JP4307809B2 - Hardening retarder, cure delay method for hydraulic solidification material and cure delay method for improved soil - Google Patents

Description

【００５６】
ここに、
Ｍ：測定最大トルク（ｋＮ・ｍ）
Ｍ_f：試験機の摩擦トルク（ｋＮ・ｍ）
Ｄ：ベーンプレードの幅（ｍ）
〔試験例１〕
試験例１として前記した鋼管ソイルセメント杭造成工法用の室内実験を行った試験結果を表１及び図１〜図４に示すが、この実験の条件は下記に示すとおりである。
【００５７】
【表１】

【００５８】
水硬性固化材である高炉セメント（Ｂ種）を使用し、かつセメントの使用量であるセメント量Ｃ＝３００ｋｇ／ｍ³（地盤土１ｍ³当たりのセメント量）として、水固化材比１００質量％とし、表１に示すように、粘土質、砂質土、シルトの各土質の地盤土試料に対し実験を行った。遅延剤、遅延強化助剤の添加量はセメント１００質量部に対する質量部（外割）の値を％と表示している。表１の備考に示すように、各土質について図１〜図４に針貫入（プロクター）試験による針貫入抵抗試験結果を、縦軸に貫入抵抗、横軸に遅延剤、遅延強化助剤及びセメントからなる固化材液を地盤土試料に対し撹拌混合した時間からの経過時間（硬化時間）を横軸として詳細な結果を示した。
【００５９】
表１中には鋼管ソイルセメント杭造成工法における鋼管のソイルセメント柱への回転埋設段階で重要となる貫入抵抗２〜４Ｎ／ｍｍ²までの硬化時間（経過時間）を示すと共に特に長期圧縮強度が問題となるシルト質の場合の圧縮強度を示した。圧縮強度の経時変化は、図５，図６に示した。
【００６０】
図１は粘土質の地盤に関するもので、その含水比は、６５．０％であった。遅延剤としてオキシカルボン酸系遅延剤（商品名ＥＲ−２，株式会社サンフローパリック製）を使用し、図１ではＥＲ−２と表示した。また、遅延強化助剤として、表１に示したように、ＮａＯＨ（試薬１級）と消石灰の等量混合物（図１中にはＮａ＋Ｃａと表示）、ＮａＯＨ（試薬１級、図１中にはＮａと表示）を用いた。添加量はそれぞれセメント１００質量部に対する質量部の値（外割）を％と表示した。遅延強化助剤を加えないものを比較例として示した。なお、本発明では除外したが、本願の遅延強化助剤と同様の効果をもつ消石灰（Ｃａ（ＯＨ） _２ 、試薬１級、図１中にはＣａと表示）を添加したものを参考例として示した。
【００６１】
貫入抵抗が２Ｎ／ｍｍ^２及びで３Ｎ／ｍｍ^２となるまでの時間は、比較例２で２．５時間及び４．３時間であるのに対し、実施例１では、６時間及び１２時間、実施例２では６時間及び８．５時間となっており、それぞれ硬化時間が遅延している。なお、参考例１も硬化時間が延長している。
【００６２】
図２は砂質土の地盤に関するもので、遅延剤として、上記したと同じオキシカルボン酸系遅延剤（商品名ＥＲ−２，株式会社サンフローパリック製）を使用し、図２ではＥＲ−２と表示した。参考例２，３，４として、表１に示したように、消石灰（Ｃａ（ＯＨ）_２、試薬１級、図２中にはＣａと表示）を用いたものを示した。添加量はそれぞれセメント１００質量部に対する質量部の値（外割）を％で表示した。遅延剤（ＥＲ−２）のみを添加したものを比較例３とし、遅延剤（ＥＲ−２）と遅延強化助剤を全く加えないものを比較例４として示した。
【００６３】
貫入抵抗値が２Ｎ／ｍｍ^２及びで３Ｎ／ｍｍ^２となるまでの時間は、表１にも記載したように、比較例４では２．６時間及び３．３時間であるのに対し、参考例２，３，４では消石灰の量が増加するにつれて遅延効果が大きくなっている。
【００６４】
図３はシルトの地盤に関するもので、遅延剤として、上記したと同じオキシカルボン酸系遅延剤（商品名ＥＲ−２，株式会社サンフローパリック製）を使用し、図３ではＥＲ−２と表示した。参考例５，６，７として、表１に示したように、消石灰（Ｃａ（ＯＨ）_２、試薬１級、図２中にはＣａと表示）を用い、その添加量を変化させたものを参考として掲げた。添加量はそれぞれセメント１００質量部に対する質量部の値（外割）を％で表示した。
【００６５】
遅延剤（ＥＲ−２）と遅延強化助剤を全く加えないものを比較例６として示した。
【００６６】
貫入抵抗値が２Ｎ／ｍｍ^２及びで４Ｎ／ｍｍ^２となるまでの時間は、表１にも記載したように、比較例６では３．９時間及び７．８時間であった。参考例５，６，７では消石灰の量が増加するにつれて遅延効果が大きくなっている。
【００６７】
図３に示した比較例及び実施例の一軸圧縮強度を図５に示した。長期強度（９１日強度）を見ると、表１にも示したように、遅延剤、遅延強化助剤を添加しない比較例に対して、実施例の強度は概略同等と見ることができる。
【００６８】
図４は同じくシルトの地盤に関するもので、遅延剤として、上記したと同じオキシカルボン酸系遅延剤（商品名ＥＲ−２，株式会社フローリック製）を使用し、図４ではＥＲ−２と表示した。遅延強化助剤として、表１に示したように、ＮａＯＨ（試薬１級、図４中にはＮａと表示）、ＭｇＯ（試薬１級、図４中にはＭｇと表示）、ＦｅＯ（ＯＨ）（試薬１級、図４中ではＦｅと表示）、及びアルミナセメント（ラファージュ社製）を用いた。添加量はそれぞれセメントの質量部に対する質量部の値（外割）を％で表示した。遅延剤（ＥＲ−２）と遅延強化助剤を全く加えないものを比較例６として示した。なお、ＣａＯを用いたものを参考例８、アルミナセメントを用いたものを参考例９として併せて示した。
【００６９】
貫入抵抗値が２Ｎ／ｍｍ^２及びで４Ｎ／ｍｍ^２となるまでの時間は、表１にも記載したように、比較例６では３．９時間及び７．８時間であるのに対し、実施例３では５．５時間及び１４時間、実施例４では７時間及び１４．３時間となっている。なお、参考例５，６，７，８も比較的良い成績を示した。図４に示す参考例、比較例及び実施例の一軸圧縮強度を図６に示した。長期強度（９１日強度）を見ると、表１にも示したように、遅延剤、強化助剤を添加しない比較例に対して、ＭｇＯを加えたものは大きく上回っており、その他の実施例の強度は同等と見ることができる。
【００７０】
〔試験例２〕
試験例２として前記したＴＲＤ工法用の室内実験を行った試験結果を表２並びに図７及び図８に示すが、この実験の条件は下記に示すとおりである。
【００７１】
【表２】

