JP4152713B2 - Hydraulic composition - Google Patents

Description

【００１３】
〔式中、
Ｒ¹¹、Ｒ¹²：水素原子又は−CH₃
Ｒ¹³：水素原子又は−COO(AO)_nX¹¹
Ｘ：水素原子又は炭素数１〜１８のアルキル基
ｎ：１以上の整数
ｐ：０〜２の数
を示す。〕
【００１４】
【化５】

【００１５】
〔式中、
Ｒ²¹、Ｒ²²、Ｒ²³：同一でも異なっていても良く、水素原子、−CH₃又は(CH₂)_rCOOM²²であり、−CH₃又は(CH₂)_rCOOM²²はCOOM²¹又は他の(CH₂)_rCOOM²²と無水物を形成していてもよく、その場合、それらの基のM²¹、M²²は存在しない。
Ｍ²¹、Ｍ²²：水素原子、アルカリ金属、アルカリ土類金属、アンモニウム基、アルキルアンモニウム基又は置換アルキルアンモニウム基
ｒ：０〜２の数
を示す。〕
【００１６】
【化６】

【００１７】
〔式中、
Ｒ³¹：水素原子又はメチル基
Ｚ：水素原子、アルカリ金属、アルカリ土類金属、アンモニウム基、アルキルアンモニウム基又は置換アルキルアンモニウム基
を示す。〕。
【００１８】
また、本発明は、上記本発明の水硬性組成物用分散剤を含有する水硬性組成物、及び該水硬性組成物を成形した水硬性組成物成形体に関する。
【００１９】
【発明の実施の形態】
水／水硬性粉体比３５％以下の超高強度コンクリート（以下、単に超高強度コンクリートということがある）を短時間で混練するには、強い分散力を有する単量体(a)と、単量体(b)との共重合体（以下、ＰＡＧエステル系共重合体ということがある）を含有するセメント分散剤を使用することが必要である。
【００２０】
その際、水硬性粉体用分散剤の分散性及び分散保持性を向上し、温度依存性を安定させるには、従来の水硬性粉体用分散剤のように単一構造のものを単独成分で使用する方法では対応できない。
【００２１】
本発明者等は、構造パラメータとして、ＰＡＧエステル系共重合体におけるアルキレンオキサイドの平均付加モル数[ｎ]、単量体(a)と単量体(b)の合計重量に対する単量体(b)の酸型換算重量％ｘの積[ｎ]＊ｘに着目し、積[ｎ]＊ｘの異なるＰＡＧエステル系共重合体の組合わせを種々検討した結果、２≦[ｎ]＜１１０を具備した上で、積[ｎ]＊ｘが特定の関係にある組合わせが、分散力及び分散保持性の温度依存性が小さく、性能が安定していることが明らかとなった。以下、単量体(a)、単量体(b)と[ｎ]＊ｘについて詳述する。
【００２２】
＜単量体(a)＞
超高強度コンクリートの型枠への充填性を確保するため、混練後の粘性を抑制する必要があり、そのためには、単量体(a)の付加モル数ｎは１以上の整数であり、好ましくは１≦ｎ＜１１０、より好ましくは２≦ｎ＜１１０である。
【００２３】
本発明では、第１、第２の共重合体におけるアルキレンオキサイドの平均付加モル数[ｎ_A]及び[ｎ_B]が共に２以上１１０未満の範囲にある。[ｎ_A]及び[ｎ_B]（まとめて[ｎ]と表記する）の範囲は、５≦[ｎ]＜１００が好ましく、５≦[ｎ]≦７５がより好ましく、５≦[ｎ]≦５０がさらに好ましく、５≦[ｎ]≦４０がさらにより好ましく、５≦[ｎ]≦３０がさらに好ましく、５≦[ｎ]≦２５が特に好ましい。通常、このような平均付加モル数の範囲は、単量体(a)として、平均付加モル数ｎ_aが２以上１１０未満の範囲のものを使用することで達成される。単量体(a)のｎ_aは、好ましくは５≦ｎ_a＜１１０である。分散性の点で、５≦ｎ_aの単量体(a)が共重合体を構成する単量体中６０重量％以上、更に９０重量％以上、特に１００重量％であることが好ましい。
【００２４】
[ｎ_A]及び[ｎ_B]が共に２以上１１０未満の範囲にある限り、単量体(a)の構造を有し、ｎ_aが２未満又は１１０を超える単量体を併用することもできるが、ｎ_aが２未満又は１１０以上の単量体の比率は、共重合体を構成する単量体中２０重量％以下、更に１０重量％以下、特に０重量％であることが好ましい。
【００２５】
また、本発明では、単量体(a)を一種又は二種以上併用することができる。何れの場合も、[ｎ_A]及び[ｎ_B]は共に上記の範囲にある。第１、第２の共重合体において、単量体(a)としてアルキレンオキサイドの平均付加モル数ｎ_aが単一ピークの分布を有する単量体だけを用いる場合、当該ピークのｎ_aを[ｎ_A]又は[ｎ_B]とする。また、単量体(a)としてｎ_aの異なる複数の単量体を用いる場合、即ち、ｎ_aが異なるｋ種の単量体を用いる場合は、各単量体の平均付加モル数を[(ｎ_a)_i]（ｉ＝１、２…ｋ）、[(ｎ_a)_i]の単量体の共重合モル％をｔ_iとしたとき、共重合体の平均付加モル数[ｎ_A]又は[ｎ_B]は、以下の式で定義される。
[ｎ]≡Σ[(ｎ_a)_i]ｔ_i／Σｔ_i
式(1)中のＡＯは、同一でも異なっていても良く、異なる場合はランダム付加でも、ブロック付加でも良いが、好ましくは、全てエチレンオキサイドであることである。
【００２６】
単量体(a)の具体例として、メトキシポリエチレングリコール、メトキシポリプロピレングリコール、エトキシポリエチレンポリプロピレングリコール等の片末端低級アルキル基封鎖ポリアルキレングリコールと（メタ）アクリル酸とのエステル化物や、（メタ）アクリル酸へのエチレンオキシド、プロピレンオキシド付加物が挙げられ、好ましくはメトキシポリエチレングリコールと（メタ）アクリル酸とのエステル化物である。
【００２７】
＜単量体(b)＞
単量体(b)は式(2-1)で表される単量体及び式(2-2)で表される単量体から選ばれる。式(2-1)で表される単量体として、（メタ）アクリル酸、クロトン酸等の不飽和モノカルボン酸系単量体、マレイン酸、イタコン酸、フマル酸等の不飽和ジカルボン酸系単量体、又はこれらの塩、例えばアルカリ金属塩、アルカリ土類金属塩、アンモニウム塩、アミン塩等が挙げられ、好ましくは、（メタ）アクリル酸又はこれらのアルカリ金属塩である。また、式(2-2)で表される単量体として、（メタ）アリルスルホン酸又はこれらの塩、例えばアルカリ金属塩、アルカリ土類金属塩、アンモニウム塩、アミン塩等が挙げられる。
【００２８】
単量体(b)は、共重合体の分子量制御の観点より、式(2-1)、式(2-2)で表される単量体のみ、又は式(2-1)及び式(2-2)で表される単量体の混合物が好ましく、式(2-1)で表される単量体のみから選ばれるのが更に好ましく、最も好ましいのは、メタクリル酸を選ぶことである。
【００２９】
＜第１、第２の共重合体＞
本発明では、上記単量体(a)由来の構造と単量体(b)由来の構造とを構成単位として含む第１、第２の共重合体が使用される。
【００３０】
