JP2005029404A - Cement composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excellent cement composition using dephosphorized slag; and to provide mortar and concrete compositions using the same, and methods for producing them. <P>SOLUTION: The cement composition contains at least (i) portland cement (PL), (ii) blast furnace slag (KS) fine powder having particle sizes, measured by a Blaine method, of 1,000-10,000 cm<SP>2</SP>/g and (iii) steel making slag (ADD) comprising the dephosphorized slag (RDS) fine powder including calcium being a component of apatite and having particle sizes, measured by the Blaine method, of 1,500-8,000 cm<SP>2</SP>/g and an average particle diameter Dn of ≤90 μm. The cement composition is characterized in that (a) the total content of the steel making slag (ADD) is 75-125 parts by weight per 100 parts by weight of the portland cement (PL), (b) the blending ratio (KS/RDS) of the blast furnace slag (KS) fine powder to the dephosphorized slag (RDS) fine powder in the steel making slag (ADD) is 95:5 to 45:55, and (c) the content of free CaO is ≤3.0%, and the content of Ca<SB>5</SB>F(PO<SB>4</SB>)<SB>3</SB>having an apatite structure is ≥3.0%, in the cement composition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００２７】
また、高炉スラグ（急冷スラグ）（ＫＳ）も、主要鉱物はメリライト（２ＣａＯ・Ａｌ_２Ｏ_３・ＳｉＯと２ＣａＯ・２ＭｇＯ・ＳｉＯの類質同像混合物）、メルビナイト、偽ケイ灰石などの斑晶構造で、メルビナイト斑晶は類帯構造を示し中心にゲーレナイト（Ｃ_２ＡＳ）を含みＳｉＯ_２，Ａｌ_２Ｏ_３含有量が比較的高いものとされ、ポルトランドセメント（ＰＬ）及び高炉スラグ（ＫＳ）の両者とも、フッ素及びリン分の含有量が極く少ないが、一方、本発明における改質済み脱リンスラグ（改質Ａ）微粉末は、脱リンのため添加したカルシウム分が比較的多い他、アパタイト構造のＣａ_５・Ｆ（ＰＯ_４）_３を上記のように５〜２０％も含むものであり、したがって、前記改質済み脱リンスラグ（ＲＤＳ）微粉末を用いた本発明のセメント組成物は、フッ素分及びリン分含有量が極めて高い点で、その余のセメント組成物と明瞭に異なり、その区別は一目瞭然である。
【００２８】
このような本発明のセメント組成物は、砕石、砂利、川砂、山砂、海砂利、などのほか、スラグ破砕物、焼粘度、焼頁岩等の通常用いられている粗細骨材、粗骨材と水の存在下で通常の割合で混合して、コンクリートモルタル又はモルタル組成物とすることができる。
【００２９】
その際、所望により、本発明の目的達成を阻害しない範囲で、高炉セメント、シリカセメント、フライアッシュセメント、メーソンリーセメント、膨張セメント、カラーセメントの場合と同様に、Ｂｕｌｋｙ ａｄｍｉｘｔｕｒｅと呼ばれる比較的多量の混和材を使用することができる。
【００３０】
さらに、所望により、界面活性材や高分子電解質、及びこれらを基材に用いたＡＥ剤、減水剤（分散剤）、消泡剤、起泡剤、消泡剤、凍結防止剤、粘性剤等、また塩化石灰、食塩、水ガラス等の急結剤、珪フッ酸ソーダのような遅結剤、塩化第一鈴、塩化第一銅などの防食剤、防水剤、撥水剤、グラウト剤、無機及び有機接着剤用混和剤、抱水剤、エフロレッセンス防止剤、耐磨耗剤、表面強化剤等、従来慣用の混和剤を添加することができる。これら混和剤の添加量は８％以内であることが好ましく、より好ましくは５％以内、さらに好ましくは２％以内である。
【００３１】
【実施例】
以下、実施例により本発明を具体的に説明する。初めに［参考例］で、改質された脱リンスラグ（ＲＤＳ）微粉末の調製法、及び該脱リンスラグ（ＲＤＳ）の特性について内容を具体的に説明し、次に［実施例］で、該脱リンスラグ（ＲＤＳ）微粉末を用いたセメント用組成物について内容を具体的に説明する。なお、これら［参考例］及び［実施例］は、本発明を説明するための例であって、本発明をこれらにより制限するためのものではない。
【００３２】
［参考例１〜２１］［改質済みの脱リンスラグ（ＲＤＳ）微粉末・モルタル組成物］
（使用材料）
脱リンスラグとして、意図的に、製鉄所で副産した後約４ヶ月間放置された脱リンスラグを採用し、これを最初、金属鉄を磁選により除去した後、ボールミルで粉砕し、４０００ブレーンに粉砕したものを実験に供した。この化学組成を表２に示す。
【００３３】
【表２】

【００３４】
強熱減量（Ｉｇ．ｌｏｓｓ）の測定を行う際には、ポルトランドセメント（ＰＬ）の強熱減量を測定するときと同様な方法、すなわち、９５０±５０℃で電気炉で加熱し、そのときの値を求めた。
【００３５】
（改質処理）
試料を、温度５００℃に調節された電気炉に入れ２時間焼成した。焼成された粉末試料の粒度をブレーン法により測定し、４０００ブレーンの値を得た。これは、焼成により、試料粒子の焼結やガラス状への表面状態変化があまり激しくなかったこと示している。しかしながら、焼結後粉砕処理して丸み形状をなくし比表面積を増加させることができ、また好ましい。同試料を、別途、温度１０５０で２時間焼成した場合には、焼成された粉末試料のブレーン粒度は３８００ブレーン以下に減少していた。
【００３６】
改質後の脱リンスラグを改質前のものと比較して粉末Ｘ線回折（ＸＲＤ）で鉱物の同定を行なった結果を図１に示す。
これより、改質前の本脱リンスラグ試料にはβ−Ｃ_２Ｓ（β−２ＣａＯ・ＳｉＯ_２）、Ｃａ_５Ｆ（ＰＯ_４）_３、ＣａＣＯ_３が存在していることが分かる。これは本試料が、一部分だけエイジングされているものであって、そのエイジング度は大きくないことを示唆している。また、製鉄所で副産直後の脱リンスラグの場合は、β−Ｃ_２Ｓ、Ｃａ_５Ｆ（ＰＯ_４）_３、ＣａＣＯ_３由来のピークがほとんどないことが示された。
【００３７】
本参考例により改質された脱リンスラグ（本明細書中ではＲＤＳ、「本改質脱リンスラグ」又は「改良脱リンスラグ」とも表現される）ではＣａ（ＯＨ）_２のピークが消滅していることから、遊離石灰（ＣａＯ）の量が低下していることを示している。また、この脱リンスラグはＸＲＤ強度（ＣＰＳ）から判断しても極めて結晶性の悪いものであることを示している。これより、組成計算によって求めた改良済み脱リンスラグの鉱物組成を表３に示すが、これは、単なる一例であって、β−Ｃ_２Ｓ含有量はこの４９．６％の値の±３０％程度の幅があってよく、Ｃａ_５Ｆ（ＰＯ_４）_３含有量はこの１４．９％の値の±５０％程度の幅があってよく、ＣａＦ_２含有量はこの５．２％の値の±２０％程度の幅があってよい。
【００３８】
【表３】

【００３９】
（改質後の脱リンスラグ（ＲＤＳ）の性質）
予備的な検討として、この改質後の脱リンスラグの性質、特にセメント材料としての使用可能性の点から見た性質を検討した。
改良脱リンスラグを混合したセメントを用いてモルタルを試製し、また、後に述べる断熱温度上昇試験に用いた使用材料の物性を次の表４に示す。
【００４０】
【表４】

【００４１】
（改質済み脱リンスラグ含有モルタルの試験）
実験に用いた改質済み脱リンスラグ含有モルタルの実施配合を次表５に示す。
【００４２】
【表５−１】

【００４３】
【表５−２】

【００４４】
（表中、ＰＬ；ポルトランドセメント、ＲＤＳ；改質（改良）脱リンスラグ、ＫＳ；高炉水砕スラグを表わし、各参考例の括弧内左辺は混和剤（Ｃ）中でＰＬを置換した材料部分を表わし、例えば参考例２（ＲＤＳ１０−４５）は、混和剤Ｃ４５部中ＲＤＳ＝１０部、ＰＬ＝バランスを、参考例３（ＲＤＳ２０−４５）は、混和剤Ｃ４５部中ＲＤＳ＝２０部、ＰＬ＝バランスを、参考例４（ＲＤＳ３０−４５）は混和剤Ｃ４５部中ＲＤＳ＝３０部、ＰＬ＝バランスを、参考例５（ＫＢ１０−４５）は混和剤Ｃ４５部中ＫＢ＝３０部、ＰＬ＝バランス、参考例１２（ＫＢ１０−５５）は混和剤Ｃ５５部中ＫＢ＝１０部、ＰＬ＝バランスを、参考例２０（ＫＢ２０−６５）は混和剤Ｃ６５部中ＫＢ＝２０部、ＰＬ＝バランスを、それぞれ表わす。また、Ｓ１；大井川産川砂、Ｗ；水、Ｃ：結合剤（＝ＰＬ＋ＫＳ＋ＲＤＳ）を表わす）
【００４５】
水結合材比は４５、５５、６５％で混和材（ＲＤＳ）の量は結合材の内割りで１０、２０、３０ｗｔ％置換し、２０℃、ＲＨ６０％の恒温恒湿室中で実験した。水中養生期間は６ヶ月まで、練り混ぜはホバードミキサで行ない、供試体は４×４×１６ｃｍとし、打設後２４時間で脱型し、所定の材齢まで２０℃で水中養生を行なった。実験は曲げ強度、圧縮強度をＪＩＳ Ｒ ５２０１に準じて行ない、長さ変化も同様な温度、湿度の条件で行ない、ＪＩＳ Ａ １１２９のダイヤルゲージ法に準じて２ヶ月まで測定した。
【００４６】
（改質済み脱リンスラグ含有のフレッシュモルタルの粘度測定）
モルタルの配合は強度実験と同様の置換率で、各水結合材比（４５，５５，６５％）で１２０秒間、手で練り混ぜを行なって、フレッシュモルタルの粘度の経時変化を測定した。粘度測定は振動式粘度計（固有振動数：３０．０Ｈｚ、感応板：ｔ＝０．２ｍｍ、φ２０ｍｍ）を使用し、水結合材比による変化及び置換率による変化を測定した。
【００４７】
［参考例２２〜２８］［改質済み脱リンスラグ含有モルタルの水和発熱特性］
（１）水和発熱速度の測定
水と練り混ぜ直後の発熱量を測定する目的で、セメント（ＰＬ）に対して内割りで改良脱リンスラグ（ＲＤＳ）を１０，２０，３０ｗｔ％置換した。このニートセメント配合で水：結合材比を１００％、２０℃の条件で双子型伝導微少熱量計にセットし、安定化させた後、２４時間まで測定した。
【００４８】
（２）断熱温度上昇試験
実験に用いた配合を次表６に示す。
【００４９】
【表６】

