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JP4937465B2 - Cement admixture and cement composition - Google Patents

Cement admixture and cement composition Download PDF

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Publication number
JP4937465B2
JP4937465B2 JP2001163732A JP2001163732A JP4937465B2 JP 4937465 B2 JP4937465 B2 JP 4937465B2 JP 2001163732 A JP2001163732 A JP 2001163732A JP 2001163732 A JP2001163732 A JP 2001163732A JP 4937465 B2 JP4937465 B2 JP 4937465B2
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JP
Japan
Prior art keywords
parts
cement
expansion
anhydrous gypsum
reducing agent
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JP2001163732A
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Japanese (ja)
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JP2002356355A (en
Inventor
寛之 大橋
実 盛岡
康宏 中島
隆行 樋口
光男 高橋
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Denka Co Ltd
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Denki Kagaku Kogyo KK
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Classifications

    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B20/00Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
    • C04B20/02Treatment
    • C04B20/04Heat treatment
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B22/00Use of inorganic materials as active ingredients for mortars, concrete or artificial stone, e.g. accelerators, shrinkage compensating agents
    • C04B22/008Cement and like inorganic materials added as expanding or shrinkage compensating ingredients in mortar or concrete compositions, the expansion being the result of a recrystallisation
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B40/00Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
    • C04B40/0028Aspects relating to the mixing step of the mortar preparation
    • C04B40/0039Premixtures of ingredients
    • C04B40/0042Powdery mixtures

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (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・建築業界において使用されるセメント混和剤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、美観等の観点から重要であり、これらを改善する効果のあるセメント混和材、すなわち、セメント系膨張材の更なる技術の進展が望まれている。従来より、セメント・コンクリートに膨張性を与えるセメント混和材としては、例えば、遊離石灰−アウイン−無水セッコウ系膨張材(特公昭42−21840号公報)や、遊離石灰−カルシウムシリケート−無水セッコウ系膨張材(特公昭53−31170号公報)等があった。
一方、近年ではコンクリートの高性能化を目的として、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。
ここでコンクリートとは、セメント、モルタル及びコンクリートを総称するものである。
【0003】
【発明が解決しようとする課題】
しかしながら、これらの高性能なコンクリートでは、膨張材の効果が十分に発揮されないことが指摘されている。現在では膨張材の混和率が低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のが実状である。
