JP4744678B2 - Cement admixture and cement composition - Google Patents
Cement admixture and cement composition Download PDFInfo
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- JP4744678B2 JP4744678B2 JP2000216857A JP2000216857A JP4744678B2 JP 4744678 B2 JP4744678 B2 JP 4744678B2 JP 2000216857 A JP2000216857 A JP 2000216857A JP 2000216857 A JP2000216857 A JP 2000216857A JP 4744678 B2 JP4744678 B2 JP 4744678B2
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
- C04B40/0028—Aspects relating to the mixing step of the mortar preparation
- C04B40/0039—Premixtures of ingredients
- C04B40/0042—Powdery mixtures
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B22/00—Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents
- C04B22/008—Cement and like inorganic materials added as expanding or shrinkage compensating ingredients in mortar or concrete compositions, the expansion being the result of a recrystallisation
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/20—Resistance against chemical, physical or biological attack
- C04B2111/27—Water resistance, i.e. waterproof or water-repellent materials
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、主に、土木・建築分野において使用されるセメント混和材及びセメント組成物に関する。
【０００２】
セメントは安価であり、かつ大きなコンクリ−ト構造物を任意の形に造ることが可能な優れた材料である。また、セメントに各種セメント混和材を併用することにより、構造物の強度や耐久性を向上させることが可能である。これまでにセメント混和材は数多く提案されているが、コンクリ−ト構造物の信頼性、耐久性、美観などの観点から、膨張性を付与するセメント混和材のさらなる技術の進展が望まれている。コンクリ−ト構造物に膨張性を付与するセメント混和材としては、例えば、遊離石灰−アウイン−無水セッコウ系膨張材（特公昭42-21840号公報）や遊離石灰−カルシウムシリケ−ト−無水セッコウ系膨張材（特公昭53-31170号公報）等がある。
【０００３】
【発明が解決しようとする課題】
しかしながら、生コンプラントのミキサにセメント混和材を開袋投入する際、セメント混和材が充分混練されないとコンクリートに均一に分散せずに塊状になっている場合があり、硬化後のコンクリ−トにおいて局所的に異常膨張する、いわゆるポップアウト現象を引き起こすことがある。ポップアウト現象を防止する方法としては、膨張材に予め不活性な無機粉末等を混和しておき、セメント混和材が充分に混練されなくても、膨張材成分同士が凝集して塊にならず、ある程度の分散が期待できるようにしておく方法が考えられるが、不活性な無機粉末を混和することにより膨張成分が希釈されるため、要求性能を満足するためには、セメント混和材の配合量を増加しなければならない問題が生じる。さらに、コンクリ−トに防水性を与えるセメント混和材も求められている。なお、本発明においてコンクリートとは、セメントペースト、モルタル及びコンクリートを総称するものである。
そこで、本発明者らはこのような状況を顧て種々検討した結果、特定の膨張材と、シリカ質微粉末および／又は石灰石微粉末とを配合することによって前記課題を解消できるセメント混和材が得られるとの知見を得て、本発明を完成するに至った。
【０００４】
【課題を解決するための手段】