【００７２】
水硬性固化材である高炉セメント（Ｂ種）を使用し、かつセメントの使用量であるセメント量Ｃ＝２５０ｋｇ／ｍ³（地盤土１ｍ³当たりのセメント量）として、水固化材比２００質量％とし、地盤土試料に対し実験を行った。遅延剤、遅延強化助剤の添加量はセメント１００質量部に対する質量部（外割）の値を％と表示している。表２並びに図７及び図８に示すようベーンせん断抵抗試験よるにベーンせん断抵抗値（せん断強さ）を縦軸に、横軸に遅延剤、遅延強化助剤及びセメントからなる固化材液を地盤土試料に対し撹拌混合した時間からの経過時間（硬化時間）を横軸として詳細な結果を示した。
【００７３】
なお、図７や図８において遅延剤としてオキシカルボン酸系遅延剤（商品名ＥＲ−２，株式会社サンフローパリック製）を使用し、図７や図８においてＥＲ−２と表示した。
【００７４】
また、ＥＲと表示したものは遅延剤としてオキシカルボン酸系遅延剤（商品名ＥＲ−２，株式会社フローリック製）を使用したことを意味する。
更に、参考例１０，１１，１２，１３として、消石灰（Ｃａ（ＯＨ）_２、試薬１級、図７や図８中にはＣａと表示）及びＣａＯを使用したものを示した。
【００７５】
添加量はそれぞれセメント１００質量部の値（外割）を％と表示した。遅延剤や遅延強化助剤を加えないものは比較例とした。
【００７６】
表２には６時間後（６Ｈ）、１２時間後（１２Ｈ）及び１８時間後（１８Ｈ）のベーンせん断抵抗値を示した。
【００７７】
ＴＲＤ工法において、Ｈ鋼等の補強材を挿入する作業が容易な範囲のベーンせん断抵抗値は、５ｋＮ／ｍ^２程度までであり、比較例１２，１３，１７では３時間〜６時間未満に制約されるが、本発明の硬化遅延剤を用いると、実施例７に示すように、１８時間程度まで延長することができる。参考例１０，１１，１２，１３も比較的良好であった。
【００７８】
以上の実施例において使用した遅延強化助剤の添加質量部を、使用した酸化物あるいは水酸化物（化合物）及びそれらの混合物の分子量に注目して、セメント１ｋｇ当り添加した化合物のモル数及び化学当量を表３に示した。
【００７９】
【表３】

【００８０】
〔試験例３〕
試験例３として対象土にシルト質粘土を用い、試験例２と同様に、ＴＲＤ工法用の室内実験を行った。結果を表４〜５並びに図９〜１５に示した。この実験の条件は次のとおりである。
【００８１】
水硬性固化材である高炉セメント（Ｂ種）を使用し、かつセメントの使用量であるセメント量Ｃ＝２５０ｋｇ／ｍ³（地盤土１ｍ³当たりのセメント量）として、水固化材比１００質量％とした。遅延剤、遅延強化助剤の添加量はセメント１００質量部に対する質量部（外割）の値を％と表示している。図９〜１５に示すように、ベーンせん断抵抗試験によるベーンせん断抵抗値（せん断強さ）を縦軸に取り、遅延剤、遅延強化助剤及びセメントからなる固化材液を地盤土試料に対し撹拌混合した時間からの経過時間（硬化時間）を横軸に取って詳細な結果を示した。
【００８２】
遅延剤として、オキシカルボン酸系遅延剤（商品名ＥＲ−２，株式会社サンフローパリック製）を用い、遅延強化助剤として、ボウ硝（硫酸ソーダ、Ｎａ_２ＳＯ_４・１０Ｈ_２Ｏ、試薬１級）、ミョウバン（カリウムアルミニウムミョウバン、ＡｌＫ（ＳＯ_４）_２・１２Ｈ_２Ｏ、試薬１級）、亜硫酸ソーダ（ＮａＨＳＯ_３、試薬１級）、にがり（塩化マグネシウムＭｇＣｌ_２・６Ｈ_２Ｏ、試薬１級）、苛性ソーダ（ＮａＯＨ、試薬１級）、水酸化亜鉛（Ｚｎ（ＯＨ）_２、試薬１級）、硫酸アルミニウム（Ａｌ_２（ＳＯ_４）_３、試薬１級）、又は水ガラス（ケイ酸ソーダ、Ｎａ_２Ｏ・ＳｉＯ_２・Ｈ_２Ｏ、試薬１級）を用いたものを表４に示した。なお、参考例として、生石灰（ＣａＯ、試薬１級）、酸化亜鉛（ＺｎＯ、試薬１級）、消石灰（Ｃａ（ＯＨ） _２ 、試薬１級）、二水石膏（ＣａＳＯ _４ ・２Ｈ _２ Ｏ、試薬１級）、塩化カルシウム（ＣａＣｌ _２ ・２Ｈ _２ Ｏ、試薬１級）、炭酸カルシウム（ＣａＣＯ _３ 、試薬１級）を用いたものも併記した。
【００８３】
表４の内、実施例８，９，１０及び比較例１８、１９を図９に示した。
【００８４】
また、遅延剤として、クエン酸、リグニンスルホン酸、ソルビトール、マルトース、イソマルオリゴ糖、又はポリアクリル酸を用い、遅延強化助剤として、苛性ソーダ（ＮａＯＨ、試薬１級）を用いたものを表５に示した。遅延剤はそれぞれほぼ同等の遅延効果を有する添加量とした。すなわち水硬性固化材１００質量部に対し、クエン酸３質量部、リグニンスルホン酸２質量部、マルトース２質量部、ソルビトール１質量部、イソマルオリゴ糖１質量部、ポリアクリル酸４質量部とした。なお、参考例として消石灰（Ｃａ（ＯＨ） _２ 、試薬１級）、酸化亜鉛（ＺｎＯ、試薬１級）を用いたものも併記した。表５の遅延剤ごとの試験結果をそれぞれ図１０〜１５に示した。
【００８５】
【表４】

【００８６】
【表５】

【００８７】
添加量はそれぞれセメント１００質量部に対する値（外割）を％と表示した。遅延剤や遅延強化助剤を加えないものを比較例として示した。また、Ｃａ化合物又はＺｎ化合物を添加したものを参考例として示した。
【００８８】
表４、５には４時間後（４Ｈ）、６時間後（６Ｈ）及び８時間後（８Ｈ）のベーンせん断抵抗値を示した。ＴＲＤ工法において、Ｈ鋼等の補強材を挿入する作業が容易な範囲のベーンせん断抵抗値は、５ｋＮ／ｍ^２程度までである。従って、明らかにこれを越えるデータについては測定を行わなかった。表４、５中に＋と表示してあるのは、概ね８ｋＮ／ｍ^２を越えるような値となると想定されるものであって測定をしなかったものである。また、表４、５中の実施例、比較例及び参考例中の主なものについて材齢７日及び２８日における圧縮強度を測定し、表４、５に併記した。
【００８９】
表４において、比較例１８は遅延剤（ＥＲ−２）のみを２％加え遅延強化助剤を加えないもの、比較例１９は遅延剤、遅延強化助剤のいずれも加えないものである。比較例１８では、ＴＲＤ工法の適用は４時間未満程度までに制約される。比較例１９では３時間以内に制約される。実施例１９では、８時間未満程度まで遅延効果を利用することができ、実施例８，９，１０，１１では６時間未満程度まで遅延効果を利用することができる。また、実施例８，９では、材齢２８日における圧縮強度も充分発現している。実施例７，１２がやや使いにくい態様を示している。
【００９０】
次に表５及び図１０〜１５について説明する。遅延剤として、クエン酸、リグニン、マルトース、イソマルオリゴ糖、又はポリアクリル酸を用いた。クエン酸（オキシカルボン酸系）は試薬１級、リグニンスルホン酸は日本製紙株式会社製リグニンスルホン酸カルシウム塩（平均分子量１３，０００）、マルトース（糖類系）は試薬１級、ソルビトール（糖アルコール系）は上野製薬製Ｄ−ソルビトール液、イソマルオリゴ糖（糖類系）は林原株式会社製イソマルオリゴ糖シラップ（商品名パノラップ（濃度７５％））、ポリアクリル酸は株式会社サンフローパリック製ポリアクリル酸ソーダ（平均分子量１４，０００）（商品名ジオスパーＫ）を用いた。遅延強化助剤として、ＮａＯＨを用いたものを表５に示した。参考例としてＣａ（ＯＨ） _２ 又はＺｎＯを用いたものも示した。表５の遅延剤ごとの試験結果をそれぞれ図１０〜１５に示した。
【００９１】
クエン酸を遅延剤とする実施例では、表５及び図１０に示すように、遅延強化助剤を加えない比較例２５に比し、実施例１３は遅延効果が大きく、せん断抵抗値が５ｋＮ／ｍ ² に達するまでに２〜４時間の付加時間の遅延効果が認められる。
【００９２】
リグニンスルホン酸を遅延剤とする実施例では、表５及び図１１に示すように、遅延強化助剤を加えない比較例２０に比べて実施例１４が遅延効果が大きく、１〜３時間程度の付加時間の遅延効果が認められる。
【００９３】
マルトースを遅延剤とする実施例では、表５及び図１２に示すように、遅延強化助剤を加えない比較例２６に比べて実施例１５は２〜４時間程度の付加時間が認められる。
【００９４】
ソルビトールを遅延剤とする実施例１６では、表５及び図１３に示すように、遅延強化助剤を加えない比較例２１に対し、１〜３時間の付加時間の遅延効果が期待される。
【００９５】
イソマルトオリゴ糖を遅延剤とする実施例１７では、表５及び図１４に示すように、遅延強化助剤を加えない比較例２２に対し、２〜４時間の遅延効果が認められる。
【００９６】
ポリアクリル酸を遅延剤とする実施例では、表５及び図１５に示すように、遅延強化助剤を加えない比較例２３に対し、０．５〜２時間の遅延効果がある。
【００９７】
次に、遅延剤としてＥＲ−２を用い、遅延強化助剤又は参考例として示した添加剤を１０％としたとき、本発明の各遅延強化助剤のランク付けは、表６に示すようになる。表６におけるクラス分けは元素の周期律表の周期を示したものである。遅延効果は左側欄が大きく右に行くに従って小さくなる。また、同じ枠内に記載したものは遅延効果が概ね同等と考えられるものである。
【００９８】
次に、実験例３で用いた遅延強化助剤又は参考例として示した添加剤の金属原子量と遅延効果との関係を表７に纏めて示した。表７中、括弧内に示した数字は、結晶水を除外した値を記載したものである。
【００９９】
【表６】