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移行が検討されており、これまでやや軽視されていた耐久性についても明確な性能規定が定められるものと考えられる。すなわち、ひび割れの耐久性に対する影響の定量化がなされるため、ひび割れの低減は重要な課題となるが、ひび割れ低減に効果のあるセメント系膨張材を広範に利用するためには、使用量を少なくして経済的負担を小さくすることが不可欠である。
一方、前記の膨張材は粉体であり、これを使用する際には、生コンプラントに荷揚げし、解袋投入作業を行わなければならない。この作業はいわゆる3K(きつい、汚い、危険)作業であり、作業員の高齢化や人手不足が進む時代の流れにあって、深刻な問題となっているのが現状である。膨張材がスラリー化できれば、生コンプラントに既に設置してある計量設備を利用できるので、3K作業は大幅に軽減できる。これまでにセメント混和材を水でスラリー化する試みもなされてきたが、セメント混和材は水硬性物質であり、長い時間練り置いておくことができない。そのため、現場で撹拌装置を準備しなければならないデメリットや、出荷トラブルが発生した場合には調製したスラリーを廃棄しなければならないなどの大きな問題を有していた。
また、膨張材は初期材齢で膨張ひずみを付与して収縮を補償する性質を有するが、その後の乾燥収縮挙動は、膨張材を混和しないものとあまり変わらないという問題もあった。
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、特定の膨張材を収縮低減剤でスラリー化することにより、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。
【0004】
【課題を解決するための手段】
すなわち、本発明は、CaO原料とCaSO4原料を含む配合物を熱処理して生成する遊離石灰と無水セッコウを有効成分とする鉱物からなり、かつ、該鉱物中の成分割合は、無水セッコウが、遊離石灰と無水セッコウの合計100部中10〜50部である膨張材と、収縮低減剤を含有してなり、膨張材と収縮低減剤の合計100部中、膨張材が50〜80部、収縮低減剤が20〜50部である、スラリー化したセメント混和剤であり、さらに、セメントと、該セメント混和剤とを含有してなるセメント組成物である。また、CaO原料とCaSO 4 原料を含む配合物を熱処理して生成する遊離石灰と無水セッコウを有効成分とする鉱物からなり、無水セッコウが遊離石灰と無水セッコウの合計100部中10〜50部である膨張材と、収縮低減剤とを、膨張材と収縮低減剤の合計100部中、膨張材が50〜80部、収縮低減剤が20〜50部となるように配合してスラリー化することを特徴とするセメント混和剤の製造方法である。
なお、本発明で使用する配合割合や添加量を表す部、%は、質量単位である。
【0005】
【発明の実施の形態】
以下、本発明をさらに詳細に説明する。
本発明の膨張材は、CaO原料とCaSO4原料を含む配合物を熱処理して生成する遊離石灰と無水セッコウを有効成分とする鉱物からなり、かつ、該鉱物中の割合は、無水セッコウが遊離石灰と無水セッコウの合計100部中10〜50部である。本発明の膨張材のCaO原料とCaSO4原料との配合割合は、生成物である遊離石灰と無水セッコウの合計100部中、無水セッコウが10〜50部となるように配合することが好ましく、20〜40部となるように配合することがより好ましい。無水セッコウが10部未満では、例えば、材齢1日までに急激な膨張性を示し、その膨張材を用いたセメント硬化体にクラックが発生したり、強度発現性が低下する場合があり、無水セッコウが50部を超える量では、膨張性能が低下する傾向がある。
【0006】
本発明の膨張材を製造する際、CaO原料とCaSO4原料を含む配合物を熱処理して、遊離石灰と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することが望ましい。また、遊離石灰と無水セッコウを別々に合成し、それらを混合することによっても本発明の膨張材と同じ組成のものを合成することが可能であるが、本発明の効果、すなわち、優れた膨張性能が得られる観点から、CaO原料とCaSO4原料を含む配合物を熱処理して、遊離石灰、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することが好ましい。
【0007】
CaO原料とCaSO4原料を配合したものを熱処理して、遊離石灰と無水セッコウとからなるクリンカーを合成し、これを粉砕して製造されたものか否かを確認する方法としては、例えば、膨張材の粗粒子、具体的には100μmよりも大きな粒子を顕微鏡等により観察して組成分析を行い、粒子中に遊離石灰と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容易に判別できる。
【0008】
本発明の膨張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はなく、1600℃を超えると無水セッコウが分解する場合がある。
原料の混合方法は特に限定されるものではなく、通常の方法が可能である。
膨張材を製造する熱処理方法としては、特に限定されるものではなく、ロータリーキルンや電気炉等を使用することによって行うことができる。
【0009】
CaO原料としては、石灰石や消石灰等が挙げられ、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。原料中に存在する、SiO2、Fe23、CaF2、MgO、TiO2等の不純物は、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。
【0010】
本発明の膨張材の粒度は、特に限定されるものではないが、通常、ブレーン比表面積で1500〜9000cm2/gが好ましく、2500〜4000cm2/gがより好ましい。膨張材の粒度が1500cm2/g未満では、長期耐久性が悪くなる場合があり、9000cm2/gを超えると十分な膨張性能が得られない場合がある。
【0011】