本発明では、第１の共重合体における単量体(a)の平均付加モル数[ｎ_A]及び単量体(a)と単量体(b)の合計に対する単量体(b)の酸型換算重量％ｘ_Aの積[ｎ_A]＊ｘ_Aと、第２の共重合体におけるアルキレングリコールの平均付加モル数[ｎ_B]及び単量体(a)と単量体(b)の合計に対する単量体(b)の酸型換算重量％ｘ_Bの積[ｎ_B]＊ｘ_Bとの差の絶対値（以下、Δｎ＊ｘと表記する）が２０以上である。すなわち、本発明では、単量体(a)由来の構造単位と単量体(b)由来の構造単位とを有する第１の共重合体と、単量体(a)由来の構造単位と単量体(b)由来の構造単位とを有し、第１の共重合体とは[ｎ]及びｘの少なくとも一方が異なる第２の共重合体が用いられる。
【００３１】
さらに、Δｎ＊ｘは、３０以上が好ましく、５０以上がより好ましく、１００以上がさらに好ましく、１３０以上がさらにより好ましく、１５０以上が特に好ましい。Δｎ＊ｘはあまり大きいと、両者の機能の相乗効果が低下し、分散性及び分散保持性がむしろ低下するので、Δｎ＊ｘは１０００以下であることが好ましく、７００以下であることがより好ましく、５００以下であることがさらに好ましい。
【００３２】
また、[ｎ_A]及び[ｎ_B]は、同一でも異なっていてもよいが、セメントの種類に対する分散性及び分散保持性の安定性を考慮すると、｜[ｎ_A]−[ｎ_B]｜≧２がより好ましく、｜[ｎ_A]−[ｎ_B]｜≧５がさらに好ましく、｜[ｎ_A]−[ｎ_B]｜≧１０が更に好ましい。
【００３３】
また、ｘ_A及びｘ_Bは、同一でも異なっていてもよく、それぞれ２重量％超３５重量％未満の範囲にあり、更に５重量％以上３５重量％未満、特に５重量％以上３０重量％未満の範囲にあることが、分散性と分散保持性のバランスの点から好ましい。
【００３４】
[ｎ_A]＊ｘ_Aと[ｎ_B]＊ｘ_Bとはどちらが大きくてもよいが、便宜上、[ｎ_A]＊ｘ_A＞[ｎ_B]＊ｘ_Bとすると、このとき、１５０≦[ｎ_A]＊ｘ_A≦１０００が好ましく、１８０≦[ｎ_A]＊ｘ_A≦７００がより好ましく、２００≦[ｎ_A]＊ｘ_A≦７００がさらに好ましく、２００≦[ｎ_A]＊ｘ_A≦５００がさらにより好ましく、３００≦[ｎ_A]＊ｘ_A≦５００が特に好ましい。この範囲の[ｎ_A]＊ｘ_Aに対して、Δｎ＊ｘが２０以上となる第２の共重合体を用いる。
【００３５】
第１、第２の共重合体を構成する単量体混合物中の単量体(a)と単量体(b)の合計量は５０重量％以上、更に８０重量％以上、特に１００重量％が好ましい。単量体(a)と単量体(b)以外の共重合可能な単量体として、アクリロニトリル、（メタ）アクリル酸アルキルエステル、（メタ）アクリルアミド、スチレンスルホン酸等が挙げられる。
【００３６】
本発明に係る共重合体は、公知の方法で製造することができる。例えば、特開平11-157897号公報の溶液重合法が挙げられ、水や炭素数１〜４の低級アルコール中、過硫酸アンモニウム、過酸化水素等の重合開始剤存在下、要すれば、亜硫酸ナトリウムやメルカプトエタノール等を添加し、５０〜１００℃で０．５〜１０時間反応させればよい。
【００３７】
本発明の共重合体は、重量平均分子量（ゲルパーミエーションクロマトグラフィー法／標準物質ポリスチレンスルホン酸ナトリウム換算／水系）が10,000〜100,000、特に10,000〜50,000の範囲が好ましい。
【００３８】
本発明において、第１、第２の共重合体の両者全体の[ｎ]の平均値ｎ_AVは、コンクリートの粘性の観点から、４０以下が好ましく、３０以下がより好ましく、２５以下がさらに好ましい。例えば、第１、第２の共重合体を、第１／第２＝Ｗ_A／Ｗ_Bの重量％（合計は１００重量％）で混合した場合、該混合物の全体の[ｎ]の平均値ｎ_AVは、以下の式で定義される。
ｎ_AV≡〔[ｎ_A]×（Ｍ_A）＋[ｎ_B]×（Ｍ_B）〕／〔Ｍ_A＋Ｍ_B〕
ここで、Ｍ_Aは、第１の共重合体Ｗ_A（ｇ）中の単量体(a)の共重合モル数であり、Ｍ_Bは、第２の共重合体Ｗ_B（ｇ）中の単量体(a)の共重合モル数である。
【００３９】
なお、本発明では、第１、第２の共重合体として、それぞれ単量体(a)、(b)から構成される共重合体を２種以上使用することもできる。例えば、第１の共重合体として、[ｎ_A]がＸの共重合体Ｘと[ｎ_A]がＹの共重合体Ｙを用い、第２の共重合体として、[ｎ_B]がＺの共重合体Ｚを併用できる。この場合、第１、第２の共重合体の組み合わせの少なくとも１つにおいて、本発明のΔｎ＊ｘを満たせば良く、他の共重合体は本発明の効果を損なわない範囲で使用される。好ましくは、用いる全ての第１、第２の共重合体同士で本発明のΔｎ＊ｘを満たすことである。
【００４０】
＜水硬性組成物用分散剤＞
本発明の分散剤において、第１の共重合体と第２の共重合体の重量比は、第１／第２＝５／９５〜９５／５が好ましく、第１／第２＝１５／８５〜８５／１５がより好ましく、第１／第２＝２５／７５〜７５／２５がさらに好ましく、第１／第２＝３０／７０〜７０／３０が特に好ましい。特に、水硬性組成物の分散性を改善するためには、ｎ＊ｘが大きい方の共重合体を多く用いることが好ましい。
【００４１】
また、本発明の分散剤において、第１の共重合体と第２の共重合体の合計の含有量は、固形分で５０重量％以上が好ましく、特に８０〜１００重量％、更に９０〜１００重量％が好ましい。
【００４２】
なお、本発明の分散剤では、本発明の性能を損なわない範囲で、別途合成したアルキレンオキサイド平均付加モル数が１１０以上のポリカルボン酸系共重合体、典型的にはＰＡＧエステル系共重合体を使用することができるが、その割合は、コンクリートの粘性の点から、第１の共重合体及び第２の共重合体の合計に対して２０重量％以下、更に１０重量％以下、特に５重量％以下である。
【００４３】
本発明の分散剤が良好に機能する水硬性組成物は、水、セメント、骨材を含有するモルタル又はコンクリートである。セメントとして、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が挙げられ、特に早強ポルトランドセメントが好ましい。
【００４４】
また、骨材のうち、細骨材は山砂、陸砂、川砂、砕砂が好ましく、粗骨材は山砂利、陸砂利、川砂利、砕石が好ましい。用途によっては、軽量骨材を使用してもよい。なお、骨材の用語は、「コンクリート総覧」（１９９８年６月１０日、技術書院発行）による。
【００４５】
特に水／水硬性粉体比（Ｗ／ＰやＷ／Ｃ）の低い範囲、例えば水／水硬性粉体比が４０重量％以下、更に５〜４０重量％、より更に５〜３０重量％、特に５〜２０重量％では、標準粒度分布の細骨材と同等の流動性を維持するために、細骨材として、粒度分布が、ＪＩＳ Ａ １１０２で用いられる呼び寸法０．３ｍｍのふるいの通過率（以下、０．３ｍｍ通過率という）が１重量％以上１０重量％未満で、かつ、粗粒率が２．５〜３．５である細骨材（以下、細骨材Ａという）が好ましい。
【００４６】
細骨材Ａは、より好ましくは、０．３ｍｍを超えるふるい呼び寸法における通過率が標準粒度分布の範囲内にあることである。
【００４７】
本発明において、細骨材Ａの０．３ｍｍ通過率は、水硬性組成物の流動性の点から、１０％未満が好ましく、より好ましくは９％以下、さらに好ましくは７％以下である。水硬性組成物の材料分離抵抗性の点から、０．３ｍｍ通過率は１％以上が好ましく、より好ましくは３％以上、さらに好ましくは５％を超えていることである。