【０１００】
【表７】

【０１０１】
なお、遅延効果のみに注目すると、遅延強化助剤又は参考例として示した添加剤では酸化亜鉛（ＺｎＯ）等が高い効果を示す。遅延剤としては、糖類は、一般に要求される２８日強度において、充分な強度の発現が期待できない場合があるため、取り扱いに注意を要する。但し、目的によっては、硬化遅延の効果及び強度発現期間などの選択によって、遅延剤及び遅延強化助剤の添加量は、本発明の添加割合の範囲内で充分に使用可能である。
【０１０２】
【発明の効果】
本発明の硬化遅延剤は、遅延剤（硬化遅延形の混和剤等の添加剤）の使用を減少させ、市中に出回っている材料を遅延強化助剤として使用することにより、従来の遅延硬化形の混和剤を多量に使用する問題点を解決することができる。すなわち、本発明の遅延硬化剤は、水硬性固化材の硬化遅延を図る技術に改良を加え、遅延強化助剤を添加することにより所期の硬化遅延効果を発揮し、多量使用する必要があった従来の硬化遅延形の混和剤を多量に使用する問題点を解決することができる。
【０１０３】
また本発明の第２の発明である水硬性固化材の硬化遅延工法に従えば、遅延強化助剤を添加することにより遅延剤の使用量を少なくしても所期の硬化遅延効果が発揮され、従来の硬化遅延形の混和剤が存在することで施工上の問題があった工事を問題なく施工することができる。
【０１０４】
次に、本発明の第３の発明である改良土の硬化遅延工法に従うと、改良土（ソイルセメント）の硬化が所望の時間に合わせるために、遅延剤（硬化遅延形の混和剤）を単独で使用する場合よりも、遅延強化助剤を併用添加することにより遅延剤（硬化遅延形の混和剤）自体の使用量を少なくしても所期の硬化遅延効果を発揮し、施工効率が上がりトータルコストが低減できる。また、遅延剤（硬化遅延形の混和剤）を単独で使用する場合、硬化を所望の時間まで遅延させるには遅延剤（硬化遅延形の混和剤）の添加量を多くする必要があり、添加量の増加により、改良土（ソイルセメント）の硬化体が十分な強度が得られない事態が発生していたが、遅延剤（硬化遅延形の混和剤）の使用量を減らしても、遅延強化助剤を添加することにより硬化を所望の時間まで遅延させることができるので、改良土（ソイルセメント）の硬化体の強度を許容範囲に収めることができる。
【０１０５】
即ち、水硬性固化材を地中に混合する改良土（ソイルセメント）造成工事中に、遅延剤（硬化遅延形の混和剤等の添加剤）の使用を減少させ、市中に出回っている材料を用いて、工費の上昇を招くことなく、短期的（数時間〜数日間）な効果を計ることができ、その後の強度発現性が改善され、従来の硬化遅延形の混和剤を多量に使用する場合、強度が十分に発現しないという問題を解決することができる。
【図面の簡単な説明】
【図１】 実施例の針貫入試験結果を示すグラフである。
【図２】 参考例の針貫入試験結果を示すグラフである。
【図３】 参考例の針貫入試験結果を示すグラフである。
【図４】 実施例の針貫入試験結果を示すグラフである。
【図５】 参考例の圧縮強度を示すグラフである。
【図６】 実施例の圧縮強度を示すグラフである。
【図７】 実施例のベーンせん断試験結果を示すグラフである。
【図８】 参考例のベーンせん断試験結果を示すグラフである。
【図９】 実施例のベーンせん断試験結果を示すグラフである。
【図１０】 実施例のベーンせん断試験結果を示すグラフである。
【図１１】 実施例のベーンせん断試験結果を示すグラフである。
【図１２】 実施例のベーンせん断試験結果を示すグラフである。
【図１３】 実施例のベーンせん断試験結果を示すグラフである。
【図１４】 実施例のベーンせん断試験結果を示すグラフである。
【図１５】 実施例のベーンせん断試験結果を示すグラフである。
【図１６】 水固化材比と施工性、残土量及び強度との関係を示すグラフである。
【図１７】 固化材使用量と施工性、残土量及び強度との関係を示すグラフである。
【符号の説明】
１０ 曲線（残土量）
１１ 曲線（強度）
１２ 範囲
１３ 曲線（強度）
１４ 曲線（残土量）
１５ 範囲[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a curing retarder that delays curing of a hydraulic solidifying material and a curing retarding method using the same. Furthermore, the present invention is also used as an effective curing retarder in the case where a delay in hardening of the improved soil is required in the construction to improve the soil by mixing and stirring with the soil to be solidified using a hydraulic solidifying material. The present invention relates to a curing retarder that can be used and a curing retardation method using the same.
[0002]
[Prior art]
When using various cements and / or cement-based solidifying materials, etc. (which are collectively referred to as “hydraulic solidifying material” in the present invention) that are hydraulic solidifying materials, the time until the hydraulic solidifying material is cured is determined. There may be a need to extend.
For example,
(1) With the transition of the construction process, such as when the construction is resumed after the construction interruption, the joining part of the solidified part that is generated becomes structurally discontinuous, resulting in a cold joint and insufficient stress transmission. In some cases, defects such as loss of water-stopping properties may occur at the cold joint. In order to avoid such a situation, it is necessary to extend the time until the portion applied at the tip of the joint portion is cured.
[0003]
(2) Also, in constructions that use hydraulic solidification materials, such as constructions that form continuous walls in the ground, steel pipes, H-shaped steels, I-type steels, while the hydraulic solidification materials are uncured. There is a method of inserting a reinforcing material such as. In this case, in the method of inserting a reinforcing material such as a steel material, the insertion becomes difficult or impossible after the hydraulic solidification material starts to harden. Moreover, it is common to insert the reinforcing material after forming a certain length of underground wall. Therefore, the time until the hydraulic solidifying material is hardened by the time of inserting the reinforcing material is extended. A need arises.
[0004]
The phenomena described in (1) and (2) above are constructions such as the following (3) and (4), etc., which are construction works that are mixed and stirred with ground soil using hydraulic solidification material. Also occurs in the case of.
[0005]
(3) Including construction to secure the supporting capacity of the ground by using soft soil as improved soil, construction of underground walls by improved soil to make earth retaining walls, water barriers, etc., or including harmful substances Construction when used for improved soil construction to detoxify contaminated soil.
[0006]
(4) In order to use as a foundation pile of a structure to be built on soft ground, a hydraulically solidified material is stirred and mixed while excavating the ground to form columnar improved soil (for example, soil cement column) in the ground. Then, a post-embedding method in which piles such as steel pipe piles are buried in the pillars of the improved soil, and, for example, excavating blades and stirring blades while discharging hydraulic solidifying material liquid (for example, cement milk) A simultaneous burying method in which piles such as steel pipe piles are laid to create a pile while forming a column of improved soil (for example, soil cement) by inserting a rod with a rod into the steel pipe and mixing with stirring (in either case) If steel pipe is used, it is called steel pipe soil cement pile construction method.)
[0007]
(A) In the post-embedding method described above, it may be difficult or impossible to insert a pile after the improved soil starts to harden.
[0008]
(B) Even in the case of the simultaneous burial method described above, the piles must be continuously sunk, and the piles need to be continuously sunk from the predetermined depth to the ground surface, and the improved soil constructed at the tip of the ground surface begins to harden. And after that time, it is difficult to move the pile down for insertion, and it may be impossible to construct a part deeper than the depth at that time. It is impossible to create piles up to a certain depth.
[0009]
In the case of pile construction using these improved soils, it is necessary to extend the time for hardening the hydraulic solidifying material to the time when the pile can be inserted to a predetermined depth.
[0010]
(5) Moreover, while discharging hydraulic solidifying material liquid (for example, cement milk), the improved soil (for example, soil cement) is deepened by inserting a drilled blade and a rod with a stirring blade into the steel pipe. In the case of construction, when the construction equipment including the drilling blade and the stirring blade at the deepest depth is collected after the construction to a predetermined depth, the portion of the drilling blade and the stirring blade is not changed after the upper improved soil begins to harden. The resistance force received is large, and it may be difficult or impossible to collect the construction equipment. Therefore, it is necessary to extend the time until the improved soil is hardened.
[0011]
In general, when the depth of construction of the improved soil is normal, immediately when the ground soil and hydraulic hardened solidified material are mixed into the improved soil (soil cement) as in (3) and (4) above, However, depending on the conditions of the soil, the start of hardening of the improved soil may be accelerated, and depending on the construction procedure, However, there are cases where it is desired to delay the start of hardening of the improved soil.
[0012]
As described above, when it is desired to delay the start of curing, it is generally performed to use a cement having a long curing time, for example, a blast furnace cement, as the hydraulic solidifying material. However, blast furnace cement has a slightly slower setting time than ordinary Portland cement, and a sufficient setting delay effect cannot be obtained.
[0013]
Therefore, in order to prevent these disadvantages, an additive having a retarding effect on the hydraulic solidifying material such as a retarding material (a conventionally known curing retarding admixture) is referred to as “retarding agent” in the present invention. ) May be added. And, it was known that the curing time was delayed by increasing the addition amount of the delayed curing type admixture, and ensuring the workability and improving the quality of the lapping part, etc. . For example, there is a technique for adjusting the curing delay of a cement-based solidified material (see, for example, Patent Document 1).
[0014]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-17864 (page 2-6)
[0015]
[Problems to be solved by the invention]
However, on the other hand, it is necessary to increase the amount of the retarder (cure retarding type admixture) to delay the curing until a desired time, and the increase in the amount added is sufficient with the hydraulic solidifying material such as cement. A situation where a sufficient strength could not be obtained occurred and sometimes caused problems in construction. In particular, this problem often occurs when the target soil is improved using a hydraulic solidifying material (for example, soil cement).
[0016]
Therefore, even if it is attempted to perform construction without using a retarder having such a problem, a situation in which construction cannot be performed occurs.
[0017]