本発明の膨張材の使用量は、特に限定されるものではないが、通常、セメントと膨張材からなるセメント組成物100部中、3〜12部が好ましく、5〜9部がより好ましい。3部未満では十分な膨張性能が得られない場合があり、12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。
【0012】
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、並びに石灰石微粉末等を混合したフィラーセメント等がある。
【0013】
本発明に係る収縮低減剤とは、特に限定されるものではなく、いかなるものでも使用可能である。主成分で大別すると、低級アルコールアルキレンオキシド付加物、アルコール系、グリコールエーテル・アミノアルコール誘導体系、ポリエーテル系、低分子量アルキレンオキシド共重合体系等が挙げられる。
収縮低減剤は各社より市販されており、その代表例としては、例えば、電気化学工業社製「エスケーガード」、エフ・ピー・ケー社製「ヒビガード」、竹本油脂社製「ヒビタン」、太平洋セメント社製「テトラガード」等が挙げられる。
【0014】
本発明のセメント混和剤中の膨張材と収縮低減剤の配合割合は、特に限定されるものではないが、通常、膨張材と収縮低減剤の合計100部中、膨張材は50〜80部が好ましく、60〜75部がより好ましい。また、収縮低減剤は20〜50部が好ましく、25〜40部がより好ましい。収縮低減剤が50部を超えたり、膨張材が50部未満であると、材料分離が生じてセメント混和剤が不均一になる恐れがある。収縮低減剤が20部未満であったり、膨張材が80部を超えると、セメント混和剤の粘性が強くなり取り扱いが困難になる恐れがある。
【0015】
本発明のセメント混和剤及びセメント組成物は、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、高分子エマルジョン及び凝結促進剤、凝結遅延剤、並びにセメント急硬剤、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、ホウ酸及びその塩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。
【0016】
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、ある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、既存のいかなる装置も使用可能であり、例えば、傾胴ミキサ、オムニミキサ、ヘンシェルミキサ、V型ミキサ及びナウタミキサ等が挙げられる。
【0017】
【実施例】
以下、実施例により本発明を詳細に説明する。
【0018】
実施例1
CaO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、ボールミルを用いて、ブレーン比表面積3300±200cm2/gに粉砕して膨張材を製造した。膨張材の化合物組成は、化学組成を基に計算により算出した。
化学組成はJIS R 5202に準じて求めた。
表1に示す膨張材75部と、収縮低減剤A25部とを混練してセメント混和剤を調製した。調製したセメント混和剤を撹拌しながら1時間練り置いた後、セメントと膨張材からなるセメント組成物100部に対して、膨張材が6部となるようにセメント混和剤を使用し、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て、長さ変化率の測定を行った。
なお、比較のため市販の膨張材を用いた場合についても同様の実験を行った。
また、収縮低減剤は水の一部とみなし、混練水量を調整した。結果を表1に併記する。
【0019】
<使用材料>
CaO原料:試薬1級、炭酸カルシウム
CaSO4原料:試薬1級、二水セッコウ
収縮低減剤A:電気化学工業社製「エスケーガード」、低分子量アルキレンオキシド共重合体系
砂:JIS標準砂(ISO679準拠)
市販品イ:市販のカルシウムサルホアルミネート系膨張材、無水セッコウ含有量40%、ブレーン比表面積2940cm2/g
市販品ロ:市販の石灰系膨張材、無水セッコウ含有量35%、ブレーン比表面積3890cm2/g
【0020】
<測定方法>
長さ変化率:JIS A 6202に準じて測定。
【0021】
【表1】

Figure 0004937465
【0022】
表1より、本発明のセメント混和剤である膨張材と収縮低減剤を混練しスラリー化して練り置いても、モルタルは優れた膨張性能を示し、収縮率が少ないことが判る。
【0023】
実施例2
実施例1の膨張材Eを使用し、収縮低減剤の種類と使用量を表2に示すように変えたこと以外は、実施例1と同様に行った。
なお、比較のため、収縮低減剤の代わりに水を用いた場合と、市販の膨張材イを用いた場合についても同様の実験を行った。結果を表2に併記する。
【0024】
<使用材料>
収縮低減剤B:エフ・ピー・ケー社製「ヒビガード」、グリコールエーテル・アミノアルコール誘導体系
収縮低減剤C:太平洋セメント社製「テトラガード」、低級アルコールのアルキレンオキシド付加物系
水:水道水
【0025】
【表2】
Figure 0004937465
【0026】
表2より、本発明のセメント混和剤である膨張材と収縮低減剤を混練りしスラリー化し練り置いても、モルタルは優れた膨張性能を示し、収縮率が少ないことが判る。
【0027】
【発明の効果】
本発明のセメント混和剤である膨張材と収縮低減剤を混練りしスラリー化し練り置いても、優れた膨張性能と収縮低減効果を奏するセメント組成物が得られる。また、スラリー化することによって、解袋作業等の3K作業を大幅に低減することが出きる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cement admixture and a cement composition mainly used in the civil engineering and construction industries.