【００４８】
従って、流動性維持と材料分離抵抗性の観点から、０．３ｍｍ通過率は１％以上１０％未満が好ましく、より好ましくは３％以上９％以下、更に好ましくは５％超７％以下である。
【００４９】
以上の要件に加え、細骨材Ａは、粗粒率（JIS A0203-3019）が２．５〜３．５であることが好ましく、より好ましくは２．６〜３．３で、更に好ましくは２．７〜３．１である。
【００５０】
粗粒率が２．５以上では、コンクリートの粘性が低減され、粗粒率が３．５以下では、材料分離抵抗性も良好となる。
【００５１】
さらに、細骨材ＡのＪＩＳ Ａ １１０２で用いられる呼び寸法０．３ｍｍを超えるふるいの通過率が、ＪＩＳ Ａ ５３０８付属書１表１の砂の標準粒度の範囲内であることが好ましい。より好ましくは、呼び寸法０．１５ｍｍのふるいの通過率が２重量％未満であり、更に好ましくは１．５重量％未満である。ただし、材料分離抵抗性の観点から、０．５重量％以上であることが好ましい。呼び寸法０．３ｍｍを超えるふるいについては、１つ以上の呼び寸法で、通過率が標準粒度の範囲内にあればよいが、好ましくは全部について標準粒度の範囲内にあることである。
【００５２】
細骨材Ａとしては、上記の粒度分布と粗粒率を満たす限り、砂、砕砂等、公知のものを適宜組み合わせて使用できる。本発明に使用できる細骨材としては、中国福建省ミン江等、特定地域の川砂が挙げられる。細孔が少なく、吸水性が低く、同じ流動性を付与するのに少量の水でよい点から、海砂よりも川砂、山砂、砕砂が好ましい。また、細骨材Ａは、絶乾比重（JIS A 0203：番号3015）が２．５６以上であることが好ましい。
【００５３】
本発明の水硬性組成物には、セメント以外の水硬性粉体として、高炉スラグ、フライアッシュ、シリカヒューム等が含まれてよく、また、非水硬性の石灰石微粉末等が含まれていてよい。セメントと混合されたシリカヒュームセメントや高炉セメントを用いてもよい。以下、水硬性組成物に水硬性粉体と非水硬性粉体が含まれる場合は、全てを一括して水硬性粉体と呼ぶ。
【００５４】
セメント以外の水硬性粉体としては、水硬性組成物の混練後の流動性の観点から、シリカヒュームが含まれることがより好ましい。
【００５５】
本発明の分散剤は、超高強度コンクリート等、水／水硬性粉体比が低い水硬性組成物に好適に用いられる。水硬性組成物の水／水硬性粉体比は、水硬性組成物の混練性と強度発現性の観点から、４０重量％以下が好ましく、更に５重量％≦水／水硬性粉体比≦４０重量％が好ましく、５重量％≦水／水硬性粉体比≦３０重量％がより好ましく、５重量％≦水／水硬性粉体比≦２０重量％が特に好ましい。
【００５６】
シリカヒュームが含まれる水硬性組成物については、混練性と強度発現性の観点から、セメント／シリカヒューム重量比が９７／３〜８０／２０、更に９５／５〜８５／１５であり、且つ４００≦セメント＋シリカヒューム≦１３００（kg/m³）、更に５００≦セメント＋シリカヒューム≦９００（kg/m³）であることが好ましい。さらに、強度発現性を考慮すると、１０≦水／（セメント＋シリカヒューム）×１００≦２０（重量％）であることが好ましい。
【００５７】
特に、強度発現性を考慮すると、以上の条件中のセメントが早強セメントであることが最も好ましい。
【００５８】
かかる水硬性組成物による成形体としては、カルバート、側溝、セグメント等の振動成形製品やポール、パイル、ヒューム管等の遠心成形製品が挙げられ、本発明の分散剤を使用することにより、年間を通じて良好な施工性と優れた強度及び耐久性を獲得することができる。
【００５９】
水／水硬性粉体比が２０重量％以下の超高強度コンクリートを用いた遠心成形の好ましい条件としては、スランプ値が１０ｃｍ以下、好ましくは５ｃｍ以下、更に２ｃｍ以下が好ましい。スランプ値が１０ｃｍ以下であると型枠への充填性及び成形性が良く、内面の落下やダレが防止され、内面の平滑性も良好となる。
【００６０】
かかる超高強度コンクリートの遠心成形条件としては、２〜４０Ｇで１３〜４０分程度必要であり、例えば、２〜５Ｇで５〜１５分、中速１０〜２０Ｇで３〜１０分、高速３０〜４０Ｇで５〜１５分が挙げられ、特に通常よりも低速時間を長くする条件が好ましい。
【００６１】
このような条件で遠心成形した場合の蒸気養生条件は、成形後１〜４時間前置後、１０〜３０℃／ｈｒで昇温し、６０〜８０℃で２〜８時間保持し、自然冷却する通常の条件が用いられる。
【００６２】
このような条件で遠心成形した場合に、成形後１〜３日後の強度を高めたい場合は、前置き１〜２時間、昇温２０〜３０℃／ｈｒ、保持７０〜８０℃で６〜８時間保持し、自然冷却が好ましい。また１４日以降の強度を高めたい場合は、前置き３〜４時間、昇温１０〜２０℃／ｈｒ、保持６０〜７０℃で２〜４時間保持し、自然冷却する条件が好ましい。
【００６３】
本発明の水硬性粉体用分散剤は、水硬性粉体に対して固形分で、０．０１〜５重量％、更に０．０５〜３重量％の比率で用いられることが好ましい。従って、本発明の水硬性組成物は、本発明の分散剤を水硬性粉体１００重量％に対して固形分で０．０１〜５重量％含有することが好ましい。
【００６４】
水硬性組成物には、上記成分以外に、ノロ低減材、早強材等の各種混和材料を使用することができる。更に、公知の添加剤（材）、例えばＡＥ剤、ＡＥ減水剤、高性能減水剤、減水剤、遅延剤、早強剤、促進剤、起泡剤、発泡剤、消泡剤、増粘剤、防水剤、防腐剤等を併用することが出来る。
【００６５】
【発明の効果】
本発明によれば、分散性に優れ、しかも温度変化による分散性能の変化が少なく、年間を通じて、従来以上の作業性及び充填性を付与できる水硬性組成物用分散剤が提供される。特に、水／水硬性粉体比が低い超高強度コンクリートについてもこの効果は顕著に発現する。また、更に、本発明の分散剤は、超高強度コンクリートの粘性を抑制して良好な充填性を確保することができる。
【００６６】
【実施例】
＜実施例１＞
《コンクリート材料》
下記のコンクリート材料を用いて表１ａの配合によりコンクリートの製造に用いた。本例は、生コン／コンクリート振動成形製品用途の組成物の実施例である。なお、表１ｂに細骨材Ｓ１、Ｓ２の物性を示した。
Ｗ：セメント分散剤を混合した水道水
Ｃ：普通ポルトランドセメント〔太平洋セメント（株）〕、表乾比重＝３．１６ＳＦＣ：シリカヒュームセメント〔宇部三菱セメント（株）〕、表乾比重＝３．０８
ＢＦＳ：高炉スラグ微粉末〔新日鉄高炉セメント（株）、エスメントスーパー６０〕、表乾比重＝２．８９
Ｓ１：細骨材、千葉県君津産山砂、表乾比重＝２．６３
Ｓ２：細骨材、中国福建省ミン江産川砂、表乾比重＝２．６３
Ｇ：粗骨材、和歌山産砕石Ｇ２０１３、表乾比重＝２．６２
Ｗ／Ｐ：［Ｗ／（Ｃ＋ＢＦＳ＋ＳＦＣ）］×１００（重量％）
ｓ／ａ：［（Ｓ１＋Ｓ２）／（Ｓ１＋Ｓ２＋Ｇ）］×１００（体積％）
空気量：２％
【００６７】
【表１ａ】

