JP3960718B2 - Cement admixture and cement composition - Google Patents
Cement admixture and cement composition Download PDFInfo
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- JP3960718B2 JP3960718B2 JP23787299A JP23787299A JP3960718B2 JP 3960718 B2 JP3960718 B2 JP 3960718B2 JP 23787299 A JP23787299 A JP 23787299A JP 23787299 A JP23787299 A JP 23787299A JP 3960718 B2 JP3960718 B2 JP 3960718B2
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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
- 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
- C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
- C04B40/0028—Aspects relating to the mixing step of the mortar preparation
- C04B40/0039—Premixtures of ingredients
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- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (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】
【従来の技術】
セメント・コンクリートのひび割れ低減や曲げ耐力の向上は、コンクリート構造物の信頼性、耐久性、美観等の観点から最も重要であり、これらを改善するためセメント系膨張材の開発が行われてきたが、更なる技術の進展が望まれている。セメント系膨張材としては、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−カルシウムシリケート−無水セッコウ系膨張材（特公昭53-31170号公報）等が知られている。
【０００３】
【発明が解決しようとする課題】
近年、コンクリートの高性能化を目的に、高流動コンクリートや高強度コンクリートの開発が盛んに行われているものの、これら高性能コンクリートにおいては、セメント系膨張材の効果が十分に発揮されない点が指摘され、膨張材の混和率が小さくても大きな膨張性を付与できる、膨張性能の優れた膨張材の開発が待たれている。
【０００４】
又、最近では従来の仕様規定型の設計体系から、性能規定型の設計体系への移行が検討されており、これまでやや軽視されていたコンクリートの耐久性についても明確な性能規定が定められる方向にある。即ち、ひび割れに対する耐久性について、その影響を定量化することが検討されているため、ひび割れの低減は一層重要な課題となってきている。従って、使用量が少なく、経済的負担が小さく、ひび割れ低減に効果のある優れた膨張性能を有するセメント系膨張材が不可欠である。
【０００５】
本発明者らは、これらの課題を解決すべく種々の検討を重ねた結果、特定のセメント混和材を使用することにより、前記課題が解決できるとの知見を得て本発明を完成するに至った。
【０００６】
【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原料及びＣａＳＯ４原料を熱処理して得られる物質であって、セメント混和材１００重量部中、３０〜６０重量部の遊離石灰、１０〜４０重量部のカルシウムアルミノフェライト及び１０〜４０重量部のセッコウ類を含有してなるセメント混和材であり、珪酸率が０．５未満であることを特徴とする該セメント混和材であり、更にセメントと、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り、該セメント混和材が、セメント組成物１００重量部中、３〜１２重量部であることを特徴とする該セメント組成物であり、セメントと、ＣａＯ原料、Ａｌ ２ Ｏ ３ 原料、Ｆｅ ２ Ｏ ３ 原料及びＣａＳＯ ４ 原料を熱処理して得られる物質であって、セメント混和材１００重量部中、３０〜６０重量部の遊離石灰、１０〜４０重量部のカルシウムアルミノフェライト及び１０〜４０重量部のセッコウ類を含有してなる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。
【０００７】
【発明の実施の形態】
以下、本発明を更に詳細に説明する。
【０００８】