[0002]
[Prior art]
Reducing cracks and improving bending strength of cement and concrete are important from the viewpoint of reliability, durability, aesthetics, etc. of concrete structures, and cement admixtures that have the effect of improving these, i.e., cement-based expansion materials. Further technical progress is desired. Conventionally, as cement admixtures that give expansibility to cement and concrete, for example, free lime-auin-anhydrous gypsum-based expansive material (Japanese Patent Publication No. 42-21840) or free lime-calcium silicate-anhydrous gypsum-based expansion There were materials (Japanese Patent Publication No. 53-31170).
On the other hand, in recent years, development of high-fluidity concrete and high-strength concrete has been actively conducted for the purpose of improving the performance of concrete.
Here, concrete is a general term for cement, mortar, and concrete.
[0003]
[Problems to be solved by the invention]
However, it has been pointed out that these high-performance concretes do not sufficiently exert the effect of the expansion material. At present, the development of an expandable material excellent in expansion performance that can impart a large expansibility even when the admixture of the expandable material is low is awaited.
Recently, a shift from a conventional specification-defining design system to a performance-defining design system has been studied, and it is considered that a clear performance rule is set for durability that has been neglected until now. In other words, the effect of cracking on durability is quantified, so reducing cracking is an important issue, but in order to use cement-based expansion materials that are effective in reducing cracking, the amount used is small. Therefore, it is essential to reduce the economic burden.
On the other hand, the expansion material is a powder, and when it is used, it must be unloaded into a raw plant and unpacked. This work is a so-called 3K (tight, dirty, dangerous) work, and it is a serious problem in the era of the aging of workers and the shortage of manpower. If the expansion material can be made into a slurry, 3K work can be greatly reduced because the weighing equipment already installed in the raw plant can be used. Attempts have been made to slurry the cement admixture with water, but the cement admixture is a hydraulic substance and cannot be kneaded for a long time. For this reason, there have been major problems such as a demerit that a stirrer must be prepared in the field and a slurry that has been prepared must be discarded when a shipping trouble occurs.
In addition, the expandable material has a property of compensating for shrinkage by applying an expansion strain at the initial age, but there is also a problem that the subsequent drying shrinkage behavior is not much different from that in which the expandable material is not mixed.
As a result of various studies to solve these problems, the present inventors obtained knowledge that the above problems can be solved by slurrying a specific expansion material with a shrinkage reducing agent. It came to be completed.
[0004]
[Means for Solving the Problems]
That is, the present invention consists of a mineral containing free lime and anhydrous gypsum produced by heat-treating a blend containing a CaO raw material and a CaSO 4 raw material, and the component ratio in the mineral is anhydrous gypsum, an expansion member is a total 10 to 50 parts in 100 parts of free lime and anhydrous gypsum, Ri Na contain shrinkage reducing agent, in a total of 100 parts of expandable material and the shrinkage reducing agent, the expansion material is 50 to 80 parts, shrinkage reducing agent is 20 to 50 parts of a slurried cement admixture, in the et, a cement and cement composition containing the said cement admixture. Further, it consists minerals and CaO feed with CaSO 4 active ingredients free lime and anhydrous gypsum to produce by heat-treating formulation containing raw materials, in total 100 parts in 10 to 50 parts of anhydrous gypsum free lime and anhydrous gypsum A certain expansion material and a shrinkage reducing agent are mixed and slurried in a total of 100 parts of the expansion material and the shrinkage reduction agent so that the expansion material is 50 to 80 parts and the shrinkage reduction agent is 20 to 50 parts. A method for producing a cement admixture characterized by the following.