【００６８】
【表１ｂ】

【００６９】
《セメント分散剤》
表２、３の単量体(a)、単量体(b)を用いて表２、３の共重合体を製造し、それらを表４、５の組み合わせで併用してセメント分散剤を得た。得られた分散剤を用いて、以下のようにコンクリートを製造し、各配合における分散性、分散保持性及び粘性を評価した。結果を表６〜１３に示す。
【００７０】
【表２】

【００７１】
＊Ｍｗは重量平均分子量である。ＭＡＡはメタクリル酸であり、ＭＡＡ−Ｎａは共重合反応後に中和度６０±１０％に水酸化ナトリウムで中和したことを意味する（以下同様）。
【００７２】
【表３】

【００７３】
【表４】

【００７４】
＊ｎ_AVは第１、第２の共重合体全体におけるｎの平均値、ｘ_AVは第１、第２の共重合体全体におけるｘの平均値である（以下同様）。
【００７５】
【表５】

【００７６】
《コンクリート製造条件》
混練量は、３０リットルとし、Ｗ／Ｐにより以下のように製造した。
（１）Ｗ／Ｐ＝３５重量％のもの
セメント分散剤と混合した水以外のコンクリート材料を６０リットル強制２軸ミキサーに投入し、１０秒間混練後、セメント分散剤と混合した水を投入し、９０秒間混練した後、排出する。
（２）Ｗ／Ｐ＝２５、２０、１５重量％のもの
セメント分散剤と混合した水と粗骨材以外のコンクリート材料を６０リットルｌ強制２軸ミキサーに投入し、１０秒間混練後、セメント分散剤と混合した水を投入し、９０秒間混練し、その後、粗骨材を投入して６０秒間混練した後、排出する。
【００７７】
《分散性》
コンクリートの分散性は、コンクリートの混練直後のスランプフロー値（コンクリートライブラリー９３：高流動コンクリート施工指針、pp160-161、土木学会）が65±1cmとなるときに要した分散剤の水硬性粉体（Ｐ）重量に対する固形分添加率を尺度とした。数値が小さい程、分散性が良好である。このとき、初期空気量は２％以下になるように起泡連行剤（マイティAE-03：花王（株）製）と消泡剤（アンチフォームE-20：花王（株）製）で調整した。
【００７８】
《分散保持性》
混練直後のスランプフロー値に対する３０分後のスランプ値の混練直後のスランプフロー値に対する百分率を分散保持性の尺度とした。数値が大きいほど分散保持性が良好である。特に３０分後の分散保持率が８０％以上で１００％以下であることが好ましい。３０分後の分散保持率が８０％以上であると、コンクリートの充填性が良好となり、１００％以下であると、振動を加えたり遠心成形する際に粗骨材がモルタルから分離することが抑制される。
【００７９】
《粘性》
上記で調製したコンクリートから目開き５ｍｍの篩で骨材を分離して取り除いたものをモルタルとした。混練後１０分経過後のモルタルを、ステンレス鋼(SUS304)を加工して作製した図１の形状の装置に、下部排出口を閉じた状態で充填し上部投入開口の面で擦り切った後、下部排出開口を開口してモルタルを自然流下させ、叙位部投入開口から目視で観察したときにモルタルの少なくとも一部に孔が確認されるまでの時間（流下時間）を測定し、粘性の尺度とした。流下時間が短いほどモルタルの粘性が低い。なお、モルタルの温度は２０℃とした。
【００８０】
【表６】

【００８１】
＊温度は、コンクリートの温度であり、添加量は、対水硬性粉体（Ｐ）固形分重量％である（以下同様）。
【００８２】
【表７】

【００８３】
【表８】

【００８４】
【表９】

【００８５】
【表１０】

【００８６】
【表１１】

【００８７】
【表１２】

【００８８】
【表１３ａ】

【００８９】
【表１３ｂ】

【００９０】
＜実施例２＞
下記のコンクリート材料を用いて表１４の配合によりコンクリートの製造に用いた。本例は、コンクリート遠心成形製品用途の組成物の実施例である。
【００９１】
《コンクリート材料》
Ｗ：セメント分散剤を混合した水道水
ＨＣ：早強ポルトランドセメント〔太平洋セメント（株）〕、表乾比重＝３．１５
ＳＦＣ：シリカヒュームセメント〔宇部三菱セメント（株）〕、表乾比重＝３．０８
Ｓ：細骨材、千葉県君津産山砂、表乾比重＝２．６３
Ｇ：粗骨材、和歌山産砕石Ｇ２０１３、表乾比重＝２．６２
Ｗ／Ｐ：［Ｗ／（Ｃ＋ＨＣ＋ＳＦＣ）］×１００（重量％）
ｓ／ａ：［Ｓ／（Ｓ＋Ｇ）］×１００（体積％）
空気量：２％
【００９２】
【表１４】

【００９３】
《セメント分散剤》
実施例１で得たセメント分散剤Ｎｏ．１〜２７を用いた。それら分散剤を用いて、以下のようにコンクリートを製造し、各配合における分散性、分散保持性及び充填性を評価した。結果を表１５〜１７に示す。
【００９４】
《コンクリート製造条件》
混練量は、３０リットルとし、セメント分散剤と混合した水以外のコンクリート材料を６０リットル強制２軸ミキサーに投入し、６０秒間混練後、セメント分散剤と混合した水を投入し、３６０秒間混練した後、排出する。
【００９５】
《分散性》
コンクリートの分散性は、コンクリートの排出直後のスランプ値（JIS A 1101）が８〜８．３ｃｍとなるときに要した分散剤の水硬性粉体（Ｐ）重量に対する固形分添加率を尺度とした。数値が小さい程、分散性が良好である。このとき、初期空気量は２％以下になるように起泡連行剤（マイティAE-03：花王（株）製）と消泡剤（アンチフォームE-20：花王（株）製）で調整した。
【００９６】
《分散保持性》
混練直後のスランプフロー値に対する１５分後のスランプ値の混練直後のスランプ値に対する百分率（保持率）を分散保持性の尺度とした。
【００９７】
《充填性》
遠心成形用超高強度コンクリートは、スランプ値を１０ｃｍ以下に抑えることが好ましいため、Ｗ／Ｃ（Ｗ／Ｐ）は単位水量を低減して調整する。そのため、分散性が小さいと混練が不足してスランプが経時増大する傾向にある。スランプが１０ｃｍを超えると、コンクリートが極めて高粘性の流動体となり型枠内の鉄筋間を粗骨材が通過できず充填不良が生じる。そこで、充填性について以下の評価を行った。
（１）上部投入開口３０ｃｍ、下部排出開口７ｃｍのプラスチック漏斗（上部投入開口面から下部排出開口面までの距離２３ｃｍ）を、直径２０ｃｍ×長さ３０ｃｍの遠心力成形型枠の上側面の直径１０ｃｍの開口に設置する（図２参照）。（２）混練直後から１５分後のコンクリート１５ｋｇを、ハンドスコップで１０回に分けて漏斗上口から投入し、投入したコンクリートを、JIS A 1101に規定の突き棒で軽く突きながら、全量を投入する。
（３）コンクリートが全て型枠に投入されるまでの時間を計測し、以下の基準で評価した。
【００９８】
（評価基準）
○：投入したコンクリート全量が１分以内で型枠内に投入される。
△：投入したコンクリート全量が１分超２分以内に型枠内に投入される。
×：投入したコンクリートが２分を超えて漏斗内に残る。
【００９９】
【表１５】

【０１００】
【表１６】

【０１０１】
【表１７】

【図面の簡単な説明】
【図１】実施例で粘性の評価のための流下時間の測定に用いた装置を示す概略図
【図２】実施例で充填性の評価のための投入時間の測定に用いた装置を示す概略図
【符号の説明】
１…上部投入開口
２…下部排出開口[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dispersant for a hydraulic composition. In particular, the present invention relates to a dispersant for a hydraulic composition that improves the workability of ultra-high-strength concrete, an ultra-high-strength concrete molded body containing the dispersant, and a method for producing the same.
[0002]
[Prior art]
Conventionally, ultra-high-strength concrete with a water / hydraulic powder ratio of 30% or less has been mainly studied at the research level, but in recent years, with the improvement of the quality of hydraulic powder such as silica fume cement. No super high strength concrete having a water / hydraulic powder ratio of 20% or less is being provided at a practical level.
[0003]
Ultra high strength concrete with a water / hydraulic powder ratio of 20% or less must be kneaded with a mixture of hydraulic powder, fine aggregate and coarse aggregate exceeding 600 kg / m ³ with a small amount of water. Therefore, it is essential to use a dispersant for hydraulic powder suitable for this. However, there is almost no disclosure of dispersants suitable for such ultra-high strength concrete.
[0004]
Patent Document 1 discloses a technique for improving workability and filling performance of ultrahigh strength concrete having a water / hydraulic powder ratio of 10 to 30% by using a polyalkylene glycol-added polycarboxylic acid-based dispersant having a specific structure. Is disclosed.
[0005]
Further, Patent Document 2 attempts to improve slump loss by using a commercially available polycarboxylic acid-based dispersant in concrete having a water cement ratio of 32% or less mainly composed of (super) early strong cement. .
[0006]
Patent Document 3 discloses that a cement admixture excellent in high water reduction rate and slump retention can be obtained by using a copolymer mixture having different oxyethylene chains.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 6-191918 [Patent Document 2]
Japanese Patent Laid-Open No. 7-304014 [Patent Document 3]
Japanese Patent Laid-Open No. 9-286645
[Problems to be solved by the invention]
However, the conventional dispersing agent for hydraulic powder has a problem that the dispersion force varies depending on the temperature, and stable workability and workability cannot be obtained throughout the year. In ultra-high-strength concrete, the amount of dispersant used for hydraulic powder is larger than that of normal concrete with a water / hydraulic powder ratio of around 40%, so the influence of the temperature dependence of the dispersibility is extremely high. large. Specifically, the dispersibility of the dispersant for hydraulic powder declines in the winter, and when discharged at the same kneading time, the dispersion proceeds even after discharge, resulting in overdispersion, and the material separation resistance of the concrete system is remarkably high. The problem arises that breathing occurs due to lowering and a water channel is generated during vibration compaction. On the contrary, in summer, the dispersibility decreases during kneading, and the fluidity of the concrete system after discharging may decrease significantly. In such a case, there is a problem that the filling property of the concrete into the mold is deteriorated, or even if the vibration is compacted, bubbles remain on the surface and the appearance is deteriorated.
[0009]
With respect to such a problem of ultra-high strength concrete, the techniques of Patent Documents 1 to 3 cannot sufficiently cope.
[0010]
In view of the above situation, the present invention provides a dispersant for a hydraulic composition capable of imparting more workability and filling ability than ever before, particularly for ultra-high strength concrete having a low water / hydraulic powder ratio. This is the issue. Furthermore, after solving such a problem, it is further to suppress the viscosity of the ultra-high strength concrete having a small water / hydraulic powder ratio to ensure good filling properties.
[0011]
[Means for Solving the Problems]
The present invention includes a structural unit derived from the monomer (a) represented by the following general formula (1) (hereinafter referred to as the monomer (a)), and a monomer represented by the following general formula (2-1) And a structural unit derived from the monomer (b) selected from the monomers represented by the following general formula (2-2) (hereinafter referred to as the monomer (b)). Containing coalescing,
The average addition mole number [n _A ] of alkylene oxide in the first copolymer and the product [n _A ] * x of the weight percentage (x _A ) in terms of acid type of (b) with respect to the sum of (a) and (b) _The product of _A and the average added mole number [n _B ] of the alkylene oxide in the second copolymer [n _B ] and the acid type equivalent weight% (x _B ) of (b) with respect to the sum of (a) and (b) [n _B ] * X The absolute value of the difference from _B is 20 or more, and
Located [n _A] and [n _B] are both ranges of 2 to less than 110, x _A and x _B are in the range of both less than 2 wt.% 35 wt%,
The present invention relates to a dispersant for a hydraulic composition.
[0012]
[Formula 4]