本発明のセメント混和材は、遊離石灰、カルシウムアルミノフェライト及びセッコウ類を含有してなるものであり、その割合については特に限定されるものではないが、セメント混和材１００重量部中、遊離石灰は３０〜６０重量部であり、４０〜５０重量部が好ましい。カルシウムアルミノフェライトは１０〜４０重量部であり、１５〜３５重量部が好ましい。さらに、セッコウ類は１０〜４０重量部であり、２０〜３５重量部が好ましい。セメント混和材中の各化合物の組成割合が前記範囲を外れると、優れた膨張性能が得られない場合がある。
【０００９】
本発明のカルシウムアルミノフェライトとは、ＣａＯ−Ａｌ2Ｏ3−Ｆｅ2Ｏ3系化合物を総称するものであり、特に限定されるものではないが、ＣａＯをＣ、Ａｌ2Ｏ3をＡ、Ｆｅ2Ｏ3をＦと略記すると、Ｃ4ＡＦやＣ6Ａ2Ｆと表せる化合物等が挙げられる。通常はＣ4ＡＦとして存在していると考えられ、本発明では、カルシウムアルミノフェライトを以下、Ｃ4ＡＦという。
【００１０】
本発明のセメント混和材は、ＣａＯ原料、Ａｌ2Ｏ3原料、Ｆｅ2Ｏ3原料及びＣａＳＯ4原料を熱処理して、遊離石灰、Ｃ4ＡＦ及び無水セッコウからなるクリンカーを合成してこれを粉砕して製造される。遊離石灰、Ｃ4ＡＦ及び無水セッコウを別々に合成し、これらを混合したものでは、本発明のような効果は得られない。
ＣａＯ原料、Ａｌ2Ｏ3原料、Ｆｅ2Ｏ3原料及びＣａＳＯ4原料を熱処理して、遊離石灰、Ｃ4ＡＦ及び無水セッコウからなるクリンカーを合成したかどうかは、例えば、粉砕物中の１００μｍ以上の粗粒子を顕微鏡観察等を行い、その粒子中に遊離石灰、Ｃ4ＡＦ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。
【００１１】
本発明のセメント混和材を製造する際の熱処理温度であるが、１１００〜１６００℃の範囲が好ましく、１２００〜１５００℃の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場合がある。
【００１２】
ＣａＯ原料としては、石灰石や消石灰等が挙げられ、Ａｌ2Ｏ3原料としては、ボー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、鉄粉及び市販の酸化鉄等が挙げられ、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、ＳｉＯ2、ＭｇＯ、ＴｉＯ2、Ｐ2Ｏ5、Ｎａ2Ｏ及びＫ2Ｏ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が、これらのうちで、特に、ＳｉＯ2は珪酸率で０．５未満の範囲であることが好ましい。珪酸率が０．５以上では、優れた膨張性能が得られない場合がある。本発明でいう珪酸率とは、セメント混和材中のＳｉＯ2量、Ａｌ2Ｏ3量及びＦｅ2Ｏ3量より次式から算出される。
珪酸率＝ＳｉＯ2／（Ａｌ2Ｏ3＋Ｆｅ2Ｏ3）
【００１３】
又、本発明のセメント混和材中のＳｉＯ2量は、５．０重量％以下が好ましく、３．０重量％以下がより好ましい。５．０重量％を超えると優れた膨張性能が得られない場合がある。
【００１４】
本発明のセメント混和材の粒度は、特に限定されるものではないが、通常、ブレーン比表面積で1500〜9000cm2/gが好ましく、2500〜4000cm2/gがより好ましい。セメント混和材の粒度がブレーン比表面積で1500cm2/g未満では、長期耐久性が悪くなる場合があり、9000cm2/gを超えると充分な膨張性能が得られない場合がある。
【００１５】
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重量部中、３〜１２重量部が好ましく、５〜９重量部がより好ましい。３重量部未満では、充分な膨張性能が得られない場合があり、１２重量部を超えて使用すると長期耐久性が悪くなる場合がある。
【００１６】
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、並びに石灰石粉末等を混合したフィラーセメント等がある。
【００１７】
本発明では、本発明のセメント混和材及びセメント組成物に、砂や砂利等の骨材の他、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、ベントナイト等の粘土鉱物及びハイドロタルサイト等のアニオン交換体等のうちの一種又は二種以上を、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。
【００１８】
本発明では、各材料の混合方法は特に限定されるものではなく、それぞれの材料を施工時に混合しても良いし、予めその一部、或いは全部を混合しておいても差し支えない。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、傾胴ミキサー、オムニミキサー、ヘンシェルミキサー、Ｖ型ミキサー及びナウターミキサー等が挙げられる。
【００１９】
【実施例】
以下、実施例により本発明を詳細に説明する。
【００２０】
実施例１