即ち、本発明は、ＣａＯ原料、Ａｌ2Ｏ3原料、Ｆｅ2Ｏ3原料、ＳｉＯ2原料及びＣａＳＯ4原料を熱処理して得られる物質であって、遊離石灰、カルシウムアルミノフェライト、カルシウムシリケート及び無水セッコウを主要な構成化合物とする膨張材１００部中、遊離石灰は３０〜７０部、カルシウムアルミノフェライトは５〜２２．５部、カルシウムシリケートは５〜２２．５部、無水セッコウは５〜３０部である膨張材と、シリカ質微粉末及び／又は石灰石微粉末とを含有してなり、セメント混和材１００部中、膨張材は５０〜９５部、シリカ質微粉末及び／又は石灰石微粉末は５〜５０部である、優れた膨張性能を付与し、ポップアウト現象を防止するセメント混和材であり、セメントと、該セメント混和材とを含有してなるセメント組成物である。
【０００５】
【発明の実施の形態】
以下、本発明を更に詳細に説明する。
【０００６】
本発明の膨張材は、ＣａＯ原料、Ａｌ2Ｏ3原料、Ｆｅ2Ｏ3原料、ＳｉＯ2原料及びＣａＳＯ4原料を熱処理して得られる物質であって、遊離石灰、カルシウムアルミノフェライト、カルシウムシリケート及び無水セッコウを主要な構成化合物とするものである。その組成割合については、特に限定されるものではないが、膨張材１００部中、遊離石灰は３０〜７０部が好ましく、４０〜６０部がより好ましい。カルシウムアルミノフェライトは５〜２２．５部が好ましく、１０〜１５部がより好ましい。カルシウムシリケートは５〜２２．５部が好ましく、１０〜１５部がより好ましい。さらに、無水セッコウは５〜３０部が好ましく、１０〜３０部がより好ましい。セメント混和材中の各化合物の組成割合が前記範囲にないと、優れた膨張性能及び流動性の保持性能が得られない場合がある。
なお、本発明で用いる部、％は質量単位を表す。
【０００７】
本発明の遊離石灰とは、通常、ｆ−ＣａＯと呼ばれるものである。
本発明のカルシウムアルミノフェライトとは、ＣａＯ−Ａｌ2Ｏ3−Ｆｅ2Ｏ3系を総称するものであり、特に限定されるものではないが、一般的に、ＣａＯをＣ、Ａｌ2Ｏ3をＡ、Ｆｅ2Ｏ3をＦとすると、Ｃ4ＡＦ、Ｃ6Ａ2Ｆ、Ｃ6ＡＦ2等の化合物がよく知られているが、通常はＣ4ＡＦとして存在していると考えて良い。また、本発明のカルシウムシリケートとは、ＣａＯ−ＳｉＯ2系を総称するものであり、特に限定されるものではないが、Ｃ2ＳやＣ3Ｓがよく知られているが、通常はＣ3Ｓとして存在していると考えて良い。以下、本発明では、カルシウムアルミノフェライトをＣ4ＡＦ、カルシウムシリケートをＣ3Ｓと略記する。
【０００８】
本発明の膨張材を製造する際、ＣａＯ原料、Ａｌ2Ｏ3原料、Ｆｅ2Ｏ3原料、ＳｉＯ2原料及びＣａＳＯ4原料を熱処理して、遊離石灰、Ｃ4ＡＦ、Ｃ3Ｓ及び無水セッコウからなるクリンカ−を合成して製造する。遊離石灰、Ｃ4ＡＦ、 Ｃ3Ｓ及び無水セッコウを別々に合成してから、それらを混合したものでは本発明の効果は得られない。ＣａＯ原料、Ａｌ2Ｏ3原料、Ｆｅ2Ｏ3原料、ＳｉＯ2原料及びＣａＳＯ4原料を熱処理して、遊離石灰、Ｃ4ＡＦ、Ｃ3Ｓ及び無水セッコウからなるクリンカ−を合成したかどうかは、例えば、粉砕物中の１００μｍ以上の粗粒子の顕微鏡観察（ＳＥＭ−ＥＤＸ）等を行い、その粒子中に遊離石灰、Ｃ4ＡＦ、Ｃ3Ｓ及び無水セッコウが混在していることを確認することによって判別できる。
【０００９】
本発明の製造する際の熱処理方法としては、特に限定されるものではないが、電気炉やキルン等を用いて、１１００〜１６００℃の温度範囲で焼成することが好ましく、１２００〜１５００℃の温度範囲がより好ましい。１１００℃未満では、得られたセメント混和材の膨張性能が十分でなく、１６００℃を超えると無水セッコウが分解する恐れがある。
【００１０】
ＣａＯ原料としては、石灰石や消石灰が挙げられ、Ａｌ2Ｏ3原料としては、ボ−キサイトやアルミ残灰等が挙げられ、Ｆｅ2Ｏ3原料としては、銅カラミ、鉄粉、市販の酸化鉄等が挙げられ、ＳｉＯ2原料としては、市販の二酸化珪素や珪石が挙げられ、ＣａＳＯ4原料としては、二水セッコウ、半水セッコウ及び無水セッコウ等が挙げられる。これら原料中には各種の不純物が存在し、その具体例としては、ＭｇＯ、ＴｉＯ2、Ｐ2Ｏ5、Ｎａ2Ｏ、Ｋ2Ｏ、フッ素、塩素等が挙げられ、本発明の目的を実質的に阻害しない範囲では特に問題とはならない。
【００１１】
本発明の膨張材の粒度は、特に限定されるものではないが、通常、ブレ−ン比表面積で１５００〜６０００ｃｍ2／ｇが好ましく、２５００〜４０００ｃｍ2／ｇがより好ましい。１５００ｃｍ2／ｇ未満では、強度発現性が悪くなる場合があり、６０００ｃｍ2／ｇを超えると優れた膨張性能が得られない場合がある。
【００１２】
本発明に使用されるシリカ質微粉末とは、特に限定されるものではないが、シリカフュ−ム、高炉スラグ、フライアッシュ、ケイソウ土や溶融シリカ等のシリカダスト等を総称するものである。シリカ質微粉末は、ポップアウト現象の抑制効果の他に、コンクリ−トの防水性を向上させる効果も奏する。