[0013]
[Where,
R ¹¹ , R ¹² : hydrogen atom or —CH ₃
R ¹³ : hydrogen atom or —COO (AO) _n X ¹¹
X: a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, n: an integer of 1 or more, p: a number of 0 to 2. ]
[0014]
[Chemical formula 5]

[0015]
[Where,
R ²¹ , R ²² , R ^23, which may be the same or different, are a hydrogen atom, —CH ₃ or (CH ₂ ) _r COOM ²² , and —CH ₃ or (CH ₂ ) _r COOM ²² is COOM ²¹ or others. (CH ₂ ) _r COOM ²² may form an anhydride, in which case M ²¹ and M ²² of those groups are not present.
M ^21, M ^22: indicates the number of 0 to 2: hydrogen atom, an alkali metal, alkaline earth metal, an ammonium group, an alkylammonium group or a substituted alkylammonium group r. ]
[0016]
[Chemical 6]

[0017]
[Where,
R ³¹ : hydrogen atom or methyl group Z: hydrogen atom, alkali metal, alkaline earth metal, ammonium group, alkylammonium group or substituted alkylammonium group. ].
[0018]
Moreover, this invention relates to the hydraulic composition molded object which shape | molded the hydraulic composition containing the dispersing agent for hydraulic compositions of the said invention, and this hydraulic composition.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
In order to knead ultra high strength concrete having a water / hydraulic powder ratio of 35% or less (hereinafter sometimes simply referred to as ultra high strength concrete) in a short time, a monomer (a) having a strong dispersion force, It is necessary to use a cement dispersant containing a copolymer with the monomer (b) (hereinafter sometimes referred to as a PAG ester copolymer).
[0020]
At that time, in order to improve the dispersibility and dispersion retention of the dispersant for hydraulic powder and to stabilize the temperature dependency, a single component having a single structure like a conventional dispersant for hydraulic powder is used. It is not possible to cope with the method used in.
[0021]
As the structural parameters, the present inventors have determined, as structural parameters, the average added mole number of alkylene oxide [n] in the PAG ester copolymer, the monomer (b) with respect to the total weight of the monomer (a) and the monomer (b). As a result of examining various combinations of PAG ester-based copolymers having different products [n] * x, focusing on the product [n] * x of acid type equivalent weight% x of 2), 2 ≦ [n] <110 In addition, it has been clarified that the combination in which the product [n] * x has a specific relationship has a small temperature dependency of the dispersion force and dispersion retention and the performance is stable. Hereinafter, the monomer (a), the monomer (b) and [n] * x will be described in detail.
[0022]
<Monomer (a)>
In order to ensure the filling property of the ultra-high-strength concrete into the formwork, it is necessary to suppress the viscosity after kneading. For this purpose, the added mole number n of the monomer (a) is an integer of 1 or more, Preferably 1 ≦ n <110, more preferably 2 ≦ n <110.
[0023]
In the present invention, the average addition mole numbers [n _A ] and [n _B ] of alkylene oxide in the first and second copolymers are both in the range of 2 or more and less than 110. The range of [n _A ] and [n _B ] (collectively expressed as [n]) is preferably 5 ≦ [n] <100, more preferably 5 ≦ [n] ≦ 75, 5 ≦ [n] ≦ 50 is more preferable, 5 ≦ [n] ≦ 40 is further more preferable, 5 ≦ [n] ≦ 30 is further more preferable, and 5 ≦ [n] ≦ 25 is particularly preferable. Usually, such an average addition mole number of ranges, as the monomer (a), the average addition mole number n _a is achieved by using a range of 2 to less than 110. The n _a of the monomer (a) is preferably 5 ≦ n _a <110. In terms of dispersibility, 5 ≦ n monomer _a (a) is copolymerized monomer in the body constituting 60 wt% or more, further 90% by weight or more, particularly preferably 100% by weight.
[0024]
[n _A] and [n _B] is as long as both the range of 2 to less than 110, have the structure of the monomer (a), also be n _a is combined monomers of more than 2, or less than 110 possible, the ratio of n _a is less than 2 or more than 110 monomers, monomer 20 wt% in the body constituting the copolymer less, further 10 wt% or less, particularly preferably 0 wt%.
[0025]
In the present invention, the monomer (a) can be used alone or in combination of two or more. In any case, both [n _A ] and [n _B ] are in the above range. In the first and second copolymers, when the average addition molar number n _a of alkylene oxide using only monomers having a distribution of single peak as the monomer (a), the n _a of the peak [ n _A ] or [n _B ]. In the case of using a plurality of different monomers of n _a as a monomer (a), i.e., if n _a is using different k species of monomers, the average addition number of moles of each monomer [ (n _a ) _i ] (i = 1, 2,..., k) and [(n _a ) _i ], where the copolymerization mole% is t _i , the average added mole number of the copolymer [n _A ] Or [n _B ] is defined by the following equation.
[n] ≡Σ [(n _a ) _i ] t _i / Σt _i
AO in formula (1) may be the same or different, and if they are different, random addition or block addition may be used, but preferably all are ethylene oxide.
[0026]
Specific examples of the monomer (a) include esterified products of (meth) acrylic acid and (meth) acrylic acid, such as methoxypolyethylene glycol, methoxypolypropylene glycol, ethoxypolyethylenepolypropylene glycol, etc. Examples include adducts of ethylene oxide and propylene oxide to the acid, preferably esterified products of methoxypolyethylene glycol and (meth) acrylic acid.
[0027]
<Monomer (b)>
The monomer (b) is selected from the monomer represented by the formula (2-1) and the monomer represented by the formula (2-2). Monomers represented by the formula (2-1) include unsaturated monocarboxylic acid monomers such as (meth) acrylic acid and crotonic acid, and unsaturated dicarboxylic acid monomers such as maleic acid, itaconic acid, and fumaric acid. Monomers or salts thereof such as alkali metal salts, alkaline earth metal salts, ammonium salts, amine salts and the like can be mentioned, and (meth) acrylic acid or alkali metal salts thereof are preferable. Examples of the monomer represented by the formula (2-2) include (meth) allylsulfonic acid or a salt thereof such as an alkali metal salt, an alkaline earth metal salt, an ammonium salt, and an amine salt.
[0028]
Monomer (b) is, from the viewpoint of controlling the molecular weight of the copolymer, only the monomer represented by Formula (2-1), Formula (2-2), or Formula (2-1) and Formula ( A mixture of monomers represented by 2-2) is preferred, more preferably selected from only monomers represented by formula (2-1), and most preferred is the selection of methacrylic acid. .
[0029]
<First and second copolymers>
In the present invention, the first and second copolymers containing the monomer (a) -derived structure and the monomer (b) -derived structure as structural units are used.
[0030]
In the present invention, the average added mole number [n _A ] of the monomer (a) in the first copolymer and the sum of the monomer (a) and the monomer (b) Acid type weight% x _A product [n _A ] * x _A , average number of moles of alkylene glycol added in the second copolymer [n _B ], monomer (a) and monomer (b) monomer to the total of the acid type converted weight% x product of _B in (b) [n _B] * absolute value of the difference between x _B (hereinafter, referred to as [Delta] n * x) is 20 or more. That is, in the present invention, the first copolymer having the structural unit derived from the monomer (a) and the structural unit derived from the monomer (b), the structural unit derived from the monomer (a) and the single unit. A second copolymer having a structural unit derived from the monomer (b) and different from at least one of [n] and x from the first copolymer is used.
[0031]
