promote water penetration.
[0006]
The present inventors further studied and as a result of mixing the hydrophilic particles, the hydrophilic particles distributed along the periphery of the hydrophobic porous particles containing and containing the freezing point depressant in the pores attract water. Since the agent elutes well, the freezing point depressant in the hydrophobic porous material exerts its effect continuously. However, if the hydrophilic particles are deliquescent, the concrete will have water permeability and will be melted by the infiltrated water before freezing is prevented, which is ineffective. In addition, if it has water absorption itself, it absorbs water and does not supply it to the hydrophobic particles, so that there is no effect. Therefore, the hydrophilic particles must be non-deliquescent and non-hydrophilic. When it is necessary to further increase the blending amount of the freezing point depressant, porous particles may be used as the hydrophilic particles, and the freezing point depressant may be contained in the pores.
[0007]
The admixture of the present invention contains 60 to 90% by weight of a freezing point depressant, 5 to 20% by weight of hydrophobic porous particles, 5 to 20% by weight of non-deliquescent and non-water-absorbing hydrophilic particles. If the amount of the agent is 60% by weight or less, there tends to be uneven distribution of the hydrophobic porous particles containing the agent. When the content is 90% by weight or more, the strength of the hydrophobic porous particles containing multiple freezing point depressants decreases, and there is a danger that the particles will be broken when mixed with concrete.
[0008]
When the content of the hydrophilic particles is less than 5% by weight, the effect of attracting water is too small.
[0009]
The admixture of the present invention is preferably blended in an amount of 1 to 15% by weight based on the solid content of concrete.
Another feature of the present invention is the incorporation of a composition comprising a freezing point depressant, hydrophobic particles, and non-deliquescent, non-absorbent hydrophilic particles into concrete. Applying or coating on the surface of a concrete structure cannot provide a long-lasting effect.
This is because, by being mixed with concrete, the freezing point depressant penetrates and gradually elutes into the freezing water to prevent freezing.
[0010]
The specialty of the anti-freezing method for concrete structures is that various road anti-icing agents were mixed with concrete and used for anti-icing tests. It is understood from the fact that was not obtained.
[0011]
Next, the materials used in the present invention will be described.
Examples of freezing point depressants include sodium chloride, calcium chloride, aluminum chloride, magnesium chloride, magnesium / calcium acetate, potassium acetate, calcium acetate, magnesium acetate, calcium phosphate, magnesium phosphate, calcium-hydrogen phosphate, magnesium-hydrogen phosphate, and nitrous acid. Sodium, sodium sulfate, potassium thiosulfate and the like are used. Potassium acetate and calcium acetate are particularly effective, and mixtures of both are also preferred.
[0012]
As a freezing point depressant, potassium acetate or calcium acetate alone or a mixture thereof may be used.For example, calcium acetate is reacted by reacting a mixed acid of phosphoric acid and acetic acid using dolomite composed of calcium carbonate and magnesium carbonate. It can also be used as a mixture in which a magnesium salt is mixed as a main component.
[0013]
As the hydrophobic porous particles, fired hydrophobic pearlite particles, expanded mica particles, shirasu balloon particles, synthetic resin porous particles such as foamed polyurethane, acrylic, and silicone carbon black particles are used. Perlite, expanded mica, shirasu balloon, and expanded polyurethane particles are preferred.
Non-deliquescent and non-water-absorbing hydrophilic particles include lava powder, quartz powder, pumice powder, foam glass powder, iron oxide powder, titanium dioxide, calcium carbonate, aluminum oxide, gypsum, magnesium oxide, barium sulfate, talc, Barium carbonate is used. Lava powder, quartz powder, pumice powder and foamed glass are preferred.
[0015]
Next, the present invention will be specifically described with reference to Examples and Comparative Examples.