【００１３】
本発明に使用される石灰石微粉末とは、特に限定されるものではないが、天然に産出する炭酸カルシウムを主成分とする鉱石を総称するものである。石灰石微粉末は、シリカ質微粉末のように防水性を向上させる効果は有しないが、ポップアウト現象の抑制効果は充分に有し、さらに地域によっては安価に入手できるという利点がある。
【００１４】
本発明に使用されるシリカ質微粉末及び／又は石灰石微粉末の粒度は、特に限定されるものではないが、通常、ブレ−ン比表面積で３０００ｃｍ2／ｇ以上が好ましい。３０００ｃｍ2／ｇ未満では、充分なポップアウト抑制効果が得られない場合がある。
【００１５】
本発明の膨張材と、シリカ質微粉末及び／又は石灰石微粉末の配合割合は、特に限定されるものではないが、通常、セメント混和材１００部中、膨張材は５０〜９５部が好ましく、６０〜９０部がより好ましい。膨張材が５０部未満では、充分な膨張性能が得られない場合があり、９５部を超えると充分なポップアウト現象の抑制効果や、防水性の向上効果が得られない場合がある。シリカ質微粉末及び／又は石灰石微粉末は、５〜５０部が好ましく、１０〜４０部がより好ましい。５部未満では、充分なポップアウト現象の抑制効果や、防水性の向上効果が得られない場合があり、５０部を超えると充分な膨張性能が得られない場合がある。
【００１６】
本発明のセメント混和材の配合量は、特に限定されるものではないが、通常、セメントとセメント混和材からなるセメント組成物１００部中、５〜１５部が好ましく、７〜１３部がより好ましい。５部未満では本発明の効果が充分に得られない場合があり、１５部を超えて使用すると強度発現性が悪くなる場合がある。
【００１７】
本発明のセメントとしては、普通セメント、早強、超早強、低熱及び中庸熱等各種ポルトランドセメントと、これらセメントに、高炉スラグ、フライアッシュ及びシリカを混合した各種混合セメント、石灰石粉末等を混合したフィラーセメント、並びにアルミナセメント等が挙げられ、これらのうちの１種又は２種以上が使用可能である。
【００１８】
本発明のセメント混和材及びセメント組成物に、砂、砂利等の骨材の他、減水剤、高性能減水剤、ＡＥ減水剤、高性能ＡＥ減水剤、流動化剤、消泡剤、増粘剤、防錆剤、防凍剤、収縮低減剤、高分子エマルジョン及び凝結調整剤、並びにセメント急硬材、セメント膨張材、ベントナイトやゼオライト等の粘土鉱物、ハイドロタルサイト等のアニオン交換体等のうちの１種又は２種以上を、本発明の目的を実質的に阻害しない範囲で使用することが可能である。
【００１９】
本発明では、各材料の混合方法は、それぞれの材料を予め全部混合しておけば特に限定されるものではない。混合装置としては、既存の如何なる装置も使用可能であり、例えば、傾胴ミキサ、オムニミキサ、ヘンシェルミキサ、Ｖ型ミキサ及びナウタミキサ等が挙げられる。
【００２０】
【実施例】
以下、実施例により本発明を詳細に説明する。
【００２１】
実施例１
ＣａＯ原料、Ａｌ2Ｏ3原料、Ｆｅ2Ｏ3原料、ＳｉＯ2原料及びＣａＳＯ4原料を配合し、混合粉砕した後、電気炉を用い１３５０℃で２時間熱処理して、表１に示す種々の化合物組成の膨張材を製造し、ブレ−ン比表面積３５００±２００ｃｍ2／ｇに粉砕した。これら膨張材を７５部、石灰石微粉末を２５部の割合で混合してセメント混和材とし、セメントとセメント混和材からなるセメント組成物１００部中、セメント混和材を１０部配合し、単位セメント組成物量が３００ｋｇ／ｍ3、水／セメント組成物比＝６２％、ｓ／ａ＝４５％のコンクリートを調製し、長さ変化率及びポップアウト試験を行った。結果を表１に併記する。
製造した膨張材を粉末Ｘ線回折装置（ＸＲＤ）により同定し、遊離石灰、Ｃ4ＡＦ、Ｃ3Ｓ及び無水セッコウを主要な構成化合物とすることを確認した。また、化学組成は化学分析により求め、化合物組成は化学分析値を基に、計算により求めた。
なお、膨張材Ｔは、遊離石灰、Ｃ4ＡＦ、Ｃ3Ｓ及び無水セッコウを別々に合成した後に混合して調製したものである。
【００２２】
＜使用材料＞
セメント：市販普通ポルトランドセメント
石灰石微粉末：新潟県青海鉱山産石灰石をブレ−ン比表面積５０００ｃｍ2／ｇに粉砕したもの。
水：水道水
砂：新潟県姫川産、比重２．６２
砂利：新潟県姫川産、比重２．６４
ＣａＯ原料：試薬１級炭酸カルシウム
Ａｌ2Ｏ3原料：試薬１級酸化アルミニウム
Ｆｅ2Ｏ3原料：試薬１級酸化鉄
ＳｉＯ2原料：試薬１級二酸化ケイ素
ＣａＳＯ4原料：試薬１級無水セッコウ
遊離石灰：ＣａＯ原料を１３５０℃で３時間焼成し合成したもの。
Ｃ4ＡＦ：ＣａＯ原料４モル、Ａｌ2Ｏ3原料１モル、Ｆｅ2Ｏ3原料１モルを混合し、１３５０℃で３時間焼成し合成したもの。