Furthermore, Δn * x is preferably 30 or more, more preferably 50 or more, still more preferably 100 or more, still more preferably 130 or more, and particularly preferably 150 or more. If Δn * x is too large, the synergistic effect of both functions will be reduced, and the dispersibility and dispersion retention will be rather lowered. Therefore, Δn * x is preferably 1000 or less, more preferably 700 or less. More preferably, it is 500 or less.
[0032]
[N _A ] and [n _B ] may be the same or different, but considering the dispersibility with respect to the type of cement and the stability of the dispersion retention, | [n _A ] − [n _B ] | ≧ 2 is more preferable, | [n _A ] − [n _B ] | ≧ 5 is more preferable, and | [n _A ] − [n _B ] | ≧ 10 is more preferable.
[0033]
X _A and x _B may be the same or different, and each is in the range of more than 2% by weight and less than 35% by weight, more preferably 5% by weight or more and less than 35% by weight, particularly 5% by weight or more and less than 30% by weight. It is preferable from the viewpoint of the balance between dispersibility and dispersion retention.
[0034]
[n _A ] * x _A and [n _B ] * x _B may be larger, but for convenience, if [n _A ] * x _A > [n _B ] * x _B , then 150 ≦ [ n _A ] * x _A ≦ 1000 is preferable, 180 ≦ [n _A ] * x _A ≦ 700 is more preferable, 200 ≦ [n _A ] * x _A ≦ 700 is further preferable, and 200 ≦ [n _A ] * x _A ≦ 500 is even more preferable, and 300 ≦ [n _A ] * x _A ≦ 500 is particularly preferable. For the [n _A ] * x _{A in} this range, a second copolymer having Δn * x of 20 or more is used.
[0035]
The total amount of the monomer (a) and the monomer (b) in the monomer mixture constituting the first and second copolymers is 50% by weight or more, further 80% by weight or more, particularly 100% by weight. Is preferred. Examples of the copolymerizable monomer other than the monomer (a) and the monomer (b) include acrylonitrile, (meth) acrylic acid alkyl ester, (meth) acrylamide, and styrene sulfonic acid.
[0036]
The copolymer according to the present invention can be produced by a known method. For example, the solution polymerization method of JP-A-11-157897 can be mentioned. In the presence of a polymerization initiator such as ammonium persulfate or hydrogen peroxide in water or a lower alcohol having 1 to 4 carbon atoms, if necessary, sodium sulfite or What is necessary is just to add mercaptoethanol etc. and to make it react at 50-100 degreeC for 0.5 to 10 hours.
[0037]
The copolymer of the present invention preferably has a weight average molecular weight (gel permeation chromatography method / standard substance sodium polystyrene sulfonate equivalent / water system) in the range of 10,000 to 100,000, particularly 10,000 to 50,000.
[0038]
In the present invention, the average value n _AV of [n] of both the first and second copolymers is preferably 40 or less, more preferably 30 or less, and even more preferably 25 or less, from the viewpoint of the viscosity of the concrete. . For example, first, second copolymer, if the weight% of the first / 2 = W _A / W _B (total 100 wt%) were mixed, the average value of the [n] of the whole of the mixture n _AV is defined by the following equation.
n _AV ≡ [[n _A ] × (M _A ) + [n _B ] × (M _B )] / [M _A + M _B ]
Here, M _A is the number of moles of copolymerization of the monomer (a) in the first copolymer W _A (g), and M _B is in the second copolymer W _B (g). The number of moles of copolymerization of the monomer (a).
[0039]
In the present invention, as the first and second copolymers, two or more kinds of copolymers each composed of the monomers (a) and (b) can be used. For example, as the first copolymer, using the copolymer Y copolymer X of [n _A] is X and [n _A] is Y, as the second copolymer, the [n _B] Z Copolymer Z can be used in combination. In this case, at least one of the combinations of the first and second copolymers only needs to satisfy Δn * x of the present invention, and other copolymers are used as long as the effects of the present invention are not impaired. Preferably, all the first and second copolymers used satisfy Δn * x of the present invention.
[0040]
<Dispersant for hydraulic composition>
In the dispersant of the present invention, the weight ratio of the first copolymer to the second copolymer is preferably 1/2 = 5/95 to 95/5, and 1/2 = 15/85. -85/15 is more preferable, 1/2 = 25 / 75-75 / 25 is further more preferable, and 1/2 = 30 / 70-70 / 30 is particularly preferable. In particular, in order to improve the dispersibility of the hydraulic composition, it is preferable to use a copolymer having a larger n * x.
[0041]
In the dispersant of the present invention, the total content of the first copolymer and the second copolymer is preferably 50% by weight or more, particularly 80 to 100% by weight, and more preferably 90 to 100% by solid content. % By weight is preferred.
[0042]
In the dispersant of the present invention, a separately synthesized polycarboxylic acid copolymer having an average added mole number of 110 or more, typically a PAG ester copolymer, as long as the performance of the present invention is not impaired. However, in terms of the viscosity of the concrete, the proportion is 20% by weight or less, more preferably 10% by weight or less, particularly 5% or less based on the total of the first copolymer and the second copolymer. % By weight or less.
[0043]
The hydraulic composition in which the dispersant of the present invention functions well is mortar or concrete containing water, cement, aggregate. Examples of the cement include ordinary Portland cement, early-strength Portland cement, and ultra-early-strength Portland cement, and particularly preferably early-strength Portland cement.
[0044]
Of the aggregates, fine aggregates are preferably mountain sand, land sand, river sand, and crushed sand, and coarse aggregates are preferably mountain gravel, land gravel, river gravel, and crushed stone. Depending on the application, lightweight aggregates may be used. The term “aggregate” is based on “Concrete Overview” (published on June 10, 1998, published by Technical Shoin).
[0045]
In particular, a low range of water / hydraulic powder ratio (W / P or W / C), for example, water / hydraulic powder ratio is 40% by weight or less, further 5 to 40% by weight, further 5 to 30% by weight, In particular, in the case of 5 to 20% by weight, in order to maintain the fluidity equivalent to the fine aggregate having the standard particle size distribution, the fine particle aggregate has a particle size distribution passing through a sieve having a nominal size of 0.3 mm used in JIS A 1102. A fine aggregate (hereinafter referred to as fine aggregate A) having a rate (hereinafter referred to as 0.3 mm passage rate) of 1% by weight or more and less than 10% by weight and a coarse particle ratio of 2.5 to 3.5. preferable.
[0046]
More preferably, the fine aggregate A has a passing rate in a sieve nominal size exceeding 0.3 mm within the range of the standard particle size distribution.
[0047]
In the present invention, the 0.3 mm passage rate of the fine aggregate A is preferably less than 10%, more preferably 9% or less, and even more preferably 7% or less, from the viewpoint of the fluidity of the hydraulic composition. From the viewpoint of material separation resistance of the hydraulic composition, the 0.3 mm passage rate is preferably 1% or more, more preferably 3% or more, and further preferably more than 5%.
[0048]
Therefore, from the viewpoint of fluidity maintenance and material separation resistance, the 0.3 mm passage rate is preferably 1% or more and less than 10%, more preferably 3% or more and 9% or less, and further preferably more than 5% and 7% or less. .
[0049]
In addition to the above requirements, the fine aggregate A preferably has a coarse particle ratio (JIS A0203-3019) of 2.5 to 3.5, more preferably 2.6 to 3.3, and still more preferably. 2.7 to 3.1.
[0050]