[0016]
【Example】
Example 1
A reaction product of 95% dolomite, 1% phosphoric acid and 4% acetic acid, that is, 1000 g of dolomite (particle diameter: 10 to 15 mm) is mixed while gradually adding 70 g of 15% phosphoric acid and 400 g of 10% acetic acid. The reaction is carried out at 150 ° C. for 30 to 40 minutes with stirring in a reaction kettle to obtain a reaction product mainly composed of calcium acetate. 60% by weight of the obtained reaction product is prepared in advance and stored separately, and 20% by weight of lava powder, which is hydrophilic and non-deliquescent, 3% by weight of quartz powder and hydrophobicity. It is mixed with 2% by weight of calcined hydrophobic pearlite, which is a porous particle, and 15% by weight of a polyurethane foam, and is subjected to dry mixing and pulverization. The particle diameter of the porous particle is 0.1 mm or less filled with a void dolomite reaction product. To obtain an admixture for concrete containing the fine particle mixture of
[0017]
Example 2
Lava powder, hydrophilic and non-deliquescent particles, prepared in advance and separately stored with a mixture of 40% by weight of potassium acetate and 20% by weight of iron (III) sulfate nonahydrate in 60% by weight. 20% by weight, 3% by weight of quartz powder, and 2% by weight of calcined hydrophobic pearlite, which is a porous particle exhibiting hydrophobicity, and 15% by weight of polyurethane foam, are mixed and pulverized in a dry manner. And a mixture of iron (III) sulfate nonahydrate and a fine particle mixture having a particle size of 0.1 mm or less is obtained.
[0018]
Example 3
A concrete admixture was obtained in the same manner as in Example 2 except that a mixture of 35% by weight of magnesium chloride and 25% by weight of calcium acetate was used as a freezing point depressant.
[0019]
Comparative Example 1
No admixture according to the invention is used.
[0020]
Comparative Example 2
Only the dolomite reaction product shown in Example 1 is used, and no hydrophilic particles and no hydrophobic porous particles are used.
[0021]
Comparative Example 3
Only a mixture of 40% by weight of potassium acetate shown in Example 2 and 20% by weight of iron (III) sulfate nonahydrate is used, and hydrophilic particles and hydrophobic porous particles are not used.
[0022]
Comparative Example 4
Only the mixture of 35% by weight of magnesium chloride and 25% by weight of calcium acetate shown in Example 3 is used, and the hydrophilic particles and the hydrophobic porous particle components are not used.
Next, Table 1 shows the results of the performance test.
[0023]
In each of the test examples, water / cement = 52%, fine aggregate / fine aggregate + coarse aggregate = 41%, and the slump target value was 5.5 cm. .
Next, a test specimen having a diameter of 10 cm and a height of 20 cm was molded and cured at a temperature of -5 ° C, -10 ° C, and 20 ° C for a predetermined time.
After the curing, the specimen was thawed by leaving it in a room at 20 ° C. for 3 hours before performing the compressive strength test.
The concrete materials used are as follows.
Cement: Onoda Cement Co., Ltd., ordinary Portland cement fine aggregate: Kawasago Specific gravity 2.60 Coarse grain ratio 2.85
Coarse aggregate: crushed stone MS20mm
[0024]
[Table 1]
(Note) C: Cement (Kg) W: Water (Kg) S: Slump (cm)
7, 28 in the column of compressive strength represent 7 days and 28 days.
[0026]
【The invention's effect】
The concrete containing the admixture of the present invention has an excellent effect that the strength does not decrease even when exposed to low temperatures.
Claims (7)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33827594A JP3566371B2 (en) | 1994-12-16 | 1994-12-16 | Concrete admixture exposed to low temperatures |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33827594A JP3566371B2 (en) | 1994-12-16 | 1994-12-16 | Concrete admixture exposed to low temperatures |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08169739A JPH08169739A (en) | 1996-07-02 |
| JP3566371B2 true JP3566371B2 (en) | 2004-09-15 |
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| Application Number | Title | Priority Date | Filing Date |
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| JP33827594A Expired - Fee Related JP3566371B2 (en) | 1994-12-16 | 1994-12-16 | Concrete admixture exposed to low temperatures |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP4514145B2 (en) * | 2005-05-26 | 2010-07-28 | 電気化学工業株式会社 | Spraying material and spraying method using the same |
| JP5192146B2 (en) * | 2005-12-26 | 2013-05-08 | 株式会社エービーシー建材研究所 | Concrete surface modifier |
| JP4822536B2 (en) * | 2006-12-27 | 2011-11-24 | 太平洋マテリアル株式会社 | Weathering prevention method for alkali metal salt |
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