【００５０】
水結合材比を６０％とし、改良脱リンスラグ（ＲＤＳ）をセメント（ＰＬ）に対して内割りで１０，２０，３０ｗｔ％置換するものとした。また、細骨材（Ｓ２）、粗骨材（Ｓ３）と混和剤（ａｄ；β−ナフタレンスルホン酸の縮合物Ｎａ塩）を使用し、無混合のコンクリートと比較した。まず、試験方法はホバートミキサを使用し、混和剤を溶解させた混練水、セメント（ＰＬ）、細骨材の順で入れ、２分間練り混ぜる。その後粗骨材を入れ１分間練り混ぜる。小スコップでかき混ぜ、ポリ容器に入れて断熱装置用のセル容器に入れセットして測定する。断熱温度上昇試験装置は空気循環式である。同時にＢ種高炉セメント、中庸熱ポルトランドセメント、低熱ポルトランドセメントとも比較し、断熱温度上昇値を測定した。装置にセットできる最大容積が３リットルと少なく、測定誤差を小さくするため粗骨材の最大骨材寸法を１３ｍｍとして行なった。
【００５１】
（結果）
（１）強度及び長さ変化
改良脱リンスラグを置換したモルタルの曲げ強度を水結合材比の違いによって測定した。この結果を図２に示す。表４に示した結合により、セメント（ＰＬ）と改良脱リンスラグ（ＲＤＳ）１０，２０，３０ｗｔ％を置換した供試体では、初期材齢（材齢４週）の場合、水結合材比と置換率によって強度に差が生じ、水結合材比の増加とともに置換率による影響が大きくなる傾向にある。図２に示したように曲げ強度は、改良脱リンスラグの置換率が増加しても長期材齢（材齢２６週）では水結合材比４５，５５％ではＰＬ−４５，ＰＬ−５５などとほぼ同等の強度が得られた。特に図３に示した高炉水砕スラグ（ＫＳ３０−ＰＬ５５）と改良脱リンスラグ（ＲＤＳ３０−ＰＬ５５）の比較でも異常な差異は認められなかった。実験は材齢４週目から測定を開始し、強度の発現も順調であり、混和材の種類、また、置換率によっても大きな違いは認められなかった。
同様に、モルタルの圧縮強度の変化を図４に示す。改良脱リンスラグを置換した場合の圧縮強度は初期において、その置換率によって多少差は認められるが、長期材齢とともにその差は小さくなる傾向にある。
【００５２】
図５は高炉水砕スラグ（ＫＳ３０−ＰＬ５５）と改良脱リンスラグ（ＲＤＳＷ３０−ＰＬ５５）それぞれ置換したものを比較したもので、強度発現の大きい順にＰＬ−５５，ＲＤＳ３０−ＰＬ５５，ＫＳ３０−ＰＬ５５であった。ＲＤＳ３０−ＰＬ５５の場合は初期ではＫＳ３０−ＰＬ５５とほぼ同等かむしろ下まわっているが、材齢とともに強度の伸びが認められ、長期材齢になるにともなって増加する傾向がある。
遊離石灰（ＣａＯ）の量が０．０６５ｗｔ％に低下させた改良脱リンスラグ（ＲＤＳ）による膨張は抑制されたと考えているが、この問題を再確認するため、セメント（ＰＬ）に改良脱リンスラグを置換したモルタルの長さ変化を測定した。この結果を図６に示す。セメント単味の供試体（ＰＬ−５５）と比較して同等な収縮が認められた。同様に高炉水砕スラグと改良脱リンスラグの比較を図７に示す。改良脱リンスラグについては前述のとおり、ＰＬ−５５に対して大きな差は認められないが、高炉水砕スラグでは収縮が少し大きくなる傾向にある。
【００５３】
（２）粘度
改良脱リンスラグを用いた用いたモルタルの粘度を図８に示す。これをセメントＣ−５５と比較すると置換率の増加にともない粘度は低下する傾向にある。また、高炉水砕スラグと改良脱リンスラグの粘度を比較した。この結果を図９に示す。高炉水砕スラグと改良脱リンスラグの比較では、改良脱リンスラグを置換したものの方が低い値を示すことが分かった。
【００５４】
（３）（水和発熱特性）
（ｉ）水和発熱速度の測定
セメント（ＰＬ）に改良脱リンスラグ（ＲＤＳ）を置換したときの水和発熱速度を２４時間まで測定した結果を図１０に示す。水和直後の発熱速度は改良脱リンスラグを混合すると１次ピーク、２次ピークともセメント（ＰＬ）単味のときの水和発熱速度曲線に対応しているが、改良脱リンスラグ置換率の増加にともない、いずれも小さくなる傾向がある。
【００５５】
（ｉｉ）断熱温度上昇試験
改良脱リンスラグを置換した場合の断熱温度上昇試験の結果を図１１に示す。乾燥（Ｄで表す、以下同様）−ポルトランドセメント（ＰＬ）と比較して置換率の増加にともない、１４日までの測定値はＤ−セメント（ＰＬ）は４７．９℃、Ｄ−ＲＤＳ１０は４４．３℃、Ｄ−ＲＤＳ２０は４１．５℃、Ｄ−ＲＤＳ３０は３７．７℃であった。このように断熱温度上昇値は減少する傾向にある。従来のβ−Ｃ_２Ｓと異なり、改良脱リンスラグ中に含まれるβ−Ｃ_２Ｓは非常に遅硬性である。そのため、前記強度特性の結果から、セメントに改良脱リンスラグを置換すると極めて低発熱型になることが分かった。
【００５６】
同時に中庸熱ポルトランドセメント、低熱ポルトランドセメント、Ｂ種高炉セメントの断熱温度上昇試験の結果を図１２に示す。これより、１４日までの測定値は中庸熱ポルトランドセメント（４２．０℃）、低熱ポルトランドセメント（３３．４℃）で材齢にかかわらずＤ−ＰＬ（４７．９℃）よりも低い値を示すが、Ｂ種高炉セメント（５５．９℃）は材齢４日でＤ−ＰＬよりも上昇し、低発熱にはならないことを示している。
【００５７】
以上の結果から、（１）改質脱リンスラグ単味の水和とその強度発現機構は次のように考えられる。
すなわち、高炉水砕スラグの強度発現はポゾラン反応によるものであり、その硬化の過程でカルシウムシリケート水和物（以下Ｃ−Ｓ−Ｈと記す）が生成されるためである。これに対して改質脱リンスラグの強度発現は、改質脱リンスラグ中に存在するβ−Ｃ_２Ｓによるものである。そのβ−Ｃ_２Ｓが水和によってＣ−Ｓ−Ｈが生成する。
【００５８】
（改質脱リンスラグの強度発現メカニズム）
改質脱リンスラグ単味のものを水和結合材比３０％、２５％で練り混ぜ、密封した試験管中に放置した。材齢１日、９０日、１年水和させた水和物のＸＲＤを図１３に、走査型電子顕微鏡写真（ＳＥＭ）を図１４に示した。
上記のように、改質脱リンスラグの結晶性は極めて悪く、むしろガラス質に近い。そのため、図１３より水和した改良脱リンスラグのＸＲＤ強度は時間とともに低下していることが分かる。水和１日と９０日を比較すると、β−Ｃ_２Ｓのピークは低下している。水和１年になるとβ−Ｃ_２Ｓのピークは確認できなくなった。これはβ−Ｃ_２Ｓの水和により、Ｃ−Ｓ−Ｈが生成するためである。
【化１】
β−Ｃ_２Ｓ＋Ｈ_２Ｏ→Ｃ−Ｓ−Ｈ（ゲル状水和物）
【００５９】
しかし、水和１年でもＸＲＤではＣ−Ｓ−Ｈを確認できなかった。ただし、ＳＥＭ写真より、水和１日では水和物はまだ確認できないが９０日でゲル状のＣ−Ｓ−Ｈが確認された。さらに針状のＣ−Ｓ−Ｈが一部認められた。１年では極めて結晶性の悪いＣ−Ｓ−Ｈのゲルが粒子表面全体をおおっているように観察された。したがって、改良脱リンスラグは極めて遅硬性であるが、単味のままでも長期材齢で強度発現が起こる。材齢とともに徐々にＣ−Ｓ−Ｈを生成し、緻密な構造になる。
強度発現機構について、他の原因としては次のことが考えられる。脱リンスラグ中のフッ素アパタイト（Ｃａ_５Ｆ（ＰＯ_４）_３）が一部のβ−Ｃ_２Ｓや遊離石灰（ＣａＯ）と結合して、
【化２】
Ｃａ_５Ｆ（ＰＯ_４）_３＋β−Ｃ_２Ｓ＋ＣａＯ（熱処理）→アパタイト群化合物
によって複雑なアパタイト群化合物が形成されるためである。フッ素アパタイト自体が高強度の得られるセラミックスであり、人工骨の素材として知られている。ここで形成されるアパタイト群化合物は長期材齢になると強度によい影響を付与するものと考察した。
以上のことから、改良脱リンスラグの強度発現は高炉水砕スラグとは異なり、遅硬性であるがそのもの自体で自硬性を呈するものであり、刺激材を必要としない可能性がきわめて高い。
【００６０】
（長さ変化の測定）
（２）セメント（ＰＬ）に改良脱リンスラグを置換した供試体の長さ変化を測定した。これは改良前の試料が遊離石灰（ＣａＯ）を含むが、改良後ではほとんど含まないことから膨張を起こすことはない。このことを再確認するため長さ変化を測定した。実験ではセメント（ＰＬ）のモルタルと比べて膨張はもちろん、異常な収縮もなかった。これは脱リンスラグを改良することによって、ほぼ完全に遊離石灰（ＣａＯ）が消滅し、その影響が起こらないことを意味している。
【００６１】
（３）セメント（ＰＬ）に改良脱リンスラグ（ＲＤＳ）を置換したフレッシュモルタルの粘度は、同じ水結合材比であっても置換率によって変動する。置換率が増加すると
（イ）セメント（ＰＬ）の量が少なくなる。
（ロ）改良脱リンスラグ（ＲＤＳ）の水和活性が低いため、水和物がまだ充分に生成していないと考えられる。
（ハ）粘度は水結合材比、粒子の粒径、粒度などによって影響される。
このような原因により粘度が小さくなる傾向がある。
【００６２】
（４）セメント（ＰＬ）に改良脱リンスラグを置換したセメントの水和発熱速度をみると、エトリンガイトの生成に起因する１次ピーク（水和後１０分）に対応するものは、改良脱リンスラグの置換率にともなって極めて小さくなる。このことは水和初期には低発熱性を示すことを示唆している。また、図１０の２次ピーク（水和後１３時間２０分）はＰＬの主要鉱物であるＣ_３Ｓの水和反応に関係している。エントリンガイトのモノサルフェートへの転化は確認できなかった。
【００６３】
（５）改良脱リンスラグ（ＲＤＳ）を置換したコンクリートの断熱温度上昇値は置換率が増加すると小さくなる傾向がある。改良脱リンスラグが全く発熱しないと仮定し、水、セメント、骨材の比熱（ｃａｌ／℃・ｇ）をそれぞれ１．００，０．１９，０．２０として１４日までの発熱温度を計算すると
Ｄ−セメント（ＰＬの発熱温度は ４７．９℃（測定値）
Ｄ−ＲＤＳ１０の発熱温度の計算値＝４３．６℃（測定値４４．３℃）
Ｄ−ＲＤＳ２０の発熱温度の計算値＝３９．１℃（測定値４１．５℃）
Ｄ−ＲＤＳ３０の発熱温度の計算値＝３４．６℃（測定値３７．７℃）
【００６４】
しかし、断熱温度上昇の実験では測定値に示すように計算値より上まわっている。この差は改良脱リンスラグから発生する発熱温度で、それぞれ０．７℃、２．４℃、３．１℃である。この原因は、改良脱リンスラグ中に存在するβ−Ｃ_２Ｓの水和によるものと考えられる。また、モルタルの断熱温度上昇値を計算すると、コンクリートの断熱温度上昇値よりも著しく上まわっていることが分かった。図１２に示したようにＢ種高炉セメントの断熱温度上昇値は、材齢４日よりＤ−セメント（ＰＬ）を上まわり、温度の上昇が著しい。本発明で提案する改良脱リンスラグを置換することによって極めて低発熱型になることが判明した。
【００６５】
以上のように、本発明における改質後の脱リンスラグの性質、特に、脱リンスラグは高炉水砕スラグのような作用をもつコンクリート混和材になり得るかどうかを纏めると、以下のようになる。
（１）改良脱リンスラグ（ＲＤＳ）を置換したモルタルの曲げ強度は、セメント（ＰＬ）モルタルと比べて大きな違いは認められず、（２）セメント（ＰＬ）に改良脱リンスラグ（ＲＳＤ）を置換したモルタルの圧縮強度はセメント（ＰＬ）モルタルと比べて初期材齢では少し小さいが、材齢と共に上昇する傾向が認められず、（３）セメント（ＰＬ）に改良脱リンスラグ（ＲＤＳ）を置換したモルタルの長さ変化は膨張することなく、セメント（ＰＬ）と同様な収縮が認められ、（４）セメント（ＰＬ）に改良脱リンスラグ（ＲＤＳ）を置換したフレッシュモルタルの粘度は、水結合材比が同じであっても混和材及び置換率によって異なり、（５）改良脱リンスラグ単味のままでも長期材齢では強度発現が起こる。セメント（ＰＬ）に改良脱リンスラグ（ＲＤＳ）を置換したモルタルの長期強度は、スラグ中のβ−Ｃ_２Ｓに起因するものであって、水和９０日でゲル状Ｃ−Ｓ−Ｈが確認され、１年では緻密な水和物の構造になり、これは強度の発現に寄与するものであり、（６）セメント（ＰＬ）の改良脱リンスラグ（ＲＤＳ）を置換したニートセメントの水和発熱速度をみると、エトリンガイトの生成に起因する１次ピークは改良脱リンスラグの混合により著しく小さくなり、水和直後から低発熱性を示しており、（７）改良脱リンスラグを置換したコンクリートの断熱温度上昇値は極めて低温で、例えばマスコンクリート用に使用する場合、低発熱型として有効であり得、以上のことから、改良脱リンスラグが新しいコンクリート混和材になり得る可能性は、その鉱物の特性などから判断して高いとの推定も一応できるが、さらにその最適な使用態様や耐久性などについては、このような予備的試験のみでは確かでない。そこで、さらに以下の実施例により、これら点について具体的に説明する。
【００６６】
［実施例１］［比較例１〜３］
［セメント組成物用の改良脱リンスラグ、及びこれを用いたセメント組成物］
（使用材料）
使用した材料を、比較例１〜３と比較して表７に示す。ここで、用いた脱リンスラグは３００μｍふるいを通過させ、５００℃の炉で２時間焼成処理したものを用いた。
【００６７】
【表７】