Ｃ3Ｓ：ＣａＯ原料３モル、ＳｉＯ2原料１モルを混合し、１６００℃で３時間焼成し合成したもの。
無水セッコウ：ＣａＳＯ4原料を１３５０℃で３時間焼成したもの。
【００２３】
＜測定方法＞
化学分析：JIS R 5202に準じて測定。
化合物組成：遊離石灰含有量をJIS R 5202に準じて測定し、それ以外の化合物については計算により求めた。即ち、Ａｌ2Ｏ3量からＣ4ＡＦ量を算出し、ＳｉＯ2量からＣ3Ｓ量を算出し、次いでＳＯ3量から無水セッコウ量を算出した。
長さ変化率：JIS A 6202 Bに準じて測定。
ポップアウト試験：セメント混和材を添加しないで予めコンクリートを調製しておき、傾胴ミキサにコンクリ−トを投入し、１２回転／分の速さでミキサをアジテ−トしながらセメント混和材を後添加し、１０分後に排出して、縦１ｍ、横５０ｃｍ、高さ１０ｃｍの型枠内へ打設しポップアウト現象を確認した。なお、環境温度は２０℃とした。
【００２４】
【表１】
表１より、本発明のセメント混和材及びセメント組成物は、コンクリートに優れた膨張性能を付与していることが分かる。
【００２６】
実施例２
工業原料であるＣａＯ原料、Ａｌ2Ｏ3原料、Ｆｅ2Ｏ3原料、ＳｉＯ2原料及びＣａＳＯ4原料を配合し、ロータリーキルンを用いて１４００℃で熱処理することで、表２に示す組成の膨張材を製造したこと以外は、実施例１と同様に行った。表３に化学組成から算出した化合物組成、表４に測定結果を示す。なお、比較のために市販の２種類の膨張材についても同様の実験を行った。
【００２７】
＜使用材料＞
ＣａＯ原料：新潟県青海鉱山産石灰石
Ａｌ2Ｏ3原料：中国産ボ−キサイト
Ｆｅ2Ｏ3原料：工業用酸化鉄
ＳｉＯ2原料：市販珪石
ＣａＳＯ4原料：タイ産天然無水セッコウ
市販膨張材Ａ：カルシウムサルホアルミネ−ト系膨張材
市販膨張材Ｂ：石灰系膨張材
【００２８】
【表２】
【表３】
【表４】
表４より、本発明のセメント混和材及びセメント組成物は、コンクリートに優れた膨張性能や流動性の保持性能を付与し、しかもポップアウト現象を防止していることが分かる。
【００３２】
実施例３
実施例２の本発明の膨張材を使用し、表５に示すシリカ質微粉末の種類と量を変えてセメント混和材としたこと以外は、実施例２と同様に行った。なお、防水性試験も併せて実施した。結果を表５に併記する。
【００３３】
＜使用材料＞
シリカ質微粉末▲１▼：市販の高炉スラグをブレ−ン比表面積５０００ｃｍ2／ｇに粉砕したもの。
シリカ質微粉末▲２▼：市販のシリカフュ−ム、ブレ−ン比表面積２０００００ｃｍ2／ｇ。
シリカ質微粉末▲３▼：市販のフライアッシュをブレ−ン比表面積５０００ｃｍ2／ｇに粉砕したもの。
シリカ質微粉末▲４▼：市販のケイソウ土をブレ−ン比表面積５０００ｃｍ2／ｇに粉砕したもの。
シリカ質微粉末▲５▼：シリカ質微粉末▲１▼とシリカ質微粉末▲２▼の等量混合物、ブレ−ン比表面積１０２５００ｃｍ2／ｇ。
シリカ質微粉末▲６▼：シリカ質微粉末▲２▼と石灰石微粉末の等量混合物、ブレ−ン比表面積１０２５００ｃｍ2／ｇ。
【００３４】
＜測定方法＞
防水性試験：φ１５×３０ｃｍ、中心孔の直径２．０ｃｍの円空供試体を作成し、材齢１日で脱型後、材齢7日までの６日間水中養生を施した後、透水性試験を実施した。試験方法はアウトプット方式とし、試験体外側から水圧１０ｋｇ／ｃｍ2を４８時間加え、中心孔から出る水量を測定し、セメント混和材を配合していないコンクリ−トの透水量を１００とした時の相対値を透水比として表した。
【００３５】
【表５】
表５より、本発明のセメント混和材及びセメント組成物は、コンクリートに優れた膨張性能を付与すると共に、ポップアウト現象を防止し、防水性を高めることが分かる。
【００３７】
実施例４
実施例２の本発明の膨張材を７５部、シリカ質微粉末▲２▼を２５部の割合で混合したセメント混和材を使用し、セメント組成物中のセメント混和材の配合量を表６に示すように変えたこと以外は、実施例２と同様に行った。結果を表６に併記する。
【００３８】
【表６】
表６より、本発明のセメント混和材は、その配合量が増加するにつれて、コンクリートの長さ変化率が大きくなる優れた膨張性能を付与すると共に、ポップアウト現象を防止し、防水性を高めることが分かる。
【００４０】
【発明の効果】
本発明のセメント混和材は配合量が少なくても、コンクリートに優れた膨張性能及び流動性の保持性能を付与し、且つ、ポップアウト現象の防止及び防水性の向上が可能である。[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to a cement admixture and a cement composition used in the field of civil engineering and construction.