ＣａＯ原料、Ａｌ2Ｏ3原料、Ｆｅ2Ｏ3原料及びＣａＳＯ4原料を配合し、混合粉砕した後、電気炉を用いて、１３５０℃で３時間熱処理して表１に示すような組成のクリンカーを合成し、ボールミルでブレーン比表面積3500±300cm2/gに粉砕して、セメント混和材を調製した。セメント混和材を粉末Ｘ線回折法で同定したところ、遊離石灰、Ｃ4ＡＦ及び無水セッコウを含有していた。セメント混和材の化合物組成は、化学組成を基に計算により算出した。化学組成はJIS R 5201に準じて求めた。セメントと、セメント混和材からなるセメント組成物１００重量部中、セメント混和材を８重量部使用し、水／セメント組成物比＝５０％、セメント組成物／砂比＝１／３のモルタルを調製し、膨張率の測定を行った。尚、比較のため、遊離石灰、Ｃ4ＡＦ及び無水セッコウを別々に合成した後、混合粉砕し、実験No.1-4と同じ化合物組成となるように配合したセメント混和材についても、同様の実験を行った。その結果を表１に示す。
【００２１】
＜使用材料＞
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。
ＣａＳＯ4原料：試薬１級二水セッコウ。
遊離石灰：ＣａＯ原料を１３５０℃で３時間熱処理して合成。
Ｃ4ＡＦ：ＣａＯ原料４モル、Ａｌ2Ｏ3原料１モル及びＦｅ2Ｏ3原料１モルの割合で配合した原料を混合粉砕した後、１３５０℃で３時間熱処理して合成。
無水セッコウ：試薬１級の二水セッコウを１３５０℃で３時間焼成して得た無水セッコウ。
砂：JIS標準砂（ISO679準拠）。
＜測定方法＞
膨張率：JIS A 6202(B)に準じて測定。
【００２２】
【表１】
本発明のセメント混和材を配合したモルタルは、比較例の遊離石灰、Ｃ4ＡＦ及び無水セッコウを別々に合成し混合して調製したセメント混和材を配合したモルタルと比べ、優れた膨張性能を示した。
【００２４】
実施例２
ＣａＯ原料、Ａｌ2Ｏ3原料、Ｆｅ2Ｏ3原料、ＣａＳＯ4原料及びＳｉＯ2原料を配合し、混合粉砕した後、電気炉を用いて、１３５０℃で熱処理して表２に示すように珪酸率の異なる種々の組成のクリンカーを合成し、ボールミルでブレーン比表面積3500±300cm2/gに粉砕して、セメント混和材を調製したこと以外は、実施例１と同様に行った。その結果を表２に示す。
【００２５】
＜使用材料＞
ＳｉＯ2原料：試薬１級二酸化珪素。
【００２６】
【表２】
本発明のＳｉＯ2量５重量％以下、珪酸率０．５未満のセメント混和材を配合したモルタルは、何れも優れた膨張性能を示した。
【００２８】
実施例３
工業原料であるＣａＯ原料、Ａｌ2Ｏ3原料、Ｆｅ2Ｏ3原料及びＣａＳＯ4原料を配合し、ロータリーキルンを用いて、１４００℃で焼成して表３に示すような組成のクリンカーを合成し、ボールミルでブレーン比表面積3500±300cm2/gに粉砕してセメント混和材を調製したこと以外は、実施例１と同様に行った。化学組成を基に算出した化合物組成を表４に示す。比較のため、市販の膨張材についても膨張率の測定を行った。その結果を表５に示す。
【００２９】
＜使用材料＞
ＣａＯ原料：新潟県青海鉱山産石灰石。
Ａｌ2Ｏ3原料：中国産ボーキサイト。
Ｆｅ2Ｏ3原料：鉄粉。
ＣａＳＯ4原料：排煙脱硫二水セッコウ。
膨張材Ａ：市販カルシウムサルホアルミネート系膨張材、ブレーン比表面積2940cm2/g。
膨張材Ｂ：市販生石灰系膨張材、ブレーン比表面積3610cm2/g。
【００３０】
【表３】
【表４】
【表５】
本発明のセメント混和材を配合したモルタルは、市販のカルシウムサルホアルミネート系膨張材及び生石灰系膨張材を配合したモルタルと比べ、優れた膨張性能を示した。
【００３４】
実施例４
実験No.3-1のセメント混和材を使用し、セメントと、セメント混和材からなるセメント組成物１００重量部中のセメント混和材の配合量を変えたこと以外は、実施例１と同様に行った。その結果を表６に示す。
【００３５】
【表６】
本発明のセメント混和材を配合したモルタルは、本発明のセメント混和材を配合していないモルタルと比べ、優れた膨張性能を示した。
【００３７】
【発明の効果】
本発明のセメント混和材を使用することにより、優れた膨張性能を有するセメント組成物が得られる。[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]
[Prior art]
Reduction of cracks in cement and concrete and improvement of bending strength are the most important from the viewpoint of reliability, durability and aesthetics of concrete structures, and cement-based expansion materials have been developed to improve these. Further technical progress is desired. Examples of the cement-based expansion material include free lime-auin-anhydrous gypsum-based expansion material (Japanese Patent Publication No. 42-21840) and free lime-calcium silicate-anhydrous gypsum-based expansion material (Japanese Patent Publication No. 53-31170). It has been known.