In addition, the part and% showing the mixture ratio and addition amount used by this invention are mass units.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
The expansion material of the present invention is composed of a mineral containing free lime and anhydrous gypsum produced by heat-treating a composition containing a CaO raw material and a CaSO 4 raw material, and the proportion of the mineral is free from anhydrous gypsum. It is 10-50 parts in a total of 100 parts of lime and anhydrous gypsum. The blending ratio of the CaO raw material and the CaSO 4 raw material of the expansion material of the present invention is preferably such that the anhydrous gypsum is 10 to 50 parts in a total of 100 parts of the product free lime and anhydrous gypsum, It is more preferable to blend so as to be 20 to 40 parts. If the anhydrous gypsum is less than 10 parts, for example, it shows rapid expansibility by the age of one day, cracks may occur in the hardened cement body using the expansive material, and strength development may be reduced. If the amount of gypsum exceeds 50 parts, the expansion performance tends to decrease.
[0006]
When producing the expandable material of the present invention, it is desirable to heat a blend containing a CaO raw material and a CaSO 4 raw material, synthesize a clinker composed of free lime and anhydrous gypsum and pulverize it. Also, it is possible to synthesize free lime and anhydrous gypsum separately and mix them together to synthesize the same composition as the expansion material of the present invention, but the effect of the present invention, that is, excellent expansion From the viewpoint of obtaining performance, it is preferable to produce a clinker composed of free lime and anhydrous gypsum by heat-treating a mixture containing a CaO raw material and a CaSO 4 raw material, and pulverizing it.
[0007]
As a method for confirming whether or not a clinker composed of free lime and anhydrous gypsum is synthesized by heat-treating a mixture of a CaO raw material and a CaSO 4 raw material, for example, expansion Coarse particles of the material, specifically, particles larger than 100 μm are observed with a microscope or the like, and composition analysis is performed, and it can be easily discriminated by confirming that free lime and anhydrous gypsum are mixed in the particles.
[0008]
Although it is the heat processing temperature at the time of manufacturing the expansion | swelling material 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, an anhydrous gypsum may decompose | disassemble.
The mixing method of the raw materials is not particularly limited, and a normal method is possible.
It does not specifically limit as the heat processing method which manufactures an expandable material, It can carry out by using a rotary kiln, an electric furnace, etc.
[0009]
Examples of the CaO raw material include limestone and slaked lime, and examples of the CaSO 4 raw material include dihydrate gypsum, half water gypsum, and anhydrous gypsum. Impurities such as SiO 2 , Fe 2 O 3 , CaF 2 , MgO, and TiO 2 present in the raw material are not particularly problematic as long as the object of the present invention is not substantially inhibited.
[0010]
Although the particle size of the expansion material of the present invention is not particularly limited, it is usually preferably from 1500 to 9000 cm 2 / g, more preferably from 2500 to 4000 cm 2 / g in terms of the specific surface area of branes. If the particle size of the expansion material is less than 1500 cm 2 / g, the long-term durability may deteriorate, and if it exceeds 9000 cm 2 / g, sufficient expansion performance may not be obtained.
[0011]
Although the usage-amount of the expandable material of this invention is not specifically limited, Usually, 3-12 parts are preferable in a cement composition which consists of a cement and an expandable material, and 5-9 parts are more preferable. If it is less than 3 parts, sufficient expansion performance may not be obtained, and if it exceeds 12 parts, long-term durability may be deteriorated.