【００６８】
（配合）
圧縮強度試験後、長さ変化率試験に用いたモルタル配合を表８に、塩化物イオン透過試験に用いたモルタル配合を表９に、断熱温度上昇試験に用いたコンクリート配合を表１０に示す。
【００６９】
【表８】

【００７０】
【表９】

【００７１】
【表１０】

【００７２】
（試験方法）
（１）圧縮強度試験
ＪＩＳ Ａ １１０８に準拠して、表８のモルタル配合で作製したφ５×ｈ１０ｃｍの比較例１及び実施例１〜３の供試体の圧縮強度を測定した。供試体は２０℃の恒温室で各材齢まで封緘養生した。
【００７３】
（２）長さ変化率試験
ＪＩＳ Ｒ １１２９に準拠して、表８のモルタル配合で作製した比較例１及び実施例１〜３の供試体の長さ変化率を測定した。供試体の寸法は４×４×１６ｃｍとし、温度２０℃の恒温室で封緘養生した。
【００７４】
（３）断熱温度上昇試験
表１０の配合に基づく比較例２及び実施例４〜６のものとして、混練ぜたフレッシュコンクリートをφ１０×ｈ２０ｃｍのモールド缶に入れ、簡易型断熱温度測定装置により断熱温度上昇値の測定を行った。なお、測定は４時間毎に計測した。
【００７５】
（４）塩化物イオン透過試験
塩化物イオン透過試験器の概略を図１５に示す。表９のモルタル配合で作製した比較例３及び実施例７〜９の供試体を２０℃の恒温室で２８日間封緘養生し、φ５×ｈ１ｃｍにカットしたものを中央部にはめ込み、左側セル内に３％ＮａＣｌ水溶液を、右側セル内に飽和Ｃａ（ＯＨ）_２水溶液を各々６００ｍｌ入れ、２０℃一定とし濃度勾配による自然拡散により塩化物イオンが透過する構造とした。飽和Ｃａ（ＯＨ）_２水溶液を採取し、イオンクロマトグラフィーにより透過した塩化物イオンの濃度を測定した。
【００７６】
（試験結果）
圧縮強度
図１６に材齢７日、２８日、９１日の圧縮強度を示す。ＫＳ３０−ＰＬ７０はＰＬ１００と比較すると各材齢において同等の圧縮強度であった。ＲＤＳ３０−ＰＬ７０は、ＰＬ１００と比較すると材齢７日で５７％減少、材齢９１日では１５％減少となった。ＫＳ１５−ＲＤＳ１５−ＰＬ７０は、ＰＬ１００と比較すると材齢７日で１４％減少であったが、材齢９１日では同等となった。
圧縮強度の点から見ると、このように、ＫＳはＰＬとＰＬ１００部当たり最高３０部程度まで置換可能である。一方、ＲＤＳは、ＰＬと置換する場合、ＰＬ１００部当たり置換量１５部程度から圧縮強度が低下し始め、置換量が３０部を超えると圧縮強度の低下が顕著になることが、一連の関連試験により確認された。しかしながら他方では、ＲＤＳは、ＰＬと置換する場合、ＫＳと併用することが好ましく、その場合のＲＤＳとＫＳの配合比は３０；７０〜７０；３０重量部の範囲であれば、ＰＬにこれら配合物を、ＰＬ１００部当たり該配合物７５〜１２５重量部を好ましく配合できることが、同時に行なわれた同一連の関連試験により確認され、したがって、脱リンスラグの長期強度発現特性が認められた。
【００７７】
（２）長さ変化率
図１７に長さ変化率を示す。各材齢における収縮率はＫＳ３０−ＰＬ７０＞ＫＳ１５−ＲＤＳ１５−ＰＬ７０＞ＰＬ１００＞ＲＤＢ３０−ＰＬ７０となった。材齢９１日におけるＰＬ１００の収縮率に対してＫＳ３０−ＰＬ７０は約１００％増加し、ＫＳ１５−ＲＤＳ１５−ＰＬ７０は約４０％増加した。しかし、ＲＤＢ３０−ＰＬ７０は約２５％減少した。これは脱リンスラグ中に残存する遊離石灰が水和反応により膨張し、収縮が抑制されたものと考えられる。
また、この結果から、圧縮強度の場合と同様に、ＲＤＳは、ＰＬと置換する場合、ＫＳと併用する場合のＲＤＳとＫＳの配合比は３０；７０〜７０；３０重量部の範囲であれば、ＰＬにこれら配合物を、ＰＬ１００部当たり該配合物７５〜１２５重量部を好ましく配合できることが、推認される。
【００７８】
（３）断熱温度上昇値
図１８に断熱温度上昇値を示す。断熱温度上昇値のピーク値を比較すると、この断熱温度上昇値についても、ＫＳ３０−ＰＬ７０＞ＫＳ１５−ＲＤＳ１５−ＰＬ７０＞ＰＬ１００＞ＲＤＢ３０−ＰＬ７０となった。ＫＳ３０−ＰＬ７０の温度上昇値がＰＬ１００の温度上昇値を約５０時間経過後に超えた。ＫＳ１５−ＲＤＳ１５−ＰＬ７０は温度上昇値のピーク値である１３０時間まではＰＬ１００を下回ったが、それ以降は同等となった。ＲＤＢ３０−ＰＬ７０の温度上昇値は各経過時間でＰＬ１００を下回り、ピーク値もＰＬ１００と比較し２２％減少した。ＫＳ１５−ＲＤＳ１５−ＰＬ７０とはかなりの差異がある。
【００７９】
（４）塩化物イオン透過量
図１９に塩化物イオン透過量の経時変化を示す。８週目においてＫＳ３０―ＰＬ７０はＰＬ１００と比較すると４７％減少、ＫＳ１５−ＲＤＳ１５−ＰＬ７０はＰＬ１００と同等、ＲＤＢ３０−ＰＬ１００はＰＬ１００と比較すると４５％増加した。脱リンスラグ自身には塩化物イオンの透過抑制効果は見られなかったが、高炉スラグとの併用により塩化物イオンの透過抑制が期待できることが明らかになった。
【００８０】
以上の結果から、高炉スラグ微粉末は脱リンスラグ微粉末と併用することにより、水和収縮量と断熱温度上昇値を低減できることが明らかとなり、かつ、ＫＳ及びＲＤＳからなる製鋼スラグ（ＡＤＤ）の合計含量が、ポルトランドセメント（ＰＬ）１００重量部当り、７５〜１２５重量部であり、製鋼スラグ（ＡＤＤ）中で前記高炉スラグ（ＫＢ）微粉末と脱リンスラグ（ＲＤＳ）微粉末との配合割合（ＫＳ：ＲＤＳの比）が（３０：７０）〜（７０：３０）の場合、ＰＬ１００重量部当たりＲＤＳ３０重量部で置換したときに比較し、好ましい結果が得られ、その差異は顕著であることが明らかとなった。
【００８１】
【発明の効果】
以上、詳細且つ具体的な説明より明らかなように、本発明により、セメント配合用脱リンスラグの好ましい改質法、これを用いた好ましいセメント組成物、これを用いたモルタル並びにコンクリート組成物が提供されるという効果が奏され、この効果は非常に顕著なものである。
【図面の簡単な説明】
【図１】本発明の例で用いた脱リンスラグの粉末Ｘ線回折（ＸＲＤ）を示す図である。
【図２】本発明例及び対比例における改良脱リンスラグ混合モルタルの曲げ強度を示す図である。
【図３】本発明例及び対比例における改良脱リンスラグ及び高炉水砕スラグ混合モルタルの曲げ強度を示す図である。
【図４】本発明例及び対比例における改良脱リンスラグ混合モルタルの圧縮強度を示す図である。
【図５】本発明例及び対比例における改良脱リンスラグ及び高炉水砕スラグ混合モルタルの圧縮強度を示す図である。
【図６】本発明例及び対比例における改良脱リンスラグ混合モルタルの長さ変化を示す図である。
【図７】本発明例及び対比例における改良脱リンスラグ及び高炉水砕スラグ混合モルタルの長さ変化を示す図である。
【図８】本発明例及び対比例における改良脱リンスラグを混合したセメントモルタルの粘度（振動式）を示す図である。
【図９】本発明例及び対比例における改良脱リンスラグ、高炉水砕スラグを混合したセメントモルタルの粘度（振動式）を示す図である。
【図１０】本発明例及び対比例における改良脱リンスラグを混合したせメントの水和発熱速度曲線を示す図である。
【図１１】本発明例及び対比例における改良脱リンスラグを混合したコンクリートの断熱温度上昇値を示す図である。
【図１２】本発明例及び対比例における中庸熱ポルトランドセメント、低熱ポルトランドセメント、Ｂ種高炉セメントを混合したコンクリートの断熱温度上昇値を示す図である。
【図１３】本発明例及び対比例における水和した改良脱リンスラグのＸ線回折（ＸＲＤ）を示す図である。
【図１４】本発明例及び対比例における水和した改良脱リンスラグの走査型電子顕微鏡写真（ＳＥＭ）を示す図である。
【図１５】塩化物イオン透過試験器の概略を示す図である。
【図１６】本発明例及び対比例における圧縮強度を示す図である。
【図１７】本発明例及び対比例における各材齢における長さ変化率を示す図である。
【図１８】本発明例及び対比例における断熱温度上昇値を示す図である。
【図１９】本発明例及び対比例における塩化物イオン透過量の経時変化を示す図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cement composition using steelmaking slag, a mortar and concrete composition using the cement composition, and a method for producing these, and in particular, dephosphorized slag-derived fine particles and blast furnace slag fine particles are blended, The present invention relates to a cement having improved strength, a mortar and a concrete composition using the cement, and a method for producing the same.
[0002]
[Prior art]
The use of steelmaking slag as a cement admixture or concrete admixture has been well-known in the past, and many proposals have been made on how to make use of the characteristics of steelmaking slag and modification to make it an admixture with favorable characteristics. ing. For example, Patent Document 1 discloses that slag basicity (CaO / SiO2) in the steelmaking process. ₂ ) Is controlled at a weight ratio of 2.0 to 5.0, and the slag to which fluorite and / or calcium chloride is added is cooled and then naturally aged at atmospheric pressure. A method for producing a steelmaking slag roadbed material that includes performing a forced aging treatment in which water vapor is blown again under atmospheric pressure after being performed is described in Patent Document 2, and steelmaking slag and / or hot metal preliminary before forced aging are described. A method for forcibly aging slag in which a mixture of coal ash so as to be 1 to 30% by weight of the total weight after blending with treated slag is treated with steam and / or warm water is described in Patent Document 3, Blaine specific surface area is 2000-15000cm ² / G of blast furnace granulated slag and / or converter slag, ultrafine powdered substance, and a solidifying material for radioactive waste containing a dispersing agent are described. Patent Document 4 describes aging before or after completion of aging. At least one of steelmaking slag and hot metal pretreatment slag is mixed with a silica-based material or a material containing both silica-based and alkaline-based materials in an amount of more than 30% and not more than 80% based on the total weight after mixing. A slag aging method is described, and in Patent Document 5, at least one of a blast furnace slag and a converter slag to be mixed is in a molten state, and 95 to 70% by weight of a blast furnace slag, a converter A method for producing a cement is described in which slag is mixed so as to be 5 to 30% by weight, melted and homogenized, then granulated, and ordinary Portland cement is blended into the granulated powder. A substance with a relatively high basicity is applied to the blast furnace slag in a molten state outside the blast furnace, and the acidic component in the blast furnace slag and the basic component in the substance with a relatively high basicity are combined with each other. A method for producing a useful material from blast furnace slag, which is obtained by reacting using sensible heat to obtain a material having increased basicity, is disclosed in Patent Document 7, and 100 parts by volume of steelmaking slag, A fine aggregate consisting of 14 to 400 parts by volume of coal ash is described. Patent Document 8 discloses a stable CaO-Al in the solidification process by adding an aluminum compound to a steelmaking slag melt. ₂ O ₃ -Precipitating the F compound in the slag, and capturing the fluorine eluted from the steelmaking slag using calcium ions and aluminum ions eluted from the steelmaking slag when the steelmaking slag is dissolved in rainwater or groundwater. It describes that the steelmaking slag containing is stabilized, and Patent Document 9 describes that blast furnace slag that is generated in an iron making process when zinc is separated and recovered by blowing zinc-containing dust containing 0.5 mass% or more of zinc into hot metal, A method for recovering zinc in dust, characterized by adding 1 to 10 kg of premelt slag composed of hot metal desiliconized slag, hot metal dephosphorized slag or decarburized slag, is described in Patent Document 10. , CaO / SiO ₂ The molar ratio is 0.10 to 1.20 and the specific surface area is 2000 to 15000 cm. ² Curable composition containing 10 to 85% by weight of molten slag powder / g, 5 to 40% by weight of water glass in solid content, and 5 to 70% by weight of alumina cement. Fluorine-containing industrial waste containing a mixture of incinerator slag powder containing calcium aluminate and powder containing sulfate radicals as a fluorine fixing agent. A stabilization treatment method is described, and Patent Document 12 discloses a powdered steelmaking slag and SiO. ₂ A method for producing a slag hardened body by kneading a contained material with water, the hot metal pretreatment slag, the SiO ₂ Blast furnace slag fine powder is used as the contained material, and among all the formulations except water, the content of hot metal pretreatment slag having a particle size of 1.18 mm or less is 15 to 55 mass%, and the content of blast furnace slag fine powder is 5 The manufacturing method of the slag hardening body which is made into 40 mass% is described, and patent document 13 is a lining material for tunnels which is hardened by wet or dry construction on the inner wall of the tunnel, as a part of the steelmaking process. The resulting powdered hot metal pretreated slag and blast furnace slag fine powder are blended with the content of hot metal pretreated slag having a particle size of 1.18 mm or less being 15 to 55 mass% and the content of blast furnace slag fine powder being 5 to 40 mass%. A tunnel lining material made from steelmaking slag is described. Patent Document 14 is a block that forms a seaweed bed that is immersed in the sea and attracts seafood. In addition, a hardened body obtained by kneading a mixture of powdered hot metal pretreatment slag and fine powder of blast furnace slag with water and curing the mixture is described as a seaweed bed forming block having a surface layer made of a substance that promotes the growth of algae. In Patent Document 15, steelmaking slag and / or blast furnace slag is disposed around the lower side of the steel underground beam, and the steelmaking slag and / or blast furnace slag is provided on the upper side of the steel underground beam. Describes a building structure having a steel underground beam in which soil concrete that is in contact with the steel is placed. Patent Document 16 describes a fishing reef block that is submerged in seawater, and P ₂ O ₅ 2 to 10 mass% of iron and 1 to 5 mass% of metallic iron, 15 to 55 mass% of hot metal pretreatment slag having a particle size of 1.18 mm or less, and 5 to 40 mass% of blast furnace slag fine powder. And SiO ₂ A fishing reef block formed by kneading a mixture of the contained substance with fine powder with water and curing is described, and Patent Document 17 describes a cured body that is cast and cured in water, before being placed. The raw material mixture contains 15 to 55 mass% of granular hot metal pretreated slag having a particle size of 1.18 mm or less and 5 to 40 mass% of blast furnace slag fine powder, and after casting, the particles of the hot metal pretreated slag and blast furnace slag fine powder An underwater hardened body made of steelmaking slag that is not separated from each other is described. Patent Document 18 is a block used as a material for a water conserving structure, and has a particle size of 1 generated as a part of the steelmaking process. A water conserving structure obtained by kneading a mixture of powdered hot metal slag 15 to 55 mass% of 18 mm or less and blast furnace slag fine powder 5 to 40 mass% with water, pouring it into a mold and curing it. Use block is described, in Patent Document 19, a particulate hot metal pretreatment slag 15 to 55 wt%, SiO ₂ Powdered steelmaking slag containing 5 to 40% by mass of blast furnace slag fine powder as a contained material and having a particle size of 1.18 mm or less and SiO ₂ A road pavement plate formed by kneading a mixture containing a contained material as a main component with water, and using as a raw material steelmaking slag having a pH of 10 or less after contact with the water in contact with the pavement plate A plate is described, and Patent Document 20 discloses a granular steel-making slag and SiO having latent hydraulic properties. ₂ A roadbed material obtained by crushing a cured product obtained by kneading and hardening a mixture containing a contained material as a main component together with water, and having a pH of 10 or less after contact with water in contact with the roadbed material A roadbed material using slag as a raw material is described, and in Patent Document 21, a reducing inorganic compound or a reducing inorganic compound is added to a liquid mainly composed of a polycarboxylic acid-based polymer compound having a polyalkylene glycol chain. One or more selected from powder obtained by adding a reducing organic compound and then powdered into dry powder, molten slag powder, blast furnace slag powder, converter slag powder, dephosphorized slag powder, desiliconized slag powder An admixture for alumina cement containing slag powder is described. Patent Document 22 discloses powdered steelmaking slag, SiO ₂ It is a hardened body formed by kneading the contained material and water, and hot metal pretreatment slag, SiO 2 ₂ While adopting blast furnace slag fine powder as the contained material, the content of hot metal pretreatment slag having a particle size of 1.18 mm or less in all the ingredients except water is 15 to 55 mass%, and the content of blast furnace slag fine powder is 5 to An underwater settling block of 40 mass% is described, and in Patent Document 23, granular steel-making slag, SiO having latent hydraulic properties are described. ₂ In the method of producing a hardened body by kneading the contained material and water, P ₂ O ₅ ≦ 0.3% by mass of steelmaking slag, SiO with latent hydraulic properties ₂ A blast furnace slag fine powder is used as a contained material, and a particle size of 1.18 mm or less in all the ingredients except water. ₂ O ₅ The manufacturing method of the steel-making slag hardening body which makes content rate of the steelmaking slag of <= 0.3 mass% 10-90 mass% and the content rate of blast furnace slag fine powder 5-40 mass% is described, and patent document 24 There are powdered steelmaking slag and latent hydraulic SiO ₂ A method of producing a slag hardened body by kneading a contained material with water, wherein the steelmaking slag is 1% by mass or less of non-contained MgO and 10% by mass or less of crystallization MgO and / or Or ladle refining slag, SiO having the latent hydraulic property ₂ Blast furnace slag fine powder is used as the contained material, and the content of the converter slag and / or ladle smelting slag having a particle size of 1.18 mm or less in all the blended materials excluding water is 10 to 90% by mass, The manufacturing method of the slag hardening body which makes the content rate of powder 9-40 mass% is described, and patent document 25 contains the coal slag obtained from coal gasification equipment, natural aggregate, and both An aggregate mixture for asphalt pavement containing 5 to 70% by weight of coal slag and 30 to 95% by weight of natural aggregate based on the total is described. Patent Document 26 discloses steelmaking slag and blast furnace water. One or two or more types of cement, blast furnace slag powder and fly ash are mixed into the crushed slag at a mixing ratio of the coal ash and the blast furnace slag fine powder in a mass ratio of 1 to 6: 1 to 2. Add water And a method for producing a concrete solidified body using steelmaking slag, which is to be immediately demolded and produced after being kneaded. Patent Document 27 discloses a pressurized fluidized bed coal combustion facility. Has been described. Patent Document 28 discloses a hydrated and hardened body obtained by kneading coal ash generated from blast furnace slag fine powder with water or water and a hardening accelerator. The excavated hole is filled with expansive slag, and the slag absorbs moisture in the soft ground, thereby expanding the slag and compacting the surrounding ground. An improved construction method for soft ground is described, and in Patent Document 29, a pile is built in an excavation hole, and an outer peripheral portion and / or an inside of the pile is filled with an expandable slag, Pile support by inflating And that it has to increase the force describes a method of applying pile whose content, in Patent Document 30, SiO having latent hydraulic and steel slag of particulate ₂ It is a hydrated and hardened body obtained by kneading the contained material with water, and a granular hot metal pretreatment slag as the steelmaking slag, and the latent hydraulic SiO ₂ Blast furnace slag fine powder and combustion ash are used as contained substances, and the content of blast furnace slag fine powder in all blended raw materials excluding water is 10 to 40 mass%, the content of combustion ash is 10 to 50 mass%, and the particle size is 1 The content of hot metal pretreatment slag of 18 mm or less is 3 to 15 mass%, and the total content of blast furnace slag fine powder and combustion ash is more than 50 mass% and less than 80 mass%, and further, alkali metal, 1-10 mass% of 1 or 2 or more types selected from oxides, hydroxides, sulfates, chlorides and cements of alkaline earth metals with respect to the total content of blast furnace slag fine powder and combustion ash A hydration-hardened body whose content is to be formed is described, and Patent Document 31 discloses powdered steelmaking slag and SiO. ₂ A method for producing a slag hardened body by kneading a contained material with water, the hot metal pretreatment slag, the SiO ₂ In addition to using fine powder of blast furnace slag as the contained material, the content of hot metal pretreatment slag having a particle size of 1.18 mm or less is 7 to 55 mass% and the content of fine blast furnace slag powder is 5 out of all the formulations except water. A method for producing a cured slag having a content of curing for 0.5 to 24 hours under an atmosphere of 40 to 105 ° C. containing water vapor after being kneaded as ˜40 mass% is described in Patent Document 32. (A) CaO / SiO ₂ 10 to 85% by weight of molten slag powder having a molar ratio of 0.10 to 1.20, (b) 5 to 40% by weight of alkali silicate in solid content, and (c) 1 to 30% by weight of alkali metal salts (D) 5-50% by weight of alumina cement, (e) 2-40% by weight of a binder selected from blast furnace slag, converter slag, dephosphorization slag, desilicate slag and desulfurization slag, and (f) aggregate A fiber-reinforced acid-resistant concrete in which (g) reinforcing fibers are mixed with acid-resistant concrete containing water is described.