[0003]
[Problems to be solved by the invention]
In recent years, high-fluidity concrete and high-strength concrete have been actively developed for the purpose of improving the performance of concrete, but it has been pointed out that the effects of cement-based expansive materials are not fully demonstrated in these high-performance concretes. However, there is a need for the development of an expandable material with excellent expansion performance that can impart large expandability even when the mixing ratio of the expandable material is small.
[0004]
Also, recently, the transition from the conventional specification-based design system to the performance-based design system has been studied, and there is a direction in which a clear performance rule is set for the durability of concrete, which has been neglected until now. It is in. That is, since it has been studied to quantify the effect on durability against cracks, reduction of cracks has become an even more important issue. Accordingly, a cement-based expansion material having an excellent expansion performance that has a small amount of use, a small economic burden, and is effective in reducing cracks is indispensable.
[0005]
As a result of various studies to solve these problems, the present inventors have obtained the knowledge that the above problems can be solved by using a specific cement admixture, and have completed the present invention. It was.
[0006]
[Means for Solving the Problems]
That is, 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, and a CaSO 4 raw material, and 30 to 60 parts by weight of 100 parts by weight of cement admixture is free. A cement admixture comprising lime, 10-40 parts by weight calcium aluminoferrite, and 10-40 parts by weight gypsum , wherein the silicic acid ratio is less than 0.5. There further cement, Ri cement composition der which comprises the said cement admixture, the said cement admixture is a cement composition 100 parts by weight, characterized in that it is a 3 to 12 parts by weight a cement composition, cement and, CaO material, Al 2 O 3 raw material, a material obtained by heat-treating the Fe 2 O 3 raw material and a CaSO 4 material, a cement admixture 100 wt Among the free lime 30-60 parts by weight and a cement composition comprising the cement admixture comprising the calcium alumino ferrite and 10-40 parts by weight of gypsum 10 to 40 parts by weight.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
[0008]
The cement admixture of the present invention contains free lime, calcium aluminoferrite and gypsum, and the ratio thereof is not particularly limited, but in 100 parts by weight of the cement admixture, free lime is 30 to 60 parts by weight, good preferable 40 to 50 parts by weight. Calcium aluminosilicate ferrite is 10 to 40 parts by weight, good preferable 15 to 35 parts by weight. Further, gypsum is 10 to 40 parts by weight, 20 to 35 parts by weight good preferable. If the composition ratio of each compound in the cement admixture is out of the above range, an excellent expansion performance may not be obtained.
[0009]
The calcium aluminoferrite of the present invention is a generic term for CaO—Al 2 O 3 —Fe 2 O 3 compounds, and is not particularly limited, but CaO is C, Al 2 O 3 is A, Fe When 2 O 3 is abbreviated as F, compounds such as C 4 AF and C 6 A 2 F can be used. It is considered that C 4 AF usually exists, and in the present invention, calcium aluminoferrite is hereinafter referred to as C 4 AF.
[0010]
The cement admixture of the present invention heats CaO raw material, Al 2 O 3 raw material, Fe 2 O 3 raw material and CaSO 4 raw material, synthesizes clinker composed of free lime, C 4 AF and anhydrous gypsum and pulverizes it. Manufactured. In the case where free lime, C 4 AF and anhydrous gypsum are synthesized separately and mixed, the effect as in the present invention cannot be obtained.
Whether the clinker composed of free lime, C 4 AF and anhydrous gypsum was synthesized by heat-treating the CaO raw material, the Al 2 O 3 raw material, the Fe 2 O 3 raw material and the CaSO 4 raw material is, for example, 100 μm or more in the pulverized product These coarse particles can be discriminated by microscopic observation and confirming that free lime, C 4 AF and anhydrous gypsum are mixed in the particles.
[0011]
Although it is the heat processing temperature at the time of manufacturing the cement admixture of this invention, the range of 1100-1600 degreeC is preferable, and the range of 1200-1500 degreeC is more preferable. If it is less than 1100 degreeC, the expansion performance of the obtained cement admixture is not enough, and when it exceeds 1600 degreeC, anhydrous gypsum may decompose | disassemble.
[0012]
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 CaSO 4 raw material include dihydrate gypsum, half water gypsum, and anhydrous gypsum. Various impurities are present in these raw materials, and specific examples thereof include SiO 2 , MgO, TiO 2 , P 2 O 5 , Na 2 O, K 2 O, and the like. However, in particular, SiO 2 is preferably in a range of less than 0.5 in terms of silicic acid. When the silicic acid ratio is 0.5 or more, an excellent expansion performance may not be obtained. The silicic acid rate as used in the present invention is calculated from the following formula from the amount of SiO 2, the amount of Al 2 O 3 and the amount of Fe 2 O 3 in the cement admixture.