When the coarse particle ratio is 2.5 or more, the viscosity of the concrete is reduced, and when the coarse particle ratio is 3.5 or less, the material separation resistance is also good.
[0051]
Further, it is preferable that the passing rate of the fine aggregate A used in JIS A 1102 exceeds a nominal size of 0.3 mm is within the standard particle size range of sand in JIS A 5308 Annex 1 Table 1. More preferably, the passage rate of a sieve having a nominal size of 0.15 mm is less than 2% by weight, and more preferably less than 1.5% by weight. However, from the viewpoint of material separation resistance, it is preferably 0.5% by weight or more. For a sieve having a nominal size of 0.3 mm or more, it is sufficient that one or more nominal sizes have a passing rate within the range of the standard particle size, but preferably all are within the standard particle size range.
[0052]
As the fine aggregate A, known materials such as sand and crushed sand can be used in appropriate combination as long as the above particle size distribution and coarse particle ratio are satisfied. Examples of fine aggregates that can be used in the present invention include river sand in specific areas such as Minjiang, Fujian, China. River sand, mountain sand, and crushed sand are preferred to sea sand because they have few pores, low water absorption, and a small amount of water is sufficient to impart the same fluidity. The fine aggregate A preferably has an absolute dry specific gravity (JIS A 0203: number 3015) of 2.56 or more.
[0053]
The hydraulic composition of the present invention may include blast furnace slag, fly ash, silica fume and the like as hydraulic powder other than cement, and may also include non-hydraulic fine limestone powder and the like. . Silica fume cement or blast furnace cement mixed with cement may be used. Hereinafter, when the hydraulic composition includes a hydraulic powder and a non-hydraulic powder, all of them are collectively referred to as a hydraulic powder.
[0054]
As the hydraulic powder other than cement, silica fume is more preferably contained from the viewpoint of fluidity after kneading of the hydraulic composition.
[0055]
The dispersant of the present invention is suitably used for hydraulic compositions having a low water / hydraulic powder ratio, such as ultra-high strength concrete. The water / hydraulic powder ratio of the hydraulic composition is preferably 40% by weight or less, more preferably 5% by weight ≦ water / hydraulic powder ratio ≦ 40, from the viewpoint of kneadability and strength development of the hydraulic composition. % By weight is preferable, 5% by weight ≦ water / hydraulic powder ratio ≦ 30% by weight is more preferable, and 5% by weight ≦ water / hydraulic powder ratio ≦ 20% by weight is particularly preferable.
[0056]
The hydraulic composition containing silica fume has a cement / silica fume weight ratio of 97/3 to 80/20, more preferably 95/5 to 85/15, and 400 from the viewpoint of kneadability and strength development. It is preferable that ≦ cement + silica fume ≦ 1300 (kg / m ³ ), and further 500 ≦ cement + silica fume ≦ 900 (kg / m ³ ). Furthermore, considering strength development, it is preferable that 10 ≦ water / (cement + silica fume) × 100 ≦ 20 (% by weight).
[0057]
In particular, considering the strength development, it is most preferable that the cement under the above conditions is an early strong cement.
[0058]
Examples of the molded body of the hydraulic composition include vibration molded products such as culverts, side grooves, and segments, and centrifugal molded products such as poles, piles, and fume tubes. Through the use of the dispersant of the present invention, the Good workability and excellent strength and durability can be obtained.
[0059]
As a preferable condition of centrifugal molding using ultrahigh strength concrete having a water / hydraulic powder ratio of 20% by weight or less, a slump value is 10 cm or less, preferably 5 cm or less, and more preferably 2 cm or less. When the slump value is 10 cm or less, the filling property and moldability to the mold are good, the inner surface is prevented from dropping and sagging, and the inner surface is also smooth.
[0060]
As centrifugal molding conditions of such ultra-high strength concrete, 2-40G requires about 13-40 minutes, for example, 2-5G for 5-15 minutes, medium speed 10-20G for 3-10 minutes, high speed 30- Examples include 5 to 15 minutes at 40G, and the condition for increasing the low-speed time is more preferable than usual.
[0061]
Steam curing conditions in the case of centrifugal molding under such conditions are as follows: 1 to 4 hours after molding, then heated at 10 to 30 ° C./hr, held at 60 to 80 ° C. for 2 to 8 hours, and naturally cooled Normal conditions are used.
[0062]
When centrifugal molding is performed under such conditions, if it is desired to increase the strength after 1 to 3 days after molding, the time is 1 to 2 hours, the temperature is raised to 20 to 30 ° C./hr, and the holding is 70 to 80 ° C. for 6 to 8 hours. Holding and natural cooling are preferred. In addition, when it is desired to increase the strength after 14 days, the condition of holding for 3 to 4 hours in advance, heating at 10 to 20 ° C./hr, holding at 60 to 70 ° C. for 2 to 4 hours, and naturally cooling is preferable.
[0063]
The dispersant for hydraulic powder of the present invention is preferably used in a solid content of 0.01 to 5% by weight, more preferably 0.05 to 3% by weight, based on the hydraulic powder. Therefore, the hydraulic composition of the present invention preferably contains the dispersant of the present invention in an amount of 0.01 to 5% by weight in solid content with respect to 100% by weight of the hydraulic powder.
[0064]
In addition to the above components, various admixture materials such as a Noro reducing material and a early strength material can be used for the hydraulic composition. Furthermore, known additives (materials), such as AE agents, AE water reducing agents, high performance water reducing agents, water reducing agents, retarders, early strengthening agents, accelerators, foaming agents, foaming agents, antifoaming agents, thickening agents , Waterproofing agents, preservatives and the like can be used in combination.
[0065]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the dispersing agent for hydraulic compositions which is excellent in a dispersibility, and there are few changes of the dispersion performance by a temperature change, and can provide workability | operativity and filling property more than the past throughout the year is provided. In particular, this effect is remarkably exhibited even for ultra high strength concrete having a low water / hydraulic powder ratio. Furthermore, the dispersant of the present invention can ensure good filling properties by suppressing the viscosity of ultra-high strength concrete.
[0066]
【Example】
<Example 1>
《Concrete material》
The following concrete materials were used for the production of concrete according to the formulation in Table 1a. This example is an example of a composition for use in a ready-mixed concrete / concrete vibration molded product. Table 1b shows the physical properties of the fine aggregates S1 and S2.
W: Tap water mixed with cement dispersant C: Ordinary Portland cement [Pacific Cement Co., Ltd.], surface dry specific gravity = 3.16 SFC: Silica fume cement [Ube Mitsubishi Cement Co., Ltd.], surface dry specific gravity = 3.08
BFS: ground granulated blast furnace slag [Nippon Steel Blast Furnace Cement Co., Ltd., Sment Super 60], surface dry specific gravity = 2.89
S1: fine aggregate, mountain sand from Kimitsu, Chiba, surface dry specific gravity = 2.63
S2: Fine aggregate, river sand from Minjiang, Fujian, China, specific gravity = 2.63
G: Coarse aggregate, Wakayama crushed stone G2013, surface dry specific gravity = 2.62
W / P: [W / (C + BFS + SFC)] × 100 (% by weight)
s / a: [(S1 + S2) / (S1 + S2 + G)] × 100 (volume%)
Air volume: 2%
[0067]
[Table 1a]