[0012]
As the cement of the present invention, various cements such as ordinary cement, early strength, very early strength, low heat and moderate heat, mixed blast furnace slag, fly ash and silica mixed with these cements, limestone fine powder, etc. There are mixed filler cements.
[0013]
The shrinkage reducing agent according to the present invention is not particularly limited, and any one can be used. The main components are roughly classified into lower alcohol alkylene oxide adducts, alcohols, glycol ether / amino alcohol derivative systems, polyether systems, low molecular weight alkylene oxide copolymer systems, and the like.
Shrinkage reducing agents are commercially available from various companies, and representative examples thereof include, for example, “ESK GUARD” manufactured by Denki Kagaku Kogyo Co., Ltd., “HIBIGUARD” manufactured by FPK Co., Ltd. “Tetragard” manufactured by the company is listed.
[0014]
The blending ratio of the expansion material and the shrinkage reducing agent in the cement admixture of the present invention is not particularly limited, but usually the expansion material is 50 to 80 parts in a total of 100 parts of the expansion material and the shrinkage reducing agent. Preferably, 60 to 75 parts are more preferable. The shrinkage reducing agent is preferably 20 to 50 parts, more preferably 25 to 40 parts. If the shrinkage-reducing agent exceeds 50 parts or the expansion material is less than 50 parts, material separation may occur and the cement admixture may become non-uniform. If the shrinkage reducing agent is less than 20 parts or the expansion material exceeds 80 parts, the cement admixture becomes so viscous that it may be difficult to handle.
[0015]
The cement admixture and cement composition of the present invention are composed of 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, thickening agent. Agents, rust inhibitors, antifreeze agents, polymer emulsions and setting accelerators, setting retarders, cement hardeners, clay minerals such as bentonite and anion exchangers such as hydrotalcite, boric acid and its salts, etc. It is possible to use 1 type (s) or 2 or more types in the range which does not inhibit substantially the objective of this invention.
[0016]
In the present invention, the mixing method of each material is not particularly limited, and the respective materials may be mixed at the time of construction, or a part or all of them may be mixed in advance. Any existing apparatus can be used as the mixing apparatus, and examples thereof include a tilting cylinder mixer, an omni mixer, a Henschel mixer, a V-type mixer, and a Nauta mixer.
[0017]
【Example】
Hereinafter, the present invention will be described in detail by way of examples.
[0018]
Example 1
The CaO raw material and the CaSO 4 raw material were blended, mixed and pulverized, then heat-treated at 1350 ° C. for 3 hours using an electric furnace to synthesize clinker having the composition shown in Table 1, and using a ball mill, the specific surface area of Blaine The expanded material was produced by grinding to 3300 ± 200 cm 2 / g. The compound composition of the expansion material was calculated by calculation based on the chemical composition.
The chemical composition was determined according to JIS R 5202.
A cement admixture was prepared by kneading 75 parts of the expansion material shown in Table 1 and 25 parts of the shrinkage reducing agent A. The prepared cement admixture is kneaded for 1 hour with stirring, and then the cement admixture is used so that the expansive material is 6 parts with respect to 100 parts of the cement composition comprising the cement and the expansive material. A mortar having a composition ratio = 50% and a cement composition / sand ratio = 1/3 was prepared, and the length change rate was measured.
For comparison, the same experiment was performed when a commercially available expansion material was used.
Further, the shrinkage reducing agent was regarded as a part of water, and the amount of kneading water was adjusted. The results are also shown in Table 1.
[0019]
<Materials used>
CaO raw material: reagent 1 grade, calcium carbonate CaSO 4 raw material: reagent 1 grade, dihydrate gypsum shrinkage reducing agent A: “SK guard” manufactured by Denki Kagaku Kogyo Co., Ltd., low molecular weight alkylene oxide copolymer system sand: JIS standard sand (ISO 679 compliant) )
Commercial product i: Commercial calcium sulfoaluminate-based expansion material, anhydrous gypsum content 40%, Blaine specific surface area 2940 cm 2 / g
Commercially available product B: Commercially available lime-based expansive material, anhydrous gypsum content 35%, Blaine specific surface area 3890 cm 2 / g
[0020]
<Measurement method>
Length change rate: Measured according to JIS A 6202.