Silicic acid ratio = SiO 2 / (Al 2 O 3 + Fe 2 O 3 )
[0013]
The amount of SiO 2 in the cement admixture of the present invention is preferably 5.0% by weight or less, more preferably 3.0% by weight or less. If it exceeds 5.0% by weight, an excellent expansion performance may not be obtained.
[0014]
The particle size of the cement admixture of the present invention is not particularly limited, but is usually preferably 1500 to 9000 cm 2 / g, more preferably 2500 to 4000 cm 2 / g in terms of Blaine specific surface area. If the particle size of the cement admixture is less than 1500 cm 2 / g in terms of Blaine specific surface area, long-term durability may be deteriorated, and if it exceeds 9000 cm 2 / g, sufficient expansion performance may not be obtained.
[0015]
The blending amount of the cement admixture of the present invention is not particularly limited, but usually 3 to 12 parts by weight, preferably 5 to 9 parts by weight, in 100 parts by weight of cement composition composed of cement and cement admixture. Is more preferable. If the amount is less than 3 parts by weight, sufficient expansion performance may not be obtained. If the amount exceeds 12 parts by weight, long-term durability may be deteriorated.
[0016]
As the cement of the present invention, various cements such as ordinary cement, early strength, very early strength, low heat and moderate heat, mixed cement obtained by mixing blast furnace slag, fly ash and silica with these cements, and limestone powder, etc. There are mixed filler cements.
[0017]
In the present invention, the cement admixture and the cement composition of the present invention are added to aggregates such as sand and gravel, water reducing agent, high performance water reducing agent, AE water reducing agent, high performance AE water reducing agent, fluidizing agent, antifoaming agent. Agents, thickeners, rust inhibitors, antifreeze agents, shrinkage reducers, polymer emulsions and setting modifiers, cement rapid hardening materials, clay minerals such as bentonite, and anion exchangers such as hydrotalcite Alternatively, two or more kinds can be used as long as the object of the present invention is not substantially inhibited.
[0018]
In this invention, the mixing method of each material is not specifically limited, Each material may be mixed at the time of construction, and the part or all may be mixed beforehand. 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 nauter mixer.
[0019]
【Example】
Hereinafter, the present invention will be described in detail by way of examples.
[0020]
Example 1
After mixing CaO raw material, Al 2 O 3 raw material, Fe 2 O 3 raw material and CaSO 4 raw material, mixing and grinding, using an electric furnace, heat treatment at 1350 ° C. for 3 hours, clinker having the composition as shown in Table 1 Was synthesized by a ball mill to a Blaine specific surface area of 3500 ± 300 cm 2 / g to prepare a cement admixture. When the cement admixture was identified by powder X-ray diffraction, it contained free lime, C 4 AF and anhydrous gypsum. The compound composition of the cement admixture was calculated by calculation based on the chemical composition. The chemical composition was determined according to JIS R 5201. Using 100 parts by weight of cement and cement admixture, 8 parts by weight of cement admixture was used to prepare a mortar with a water / cement composition ratio = 50% and a cement composition / sand ratio = 1/3. The expansion coefficient was measured. For comparison, free lime, C 4 AF and anhydrous gypsum were synthesized separately, mixed and pulverized, and the same was applied to the cement admixture compounded to have the same compound composition as Experiment No. 1-4. The experiment was conducted. The results are shown in Table 1.
[0021]
<Materials used>
CaO raw material: Reagent primary calcium carbonate.
Al 2 O 3 raw material: Reagent primary aluminum oxide.
Fe 2 O 3 raw material: Reagent primary iron oxide.
CaSO 4 raw material: Reagent grade 1 dihydrate gypsum.
Free lime: synthesized by heat treatment of CaO raw material at 1350 ° C. for 3 hours.
C 4 AF: raw material blended at a ratio of 4 moles of CaO raw material, 1 mole of Al 2 O 3 raw material and 1 mole of Fe 2 O 3 raw material, mixed and pulverized, and then heat treated at 1350 ° C. for 3 hours for synthesis.
Anhydrous gypsum: An anhydrous gypsum obtained by calcining reagent grade 1 dihydrate gypsum at 1350 ° C. for 3 hours.
Sand: JIS standard sand (ISO679 compliant).
<Measurement method>
Expansion coefficient: Measured according to JIS A 6202 (B).