[0003]
Steelmaking slag generated in the copper making process in Japan is about 10 million tons per year. Of this, dephosphorized slag, which accounts for about 3.8 million tons, is almost effectively used due to hydration of free lime and expansion self-destruction due to oxidation of iron. The current situation is not, and this is an important issue related to environmental problems in the steel industry.
[0004]
In other words, in order to solve the conflicting demands of upgrading the quality of steel materials and rationalizing the steelmaking process, silicon (Si), sulfur (S) and phosphorus (P), which are harmful to steel materials, are removed at the molten iron stage, In the furnace, new steelmaking processes that only decarburize and raise the temperature are put into practical use by steel manufacturers. Under such circumstances, the present inventors have intensively studied a method for effectively using dephosphorization slag, which is generated when hot metal is dephosphorized and is produced as a by-product of several million tons per year, as a hydraulic material. The use as a hard material has already been recognized and announced, but recently, it can be stabilized by low-temperature firing, and as part of the study on its use as a low heat-generating concrete admixture, It confirmed that it could stabilize by baking (nonpatent literature 1, nonpatent literature 2).
[0005]
The dephosphorization slag consists of CaO derived from added materials used to remove phosphorus in steel, fluorine content, and SiO derived from steel. ₂ , FeO, Fe ₂ O ₃ , Al ₂ 0 ₃ Starting with P ₂ O ₃ TiO ₂ It contains many elements such as MgO and SiO compared to blast furnace slag. ₂ , Al ₂ 0 ₃ It is said to be low and highly basic, but by XPS (fluorescence X-ray analysis), oxides of many kinds of heavy elements (Si, Ca, etc. heavier than F and heavier than them) present in the dephosphorization slag Many spots derived from salt and salt were observed. The main minerals for dephosphorization slag are β-2CaO · SiO ₂ (Hereinafter β-C ₂ S), fluorapatite (Ca ₅ F (PO ₄ ) ₃ In addition, 2-5% of free lime (CaO) is contained. This free lime (CaO) content is very high compared to that of Portland cement. Therefore, concrete blended with dephosphorized slag has a low setting speed, resulting in strength deterioration and expansion failure. Therefore, if the dephosphorized slag powder is to be blended with cement, it is preliminarily left in the atmosphere for a long time to cause CaCO. ₃ Or Ca (OH) by steam aging ₂ It is necessary to adopt a method of stabilizing the current. However, this requires a great deal of time, space, and cost. Also by this method, the aging is only on the particle surface, and it is difficult to completely age the interior. For this reason, dephosphorized slag cannot be mixed with Portland cement (PL) as it is.
[0006]
Conventionally, blast furnace granulated slag, fly ash, silica fume, and the like are known as concrete admixtures that cause a pozzolanic reaction (hardening in the presence of water). However, in order to effectively use dephosphorized slag as a hydraulic material, not only the presence of self-hardening itself or the presence of pozzolanic reaction, but also the strength development and viscosity depending on the age when mixed with Portland cement, The fluidity of mortar that has not yet solidified (fresh mortar) and the hydration heat generation characteristics, such as the heat generation behavior when used in large quantities as concrete, must be accurately grasped. Furthermore, it is preferable to have the same performance as conventional blast furnace granulated slag and B-type blast furnace cement in terms of curing strength, expansion rate, toughness, solidification speed, durability, and the like.
[0007]
Therefore, as described above, the present inventors pay attention to the phosphorus content and fluorine content contained in the dephosphorization slag in a considerable amount, and thereby, one measure for negatively activating the active CaO in the dephosphorization slag. As a result of low temperature firing of the dephosphorization slag, the dephosphorization slag fired by low temperature firing of the dephosphorization slag is the Bragg angle 2θ derived from the active CaO crystal in XRD (X-ray diffraction) using Cu · Kα as a radiation source. The sharp peak of (20.0 ± 2 °) has almost disappeared. Instead, Ca ₅ F (PO ₄ ) ₃ Of the four Bragg angles 2θ derived from apatite crystals, the second low Bragg angle 2θ (= 33.5 ± 2 °; this diffraction peak is β-C ₂ It is confirmed that both diffraction peaks are overlapped with the Bragg angle 2θ derived from the S phase as a shoulder portion, and thus, the active CaO in the dephosphorized slag is obtained by calcination. ₅ F (PO ₄ ) ₃ It has already been confirmed that it is apatite.
[0008]
However, specific measures for using dephosphorization slag as a construction material, in particular, cement composition using the dephosphorization slag, its preferred embodiment, specific composition, performance of such cement, etc. have not yet been proposed. There is nothing.
[0009]
[Patent Document 1]
JP-A-7-62346
[Patent Document 2]
Japanese Patent Laid-Open No. 7-223857
[Patent Document 3]
Japanese Patent Laid-Open No. 8-179095
[Patent Document 4]
JP-A-8-253349
[Patent Document 5]
JP-A-8-337448
[Patent Document 6]
Japanese Patent Laid-Open No. 10-279331
[Patent Document 7]
JP-A-10-287454
[Patent Document 8]
JP 2000-247694 A
[Patent Document 9]
JP 2001-49361 A
[Patent Document 10]
JP 2001-163660 A
[Patent Document 11]
JP 2001-259570 A
[Patent Document 12]
JP 2001-270746 A
[Patent Document 13]
JP 2001-294454 A
[Patent Document 14]
JP 2001-299129 A
[Patent Document 15]
JP 2001-311661 A
[Patent Document 16]
JP 2001-321006 A
[Patent Document 17]
JP 2001-322842 A
[Patent Document 18]
JP 2001-322862 A
[Patent Document 19]
JP 2001-323403 A
[Patent Document 20]
JP 2002-20156 A
[Patent Document 21]
JP 2002-104855 A
[Patent Document 22]
JP 2002-105925 A
[Patent Document 23]
JP 2002-241169 A
[Patent Document 24]
JP 2002-308662 A
[Patent Document 25]
JP 2002-309505 A
[Patent Document 26]
JP 2003-2726 A
[Patent Document 27]
JP 2003-1119068 A
[Patent Document 28]
JP 2003-82649 A
[Patent Document 29]
JP 2003-90037 A
[Patent Document 30]
JP 2003-55025 A
[Patent Document 31]
JP 2003-146732 A
[Patent Document 32]
JP 2003-165663 A
[Non-Patent Document 1]
崔 Current country, Naomitsu Tsukigi, Masaaki Sakuta; Mortar characteristics of dephosphorized slag mixed cement, Proceedings of Concrete Engineering Vol. 6 No. 2 (July 1995), pp 39-46
[Non-Patent Document 2]
Akihiro Umemura, Naomitsu Tsukigi, Yuichi Otsu; Research on admixtures using dephosphorized slag in steelmaking process, Symposium on recycling into waste concrete materials, pp105-110 (2002)
[0010]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a preferred cement composition using dephosphorized slag, a mortar and a concrete composition using the same, and a method for producing them, in view of the current state of the prior art.
[0011]
[Means for Solving the Problems]
The object is (1) “at least (i) Portland cement (PL), (ii) grain size particle size 1000 to 10,000 cm according to the Blaine method of the present invention. ² / G blast furnace slag (KS) fine powder, and (iii) apatite calcium, particle size 1500-8000 cm according to Blaine method ² Steelmaking slag (ADD) made of fine powder of dephosphorization slag (RDS) having an average particle diameter Dn of 90 μm or less at a g / g, and (a) the total content of the steelmaking slag (ADD) is 100 It is 75 to 125 parts by weight per part by weight, and (b) the mixing ratio of the blast furnace slag (KB) fine powder and the dephosphorized slag (RDS) fine powder in the steelmaking slag (ADD) (ratio of KS: RDS) Is a cement composition of (95: 5) to (45:55), and (c) the free CaO content in the cement composition is 3.0% or less, and the apatite structure Ca ₅ ・ F (PO ₄ ) ₃ It is achieved by a “cement composition characterized in that the content is 3.0% or more”.
[0012]
Further, the object is (2) “a mortar or concrete composition comprising the cement composition according to the above item (1), aggregate, water, and optionally a chemical admixture for concrete”. Is achieved.
[0013]
In addition, the object is (3) “β-2CaO.SiO” of the present invention. ₂ The content is 49.6 × (1 ± 0.3) wt%, Ca ₅ F (PO ₄ ) ₃ The content is 14.9 × (1 ± 0.5) wt%, CaF ₂ The content is 5.2 × (1 ± 0.2) wt%, Fe ₂ O ₃ Modified degreasing for cement mixing, characterized in that it has a composition with a content of 8.2% by weight or less, a free CaO content of 3.0% by weight or less and an average particle size Dn of 90 μm or less. Achieved by “Rinse Slag (RDS) powder”.
[0014]
In addition, the above-mentioned object is to oxidize the active state contained in the fine particles by calcining the pulverized dephosphorized slag (KS) fine particles for 20 to 180 minutes at a temperature of 1000 ° C. or less. At least (i) Portland cement (PL), (ii) Blaine, characterized in that it comprises the steps of converting calcium into a solid solution belonging to the fluorapatite group and mixing the product with blast furnace slag fine powder and Portland cement. Particle size 1000-10000cm by the method ² Blast furnace slag fine powder (KS) having a number average particle diameter of 3 to 90 μm / g, and (iii) apatitic calcium, and a grain size of 1500 to 8000 cm by the Blane method ² / G of steelmaking slag (ADD) composed of fine powder of dephosphorization slag (RDS), and (a) the total content of steelmaking slag (ADD) is 75 to 125 weight per 100 parts by weight of Portland cement (PL). (B) The mixing ratio (KS: RDS ratio) of the blast furnace slag (KS) fine powder and the dephosphorized slag (RDS) fine powder in the steelmaking slag (ADD) is (95: 5) to (45:55) a cement composition, wherein (c) the free CaO content in the cement composition is 3.0% or less, and the apatite structure Ca ₅ ・ F (PO ₄ ) ₃ This is achieved by “a method for producing a cement composition having a content of 3.0% or more”.
[0015]
Hereinafter, the present invention will be described in detail.
As mentioned above, the main mineral of dephosphorization slag is β-2CaO · SiO ₂ (Hereinafter β-C ₂ S), fluorapatite (Ca ₅ F (PO ₄ ) ₃ In addition to this, when dephosphorization slag is blended with concrete, it contains 2-5% of free lime (CaO) that causes a reduction in the setting speed, strength deterioration, and expansion failure. On the other hand, the modified (improved) dephosphorized slag (RDS) powder of the present invention has a free lime (CaO) content reduced to 3.0% or less. Further, in the modified (improved) dephosphorization slag (RDS) according to the present invention, usually, fluorapatite (Ca ₅ F (PO ₄ ) ₃ ) Is contained in an amount of 5 to 20% by weight.
[0016]
This modified (improved) dephosphorized slag powder has a bulk density of 2.80 g / cm according to “Physical Test Method for Cement” of JIS R 5201. ³ Or more, more preferably 3.0 g / cm. ³ It is. The particle size is a particle having a number average particle size Mn of 100 or more when measured based on a projection photographic image of SEM (scanning electron microscope), 90 μm or less, preferably 60 μm or less, and a coarse particle having a particle size of 500 μm or more. Is 1% or less. Bulk density is 2.80 g / cm ³ If it is less than the range, it tends to be smoked during handling, which is inconvenient to handle, and there is a difficulty in compressive strength. When the number average particle size Mn exceeds 90 μm and becomes coarse, the cement dough mixed with this tends to be non-uniform, and such coarse powder may not be uniformly modified to the inside of the particles. Further, when the number average particle size Mn is less than 3 μm and excessively pulverized, it is not preferable from the viewpoint of production efficiency.
[0017]
Coarse particles having a particle size of 500 μm or more indicate that, on the one hand, the metal powder may not be removed well during the magnetic separation process of the raw material dephosphorization slag in the modification of the dephosphorization slag powder. This indicates that the pulverization is not sufficient, or that the fine particles in the raw material powder may be sintered or agglomerated during the firing process, which is not preferable anyway. Coarse particles, for example, coarse particles having a particle size of 500 μm or more, can be removed by pulverization after baking or by classification.
[0018]
The modified (improved) dephosphorized slag powder according to the present invention is obtained by roughly pulverizing dephosphorized slag fine particles, removing the metal powder by magnetic separation, finely pulverizing, and then finely pulverizing dephosphorized slag. Can be obtained by firing at a low temperature, or preferably by roughly pulverizing the dephosphorized slag fine particles, removing the metal powder by magnetic separation, firing and then finely pulverizing at low temperature. Such crushing and pulverization can be performed by a wet method or preferably a dry method. Known crushing means such as jaw crusher, hammer mill, roll mill, atomizer and ball mill can be used for crushing, and known crushing means such as jet mill, attritor and ball mill can be used for fine crushing, and classification In particular, it is possible to achieve efficient pulverization by combining pneumatic classification and pulverization in which only uncrushed coarse particles are recycled to the pulverized portion using an air bag filter having a predetermined mesh.
[0019]
The raw material dephosphorized slag powder finely pulverized to a predetermined particle size having a number average particle size Mn of 90 μm or less in this way contains both activated calcium oxide contained in the particles. Phosphorus (predominantly present in the form of phosphate) and fluorine (partially present in the form of fluorapatite, but this is already stabilized and cannot capture active CaO, so it exists mainly in the form of calcium fluoride. In order to convert the complex into a complex belonging to the group of fluorapatite. Or preferably, it is pulverized after the baking treatment.
[0020]
Although the firing temperature depends on the firing time, it is usually 1000 ° C. or less, preferably 9500 ° C. or less, more preferably 550 ° C. or less and 300 ° C. or more. The firing time also depends on the firing temperature, but is 20 to 180 minutes. Preferably it is 40 to 120 minutes. If the calcination temperature is too high or / and the calcination time is too long, the glass particle solid phase is likely to develop in the powder particles of the modified dephosphorized slag powder produced, or the particle size by the Blaine method is too small. Therefore, the strength of the cement mixed with this will be hindered. Although not yet fully elucidated, not only are the particles rounded by melting and the specific surface area is reduced, but the cement composition is not sufficiently wetted by water and is subject to increased volume during expansion. It is presumed that this is caused by a lack of acceptable alliances (for example, minute recesses, crack-like minute gaps, phase interfaces and crystal defects). If the firing temperature is less than 300 ° C. and / or if the firing time is less than 20 minutes, the modification is not sufficient.
[0021]
The fine powder of modified dephosphorization slag (RDS) in the present invention has a particle size of 1500 to 8000 cm according to the Blaine method. ² / G is preferable, and more preferably 2000 to 8000 cm. ² / G, more preferably 2500-8000 cm ² / G.
[0022]
In the present invention, when such modified dephosphorization slag (RDS) powder is blended with Portland cement (PL) as a cement raw material, the modified dephosphorization slag (RDS) powder is converted into blast furnace slag (KS) powder. And (KS: RDS) is preferably blended with Portland cement (PL) in a blending ratio range of (95: 5) to (45:55), and consists of such KS-RDS. It has been found that steelmaking slag (ADD) is preferably blended in an amount of 75 to 125 parts by weight per 100 parts by weight of Portland cement (PL).
[0023]
The fine powder of blast furnace slag (KS) powder used in the present invention has a particle size of 1500 to 8000 cm by the brane method. ² / G is preferable, and more preferably 2000 to 8000 cm. ² / G, more preferably 2500-8000 cm ² / G.
[0024]
In the present invention, the blending order of the modified dephosphorized slag (RDS) powder, blast furnace slag (KS) powder, and Portland cement (PL) is of course not a problem. For example, three-way simultaneous mixing may be used. Alternatively, any two of the three may be mixed first and then mixed with the remaining one. For mixing, various known mixing means such as a V-type mixer, a cylinder mixer, a ribbon mixer, a nauter mixer, a pony mixer, a paddle agitator, a screw mixer, and a flexo mixer can be used.
[0025]
For Portland cement (PL), C ₃ S [= 3Ca · SiO ₂ ], C ₂ S [= β-2CaO · SiO ₂ ], C ₃ A [= 3CaO · Al ₂ O ₃ ], C ₃ AF [= 3CaO · Al ₂ O ₃ ・ Fe ₂ O ₃ ], HM (hydraulic modulus), SM (silicic acid rate), and IM (iron) are usually the ratios (composition%) as shown in Table 1 below.
[0026]
[Table 1]