[0002]
Cement is an excellent material that is inexpensive and capable of forming large concrete structures in any shape. Moreover, it is possible to improve the strength and durability of the structure by using various cement admixtures in combination with cement. Many cement admixtures have been proposed so far, but from the viewpoints of reliability, durability, aesthetics, etc. of concrete structures, further development of cement admixtures that impart expansibility is desired. . Concrete - The cement admixture that imparts the inflatable Doo structures, for example, free lime - Auin - anhydrous gypsum-based expansive (Sho 42 - 21840 JP) and free lime - calcium silicate are - DOO - anhydrous gypsum it is - (31170 JP Sho 53), etc. system expansion material.
[0003]
[Problems to be solved by the invention]
However, when the cement admixture is unpacked into the mixer of a green plant, if the cement admixture is not sufficiently kneaded, it may be agglomerated without being uniformly dispersed in the concrete. This may cause a so-called pop-out phenomenon that causes abnormal expansion. As a method of preventing the pop-out phenomenon, inactive inorganic powder or the like is mixed in advance in the expansion material, and even if the cement admixture is not sufficiently kneaded, the expansion material components do not aggregate and become a lump. In order to satisfy the required performance, the amount of the cement admixture must be blended so that a certain degree of dispersion can be expected, but the expansion component is diluted by mixing inert inorganic powder. The problem arises that must be increased. There is also a need for a cement admixture that provides waterproofing to the concrete. In the present invention, concrete is a general term for cement paste, mortar, and concrete.
Therefore, as a result of various studies in view of such a situation, the present inventors have found a cement admixture that can solve the above-mentioned problems by blending a specific expansion material with fine siliceous powder and / or fine limestone powder. Obtaining knowledge that it can be obtained, the present invention has been completed.
[0004]
[Means for Solving the Problems]
That is, the present invention is a substance obtained by heat treatment of CaO raw material, Al 2 O 3 raw material, Fe 2 O 3 raw material, SiO 2 raw material and CaSO 4 raw material, and includes free lime, calcium aluminoferrite, calcium silicate and anhydrous In 100 parts of expanded material containing gypsum as a main constituent compound , free lime is 30 to 70 parts, calcium aluminoferrite is 5 to 22.5 parts, calcium silicate is 5 to 22.5 parts, and anhydrous gypsum is 5 to 30 parts. an expansion member is siliceous Ri name contains a fine powder and / or limestone powder in 100 parts of cement admixture, the expansion member 50 to 95 parts of siliceous fine powder and / or limestone fine powder 5 to 50 parts, and impart excellent expansion performance, a cement admixture for preventing pop-out phenomenon, cementite which comprises cement, a said cement admixture It is a door composition.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
[0006]
The expansion material of the present invention is a substance obtained by heat-treating a CaO raw material, an Al 2 O 3 raw material, an Fe 2 O 3 raw material, an SiO 2 raw material, and a CaSO 4 raw material, and includes free lime, calcium aluminoferrite, calcium silicate, and Anhydrous gypsum is the main constituent compound. About the composition ratio, although it does not specifically limit, 30-70 parts of free lime are preferable in 100 parts of expansion | swelling materials, and 40-60 parts are more preferable. The calcium aluminoferrite is preferably 5 to 22.5 parts, more preferably 10 to 15 parts. The calcium silicate is preferably 5 to 22.5 parts, more preferably 10 to 15 parts. Furthermore, 5-30 parts are preferable and, as for anhydrous gypsum, 10-30 parts are more preferable. If the composition ratio of each compound in the cement admixture is not within the above range, excellent expansion performance and fluidity retention performance may not be obtained.
In addition, the part used by this invention and% represent a mass unit.
[0007]
The free lime of the present invention is usually called f-CaO.
The calcium aluminoferrite of the present invention is a generic term for the CaO—Al 2 O 3 —Fe 2 O 3 system and is not particularly limited, but in general, CaO is C, and Al 2 O 3 is When A and Fe 2 O 3 are F, compounds such as C 4 AF, C 6 A 2 F, and C 6 AF 2 are well known, but it may be considered that they are usually present as C 4 AF. . The calcium silicate of the present invention is a generic term for CaO—SiO 2 system and is not particularly limited, but C 2 S and C 3 S are well known, but usually C 3 You can think of it as S. Hereinafter, in the present invention, calcium aluminoferrite is abbreviated as C 4 AF and calcium silicate as C 3 S.
