JPH11147746A - Cement composition having reduced slump loss - Google Patents

Cement composition having reduced slump loss

Info

Publication number
JPH11147746A
JPH11147746A JP9310381A JP31038197A JPH11147746A JP H11147746 A JPH11147746 A JP H11147746A JP 9310381 A JP9310381 A JP 9310381A JP 31038197 A JP31038197 A JP 31038197A JP H11147746 A JPH11147746 A JP H11147746A
Authority
JP
Japan
Prior art keywords
gypsum
anhydrous gypsum
cement
soluble
hemihydrate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP9310381A
Other languages
Japanese (ja)
Inventor
Ryukichi Okamura
隆吉 岡村
Sachiko Togawa
祥子 外川
Fumio Kanbayashi
文夫 神林
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Taiheiyo Cement Corp
Original Assignee
Taiheiyo Cement Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Taiheiyo Cement Corp filed Critical Taiheiyo Cement Corp
Priority to JP9310381A priority Critical patent/JPH11147746A/en
Publication of JPH11147746A publication Critical patent/JPH11147746A/en
Pending legal-status Critical Current

Links

Classifications

    • 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
    • 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
    • C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
    • C04B2103/30—Water reducers, plasticisers, air-entrainers, flow improvers
    • C04B2103/308—Slump-loss preventing agents

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Curing Cements, Concrete, And Artificial Stone (AREA)

Abstract

PROBLEM TO BE SOLVED: To obtain a composition able to effectively suppress slump loss by including hemihydrate or soluble anhydrous gypsum (III-type anhydrous gypsum) in a specific quantity in terms of SO3 . SOLUTION: This cement composition is prepared by blending (A) hemihydrate or soluble anhydrous gypsum (III-type anhydrous gypsum) both having a specific surface area of 3,000-12,000 cm<2> /g with (B) general-purpose cement such as Portland cement in or after grinding it or in kneading it in such a way that the content of the component A becomes 1.0-2.5 wt.% in terms of SO3 and the total amount of SO3 in the cement composition becomes 1.5-3.5 wt. %. Moreover, it is possible both to increase a slump loss-reducing effect and to increase the initial strength of concrete cured in a high temperature or the like by including insbluble anhydrous gypsum (III-type anhydrous gypsum) along with hemihydrate or soluble anhydrous gypsum so that the content of insoluble anhydrous gypsum may become 0.5-1.5 wt.% in terms of SO3 . Mortar is prepared by adding sand and high-performance AE water reducing agent or the like to the composition.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、セメントペース
ト、モルタルまたはコンクリート（以下、セメント組成
物と云う）のスランプロスを低減したセメント組成物に
関する。本発明のセメント組成物は、一般土木や建築構
造物におけるコンクリートやコンクリート製品等につい
て、これらの製造時に適用される。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement composition having reduced slump loss of cement paste, mortar or concrete (hereinafter referred to as cement composition). INDUSTRIAL APPLICABILITY The cement composition of the present invention is applied to the production of concrete and concrete products in general civil engineering and building structures.

【０００２】[0002]

【従来技術】近年、建築構造物に対するニーズの多様化
に伴い、高強度コンクリートや高流動コンクリートが盛
んに使用されるようになってきた。このようなコンクリ
ートでは、流動性と材料分離抵抗性の両者を高い次元で
バランスさせることが必要である。一般には、水セメン
ト比または水粉体比により材料分離抵抗性を調節し、高
性能減水剤や高性能ＡＥ減水剤等の有機混和剤の添加量
により流動性を調節する事が行なわれている。ところ
が、有機混和剤の種類や使用量あるいはセメントの品質
によっては流動性が経時的に低下するスランプ(フロー)
ロスが大きくなる問題がある。また、最近主に使用され
ている高性能ＡＥ減水剤はコンクリートのスランプを保
持する作用を有するのでスランプロスの程度は少ないも
ののやはり流動性の低下は避けられない。2. Description of the Related Art In recent years, with the diversification of needs for building structures, high-strength concrete and high-fluidity concrete have been actively used. In such concrete, it is necessary to balance both fluidity and material separation resistance at a high level. Generally, the material separation resistance is adjusted by the water cement ratio or the water powder ratio, and the fluidity is adjusted by the addition amount of an organic admixture such as a high performance water reducing agent or a high performance AE water reducing agent. . However, depending on the type and amount of the organic admixture or the quality of the cement, the slump (flow) whose fluidity decreases over time
There is a problem that loss increases. In addition, a high-performance AE water reducing agent mainly used recently has an action of retaining a slump of concrete, so that although the degree of slump loss is small, a decrease in fluidity is still unavoidable.

【０００３】そこで、セメント自体の改良による高流動
化も試みられており、その１つとしてビーライト(2CaO・
SiO2)の含有量を高めた高ビーライトセメントが用いら
れることも多くなってきたが、この種のセメントでもス
ランプロスの低減は十分ではない。初期の流動性が良好
でも、１時間以内に流動性が大きく低下しては施工に必
要な時間が確保できない等の不都合を生じ実用に適さな
い。従って、できるだけスランプロスが少ないことが要
求される。[0003] Therefore, attempts have been made to improve the fluidity of cement by improving the cement itself, and one of them is belite (2CaO.
High belite cements with an increased content of SiO 2 ) have been increasingly used, but even with this type of cement, the reduction of slump loss is not sufficient. Even if the initial fluidity is good, if the fluidity is significantly reduced within one hour, the time required for the construction cannot be secured, which is not suitable for practical use. Therefore, it is required that the slump loss is as small as possible.