[0027]
The main mineral of blast furnace slag (quenched slag) (KS) is melilite (2CaO · Al ₂ O ₃ ・ Similar mixture of SiO and 2CaO.2MgO.SiO), melvinite, pseudo wollastonite, etc. ₂ AS) and SiO ₂ , Al ₂ O ₃ The content is relatively high, and both Portland cement (PL) and blast furnace slag (KS) have very low fluorine and phosphorus contents, while the modified dephosphorization slag (modified A) The fine powder contains a relatively large amount of calcium added for dephosphorization, as well as apatite-structured Ca. ₅ ・ F (PO ₄ ) ₃ Therefore, the cement composition of the present invention using the modified dephosphorized slag (RDS) fine powder has a very high fluorine content and phosphorus content. Therefore, it is clearly different from the other cement compositions, and the distinction is obvious.
[0028]
Such a cement composition of the present invention includes crushed stone, gravel, river sand, mountain sand, sea gravel, etc., as well as coarse aggregates and coarse aggregates that are usually used such as slag crushed material, burning viscosity, and shale. It can be made into a concrete mortar or a mortar composition by mixing at a normal ratio in the presence of water.
[0029]
At that time, as long as it does not hinder the achievement of the object of the present invention, a relatively large amount called Bulky admixture is used as in the case of blast furnace cement, silica cement, fly ash cement, masonry cement, expanded cement, and color cement. Admixtures can be used.
[0030]
Furthermore, surfactants, polymer electrolytes, and AE agents, water reducing agents (dispersing agents), antifoaming agents, foaming agents, antifoaming agents, antifreezing agents, viscosity agents, etc. using these as base materials, as desired. In addition, quick setting agents such as lime chloride, salt, water glass, retarding agents such as sodium silicate hydrofluoride, anticorrosive agents such as first bell chloride and cuprous chloride, waterproofing agents, water repellents, grouting agents, Conventional admixtures such as admixtures for inorganic and organic adhesives, water-holding agents, efflorescence inhibitors, antiwear agents, surface strengthening agents and the like can be added. The addition amount of these admixtures is preferably within 8%, more preferably within 5%, and even more preferably within 2%.
[0031]
【Example】
Hereinafter, the present invention will be described specifically by way of examples. First, in [Reference Example], the content of the modified dephosphorization slag (RDS) fine powder preparation method and the characteristics of the dephosphorization slag (RDS) will be described in detail. Next, in [Example], The content of the cement composition using the dephosphorized slag (RDS) fine powder will be specifically described. These [Reference Examples] and [Examples] are examples for explaining the present invention, and are not intended to limit the present invention.
[0032]
[Reference Examples 1 to 21] [Modified dephosphorized slag (RDS) fine powder / mortar composition]
(Materials used)
As dephosphorization slag, dephosphorization slag was intentionally used as a by-product at an ironworks and then left for about 4 months, and after removing metallic iron by magnetic separation, this was first pulverized by a ball mill and pulverized to 4000 branes. What was done was used for experiment. This chemical composition is shown in Table 2.
[0033]
[Table 2]