[0008]
When producing the expansion material of the present invention, the CaO raw material, the Al 2 O 3 raw material, the Fe 2 O 3 raw material, the SiO 2 raw material and the CaSO 4 raw material are heat-treated to produce free lime, C 4 AF, C 3 S and anhydrous gypsum. A clinker made of The effects of the present invention cannot be obtained if free lime, C 4 AF, C 3 S and anhydrous gypsum are synthesized separately and then mixed. Whether the clinker made of free lime, C 4 AF, C 3 S and anhydrous gypsum was synthesized by heat-treating the CaO raw material, Al 2 O 3 raw material, Fe 2 O 3 raw material, SiO 2 raw material and CaSO 4 raw material For example, microscopic observation (SEM-EDX) of coarse particles of 100 μm or more in the pulverized product is performed, and it is confirmed that free lime, C 4 AF, C 3 S and anhydrous gypsum are mixed in the particles. Can be determined.
[0009]
Although it does not specifically limit as the heat processing method at the time of manufacture of this invention, It is preferable to bake in the temperature range of 1100-1600 degreeC using an electric furnace, a kiln, etc., and the temperature of 1200-1500 degreeC is preferable. A range is more preferred. If it is less than 1100 degreeC, the expansion | swelling performance of the obtained cement admixture is not enough, and when it exceeds 1600 degreeC, there exists a possibility that an anhydrous gypsum may decompose | disassemble.
[0010]
Examples of the CaO raw material include limestone and slaked lime. Examples of the Al 2 O 3 raw material include bauxite and aluminum residual ash. Examples of the Fe 2 O 3 raw material include copper calami, iron powder, and commercially available iron oxide. Examples of the SiO 2 raw material include commercially available silicon dioxide and silica stone, and examples of the CaSO 4 raw material include dihydrate gypsum, semi-water gypsum and anhydrous gypsum. Various impurities are present in these raw materials, and specific examples thereof include MgO, TiO 2 , P 2 O 5 , Na 2 O, K 2 O, fluorine, chlorine and the like. This is not a problem as long as it is not hindered.
[0011]
The particle size of the expanded material of the present invention is not particularly limited, usually, blurring - is preferably 1500~6000cm 2 / g in down specific surface area, 2500~4000cm 2 / g is more preferable. If it is less than 1500 cm < 2 > / g, strength development may worsen, and if it exceeds 6000 cm < 2 > / g, an excellent expansion performance may not be obtained.
[0012]
The siliceous fine powder used in the present invention is not particularly limited, but is a general term for silica fume, blast furnace slag, fly ash, silica dust such as diatomaceous earth and fused silica, and the like. The siliceous fine powder has the effect of improving the waterproof property of the concrete in addition to the effect of suppressing the pop-out phenomenon.
[0013]
The fine limestone powder used in the present invention is not particularly limited, but is a general term for ores composed mainly of calcium carbonate produced in nature. Limestone fine powder does not have the effect of improving waterproofness like siliceous fine powder, but has a sufficient effect of suppressing the pop-out phenomenon, and has an advantage that it can be obtained at a low cost depending on the region.
[0014]
The particle size of the siliceous fine powder and / or limestone fine powder used in the present invention is not particularly limited, but is usually preferably 3000 cm 2 / g or more in terms of the specific surface area of the brain. If it is less than 3000 cm 2 / g, a sufficient pop-out suppressing effect may not be obtained.
[0015]
The blending ratio of the expandable material of the present invention and the siliceous fine powder and / or limestone fine powder is not particularly limited, but usually the expandable material is preferably 50 to 95 parts in 100 parts of the cement admixture, 60 to 90 parts are more preferred. If the expansion material is less than 50 parts, sufficient expansion performance may not be obtained, and if it exceeds 95 parts, a sufficient pop-out phenomenon suppressing effect or waterproof improvement effect may not be obtained. The siliceous fine powder and / or limestone fine powder is preferably 5 to 50 parts, more preferably 10 to 40 parts. If it is less than 5 parts, there may be a case where a sufficient pop-out phenomenon suppressing effect and a waterproof effect cannot be obtained, and if it exceeds 50 parts, sufficient expansion performance may not be obtained.
[0016]
The blending amount of the cement admixture of the present invention is not particularly limited, but is usually preferably 5 to 15 parts, more preferably 7 to 13 parts in 100 parts of a cement composition composed of cement and a cement admixture. . If the amount is less than 5 parts, the effects of the present invention may not be sufficiently obtained. If the amount exceeds 15 parts, strength development may be deteriorated.
[0017]
As the cement of the present invention, various cements such as ordinary cement, early strength, super early strength, low heat and moderate heat, and various cements mixed with blast furnace slag, fly ash and silica, limestone powder, etc. are mixed. Filler cement, alumina cement, and the like, and one or more of these can be used.