The present invention improves the technology for delaying the curing of the hydraulic solidifying material, and exhibits a desired curing delay effect by adding a delay strengthening auxiliary, and the mixed cured product is desired even when mixed with soil. It aims at providing the hardening retarder which can exhibit intensity | strength. Another object of the method of the present invention is to provide a method for retarding the curing of improved soil (eg, soil cement) using such a retarder.
[0018]
[Means for Solving the Problems]
  1st invention of this invention consists of a retarder and the delay reinforcement | strengthening adjuvant which is 1 type, or 2 or more types chosen from the group which consists of the following substance,Mix with soilHydraulic solidifying materialDuring ~It is a curing retarder characterized by being a material mixed in.
[0019]
                                Record
  Alkali metal oxides, hydroxides, silicates; magnesium oxides, chlorides; iron oxides, hydroxides;as well asAluminum oxide, hydroxylationobject
  In the present invention, the term “retarder” is not limited to a powdery or liquid form, and an additive having a retarding effect on a hydraulic solidifying material, such as a conventionally known curing retarding admixture. included. For example, the following (A) to (F) are included.
[0020]
(A) Commercial chemical admixtures for retarding concrete, dispersants for soil cement, retarders
(I) Oxycarboxylic acid or / and its salt
Examples of oxycarboxylic acids include gluconic acid, glucoheptonic acid, glycolic acid, hydroxypropanoic acid (eg, lactic acid, 3-hydroxypropanoic acid, etc.), hydroxybutyric acid (eg, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, etc.) Hydroxy valeric acid (for example, 2-hydroxy valeric acid, 3-hydroxy valeric acid, 4-hydroxy valeric acid, 5-hydroxy valeric acid, etc.), glyceric acid, tartaric acid, citric acid, tartronic acid, malic acid, citramalic acid, etc. Can be mentioned.
[0021]
Examples of the oxycarboxylate include ammonium salts, alkali metal salts (for example, sodium salts and potassium salts), and alkaline earth metal salts (for example, calcium salts and magnesium salts).
[0022]
Among the oxycarboxylic acids or salts thereof, preferred are sodium gluconate and / or sodium glucoheptonate.
[0023]
(C) Lignin sulfonate
Lignin sulfonate is a natural polymer (molecular weight is said to be distributed from several hundred to several million), which is usually contained in natural pulp raw materials by about 50 to 60%. It is classified into general lignin and high performance lignin. Lignin sulfonates classified as general lignin are obtained by desugaring the cooking eluate during sulfite pulp production, and the average molecular weight (Mw) is 20,000 or less (usually 10,000 to 14). About 1,000,000). In addition, lignin sulfonates classified as high-performance lignin are polymer fraction portions obtained by fractionating the above-mentioned digestion eluate or its desugared solution into a polymer fraction and a low-molecular fraction, and have an average molecular weight (Mw). ) Is said to be 20,000 or more (usually about 24,000 to 28,000), and these lignin sulfonates are roughly classified into Ca salts, Na salts, and Mg salts by a desugaring treatment method.
[0024]
(D) Sugars and their mixtures
Sugars include monosaccharides such as glucose, galactose, mannose, fructose, xylose, arabinose, ribose and deoxyribose, and oligosaccharides such as sucrose, maltose and lactose. Moreover, the mixture and also saccharide residue are mentioned.
[0025]
(E) Sugar alcohols
Examples of the sugar alcohol include erythritol, xylitol, arabitol, adonitol, sorbitol, mannitol, iditol, taritol, galactitol, and allitol.
[0026]
(F) Ester compound of sugar alcohol and higher fatty acid
The ester compound of sugar alcohol and higher fatty acid is the above polyhydric alcohol and stearic acid, oleic acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecyl acid, lauric acid having about 6 to 22 carbon atoms. And ester compounds with higher fatty acids such as tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, nonadecanoic acid, behenic acid, elaidic acid and erucic acid.
[0027]
  Next, in the present invention, the “curing retarder” refers to a conventional “retarder” obtained by adding the “retard strengthening aid” according to the present invention. The “retard strengthening aid” according to the present invention includes alkali metal oxides, hydroxides, sulfites, sulfates, silicates; alkaline earth metal oxides, hydroxides, sulfates, chlorides, Carbonate; iron oxide, hydroxide; zinc oxide, hydroxide;as well asAluminum oxide, hydroxylationWith thingsis there.
[0030]
Next, the hydraulic solidification material targeted in the present invention is various cements and / or cement-based solidification materials that are hydraulic solidification materials. Examples of various cements include ordinary Portland cement and blast furnace cement. Can be mentioned.
[0031]
And the said retarder, the delay reinforcement | strengthening adjuvant, and the hydraulic solidification material may each be a single item, or can be made into the mixed item which mixed 2 or more beforehand. In other words, the retarder (cure retarding type admixture) and the delay-enhancing auxiliary agent according to the present invention may be kept separate, and the blending design may be appropriately performed at the time of use, or both may be mixed in advance. In addition, it is possible to obtain a premix product in which preparation at the site of use is omitted. Moreover, you may decide to mix a delay agent and a delay reinforcement | strengthening adjuvant, a delay reinforcement assistant, and a hydraulic solidification material or a delay agent and a hydraulic solidification material previously. These mixed products have the merit that the field work can be facilitated by supplying the mixture according to the use conditions.
[0032]
  Next, the second invention of the present invention uses at least the retarder of the first invention and the curing retarder.Mixed with soilThis is a method for delaying the curing of a hydraulic solidified material, characterized by delaying the curing of the hydraulic solidified material.
[0033]
According to this hardening delay construction method, the desired hardening delay effect is exhibited even if the amount of the retarder used is reduced by adding a delay strengthening auxiliary agent, and the mixed cured product is desired even when mixed with soil. The strength can be exhibited. In addition, it is possible to perform construction that cannot be performed without using a conventional retarder. Furthermore, when the curing retarder of the present invention is used, the improved soil during construction is maintained in a soft state for a long time, so that sufficiently good stirring can be achieved, so that stirring efficiency is improved and energy consumption for stirring is reduced. Reduction of construction costs by reducing the amount of work, shortening of the construction period by increasing the construction speed, reduction of wear of construction machines by reducing stirring resistance, recovery work of construction machines that could not be recovered in the past From the effects, the effect desired by the installer can be selected.
[0034]
Next, according to a third aspect of the present invention, there is provided a hardened material obtained by adding 0.2 to 12 parts by weight of a retarder and 1 to 50 parts by weight of a delay strengthening aid to 100 parts by weight of a hydraulic solidifying material. This is an improved soil retarding method characterized in that after the required construction is completed within the unhardened time of the improved soil, the improved soil is solidified after stirring. According to such a construction method, the hardening of the improved soil (for example, soil cement) can be adjusted to a desired time, so that it is less expensive than the case of using a retarding agent (delayed curing type admixture) alone. By adding such a delayed strengthening aid, even if the amount of the retarder (delayed curing type admixture) itself is reduced, the desired curing delay effect can be exhibited and the total cost can be reduced. In addition, when a retarder (cure retarding admixture) is used alone, it is necessary to increase the amount of retarder (cure retarding admixture) added in order to delay curing until the desired time. There was a situation where the hardened body of the improved soil (for example, soil cement) could not obtain sufficient strength due to the increase in the amount, but even if the amount of retarder (delayed-curing admixture) was reduced, it was delayed. Since the hardening can be delayed to a desired time by adding a reinforcing aid, the strength of the hardened body of the improved soil (for example, soil cement) can be kept within an allowable range.
[0035]
Examples of the above-mentioned solidification target soil include ground soil, soil discharge, industrial waste containing soil, etc., and for the purpose of improving soil, fluidized soil that forms soil cement and fluidizes and solidifies the soil. And so on.
[0036]
Further, as a specific example of performing the required work while the improved soil of the third invention (for example, soil cement) is uncured, a reinforcing material such as a steel pipe, H-shaped steel, or I-shaped steel is inserted into the improved soil. There are the following methods (a) and (b).