[0034]
When measuring the loss on ignition (Ig. Loss), the same method as when measuring the loss on ignition of Portland cement (PL), that is, heating in an electric furnace at 950 ± 50 ° C., The value was determined.
[0035]
(Modification process)
The sample was placed in an electric furnace adjusted to a temperature of 500 ° C. and baked for 2 hours. The particle size of the fired powder sample was measured by the brane method, and a value of 4000 branes was obtained. This indicates that the sintering of the sample particles and the change of the surface state to glass were not so severe due to the firing. However, it can be pulverized after sintering to eliminate the round shape and increase the specific surface area. When the sample was separately fired at a temperature of 1050 for 2 hours, the grain size of the fired powder sample was reduced to 3800 branes or less.
[0036]
FIG. 1 shows the result of mineral identification by powder X-ray diffraction (XRD) comparing the dephosphorized slag after modification with that before modification.
From this, the present dephosphorization slag sample before reforming has β-C ₂ S (β-2CaO · SiO ₂ ), Ca ₅ F (PO ₄ ) ₃ , CaCO ₃ It can be seen that exists. This suggests that this sample is only partially aged and the degree of aging is not large. In the case of dephosphorization slag immediately after by-product at steelworks, β-C ₂ S, Ca ₅ F (PO ₄ ) ₃ , CaCO ₃ It was shown that there were almost no peaks from origin.
[0037]
Dephosphorization slag modified according to this reference example (herein referred to as RDS, also referred to as “modified dephosphorization slag” or “modified dephosphorization slag”) Ca (OH) ₂ The disappearance of the peak indicates that the amount of free lime (CaO) is reduced. In addition, this dephosphorization slag shows extremely poor crystallinity even when judged from the XRD strength (CPS). From this, the mineral composition of the improved dephosphorized slag obtained by composition calculation is shown in Table 3, which is merely an example, and β-C ₂ The S content may have a range of about ± 30% of this 49.6% value. ₅ F (PO ₄ ) ₃ The content may have a range of about ± 50% of this 14.9% value. ₂ The content may have a width of about ± 20% of this 5.2% value.
[0038]
[Table 3]

[0039]
(Properties of dephosphorization slag (RDS) after reforming)
As a preliminary study, the properties of the dephosphorized slag after the modification, particularly the properties from the viewpoint of the possibility of use as a cement material, were examined.
Table 4 below shows the physical properties of materials used in trials of mortar using cement mixed with improved dephosphorization slag, and used in an adiabatic temperature rise test described later.
[0040]
[Table 4]

[0041]
(Test of modified mortar containing dephosphorized slag)
Table 5 shows the implementation of the modified dephosphorized slag-containing mortar used in the experiment.
[0042]
[Table 5-1]

[0043]
[Table 5-2]

[0044]
(In the table, PL: Portland cement, RDS: Modified (improved) dephosphorization slag, KS: Blast furnace granulated slag, the left side in parentheses of each reference example is the material part in which PL is substituted in the admixture (C). For example, Reference Example 2 (RDS10-45) has RDS = 10 parts, PL = balance in admixture C45 parts, Reference Example 3 (RDS20-45) has RDS = 20 parts, PL = balance in admixture C45 parts. Balance, Reference Example 4 (RDS30-45) is RDS = 30 parts, PL = balance in admixture C45 parts, Reference Example 5 (KB10-45) is KB = 30 parts, PL = balance in admixture C45 parts, Reference Example 12 (KB 10-55) represents KB = 10 parts and PL = balance in admixture C55, and Reference Example 20 (KB20-65) represents KB = 20 parts and PL = balance in admixture C65. . And, S1; Oi production river sand, W; water, C: represents the binder (= PL + KS + RDS))
[0045]
The water binder ratio was 45, 55, 65%, and the amount of the admixture (RDS) was replaced by 10, 20, 30 wt% of the binder, and the experiment was conducted in a constant temperature and humidity chamber at 20 ° C. and RH 60%. Underwater curing period was up to 6 months, kneading was performed with a Hobbard mixer, the specimen was 4 × 4 × 16 cm, demolded 24 hours after placement, and underwater curing was performed at 20 ° C. until a predetermined age. The experiment was performed according to JIS R 5201 for bending strength and compressive strength, and the length change was performed under the same temperature and humidity conditions, and was measured for up to 2 months according to the dial gauge method of JIS A 1129.
[0046]
(Viscosity measurement of fresh mortar containing modified dephosphorization slag)
The mortar was blended by hand for 120 seconds at a water binder ratio (45, 55, 65%) at the same substitution rate as in the strength experiment, and the change over time in the viscosity of the fresh mortar was measured. The viscosity was measured using a vibration viscometer (natural frequency: 30.0 Hz, sensitive plate: t = 0.2 mm, φ20 mm), and the change due to the water binder ratio and the change due to the substitution rate were measured.
[0047]
[Reference Examples 22 to 28] [Hydration exothermic characteristics of mortar containing modified dephosphorization slag]
(1) Measurement of hydration exotherm rate
For the purpose of measuring the calorific value immediately after mixing with water, the modified dephosphorization slag (RDS) was replaced by 10, 20, and 30 wt% with respect to the cement (PL). This neat cement blend was set in a twin-type conductive microcalorimeter at a water: binder ratio of 100% and 20 ° C., stabilized, and then measured for up to 24 hours.
[0048]
(2) Adiabatic temperature rise test
The formulation used in the experiment is shown in Table 6 below.
[0049]
[Table 6]