[0018]
In addition to aggregates such as sand and gravel, the cement admixture and cement composition of the present invention, water reducing agent, high performance water reducing agent, AE water reducing agent, high performance AE water reducing agent, fluidizing agent, antifoaming agent, thickening agent. Agents, rust inhibitors, antifreeze agents, shrinkage reducers, polymer emulsions and setting modifiers, cement hardeners, cement expansion materials, clay minerals such as bentonite and zeolite, anion exchangers such as hydrotalcite, etc. It is possible to use 1 type (s) or 2 or more types in the range which does not substantially inhibit the objective of this invention.
[0019]
In the present invention, the mixing method of each material is not particularly limited as long as all the respective materials are mixed in advance . Any existing apparatus can be used as the mixing apparatus, and examples thereof include a tilting cylinder mixer, an omni mixer, a Henschel mixer, a V-type mixer, and a Nauta mixer.
[0020]
【Example】
Hereinafter, the present invention will be described in detail by way of examples.
[0021]
Example 1
A CaO raw material, an Al 2 O 3 raw material, an Fe 2 O 3 raw material, a SiO 2 raw material and a CaSO 4 raw material were blended, mixed and pulverized, and then heat treated at 1350 ° C. for 2 hours using an electric furnace. An expanding material having a compound composition was produced and ground to a brain specific surface area of 3500 ± 200 cm 2 / g. 75 parts of these expansion materials and 25 parts of limestone fine powder are mixed to form a cement admixture, and 10 parts of the cement admixture are blended in 100 parts of a cement composition composed of cement and cement admixture. Concrete having a physical quantity of 300 kg / m 3 , a water / cement composition ratio = 62%, and s / a = 45% was prepared, and a length change rate and a pop-out test were performed. The results are also shown in Table 1.
The produced expanded material was identified by a powder X-ray diffractometer (XRD), and it was confirmed that free lime, C 4 AF, C 3 S and anhydrous gypsum were the main constituent compounds. The chemical composition was determined by chemical analysis, and the compound composition was determined by calculation based on the chemical analysis values.
The expansion material T is prepared by separately synthesizing free lime, C 4 AF, C 3 S, and anhydrous gypsum and then mixing them.
[0022]
<Materials used>
Cement: Commercially available ordinary Portland cement limestone fine powder: pulverized limestone from Aomi mine, Niigata Prefecture, to a specific surface area of 5000 cm 2 / g.
Water: tap water sand: produced in Himekawa, Niigata Prefecture, specific gravity 2.62
Gravel: Niigata prefecture Himekawa production, specific gravity 2.64
CaO material: first grade reagent calcium carbonate Al 2 O 3 material: first grade reagent Aluminum oxide Fe 2 O 3 material: first grade reagent iron oxide SiO 2 raw material: first grade reagent Silicon Dioxide CaSO 4 material: first grade reagent anhydrite free lime : CaO raw material synthesized by firing at 1350 ° C. for 3 hours.
C 4 AF: 4 mol of CaO raw material, 1 mol of Al 2 O 3 raw material and 1 mol of Fe 2 O 3 raw material were mixed and sintered at 1350 ° C. for 3 hours for synthesis.
C 3 S: 3 mol of CaO raw material and 1 mol of SiO 2 raw material were mixed and baked at 1600 ° C. for 3 hours for synthesis.
Anhydrous gypsum: CaSO 4 raw material calcined at 1350 ° C. for 3 hours.
[0023]
<Measurement method>
Chemical analysis: Measured according to JIS R 5202.
Compound composition: Free lime content was measured according to JIS R 5202, and other compounds were calculated. That is, the C 4 AF amount was calculated from the Al 2 O 3 amount, the C 3 S amount was calculated from the SiO 2 amount, and then the anhydrous gypsum amount was calculated from the SO 3 amount.
Length change rate: Measured according to JIS A 6202 B.
Pop-out test: Concrete is prepared in advance without adding cement admixture, concrete is put into the tilting mixer, and the cement admixture is moved while agitating the mixer at a speed of 12 revolutions / minute. It was added, discharged 10 minutes later, and placed in a mold having a length of 1 m, a width of 50 cm, and a height of 10 cm, and a pop-out phenomenon was confirmed. The ambient temperature was 20 ° C.
[0024]
[Table 1]
From Table 1, it can be seen that the cement admixture and the cement composition of the present invention impart excellent expansion performance to concrete.
[0026]
Example 2
An expansion material having the composition shown in Table 2 is prepared by blending CaO raw material, Al 2 O 3 raw material, Fe 2 O 3 raw material, SiO 2 raw material and CaSO 4 raw material, which are industrial raw materials, and heat-treating them at 1400 ° C. using a rotary kiln. The same procedure as in Example 1 was carried out except that was manufactured. Table 3 shows the compound composition calculated from the chemical composition, and Table 4 shows the measurement results. For comparison, the same experiment was performed on two types of commercially available expansion materials.