[0021]
[Table 1]
Figure 0004937465
[0022]
From Table 1, it can be seen that the mortar exhibits excellent expansion performance and has a low shrinkage rate even when the expansion agent, which is the cement admixture of the present invention, and the shrinkage reducing agent are kneaded and slurried.
[0023]
Example 2
The same procedure as in Example 1 was performed except that the expansion material E of Example 1 was used and the type and amount of shrinkage reducing agent were changed as shown in Table 2.
For comparison, the same experiment was conducted for the case where water was used instead of the shrinkage reducing agent and for the case where a commercially available expansion material A was used. The results are also shown in Table 2.
[0024]
<Materials used>
Shrinkage reducing agent B: “HIBIGUARD” manufactured by FPK Corporation, glycol ether / amino alcohol derivative-based shrinkage reducing agent C: “Tetragard” manufactured by Taiheiyo Cement Co., Ltd., alkylene oxide adduct water of lower alcohol: tap water [0025]
[Table 2]
Figure 0004937465
[0026]
From Table 2, it can be seen that the mortar exhibits an excellent expansion performance and has a small shrinkage rate even when the expansion material which is the cement admixture of the present invention and the shrinkage reducing agent are kneaded and slurried.
[0027]
【Effect of the invention】
Even if the expansion material which is the cement admixture of the present invention and the shrinkage reducing agent are kneaded and slurried and kneaded, a cement composition having excellent expansion performance and shrinkage reduction effect can be obtained. In addition, by slurrying, 3K work such as unpacking work can be greatly reduced.

Claims (3)

CaO原料とCaSO4原料を含む配合物を熱処理して生成する遊離石灰と無水セッコウを有効成分とする鉱物からなり、無水セッコウが遊離石灰と無水セッコウの合計100部中10〜50部である膨張材と、収縮低減剤を含有してなり、膨張材と収縮低減剤の合計100部中、膨張材が50〜80部、収縮低減剤が20〜50部である、スラリー化したセメント混和剤。An expansion comprising 10 to 50 parts of a total of 100 parts of free lime and anhydrous gypsum, comprising free lime and anhydrous gypsum produced by heat-treating a blend containing CaO raw material and CaSO 4 raw material. and wood, Ri Na contain shrinkage reducing agents, expanding material and in total 100 parts of the shrinkage reducing agent, 50 to 80 parts of the expansion member, shrinkage reducing agent is 20 to 50 parts, slurried cement admixture . セメントと、請求項1に記載のセメント混和剤とを含有してなるセメント組成物。A cement composition comprising cement and the cement admixture according to claim 1 . CaO原料とCaSOCaO raw materials and CaSO 4Four 原料を含む配合物を熱処理して生成する遊離石灰と無水セッコウを有効成分とする鉱物からなり、無水セッコウが遊離石灰と無水セッコウの合計100部中10〜50部である膨張材と、収縮低減剤とを、膨張材と収縮低減剤の合計100部中、膨張材が50〜80部、収縮低減剤が20〜50部となるように配合してスラリー化することを特徴とするセメント混和剤の製造方法。It consists of minerals containing free lime and anhydrous gypsum produced by heat-treating a blend containing raw materials as active ingredients, and the expanded gypsum is 10-50 parts in total of 100 parts of free lime and anhydrous gypsum, and shrinkage reduction Cement admixture characterized in that the additive is blended into a slurry so that the expansion material is 50 to 80 parts and the shrinkage reduction agent is 20 to 50 parts in a total of 100 parts of the expansion material and the shrinkage reduction agent Manufacturing method.
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