[0050]
The water binder ratio was 60%, and the improved dephosphorization slag (RDS) was replaced by 10, 20, 30 wt% with respect to the cement (PL). Further, fine aggregate (S2), coarse aggregate (S3) and an admixture (ad; Na-condensate of β-naphthalenesulfonic acid) were used and compared with unmixed concrete. First, a Hobart mixer is used as a test method, and kneaded water in which an admixture is dissolved, cement (PL), and fine aggregate are put in this order and kneaded for 2 minutes. Then add coarse aggregate and mix for 1 minute. Stir with a small scoop, place in a plastic container, place in a cell container for insulation, and measure. The adiabatic temperature rise test apparatus is an air circulation type. At the same time, the adiabatic temperature rise value was measured by comparing with Type B blast furnace cement, medium heat Portland cement, and low heat Portland cement. The maximum volume that can be set in the apparatus is as small as 3 liters, and the maximum aggregate size of the coarse aggregate was set to 13 mm in order to reduce the measurement error.
[0051]
(result)
(1) Strength and length change
The bending strength of mortar substituted with improved dephosphorization slag was measured by the difference of water binder ratio. The result is shown in FIG. In the specimens in which cement (PL) and modified dephosphorization slag (RDS) 10, 20, and 30 wt% were replaced by the bonding shown in Table 4, in the case of the initial age (4 weeks of age), the water binder ratio and substitution were replaced. There is a difference in strength depending on the rate, and the influence of the substitution rate tends to increase as the water binder ratio increases. As shown in FIG. 2, even when the replacement rate of the improved dephosphorization slag is increased, the long-term material age (material age 26 weeks) is PL-45, PL-55, etc. at a water bonding material ratio of 45, 55%. Almost the same strength was obtained. In particular, no abnormal difference was found in the comparison between the granulated blast furnace slag (KS30-PL55) and the improved dephosphorization slag (RDS30-PL55) shown in FIG. In the experiment, measurement was started from the fourth week of the age of the material, the development of strength was also steady, and no significant difference was observed depending on the type of admixture and the substitution rate.
Similarly, the change in the compressive strength of the mortar is shown in FIG. In the initial stage, the compressive strength when the improved dephosphorization slag is replaced is somewhat different depending on the replacement rate, but the difference tends to decrease with the long-term age.
[0052]
FIG. 5 is a comparison of blast furnace granulated slag (KS30-PL55) and modified dephosphorization slag (RDSW30-PL55), respectively. . In the case of RDS30-PL55, although it is almost equal to or lower than KS30-PL55 at the beginning, an increase in strength is observed with the age of the material, and there is a tendency to increase as the material age becomes longer.
Although it is thought that the expansion by the improved dephosphorization slag (RDS) in which the amount of free lime (CaO) was reduced to 0.065 wt%, the improved dephosphorization slag was applied to the cement (PL) to reconfirm this problem. The change in length of the substituted mortar was measured. The result is shown in FIG. Equivalent shrinkage was observed as compared to the cement-only specimen (PL-55). Similarly, a comparison between granulated blast furnace slag and improved dephosphorization slag is shown in FIG. As described above, the improved dephosphorization slag is not greatly different from that of PL-55, but the blast furnace granulated slag tends to have a slightly larger shrinkage.
[0053]
(2) Viscosity
FIG. 8 shows the viscosity of the mortar using the improved dephosphorization slag. When this is compared with cement C-55, the viscosity tends to decrease as the substitution rate increases. In addition, the viscosity of granulated blast furnace slag and improved dephosphorized slag were compared. The result is shown in FIG. In the comparison of granulated blast furnace slag and improved dephosphorized slag, it was found that those with the improved dephosphorized slag replaced showed lower values.
[0054]
(3) (Hydration exothermic characteristics)
(I) Measurement of hydration exotherm rate
FIG. 10 shows the results of measuring the hydration exothermic rate up to 24 hours when the modified dephosphorization slag (RDS) was replaced with cement (PL). The exothermic rate immediately after hydration corresponds to the hydration exothermic rate curve when cemented (PL) is simple for both primary and secondary peaks when improved dephosphorization slag is mixed. At the same time, both tend to be smaller.
[0055]
(Ii) Adiabatic temperature rise test
The result of the adiabatic temperature rise test when the improved dephosphorization slag is replaced is shown in FIG. Dry (denoted by D, the same shall apply hereinafter)-With an increase in substitution rate compared to Portland cement (PL), the measured values up to 14 days are 47.9 ° C for D-cement (PL) and 44 for D-RDS10. 3 ° C, D-RDS20 was 41.5 ° C, and D-RDS30 was 37.7 ° C. Thus, the adiabatic temperature rise value tends to decrease. Conventional β-C ₂ Unlike S, β-C contained in the improved dephosphorization slag ₂ S is very slow-hardening. Therefore, from the result of the strength characteristics, it was found that when the improved dephosphorization slag was replaced with cement, a very low heat generation type was obtained.
[0056]
At the same time, the results of the adiabatic temperature rise test of medium heat Portland cement, low heat Portland cement, and Class B blast furnace cement are shown in FIG. Thus, the measured values up to 14 days are moderately hot Portland cement (42.0 ° C) and low heat Portland cement (33.4 ° C), which are lower than D-PL (47.9 ° C) regardless of age. As shown, the B-type blast furnace cement (55.9 ° C.) is higher than the D-PL at the age of 4 days, and does not show a low heat generation.
[0057]
From the above results, (1) the hydration of the modified dephosphorization slag and its strength development mechanism are considered as follows.
That is, the strength development of granulated blast furnace slag is due to the pozzolanic reaction, and calcium silicate hydrate (hereinafter referred to as CSH) is generated during the curing process. On the other hand, the strength development of the modified dephosphorization slag is the β-C present in the modified dephosphorization slag. ₂ This is due to S. The β-C ₂ C—S—H is generated by hydration of S.
[0058]
(Mechanism of strength improvement of modified dephosphorization slag)
The modified dephosphorized slag was kneaded at a hydrated binder ratio of 30% and 25% and left in a sealed test tube. The XRD of a hydrate hydrated for 1 day, 90 days, and 1 year is shown in FIG. 13, and a scanning electron micrograph (SEM) is shown in FIG.
As described above, the crystallinity of the modified dephosphorization slag is extremely poor, and is rather close to glassy. Therefore, it can be seen from FIG. 13 that the XRD strength of the hydrated improved dephosphorization slag decreases with time. Comparing 1 day and 90 days of hydration, β-C ₂ The peak of S is decreasing. Β-C after 1 year of hydration ₂ The peak of S could not be confirmed. This is β-C ₂ This is because C—S—H is formed by hydration of S.
[Chemical 1]
β-C ₂ S + H ₂ O → C—S—H (gel hydrate)
[0059]
However, C—S—H could not be confirmed by XRD even after one year of hydration. However, from the SEM photograph, hydrates could not be confirmed after 1 day of hydration, but gel-like C—S—H was confirmed after 90 days. Furthermore, a part of acicular C—S—H was recognized. In one year, it was observed that C—S—H gel having extremely poor crystallinity covered the entire particle surface. Therefore, although improved dephosphorization slag is extremely slow-hardening, strength development occurs with long-term aging even if it remains simple. C—S—H is gradually generated with the age of the material and becomes a dense structure.
Regarding the strength development mechanism, other causes are considered as follows. Fluoroapatite (Ca in dephosphorization slag ₅ F (PO ₄ ) ₃ ) Is part of β-C ₂ Combined with S and free lime (CaO),
[Chemical 2]
Ca ₅ F (PO ₄ ) ₃ + Β-C ₂ S + CaO (heat treatment) → apatite group compound
This is because a complex apatite group compound is formed. Fluoroapatite itself is a ceramic with high strength and is known as a material for artificial bones. The apatite group compound formed here was considered to give a good effect on strength at long-term ages.
From the above, unlike the blast furnace granulated slag, the strength development of the improved dephosphorized slag is slow-hardening but exhibits self-hardening itself, and it is highly possible that no stimulant is required.
[0060]
(Measurement of length change)
(2) The change in the length of the specimen in which the improved dephosphorization slag was replaced with cement (PL) was measured. This is because the sample before improvement contains free lime (CaO), but does not cause expansion since it hardly contains after improvement. To reconfirm this, the length change was measured. In the experiment, there was no expansion or abnormal shrinkage compared to cement (PL) mortar. This means that by improving the dephosphorization slag, the free lime (CaO) disappears almost completely and the effect does not occur.
[0061]
(3) Viscosity of fresh mortar in which improved dephosphorization slag (RDS) is substituted for cement (PL) varies depending on the substitution rate even at the same water binder ratio. As the replacement rate increases
(A) The amount of cement (PL) is reduced.
(B) Since the hydration activity of the improved dephosphorization slag (RDS) is low, it is considered that the hydrate has not been sufficiently formed.
(C) Viscosity is affected by the water binder ratio, particle size, particle size, and the like.
For these reasons, the viscosity tends to decrease.
[0062]
(4) Looking at the rate of hydration exotherm of cement (PL) with improved dephosphorization slag, the one corresponding to the primary peak (10 minutes after hydration) resulting from the formation of ettringite is It becomes extremely small with the substitution rate. This suggests a low exothermic property at the initial stage of hydration. Further, the secondary peak in FIG. 10 (13 hours and 20 minutes after hydration) is C, which is the main mineral of PL. ₃ It is related to the hydration reaction of S. Conversion of entonite to monosulfate could not be confirmed.
[0063]
(5) The adiabatic temperature rise value of concrete substituted with improved dephosphorization slag (RDS) tends to decrease as the replacement rate increases. Assuming that the improved dephosphorization slag does not generate heat at all, and calculating the exothermic temperature up to 14 days with specific heat (cal / ° C · g) of water, cement and aggregate being 1.00, 0.19 and 0.20, respectively.
D-cement (PL exothermic temperature is 47.9 ° C (measured value)
Calculated value of heat generation temperature of D-RDS10 = 43.6 ° C. (measured value 44.3 ° C.)
Calculated value of heat generation temperature of D-RDS20 = 39.1 ° C. (measured value 41.5 ° C.)
Calculated value of heat generation temperature of D-RDS30 = 34.6 ° C. (measured value 37.7 ° C.)
[0064]
However, in the experiment of the adiabatic temperature rise, as shown in the measured value, it exceeds the calculated value. This difference is an exothermic temperature generated from the improved dephosphorization slag, which is 0.7 ° C, 2.4 ° C, and 3.1 ° C, respectively. This is due to the β-C present in the improved dephosphorization slag. ₂ This is thought to be due to the hydration of S. Moreover, when the heat insulation temperature rise value of mortar was calculated, it was found that it was significantly higher than the heat insulation temperature rise value of concrete. As shown in FIG. 12, the adiabatic temperature rise value of Type B blast furnace cement exceeds D-cement (PL) from the age of 4 days, and the temperature rise is remarkable. It has been found that the replacement of the improved dephosphorization slag proposed in the present invention results in a very low heat generation type.
[0065]
As described above, the properties of the dephosphorized slag after the reforming in the present invention, particularly whether the dephosphorized slag can be a concrete admixture having an action like a blast furnace granulated slag is summarized as follows.
(1) The bending strength of the mortar substituted with the improved dephosphorization slag (RDS) was not significantly different from that of the cement (PL) mortar, and (2) the improved dephosphorization slag (RSD) was replaced with the cement (PL). The compressive strength of mortar is a little smaller at the initial age than cement (PL) mortar, but the tendency to increase with age is not recognized. (3) Mortar with cement (PL) replaced with improved dephosphorization slag (RDS) The change in length of the mortar does not expand, and the same shrinkage as that of cement (PL) is observed. (4) The viscosity of fresh mortar in which improved dephosphorization slag (RDS) is substituted for cement (PL) Even if it is the same, it differs depending on the admixture and the substitution rate, and (5) even if the improved dephosphorization slag remains as it is, strength development occurs in the long-term material age. The long-term strength of mortar in which cement (PL) is replaced with improved dephosphorization slag (RDS) is the β-C in the slag. ₂ Due to S, gel CSH is confirmed in 90 days of hydration, and in 1 year it becomes a dense hydrate structure, which contributes to the development of strength, (6) Looking at the hydration heat generation rate of neat cement substituted with improved dephosphorization slag (RDS) of cement (PL), the primary peak due to the formation of ettringite becomes significantly smaller due to the mixing of improved dephosphorization slag. Immediately after that, it shows low exothermic property. (7) The heat insulation temperature rise value of the concrete replaced with improved dephosphorization slag is extremely low, for example, when used for mass concrete, it can be effective as a low exothermic type. Therefore, the possibility that the improved dephosphorization slag can be a new concrete admixture can be presumed to be high based on the characteristics of the minerals, etc. For such sexual, it is not certainly the only such preliminary tests. Therefore, these points will be specifically described by the following examples.
[0066]
[Example 1] [Comparative Examples 1-3]
[Improved dephosphorization slag for cement composition and cement composition using the same]
(Materials used)
The materials used are shown in Table 7 in comparison with Comparative Examples 1-3. The dephosphorization slag used here was passed through a 300 μm sieve and baked in a furnace at 500 ° C. for 2 hours.
[0067]
[Table 7]