[0037]
(I) Steel pipe soil cement pile construction method
This construction method is the construction method described in the prior art (4). Synthetic piles in which this improved soil and steel pipe are integrated become a composite pile with high toughness and high bearing capacity. In the case of pile construction using this improved soil, hydraulic solidification is performed until the pile can be inserted to a predetermined depth. Extend the time for the material to cure.
[0038]
(B) Soil cement underground continuous wall construction method
By moving the chain saw-shaped cutter inserted in the ground in the horizontal direction and excavating the grooves, the solidified material liquid is injected to mix and agitate the ground soil and the solidified material liquid, thereby improving the soil continuously in the ground. This is an operation of inserting a reinforcing material such as H-shaped steel into a wall body in a construction method (hereinafter referred to as “TRD construction method”) for constructing a (soil cement) wall body. Such wall bodies are used for retaining walls, water blocking walls, liquefaction countermeasures, ground reinforcement, groundwater blocking, and the like.
[0039]
Next, numerical limitation of the present invention will be described. The amount of the retarder in the curing retarder is 0.2 to 12 parts by mass of the retarder to 100 parts by mass of the hydraulic solidifying material. If the amount is less than 0.2 parts by mass, the delay effect is poor even if the delay strengthening auxiliary according to the present invention is added. Moreover, even if it adds exceeding 12 mass parts, since a delay effect will be saturated, 12 mass parts was made into the upper limit. Since the basic technical idea of the present invention is to use an inexpensive delay strengthening aid by reducing the amount of retarder added, a value lower than this upper limit is usually adopted. A preferable value is 5 parts by mass or less. The amount of delay strengthening aid varies depending on the soil quality of the soil to be solidified, its water content, the amount of delay agent added, the type of delay strengthener, the length of the delay time, etc. Part. If the amount is less than 1 part by mass, the effect is poor, and even if added in excess of 50 parts by mass, the effect is saturated.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
First, a general blending design will be described by taking the case of steel pipe soil cement pile construction method as an example. In determining the blending amount, the strength of the soil cement (improved soil) satisfies the target value and is within a range where both workability and economic efficiency can be achieved. When the solidifying material addition amount is constant, the horizontal axis is the water solidifying material ratio, and the horizontal axis is the residual soil amount and strength, a schematic graph as shown in FIG. 16 can be drawn. Curve 10 shows the amount of residual soil. The amount of remaining soil is the amount of soil discharged to the ground with the formation of soil cement (improved soil) by excavation and stirring due to the increase in volume due to the addition of the solidifying material liquid to the ground. Curve 11 shows the intensity.
[0041]
As the water-solidifying material ratio increases, the workability improves, but the strength expression decreases as shown by the curve 11. From this, the water solidifying material ratio within the range where the target strength is satisfied and the solidifying material can be pumped is indicated by a range 12. However, as the water-solidifying material ratio increases, the amount of residual soil increases as shown by the curve 10. Therefore, it is desirable to select a water-solidifying material ratio that is as small as possible in the range where workability is good.
[0042]
Also, when determining the optimum addition amount of the solidifying material, it should be considered that the target strength is often not satisfied when the addition amount of the solidifying material is small. FIG. 17 schematically shows the relationship between workability, strength (curve 13), and amount of residual soil (curve 14), with the horizontal axis representing the amount of solidifying material added when the water-solidifying material ratio is constant. As the solidifying material addition amount increases, the injection amount increases, so that the workability improves and the strength expression also increases. On the other hand, the amount of residual soil increases in proportion to the amount of solidification material added. Therefore, it is desirable to set an economical blending amount so as to minimize the amount of remaining soil in the range 15 that satisfies the target strength and also has good workability.
[0043]
From the above, based on the results of past workability and indoor blending tests, judging from the aspects of soil cement strength, workability, and economic efficiency, etc. is there.
[0044]
Solidification material addition amount (kg / m^Three: Ground 1m^ThreePer cement)
For simultaneous laying method: 300 kg / m^Three
In the case of post-sinking method: 300 to 400 kg / m^Three
Water-solidifying material ratio (% by mass)
For simultaneous installation method: 100-120%
For post-sinking method: 120-150%
The amount of hydraulic solidification material used in the steel pipe soil cement pile construction method has been described above.
[0045]
Next, the curing retarder of the present invention will be described based on experiments conducted for confirming the effect.
[0046]
It is a problem when judging the workability by conducting a laboratory test under normal conditions normally used for steel pipe soil cement pile construction and a laboratory test under normal conditions normally performed for soil cement underground continuous wall construction. As a fluidity test of slurry, it is usually used in the laboratory test of the soil cement continuous wall construction method and the needle penetration (proctor) test of the improved soil (soil cement) usually used in the laboratory test of steel pipe soil cement pile construction method The vane shear resistance test was measured. For strength development, a uniaxial compressive strength test of soil cement (improved soil) was conducted. The effectiveness of the delay strengthening aid was confirmed by such laboratory tests.
[0047]
For the needle penetration (Proctor) test of improved soil (soil cement), the concrete setting time test method of Annex 1 of JIS A6204 is applied mutatis mutandis, and a hydraulic Proctor tester (manufactured by Maruto Seisakusho Co., Ltd.) is used. Used. The measurement specifications are as follows.
[0048]
Penetration method: Method to turn the handle manually
Penetration resistance measurement: Hydraulic load meter placement needle indicating type
Load meter: Hydraulic bellows type, maximum capacity 1000N, minimum scale 10N
Pointer zero adjustment: Equipped with manual adjustment unit
Penetrating needle head: 100mm², With penetrating support wire
Sample container: cylindrical container having a diameter of 150 mm and a height of 150 mm
The sample container was filled with improved soil (soil cement) as a sample so that the upper surface was about 1 cm lower than the upper end, and the surface was measured as a smooth surface.
[0049]
The measurement was performed by operating the handle and penetrating the penetrating needle head 25 mm into the sample. The penetration depth was confirmed by a score line on the penetration needle head. The time required for the penetration was about 10 seconds, and the time when the penetration test was performed and the force (N) required for the penetration were read from the needle of the load meter and recorded. Such a measurement was performed every specified elapsed time. The distance between the needle traces of the penetrating needle head was not less than twice the diameter of the penetrating needle head used and 15 mm or more, and the distance between the side surface of the sample container and the needle trace was not 20 mm or less.
[0050]
Cross-sectional area of penetration needle head used (mm²), The force required for penetration (N) is removed, and the penetration resistance (N / mm²) Was calculated.
[0051]
In addition, the vane shear resistance test was performed in accordance with the in-situ vane shear test method of the Japan Geotechnical Society standard (JGS 1411-195). That is, the vane shear resistance test uses an apparatus having four blades (vane blades) as a measuring section, and after pushing the blades into a sample at a predetermined depth, the vanes are rotated to shear the sample. At this time, the shear strength is obtained from the maximum resistance value received by the blade.
[0052]
More specifically, a vane blade having a height of 40 mm and a width of 20 mm, called a pocket vane, is used, and the loading and measuring device rotates the vane blade pushed into the sample via the rotating rod and the vane shaft. Measure the torque with a torque meter.
[0053]
In the measurement, only the vane (blade) is slowly pushed to a predetermined depth without twisting the rotating rod. The rotating rod is loaded and fixed to the measuring device, and the blade is rotated later to shear the sample.
[0054]
Sample shear strength τ_v(KN / m²) Was calculated by the following formula.
[0055]
[Expression 1]