[0068]
[Table 1b]

[0069]
<Cement dispersant>
Using the monomer (a) and monomer (b) in Tables 2 and 3, the copolymers in Tables 2 and 3 were produced, and these were used in combination in Tables 4 and 5 to obtain a cement dispersant. It was. Using the obtained dispersant, concrete was produced as follows, and the dispersibility, dispersion retention, and viscosity in each formulation were evaluated. The results are shown in Tables 6-13.
[0070]
[Table 2]

[0071]
* Mw is a weight average molecular weight. MAA is methacrylic acid, and MAA-Na means neutralization with sodium hydroxide to a degree of neutralization of 60 ± 10% after the copolymerization reaction (the same applies hereinafter).
[0072]
[Table 3]

[0073]
[Table 4]

[0074]
* N _AV is an average value of n in the entire first and second copolymers, and x _AV is an average value of x in the entire first and second copolymers (the same applies hereinafter).
[0075]
[Table 5]

[0076]
《Concrete production conditions》
The kneading amount was 30 liters, and it was manufactured by W / P as follows.
(1) Concrete material other than water mixed with cement dispersant with W / P = 35% by weight is put into a 60 liter forced biaxial mixer, kneaded for 10 seconds, and then mixed with cement dispersant. After kneading for 90 seconds, it is discharged.
(2) Concrete material other than coarse aggregate with water mixed with cement dispersant with W / P = 25, 20, 15% by weight is put into 60 liter l forced biaxial mixer, kneaded for 10 seconds, then cement dispersed Water mixed with the agent is added and kneaded for 90 seconds, then coarse aggregate is added and kneaded for 60 seconds, and then discharged.
[0077]
《Dispersibility》
The dispersibility of the concrete is the hydraulic powder of the dispersant required when the slump flow value immediately after mixing the concrete (Concrete Library 93: Guidelines for Construction of High Fluid Concrete, pp160-161, Japan Society of Civil Engineers) is 65 ± 1 cm. (P) The solid content addition rate relative to the weight was taken as a scale. The smaller the value, the better the dispersibility. At this time, the initial air volume was adjusted to 2% or less with a foaming agent (Mighty AE-03: manufactured by Kao Corporation) and an antifoaming agent (Antifoam E-20: manufactured by Kao Corporation). .
[0078]
<Dispersion retention>
The percentage of the slump value 30 minutes after the slump flow value immediately after kneading to the slump flow value immediately after kneading was used as a measure of dispersion retention. The larger the numerical value, the better the dispersion retention. In particular, the dispersion retention after 30 minutes is preferably 80% or more and 100% or less. When the dispersion retention rate after 30 minutes is 80% or more, the filling property of the concrete is good, and when it is 100% or less, the coarse aggregate is prevented from separating from the mortar during vibration or centrifugal molding. Is done.
[0079]
"viscosity"
Mortar was obtained by separating and removing the aggregate from the concrete prepared above with a sieve having an opening of 5 mm. The mortar 10 minutes after kneading is filled in the apparatus of the shape shown in FIG. 1 manufactured by processing stainless steel (SUS304) with the lower discharge port closed, and is scraped off on the surface of the upper input opening. The lower discharge opening is opened to allow the mortar to flow down naturally, and the time (flowing time) until a hole is confirmed in at least a part of the mortar when visually observed from the elevation input opening, measures the viscosity. did. The shorter the flow-down time, the lower the viscosity of the mortar. The mortar temperature was 20 ° C.
[0080]
[Table 6]

[0081]
* Temperature is the temperature of concrete, and the amount added is solid powder (P) solid content weight% (the same applies hereinafter).
[0082]
[Table 7]

[0083]
[Table 8]

[0084]
[Table 9]

[0085]
[Table 10]

[0086]
[Table 11]

[0087]
[Table 12]

[0088]
[Table 13a]

[0089]
[Table 13b]

[0090]
<Example 2>
It used for manufacture of concrete by the mixing | blending of Table 14 using the following concrete material. This example is an example of a composition for concrete centrifugal molded product applications.
[0091]
《Concrete material》
W: Tap water mixed with cement dispersant HC: Hayashi Portland cement [Pacific Cement Co., Ltd.], surface dry specific gravity = 3.15
SFC: Silica fume cement [Ube Mitsubishi Cement Co., Ltd.], surface dry specific gravity = 3.08
S: Fine aggregate, mountain sand from Kimitsu, Chiba Prefecture, surface dry specific gravity = 2.63
G: Coarse aggregate, Wakayama crushed stone G2013, surface dry specific gravity = 2.62
W / P: [W / (C + HC + SFC)] × 100 (% by weight)
s / a: [S / (S + G)] × 100 (volume%)
Air volume: 2%
[0092]
[Table 14]

[0093]
<Cement dispersant>
The cement dispersant No. 1 obtained in Example 1 was used. 1-27 were used. Using these dispersants, concrete was produced as follows, and the dispersibility, dispersion retention and filling properties in each formulation were evaluated. The results are shown in Tables 15-17.
[0094]
《Concrete production conditions》
The kneading amount is 30 liters, and concrete materials other than water mixed with the cement dispersant are put into a 60 liter forced biaxial mixer, kneaded for 60 seconds, then water mixed with the cement dispersant is put in and kneaded for 360 seconds. Then drain.
[0095]
《Dispersibility》
The dispersibility of the concrete was measured using the solid content addition ratio with respect to the weight of the hydraulic powder (P) of the dispersant required when the slump value (JIS A 1101) immediately after discharging the concrete is 8 to 8.3 cm. . The smaller the value, the better the dispersibility. At this time, the initial air volume was adjusted to 2% or less with a foaming agent (Mighty AE-03: manufactured by Kao Corporation) and an antifoaming agent (Antifoam E-20: manufactured by Kao Corporation). .
[0096]
<Dispersion retention>
The percentage (retention rate) of the slump value after 15 minutes to the slump value immediately after kneading with respect to the slump flow value immediately after kneading was used as a measure of dispersion retention.
[0097]
<Fillability>
Since ultra-high-strength concrete for centrifugal molding preferably has a slump value of 10 cm or less, W / C (W / P) is adjusted by reducing the unit water amount. Therefore, if the dispersibility is small, kneading is insufficient and the slump tends to increase with time. If the slump exceeds 10 cm, the concrete becomes a very viscous fluid and the coarse aggregate cannot pass between the reinforcing bars in the mold, resulting in poor filling. Then, the following evaluation was performed about the filling property.
(1) A plastic funnel having an upper input opening of 30 cm and a lower discharge opening of 7 cm (a distance of 23 cm from the upper input opening surface to the lower discharge opening surface) is 20 cm in diameter and 10 cm in diameter on the upper surface of the centrifugal force forming mold having a length of 30 cm (See FIG. 2). (2) 15kg of concrete 15 minutes after mixing is divided into 10 times with a hand scoop and charged from the top of the funnel. To do.
(3) The time until all the concrete was put into the formwork was measured and evaluated according to the following criteria.
[0098]
(Evaluation criteria)
○: The total amount of concrete thrown in the mold within 1 minute.
Δ: The total amount of concrete thrown in the formwork within 1 minute and 2 minutes.
X: The thrown-in concrete remains in the funnel for more than 2 minutes.
[0099]
[Table 15]

[0100]
[Table 16]

[0101]
[Table 17]

[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an apparatus used for measuring a flow-down time for evaluating viscosity in an embodiment. FIG. 2 is an outline showing an apparatus used for measuring a charging time for evaluating fillability in an embodiment. Figure [Explanation of symbols]
1 ... Upper input opening 2 ... Lower discharge opening

Claims (7)

A hydraulic composition having a water / hydraulic powder ratio of 5 to 30% by weight, comprising water, cement, aggregate, silica fume, and a dispersant for hydraulic composition,
[I] The above-mentioned dispersant for hydraulic powder is contained in a solid content of 0.01 to 5% by weight with respect to the hydraulic powder,
[II] The hydraulic composition dispersant has a structural unit derived from the monomer (a) represented by the following general formula (1), a monomer represented by the following general formula (2-1) (b ) containing first, second copolymer having a structural unit derived from,
The weight ratio of the first copolymer to the second copolymer is 1/2 = 25/75 to 75/25,
The average addition mole number [n _A ] of alkylene oxide in the first copolymer and the product [n _A ] * x of the acid type equivalent weight% (x _A ) of (b) to the sum of (a) and (b) _The product of _A and the average added mole number [n _B ] of the alkylene oxide in the second copolymer [n _B ] and the acid type equivalent weight% (x _B ) of (b) to the sum of (a) and (b) [n _B ] * X The absolute value of the difference from _B is 41.5 or more, and
[n _A ] and [n _B ] are both in the range of 5 or more and 50 or less, and both x _A and x _B are in the range of more than 2 wt% and less than 35 wt%,
A dispersant for a hydraulic composition,
Hydraulic composition.

[Where,
R ¹¹ , R ¹² : hydrogen atom or —CH ₃
R ^13: a hydrogen atom X: a hydrogen atom or an alkyl group having 1 to 18 carbon atoms n: 1 or more integer p: indicates the number of 0 to 2. ]

[Where,
R ²¹ , R ²² , R ²³ may be the same or different, and is a hydrogen atom or —C H ₃
M ^21: a hydrogen atom, an alkali metal, alkaline earth metal, an ammonium group, an alkylammonium group or a substituted alkylammonium group. ] 2. The hydraulic composition according to claim 1, wherein the cement / silica fume weight ratio is 97/3 to 80/20, and 400 ≦ cement + silica fume ≦ 1300 (kg / m ³ ).   The hydraulic composition according to claim 1 or 2, wherein the cement is an early strong cement.   The hydraulic composition according to any one of claims 1 to 3, which has a water / hydraulic powder ratio of 20 wt% or less and a slump value of 10 cm or less and is used for centrifugal molding.   A fine aggregate having a particle size distribution of a sieve having a nominal size of 0.3 mm used in JIS A 1102 having a passing rate of 1% by weight or more and less than 10% by weight and a coarse particle rate of 2.5 to 3.5. The hydraulic composition in any one of Claims 1-4 contained. In the dispersant for hydraulic composition, the larger one of [n _A ] * x _A and [n _B ] * x _B ([n] * x) is 150 ≦ [n] * x ≦ 1000. The hydraulic composition according to any one of claims 1 to 5, which is in the range of   The hydraulic composition molded object which shape | molded the hydraulic composition in any one of Claims 1-6.

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