[0022]
[Table 1]
The mortar blended with the cement admixture of the present invention exhibits superior expansion performance compared to the mortar blended with the cement admixture prepared by separately synthesizing and mixing the free lime, C 4 AF and anhydrous gypsum of the comparative example. It was.
[0024]
Example 2
After mixing CaO raw material, Al 2 O 3 raw material, Fe 2 O 3 raw material, CaSO 4 raw material and SiO 2 raw material, mixing and grinding, using an electric furnace, heat treatment at 1350 ° C. and silicic acid as shown in Table 2 The same procedure as in Example 1 was carried out except that clinker of various compositions with different rates were synthesized and ground with a ball mill to a Blaine specific surface area of 3500 ± 300 cm 2 / g to prepare a cement admixture. The results are shown in Table 2.
[0025]
<Materials used>
SiO 2 raw material: reagent grade 1 silicon dioxide.
[0026]
[Table 2]
Mortars containing a cement admixture with an SiO 2 content of 5% by weight or less and a silicic acid ratio of less than 0.5 of the present invention all exhibited excellent expansion performance.
[0028]
Example 3
Combining industrial raw materials such as CaO raw material, Al 2 O 3 raw material, Fe 2 O 3 raw material and CaSO 4 raw material, using a rotary kiln, firing at 1400 ° C. to synthesize clinker having the composition shown in Table 3, The same procedure as in Example 1 was carried out except that a cement admixture was prepared by pulverizing to a Blaine specific surface area of 3500 ± 300 cm 2 / g with a ball mill. Table 4 shows the compound composition calculated based on the chemical composition. For comparison, the expansion coefficient was also measured for a commercially available expansion material. The results are shown in Table 5.
[0029]
<Materials used>
CaO raw material: Limestone from Aomi mine, Niigata Prefecture.
Al 2 O 3 raw material: Chinese bauxite.
Fe 2 O 3 raw material: iron powder.
CaSO 4 raw material: flue gas desulfurization dihydrate gypsum.
Expansion material A: Commercial calcium sulfoaluminate-based expansion material, Blaine specific surface area 2940 cm 2 / g.
Expandable material B: Commercial quicklime-based expanded material, Blaine specific surface area 3610 cm 2 / g.
[0030]
[Table 3]
[Table 4]
[Table 5]
The mortar blended with the cement admixture of the present invention showed excellent expansion performance as compared with a mortar blended with a commercially available calcium sulfoaluminate-based expansion material and quicklime-based expansion material.
[0034]
Example 4
The same procedure as in Example 1 was conducted except that the cement admixture of Experiment No. 3-1 was used and the blending amount of the cement and the cement admixture in 100 parts by weight of the cement composition composed of the cement admixture was changed. It was. The results are shown in Table 6.
[0035]
[Table 6]
The mortar blended with the cement admixture of the present invention showed excellent expansion performance compared to the mortar not blended with the cement admixture of the present invention.
[0037]
【The invention's effect】
By using the cement admixture of the present invention, a cement composition having excellent expansion performance can be obtained.
Claims (5)
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| JP4567211B2 (en) * | 2001-01-29 | 2010-10-20 | 電気化学工業株式会社 | Expandable material and cement composition |
| JP4606631B2 (en) * | 2001-03-29 | 2011-01-05 | 電気化学工業株式会社 | Cement admixture and cement composition |
| JP4606632B2 (en) * | 2001-03-29 | 2011-01-05 | 電気化学工業株式会社 | Cement admixture and cement composition |
| JP4937465B2 (en) * | 2001-05-31 | 2012-05-23 | 電気化学工業株式会社 | Cement admixture and cement composition |
| JP4937468B2 (en) * | 2001-06-26 | 2012-05-23 | 電気化学工業株式会社 | Cement admixture and cement composition |
| JP5116193B2 (en) * | 2001-08-30 | 2013-01-09 | 電気化学工業株式会社 | Cement admixture, cement composition, and high fluid concrete using the same |
| JP2003095720A (en) * | 2001-09-27 | 2003-04-03 | Denki Kagaku Kogyo Kk | Cement admixture, and cement composition |
| JP5876836B2 (en) | 2010-12-08 | 2016-03-02 | デンカ株式会社 | Cement admixture, cement composition, and hexavalent chromium reduction method using the same |
| JP6509586B2 (en) * | 2015-03-03 | 2019-05-08 | デンカ株式会社 | Salt damage control admixture and reinforced concrete salt damage control method |
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