[0056]
here,
M: Maximum measured torque (kN · m)
M_f: Friction torque of testing machine (kN · m)
D: Width of vane blade (m)
[Test Example 1]
Table 1 and FIGS. 1 to 4 show the test results of the laboratory experiment for the steel pipe soil cement pile construction method described above as Test Example 1, and the conditions of this experiment are as shown below.
[0057]
[Table 1]

[0058]
Blast furnace cement (type B) which is a hydraulic solidifying material is used, and the amount of cement used is the amount of cement C = 300 kg / m^Three(Ground soil 1m^ThreeExperiments were conducted on soil soil samples of clay, sandy soil, and silt, as shown in Table 1, with a water-solidifying material ratio of 100% by mass. As for the addition amount of the retarder and the delay strengthening aid, the value of the part by mass (external ratio) with respect to 100 parts by mass of cement is indicated as%. As shown in the remarks in Table 1, for each soil, the results of needle penetration resistance test by the needle penetration (Proctor) test are shown in Figs. 1 to 4, the vertical axis is penetration resistance, the horizontal axis is retarder, delay reinforcement aid and cement Detailed results were shown with the horizontal axis representing the elapsed time (curing time) from the time when the solidified material solution consisting of was ground and mixed with the ground soil sample.
[0059]
Table 1 shows the penetration resistance of 2 to 4 N / mm, which is important at the stage of rotary embedding of steel pipes into soil cement columns in the steel pipe soil cement pile construction method.²In addition to the curing time (elapsed time), the compressive strength in the case of silty, in which long-term compressive strength is a problem, was shown. The change over time in the compressive strength is shown in FIGS.
[0060]
  FIG. 1 relates to clayey ground, and the water content was 65.0%. As the retarder, an oxycarboxylic acid-based retarder (trade name ER-2, manufactured by Sunflow Palic Co., Ltd.) was used, which is indicated as ER-2 in FIG. Moreover, as shown in Table 1, as a delay strengthening aid, NA mixture of equal amounts of aOH (reagent grade 1) and slaked lime (indicated as Na + Ca in FIG. 1) and NaOH (reagent grade 1, indicated as Na in FIG. 1) were used. As for the amount added, the value (external ratio) of parts by mass with respect to 100 parts by mass of cement was indicated as%. A comparative example in which no delay strengthening aid was added was shown.Although excluded in the present invention, slaked lime (Ca (OH)) having the same effect as the delay strengthening aid of the present application. ₂ A reagent grade 1 and labeled with Ca in FIG. 1 are shown as reference examples.
[0061]
  Penetration resistance is 2 N / mm²And 3 N / mm²In Comparative Example 2, the time to be 2.5 hours and 4.3 hours, whereas in Example 1,6Time and 12:00while,In Example 2, it took 6 hours.8. It is 5 hours, and each curing time is delayed.In Reference Example 1, the curing time is extended.
[0062]
  FIG. 2 relates to the ground of sandy soil. As the retarder, the same oxycarboxylic acid-based retarder (trade name ER-2, manufactured by Sunflow Paric Co., Ltd.) as described above is used. In FIG. 2 is displayed.Reference examples 2, 3, 4As shown in Table 1, slaked lime (Ca (OH)₂, Reagent grade 1, using Ca in Fig. 2)Showed. The amount added was expressed in terms of% by mass (external ratio) with respect to 100 parts by mass of cement. A comparative example 3 was obtained by adding only the retarder (ER-2), and a comparative example 4 was obtained by adding neither the retarder (ER-2) nor the retardation enhancing aid.
[0063]
  Penetration resistance value is 2 N / mm²And 3 N / mm²As shown in Table 1, the time until the time becomes 2.6 hours and 3.3 hours in Comparative Example 4, whereasReference examples 2, 3,4Is offThe delay effect increases as the amount of lime increases.
[0064]
  FIG. 3 relates to the ground of silt. As the retarder, the same oxycarboxylic acid retarder as described above (trade name ER-2, manufactured by Sunflow Paric Co., Ltd.) is used. In FIG. displayed.Reference examples 5, 6, 7As shown in Table 1, slaked lime (Ca (OH)₂, Reagent 1 grade, indicated as Ca in FIG. 2), and the amount added was changedStuff as a reference. The amount added was expressed in terms of% by mass (external ratio) with respect to 100 parts by mass of cement.
[0065]
A comparative example 6 in which neither a retarder (ER-2) nor a delay-enhancing auxiliary was added was shown.
[0066]
  Penetration resistance value is 2 N / mm²And 4 N / mm²As described in Table 1, the time until the time is 3.9 hours and 7.8 hours in Comparative Example 6It was. Reference examples 5, 6,7Is offThe delay effect increases as the amount of lime increases.
[0067]
The uniaxial compressive strengths of the comparative example and the example shown in FIG. 3 are shown in FIG. Looking at the long-term strength (91-day strength), as shown in Table 1, the strength of the examples can be seen to be roughly equivalent to the comparative example in which the retarder and the delay-strengthening aid are not added.
[0068]
  FIG. 4 also relates to the ground of silt. As the retarder, the same oxycarboxylic acid-based retarder as described above (trade name ER-2, Inc.Floric4) and indicated as ER-2 in FIG. As shown in Table 1, as delay enhancement aids, NaOH (reagent grade 1, indicated as Na in FIG. 4), MgO (reagent grade 1, indicated as Mg in FIG. 4), FeO (OH) (Reagent grade 1, indicated as Fe in FIG. 4) and alumina cement (Lafarge) were used. The amount added was expressed as a percentage (external ratio) of parts by mass with respect to parts by mass of cement. A comparative example 6 in which neither a retarder (ER-2) nor a delay-enhancing auxiliary was added was shown. In addition, the thing using CaO is the reference example 8.Example 9 using alumina cementAs shown together.
[0069]
  Penetration resistance value is 2 N / mm²And 4 N / mm²As described in Table 1, the time until the time becomes 3.9 hours and 7.8 hours in Comparative Example 6, while 5.5 hours and 14 hours in Example 3, and Example 4 Then it is 7 hours and 14.3 hours. Reference examples 5, 6, and 7, 8Also showed relatively good results. The uniaxial compressive strengths of the reference example, comparative example, and example shown in FIG. 4 are shown in FIG. Looking at the long-term strength (91-day strength), as shown in Table 1, compared to the comparative example in which no retarder or reinforcing aid was added, the one with MgO greatly exceeded the other examples. The strength of can be seen as equivalent.
[0070]
[Test Example 2]
Table 2 and FIG. 7 and FIG. 8 show the results of a laboratory experiment for the TRD method described above as Test Example 2. The conditions for this experiment are as follows.
[0071]
[Table 2]