[0068]
(Combination)
Table 8 shows the mortar formulation used for the length change rate test after the compressive strength test, Table 9 shows the mortar formulation used for the chloride ion permeation test, and Table 10 shows the concrete formulation used for the adiabatic temperature rise test.
[0069]
[Table 8]

[0070]
[Table 9]

[0071]
[Table 10]

[0072]
(Test method)
(1) Compressive strength test
In accordance with JIS A 1108, the compressive strengths of the specimens of Comparative Example 1 and Examples 1 to 3 having a diameter of 5 × h10 cm prepared by blending the mortars shown in Table 8 were measured. The specimens were sealed and cured until each age in a constant temperature room at 20 ° C.
[0073]
(2) Length change rate test
In accordance with JIS R 1129, the rate of change in length of the specimens of Comparative Example 1 and Examples 1 to 3 prepared with the mortar formulations shown in Table 8 was measured. The size of the specimen was 4 × 4 × 16 cm, and sealed and cured in a temperature-controlled room at a temperature of 20 ° C.
[0074]
(3) Adiabatic temperature rise test
As those of Comparative Example 2 and Examples 4 to 6 based on the composition of Table 10, the kneaded fresh concrete was put into a mold can of φ10 × h20 cm, and the adiabatic temperature rise value was measured with a simple adiabatic temperature measuring device. . The measurement was performed every 4 hours.
[0075]
(4) Chloride ion permeation test
An outline of the chloride ion permeation tester is shown in FIG. The specimens of Comparative Example 3 and Examples 7 to 9 prepared by blending the mortars shown in Table 9 were sealed and cured in a constant temperature room at 20 ° C. for 28 days, and cut into φ5 × h1 cm and fitted into the center, and placed in the left cell. A 3% NaCl aqueous solution was added to the saturated Ca (OH) in the right cell. ₂ 600 ml of each aqueous solution was added, and the structure was such that chloride ions permeated by natural diffusion due to a concentration gradient at a constant 20 ° C. Saturated Ca (OH) ₂ An aqueous solution was collected and the concentration of permeated chloride ions was measured by ion chromatography.
[0076]
(Test results)
Compressive strength
FIG. 16 shows the compressive strength of the ages 7 days, 28 days, and 91 days. KS30-PL70 had comparable compressive strength at each age when compared with PL100. RDS30-PL70 decreased by 57% at a material age of 7 days and decreased by 15% at a material age of 91 days compared to PL100. KS15-RDS15-PL70 decreased by 14% at 7 days of age when compared to PL100, but became equivalent at 91 days of age.
From the viewpoint of compressive strength, KS can be replaced up to about 30 parts per PL and 100 parts of PL. On the other hand, when RDS replaces PL, the compression strength starts to decrease from about 15 parts per 100 parts of PL, and when the replacement amount exceeds 30 parts, the decrease in compressive strength becomes significant. Confirmed by However, on the other hand, when replacing RDS with PL, it is preferable to use it together with KS. In this case, if the mixing ratio of RDS and KS is in the range of 30; 70 to 70; The fact that 75 to 125 parts by weight of the blend per 100 parts of PL can be preferably blended was confirmed by the same series of related tests conducted at the same time, and thus the long-term strength development characteristics of dephosphorized slag were observed.
[0077]
(2) Length change rate
FIG. 17 shows the length change rate. The shrinkage rate at each age was KS30-PL70>KS15-RDS15-PL70>PL100> RDB30-PL70. KS30-PL70 increased by about 100% and KS15-RDS15-PL70 increased by about 40% with respect to the shrinkage rate of PL100 at the age of 91 days. However, RDB30-PL70 decreased by about 25%. This is considered that the free lime remaining in the dephosphorized slag was expanded by the hydration reaction, and the contraction was suppressed.
Also, from this result, as in the case of compressive strength, when RDS is replaced with PL, the mixing ratio of RDS and KS when used in combination with KS is in the range of 30; 70 to 70; 30 parts by weight. It is presumed that these blends can be preferably blended with 75 to 125 parts by weight of these blends per 100 parts of PL.
[0078]
(3) Adiabatic temperature rise
FIG. 18 shows the adiabatic temperature rise value. Comparing the peak values of the adiabatic temperature rise value, the adiabatic temperature rise value was also KS30-PL70>KS15-RDS15-PL70>PL100> RDB30-PL70. The temperature rise value of KS30-PL70 exceeded the temperature rise value of PL100 after about 50 hours. KS15-RDS15-PL70 was less than PL100 until 130 hours, which is the peak value of the temperature rise value, but thereafter became equal. The temperature rise value of RDB30-PL70 was less than PL100 at each elapsed time, and the peak value was also reduced by 22% compared to PL100. There is a considerable difference from KS15-RDS15-PL70.
[0079]
(4) Chloride ion permeation amount
FIG. 19 shows changes with time in the amount of chloride ion permeation. At 8 weeks, KS30-PL70 decreased by 47% compared to PL100, KS15-RDS15-PL70 was equivalent to PL100, and RDB30-PL100 increased by 45% compared to PL100. Although the dephosphorization slag itself did not show the chloride ion permeation suppression effect, it became clear that the suppression of chloride ion permeation can be expected by using it together with the blast furnace slag.
[0080]
From the above results, it is clear that the blast furnace slag fine powder can be used together with the dephosphorized slag fine powder to reduce the amount of hydration shrinkage and the adiabatic temperature rise, and the total of steelmaking slag (ADD) composed of KS and RDS. The content is 75 to 125 parts by weight per 100 parts by weight of Portland cement (PL), and the blending ratio of the blast furnace slag (KB) fine powder and the dephosphorized slag (RDS) fine powder in steelmaking slag (ADD) (KS) : RDS ratio) is (30:70) to (70:30), a preferable result is obtained, and the difference is remarkable, compared with the case of replacing with 30 parts by weight of RDS per 100 parts by weight of PL. It became.
[0081]
【The invention's effect】
As described above, as is clear from the detailed and specific description, the present invention provides a preferred method for modifying a dephosphorization slag for cement blending, a preferred cement composition using the same, a mortar and a concrete composition using the same. This effect is very remarkable.
[Brief description of the drawings]
FIG. 1 is a graph showing powder X-ray diffraction (XRD) of dephosphorization slag used in an example of the present invention.
FIG. 2 is a diagram showing the bending strength of an improved dephosphorized slag mixed mortar in the example of the present invention and in comparison.
FIG. 3 is a diagram showing the bending strength of an improved dephosphorization slag and blast furnace granulated slag mixed mortar in the example of the present invention and in comparison.
FIG. 4 is a diagram showing the compressive strength of an improved dephosphorized slag mixed mortar in the example of the present invention and in comparison.
FIG. 5 is a diagram showing the compressive strength of the improved dephosphorization slag and blast furnace granulated slag mixed mortar in the example of the present invention and in comparison.
FIG. 6 is a diagram showing a change in length of an improved dephosphorization slag mixed mortar in the example of the present invention and in comparison.
FIG. 7 is a view showing a change in length of an improved dephosphorization slag and blast furnace granulated slag mixed mortar in the example of the present invention and in comparison with each other.
FIG. 8 is a diagram showing the viscosity (vibration type) of cement mortar mixed with an improved dephosphorization slag in the example of the present invention and in comparison.
FIG. 9 is a diagram showing the viscosity (vibration type) of cement mortar in which improved dephosphorization slag and blast furnace granulated slag are mixed in the example of the present invention and in comparison.
FIG. 10 is a graph showing a hydration exothermic rate curve of a mentament mixed with an improved dephosphorization slag in the example of the present invention and in comparison.
FIG. 11 is a diagram showing a heat insulation temperature rise value of concrete mixed with improved dephosphorization slag in the example of the present invention and comparison.
FIG. 12 is a graph showing the heat insulation temperature rise value of concrete mixed with medium heat Portland cement, low heat Portland cement, and Class B blast furnace cement in the example of the present invention and in comparison.
FIG. 13 is an X-ray diffraction (XRD) diagram of a hydrated modified dephosphorization slag in comparison with an example of the present invention.
FIG. 14 is a scanning electron micrograph (SEM) of a hydrated modified dephosphorization slag in comparison with an example of the present invention.
FIG. 15 is a schematic view of a chloride ion permeation tester.
FIG. 16 is a diagram showing compressive strength in the example of the present invention and comparison.
FIG. 17 is a diagram showing the rate of change in length at each age in comparison with the example of the present invention.
FIG. 18 is a diagram showing an adiabatic temperature rise value in the example of the present invention and comparison.
FIG. 19 is a graph showing changes in chloride ion permeation over time in the example of the present invention and in comparison.

Claims (4)

It contains at least (i) Portland cement (PL), (ii) fine powder of blast furnace slag (KS) having a particle size particle size of 1000 to 10,000 cm ² / g by the Blaine method, and (iii) a particle size by the Blaine method. Including steelmaking slag (ADD) made of fine powder of dephosphorization slag (RDS) having an average particle diameter Dn of 90 μm or less at 1500 to 8000 cm ² / g, (a) the total content of the steelmaking slag (ADD) is the Portland cement (PL) It is 75 to 125 parts by weight per 100 parts by weight, and (b) the mixing ratio of the blast furnace slag (KB) fine powder and the dephosphorized slag (RDS) fine powder in the steelmaking slag (ADD) (KS: RDS ratio) (95: 5) to (45:55) cement composition, (c) free CaO in the cement composition Yes constant of less _{3.0%, Ca 5 · F (} PO 4) 3 cement composition, wherein the content of 3.0% or more of the apatite structure. A mortar or concrete composition comprising a cement composition according to claim 1, aggregate, water and optionally a surfactant. β-2CaO · SiO ₂ content is 49.6 × (1 ± 0.3) wt%, Ca ₅ F (PO ₄ ) ₃ content is 14.9 × (1 ± 0.5) wt%, CaF ₂ content is It has a composition of 5.2 × (1 ± 0.2)% by weight, Fe ₂ O ₃ content of 8.2% by weight or less, free CaO content of 3.0% by weight or less, and average particle diameter Dn of 90 μm or less. A modified dephosphorization slag (RDS) powder for mixing cement, characterized in that it is composed of fine particles of A step of converting the activated calcium oxide contained in the fine particles into a solid solution belonging to the fluorapatite group by firing the pulverized dephosphorized slag (KS) fine particles at a temperature of 1000 ° C. or lower for 20 to 180 minutes, And at least (i) Portland cement (PL), (ii) a number average particle size with a grain size of 1000 to 10,000 cm ² / g according to the Blaine method, characterized by comprising mixing the product with fine blast furnace slag powder and Portland cement Steelmaking slag (ADD) containing fine powder of blast furnace slag (KS) having a diameter of 3 to 90 μm and (iii) fine powder of dephosphorized slag (RDS) having a grain size of 1500 to 8000 cm ² / g by a brane method containing apatite calcium And (a) the total content of the steelmaking slag (ADD) is 75 to 125 parts by weight per 100 parts by weight of cement (PL), (b) blending ratio of the blast furnace slag (KS) fine powder and dephosphorization slag (RDS) fine powder in the steelmaking slag (ADD) ( (Ratio of KS: RDS) of (95: 5) to (45:55), wherein (c) the free CaO content in the cement composition is 3.0% or less, and the apatite structure A method for producing a cement composition having a Ca ₅ · F (PO ₄ ) ₃ content of 3.0% or more.

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