[0027]
<Materials used>
CaO raw material: Limestone Al 2 O 3 raw material from Aomi mine, Niigata Prefecture: Chinese bauxite Fe 2 O 3 raw material: Industrial iron oxide SiO 2 raw material: Commercial silica CaSO 4 raw material: Thai natural anhydrous gypsum commercial expanded material A: Calcium sulfoaluminate-based expansion material Commercial expansion material B: Lime-based expansion material
[Table 2]
[Table 3]
[Table 4]
From Table 4, it can be seen that the cement admixture and cement composition of the present invention impart excellent expansion performance and fluidity retention performance to concrete, and prevent pop-out phenomenon.
[0032]
Example 3
The same procedure as in Example 2 was performed except that the expansion material of the present invention of Example 2 was used and the cement admixture was changed by changing the type and amount of the siliceous fine powder shown in Table 5. A waterproof test was also conducted. The results are also shown in Table 5.
[0033]
<Materials used>
Siliceous fine powder (1): Commercially available blast furnace slag ground to a specific surface area of 5000 cm 2 / g.
Siliceous fine powder (2): Commercially available silica fume, brain specific surface area of 200,000 cm 2 / g.
Silica fine powder (3): Commercially available fly ash ground to a specific surface area of 5000 cm 2 / g.
Siliceous fine powder (4): A commercially available diatomaceous earth ground to a brain specific surface area of 5000 cm 2 / g.
Siliceous fine powder (5): A mixture of equal amounts of siliceous fine powder (1) and siliceous fine powder (2), brain specific surface area of 102500 cm 2 / g.
Siliceous fine powder (6): Silica fine powder (2) and an equivalent mixture of limestone fine powder, brain specific surface area of 102500 cm 2 / g.
[0034]
<Measurement method>
Waterproof test: A circular empty specimen with a diameter of 15 x 30 cm and a center hole diameter of 2.0 cm was prepared. After demolding at a material age of 1 day, it was subjected to underwater curing for 6 days until the material age of 7 days, and then water permeability The test was conducted. When the test method is an output method, water pressure of 10 kg / cm 2 is applied from the outside of the specimen for 48 hours, the amount of water coming out from the center hole is measured, and the water permeability of the concrete containing no cement admixture is 100 The relative value was expressed as a water permeability ratio.
[0035]
[Table 5]
From Table 5, it can be seen that the cement admixture and the cement composition of the present invention impart excellent expansion performance to concrete, prevent pop-out phenomenon, and improve waterproofness.
[0037]
Example 4
A cement admixture prepared by mixing 75 parts of the expansion material of the present invention of Example 2 and 25 parts of siliceous fine powder (2) was used. Table 6 shows the blending amount of the cement admixture in the cement composition. The procedure was the same as in Example 2 except that the changes were made as shown. The results are also shown in Table 6.
[0038]
[Table 6]
From Table 6, the cement admixture of the present invention gives an excellent expansion performance in which the rate of change in the length of the concrete increases as the blending amount increases, and prevents pop-out phenomenon and enhances waterproofness. I understand.
[0040]
【The invention's effect】
The cement admixture of the present invention imparts excellent expansion performance and fluidity retention performance to concrete even when the blending amount is small, and can prevent pop-out phenomenon and improve waterproofness.
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| JP2007269556A (en) * | 2006-03-31 | 2007-10-18 | Sumitomo Osaka Cement Co Ltd | Expanding admixture and expanding concrete using admixture |
| JP4776426B2 (en) * | 2006-04-28 | 2011-09-21 | 株式会社デイ・シイ | Cement admixture and low expansion cement composition using the cement admixture |
| JP4538438B2 (en) * | 2006-10-13 | 2010-09-08 | 電気化学工業株式会社 | Grout composition and grout material using the same |
| WO2009146572A1 (en) * | 2008-06-02 | 2009-12-10 | 天津新技术产业园区中核防水材料有限公司 | A penetration-crystallization type cement-based water-proof material with molecular sieve structure and a method of producing the same |
| JP7260998B2 (en) * | 2018-11-14 | 2023-04-19 | デンカ株式会社 | Expansive composition, cement composition and cement-concrete |
| JP7293019B2 (en) * | 2019-07-18 | 2023-06-19 | デンカ株式会社 | EXPANDING COMPOSITION FOR CEMENT, CEMENT COMPOSITION, AND METHOD FOR PRODUCING THE EXPANSION COMPOSITION FOR CEMENT |
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| JPH0288451A (en) * | 1988-09-26 | 1990-03-28 | Denki Kagaku Kogyo Kk | Waterproof cement admixture |
| JP2730234B2 (en) * | 1989-12-22 | 1998-03-25 | 三菱マテリアル株式会社 | High flow and high durability fiber reinforced filling mortar with excellent salt barrier properties |
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