[0072]
Blast furnace cement (type B), which is a hydraulic solidifying material, is used, and the amount of cement used is Cement amount C = 250 kg / m^Three(Ground soil 1m^ThreeThe amount of cement per unit) was 200% by mass of the water-solidifying material, and an experiment was performed on a ground soil sample. As for the addition amount of the retarder and the delay strengthening aid, the value of the part by mass (external ratio) with respect to 100 parts by mass of cement is indicated as%. As shown in Table 2 and FIG. 7 and FIG. 8, according to the vane shear resistance test, the vertical axis indicates the vane shear resistance value (shear strength), and the horizontal axis indicates the solidifying material liquid composed of the retarder, the delay strengthening aid and cement. Detailed results are shown with the elapsed time (curing time) from the time of stirring and mixing with the soil sample as the horizontal axis.
[0073]
In FIG. 7 and FIG. 8, an oxycarboxylic acid type retarder (trade name ER-2, manufactured by Sunflow Paric Co., Ltd.) was used as the retarder, and indicated as ER-2 in FIG. 7 and FIG.
[0074]
  Moreover, what is indicated as ER is an oxycarboxylic acid type retarder (trade name ER-2, Inc.) as a retarder.FloricMeans that it was used.
Furthermore, reference examples10, 11, 12, 13As slaked lime (Ca (OH)₂, Reagent grade 1, indicated as Ca in FIGS. 7 and 8, and those using CaO.
[0075]
The amount added was indicated by 100% (external percentage) of 100 parts by mass of cement. Those without the addition of a retarding agent or retardation enhancing aid were used as comparative examples.
[0076]
Table 2 shows the vane shear resistance values after 6 hours (6H), 12 hours (12H) and 18 hours (18H).
[0077]
  In the TRD method, the vane shear resistance value in the range where the work of inserting a reinforcing material such as H steel is easy is 5 kN / m.²In Comparative Examples 12, 13, and 17, it is limited to 3 to less than 6 hours. However, when the curing retarder of the present invention is used, it is extended to about 18 hours as shown in Example 7. Can do. Reference example10, 11, 12, 13Was also relatively good.
[0078]
Paying attention to the molecular weight of the oxides or hydroxides (compounds) used and the mixtures thereof, the added mass parts of the delay strengthening aid used in the above examples, the number of moles of compounds added per 1 kg of cement and the chemistry The equivalent weight is shown in Table 3.
[0079]
[Table 3]

[0080]
[Test Example 3]
As Test Example 3, silt clay was used as the target soil, and a laboratory experiment for the TRD method was conducted in the same manner as Test Example 2. The results are shown in Tables 4 to 5 and FIGS. The conditions of this experiment are as follows.
[0081]
Blast furnace cement (type B), which is a hydraulic solidifying material, is used, and the amount of cement used is Cement amount C = 250 kg / m^Three(Ground soil 1m^ThreeThe amount of cement per unit weight) was 100% by mass of the water-solidifying material ratio. As for the addition amount of the retarder and the delay strengthening aid, the value of the part by mass (external ratio) with respect to 100 parts by mass of cement is indicated as%. As shown in FIGS. 9 to 15, the vane shear resistance value (shear strength) by the vane shear resistance test is taken on the vertical axis, and the solidified material liquid composed of a retarder, a delay strengthening auxiliary agent and cement is stirred to the ground soil sample. Detailed results are shown by taking the elapsed time (curing time) from the mixing time on the horizontal axis.
[0082]
  As a retarder, an oxycarboxylic acid-based retarder (trade name ER-2, manufactured by Sunflow Paric Co., Ltd.) is used as a delay strengthening aid., BoSodium nitrate (sodium sulfate, Na₂SO₄・ 10H₂O, reagent grade 1), alum (potassium aluminum alum, AlK (SO₄)₂・ 12H₂O, reagent grade 1), SubSodium sulfate (NaHSO₃, Reagent grade 1), bittern (magnesium chloride MgCl)₂・ 6H₂O, reagent grade 1),Soda (NaOH, reagent grade 1),waterZinc oxide (Zn (OH)₂, Reagent grade 1), aluminum sulfate (Al₂(SO₄)₃, Reagent grade 1), or water glass (sodium silicate, Na₂O ・ SiO₂・ H₂Table 4 shows the results using O, reagent grade 1).As reference examples, quick lime (CaO, reagent grade 1), zinc oxide (ZnO, reagent grade 1), slaked lime (Ca (OH)) ₂ , Reagent grade 1), dihydrate gypsum (CaSO ₄ ・ 2H ₂ O, reagent grade 1), calcium chloride (CaCl ₂ ・ 2H ₂ O, reagent grade 1), calcium carbonate (CaCO ₃ , Reagent grade 1) was also shown.
[0083]
  Example of Table 48, 9, 109 and Comparative Examples 18 and 19 are shown in FIG.
[0084]
  Also delayAgentAs citric acid, lignin sulfonic acid, sorbitol, maltose, isomaly oligosaccharide, or polyacrylic acidAgentAs,Table 5 shows the results using the soda (NaOH, reagent grade 1). Each of the retarders was added in an amount having a substantially equivalent delay effect. In other words, 3 parts by mass of citric acid, 2 parts by mass of lignin sulfonic acid, 2 parts by mass of maltose, 1 part by mass of sorbitol, 1 part by mass of isomaligoligosaccharides, and 4 parts by mass of polyacrylic acid were added to 100 parts by mass of the hydraulic solidifying material.As a reference example, slaked lime (Ca (OH) ₂ , Reagent grade 1), and those using zinc oxide (ZnO, reagent grade 1) are also shown.The test results for each retarder in Table 5 are shown in FIGS.
[0085]
[Table 4]

[0086]
[Table 5]

[0087]
  The amount added (external ratio) with respect to 100 parts by mass of cement was indicated as%. A comparative example in which no retarding agent or retardation enhancing aid was added was shown.Moreover, what added Ca compound or Zn compound was shown as a reference example.
[0088]
  Tables 4 and 5 show the vane shear resistance values after 4 hours (4H), 6 hours (6H) and 8 hours (8H). In the TRD method, the vane shear resistance value in the range where the work of inserting a reinforcing material such as H steel is easy is 5 kN / m.²To the extent. Therefore, no measurements were made on data that clearly exceeded this. What is indicated as + in Tables 4 and 5 is approximately 8 kN / m²It was assumed that the value would exceed, and was not measured. Also, in Tables 4 and 5Examples, comparative examples and reference examplesThe compressive strength at the age of 7 and 28 days was measured for the main ones, and the results were also shown in Tables 4 and 5.
[0089]
  In Table 4, Comparative Example 18 is one in which only 2% of the retarding agent (ER-2) is added and no delay strengthening aid is added, and Comparative Example 19 is one in which neither the retarding agent nor the delay strengthening aid is added. In Comparative Example 18, application of the TRD method is restricted to less than about 4 hours. In Comparative Example 19, it is restricted within 3 hours. In Example 19, the delay effect can be used up to about 8 hours.8, 9, 10, 11Then, the delay effect can be used up to about 6 hours. Examples8,9Then, the compressive strength at the age of 28 days is sufficiently expressed. Example7, 12However, it is a little difficult to use.
[0090]
  Next, Table 5 and FIGS. delayAgentAs citric acid, lignin, maltose, isomaly oligosaccharide, or polyacrylic acid was used. Citric acid (oxycarboxylic acid type) is reagent grade 1, lignin sulfonic acid is lignin sulfonic acid calcium salt (average molecular weight 13,000) manufactured by Nippon Paper Industries Co., Ltd., maltose (sugar type) is reagent grade 1, sorbitol (sugar alcohol type) ) Is a D-sorbitol solution manufactured by Ueno Pharmaceutical Co., Ltd., isomaly-oligosaccharides (sugars) is isomali-oligosaccharide syrup (trade name panorup (concentration 75%)) manufactured by Hayashibara Co., Ltd. (Average molecular weight 14,000) (trade name Geosper K) was used. Delay enhancement assistantAgentAs, NTable 5 shows the results using aOH.Ca (OH) as a reference example ₂ Or what used ZnO was also shown.Table 5 DelayAgentThe test results for each are shown in FIGS.
[0091]
  In the example using citric acid as a retarding agent, as shown in Table 5 and FIG.13Has a large delay effect and a shear resistance of 5 kN / m ² A delay effect of 2 to 4 hours additional time is observed before reaching.
[0092]
  In the example using lignin sulfonic acid as a retarder, as shown in Table 5 and FIG.14However, the delay effect is large, and a delay effect of about 1 to 3 hours is recognized.
[0093]
  In the example using maltose as a retarding agent, as shown in Table 5 and FIG.15The addition time of about 2 to 4 hours is recognized.
[0094]
  Examples using sorbitol as a retarder16Then, as shown in Table 5 and FIG. 13, with respect to the comparative example 21 which does not add a delay reinforcement | strengthening adjuvant, the delay effect of 1-3 hours of addition time is anticipated.
[0095]
  Examples using isomaltoligosaccharide as a retarder17Then, as shown in Table 5 and FIG. 14, a delay effect of 2 to 4 hours is observed with respect to Comparative Example 22 in which no delay strengthening aid is added.
[0096]
In the Example which uses polyacrylic acid as a retarder, as shown in Table 5 and FIG. 15, there is a delay effect of 0.5 to 2 hours compared to Comparative Example 23 in which no delay strengthening aid is added.
[0097]
  Then delayAgentER-2 as a delay enhancement aidOr additives shown as reference examplesTable 6 shows the ranking of each delay strengthening aid of the present invention. The classification in Table 6 shows the period of the periodic table of elements. The delay effect decreases as the left column increases to the right. Moreover, what was described in the same frame is considered that the delay effect is substantially equivalent.
[0098]
  Next, the delayed strengthening aid used in Experimental Example 3Or additives shown as reference examplesTable 7 summarizes the relationship between the amount of metal atoms and the delay effect. In Table 7, the numbers shown in parentheses are values excluding crystallization water.
[0099]
[Table 6]

[0100]
[Table 7]

[0101]
  If you focus only on the delay effect, the delay enhancement aidOr the additive shown as a reference exampleShows high effect of zinc oxide (ZnO) or the like. As a retarder, saccharides need to be handled with care because there may be cases where expression of sufficient strength cannot be expected at the generally required 28-day strength. However, depending on the purpose, the addition amount of the retarder and the delay strengthening aid can be sufficiently used within the range of the addition ratio of the present invention, depending on the selection of the effect of retarding curing and the strength development period.
[0102]
【The invention's effect】
The curing retarder of the present invention reduces the use of retarding agents (additives such as retarding type admixtures) and uses conventional materials on the market as a delayed strengthening aid, thereby delaying the conventional delayed curing. The problem of using a large amount of the admixture in the form can be solved. That is, the delayed curing agent of the present invention has been improved by improving the technology for delaying the curing of the hydraulic solidifying material, and exhibits the desired curing delay effect by adding a delay-strengthening aid, so that it needs to be used in a large amount. In addition, the problem of using a large amount of conventional curing retarding admixture can be solved.
[0103]
In addition, according to the method of delaying hardening of the hydraulic solidified material according to the second aspect of the present invention, the expected effect of delaying curing is exhibited even if the amount of the retarder used is reduced by adding a delay reinforcing aid. In addition, it is possible to construct a construction that has a problem in construction due to the presence of the conventional delayed curing type admixture.
[0104]
Next, according to the method for delaying hardening of the improved soil according to the third aspect of the present invention, in order to set the improved soil (soil cement) to the desired time, a retarder (setting delay type admixture) is used alone. Compared to the case of using at the same time, by adding a delay-intensifying aid together, even if the amount of retarder (cure retarding admixture) itself is reduced, the expected retarding effect is exhibited and construction efficiency is increased. Total cost can be reduced. In addition, when a retarder (cure retarding admixture) is used alone, it is necessary to increase the amount of retarder (cure retarding admixture) added in order to delay curing until the desired time. Although the hardened body of the improved soil (soil cement) did not have sufficient strength due to the increase in the amount, it was delayed and strengthened even if the amount of retarder (hardening delay type admixture) was reduced. Since the hardening can be delayed to a desired time by adding an auxiliary agent, the strength of the hardened body of the improved soil (soil cement) can be kept within an allowable range.
[0105]
In other words, during the construction of improved soil (soil cement) that mixes hydraulic solidification material into the ground, the use of retarders (additives such as hardened retarded admixtures) is reduced, and the materials that are on the market Can be used for a short-term (several hours to several days) without incurring an increase in construction costs, improve the subsequent strength development, and use a large amount of conventional delayed-type admixtures When it does, the problem that intensity | strength does not fully express can be solved.
[Brief description of the drawings]
FIG. 1 is a graph showing the results of a needle penetration test of an example.
[Figure 2]referenceIt is a graph which shows the needle penetration test result of an example.
[Fig. 3]referenceIt is a graph which shows the needle penetration test result of an example.
FIG. 4 is a graph showing the results of a needle penetration test of an example.
[Figure 5]referenceIt is a graph which shows the compressive strength of an example.
FIG. 6 is a graph showing the compressive strength of Examples.
FIG. 7 is a graph showing the results of a vane shear test of an example.
[Fig. 8]referenceIt is a graph which shows the vane shear test result of an example.
FIG. 9 is a graph showing the results of a vane shear test of an example.
FIG. 10 is a graph showing the results of a vane shear test of an example.
FIG. 11 is a graph showing the results of a vane shear test of an example.
FIG. 12 is a graph showing the results of a vane shear test of an example.
FIG. 13 is a graph showing the results of a vane shear test of an example.
FIG. 14 is a graph showing the results of a vane shear test of an example.
FIG. 15 is a graph showing the results of a vane shear test of an example.
FIG. 16 is a graph showing the relationship between the water-solidifying material ratio, workability, amount of residual soil, and strength.
FIG. 17 is a graph showing the relationship between the amount of solidifying material used, workability, amount of residual soil, and strength.
[Explanation of symbols]
10 Curve (Remaining soil amount)
11 Curve (Intensity)
12 range
13 Curve (Intensity)
14 Curve (Remaining soil amount)
15 range

Claims (3)

Characterized in that the retarder consists of a one or two or more at a delay reinforcing aids selected from the group consisting of substances indicated below, a material to be mixed into hydraulic solidifying material during mixing with the soil Curing retarder.
Alkali metal oxides, hydroxides, silicates; magnesium oxides, chlorides; iron oxides, hydroxides; and aluminum oxides, hydroxides A method for delaying the curing of a hydraulic solidifying material, comprising delaying the curing of the hydraulic solidifying material mixed with soil using at least a retarding agent and the delay strengthening auxiliary agent according to claim 1.   A hardened material obtained by adding 0.2 to 12 parts by weight of a retarder and 1 to 50 parts by weight of the delay strengthening auxiliary agent according to claim 1 to 100 parts by weight of a hydraulic solidifying material is a device having an excavation blade and a stirring blade. A method for delaying hardening of an improved soil, characterized in that the improved soil is agitated and mixed with the soil to be solidified to obtain a hardened delayed soil, and after the required construction is performed within the unhardened time of the improved soil, the improved soil is solidified.

Images