【０００４】[0004]

【発明の解決しようとする課題】本発明は、このような
モルタルやコンクリート等のセメント組成物における従
来の流動性の問題を解決したものであり、スランプロス
を効果的に抑制したセメント組成物を提供することを目
的とする。SUMMARY OF THE INVENTION The present invention solves the conventional problem of fluidity in cement compositions such as mortar and concrete, and provides a cement composition in which slump loss is effectively suppressed. The purpose is to provide.

【０００５】[0005]

【課題を解決するための手段】すなわち、本発明は、
(１)ＳＯ3換算量で１.０〜２.５重量％の半水石膏また
は可溶性無水石膏(III型無水石膏)を含有させることに
よりスランプロスを低減したことを特徴とするセメント
組成物に関する。That is, the present invention provides:
(1) A cement composition characterized in that slump loss is reduced by including 1.0 to 2.5% by weight of SO 3 in terms of hemihydrate gypsum or soluble anhydrite (type III anhydrite). .

【０００６】本発明のセメント組成物は以下の態様を含
む。 (２)半水石膏または可溶性無水石膏(III型無水石膏)の
含有量がＳＯ3換算量で１.５〜２.０重量％であるセメ
ント組成物。 (３)半水石膏または可溶性無水石膏(III型無水石膏)と
共に、ＳＯ3換算量で０.５〜１.５重量％の不溶性無水
石膏(II型無水石膏)を含むセメント組成物。 (４)半水石膏または可溶性無水石膏(III型無水石膏)
を、セメントの粉砕時ないし粉砕後、あるいはセメント
の混練時に添加したセメント組成物。 (５)不溶性無水石膏(II型無水石膏)を、セメントの粉砕
時ないし粉砕後、あるいはセメントの混練時に添加した
セメント組成物。[0006] The cement composition of the present invention includes the following embodiments. (2) A cement composition in which the content of hemihydrate gypsum or soluble anhydrous gypsum (type III anhydrous gypsum) is 1.5 to 2.0% by weight in terms of SO 3 . (3) A cement composition containing 0.5 to 1.5% by weight in terms of SO 3 of insoluble anhydrous gypsum (type II anhydrous gypsum) together with hemihydrate gypsum or soluble anhydrous gypsum (type III anhydrous gypsum). (4) Hemihydrate gypsum or soluble anhydrous gypsum (type III anhydrous gypsum)
Is added during or after pulverizing cement, or during kneading of cement. (5) A cement composition in which insoluble anhydrous gypsum (II type anhydrous gypsum) is added at the time of pulverizing or after pulverizing cement, or at the time of kneading cement.

【０００７】[0007]

【発明の実施の態様】以下に本発明を実施例と共に詳細
に説明する。本発明は、セメント組成物に、ＳＯ3換算
量で１.０〜２.５重量％の半水石膏または可溶性無水石
膏(III型無水石膏)を含有させることによりスランプロ
スを低減したものである。本発明は各種セメントの石膏
の処方に関わるものであり、本発明が適用されるセメン
トの種類は限定されない、ポルトランドセメントや各種
混合セメントなどの汎用セメントのいずれでも用いるこ
とができる。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to examples. In the present invention, slump loss is reduced by adding 1.0 to 2.5% by weight in terms of SO 3 of a hemihydrate gypsum or soluble anhydrite (type III anhydrite) to a cement composition. . The present invention relates to the prescription of gypsum of various cements, and the type of cement to which the present invention is applied is not limited, and any of general-purpose cements such as Portland cement and various mixed cements can be used.

【０００８】石膏は半水石膏または可溶性無水石膏(III
型無水石膏、以下単に可溶性無水石膏と示す)が用いら
れる。半水石膏と可溶性無水石膏とを併用しても良い。
本発明において、半水石膏または可溶性無水石膏とは、
これを単独に使用する場合および併用する場合を含む。[0008] Gypsum is hemihydrate gypsum or soluble anhydrous gypsum (III
Type anhydrous gypsum, hereinafter simply referred to as soluble anhydrous gypsum). Hemihydrate gypsum and soluble anhydrous gypsum may be used in combination.
In the present invention, hemihydrate gypsum or soluble anhydrite is
This includes the case where these are used alone and the case where they are used in combination.

【０００９】これらの半水石膏および可溶性無水石膏の
製造方法は限定されない。セメントクリンカー焼成後に
添加した二水石膏を粉砕時にミル内温度を調整して半水
化あるいは可溶性無水化することにより製造したもので
も良い。また、予め半水石膏または可溶性無水石膏とし
たものをセメントに添加しても良い。さらに、これらの
半水石膏または可溶性無水石膏は天然物でも副産物でも
良く、一般にセメント用として使用されているものであ
れば起源は問わない。The method for producing these hemihydrate gypsum and soluble anhydrite is not limited. The dihydrate gypsum added after firing of the cement clinker may be manufactured by adjusting the temperature in the mill at the time of pulverization so as to be hemihydrated or soluble dehydrated. Moreover, what was previously made into hemihydrate gypsum or soluble anhydrous gypsum may be added to cement. Further, these hemihydrate gypsum or soluble anhydrite may be a natural product or a by-product, and may be of any origin as long as it is generally used for cement.

【００１０】半水石膏または可溶性無水石膏のセメント
への添加時期は制限されず、セメントの粉砕時ないし粉
砕後、あるいはセメントの混練時に添加することができ
る。混練時に所定量の半水石膏または可溶性無水石膏が
セメント組成物に含有されていれば良い。なお、半水石
膏または可溶性無水石膏をセメント製造後に添加する場
合、これらの粒度は比表面積3000〜12000cm2/g程度が良
い。The timing of adding the hemihydrate gypsum or the soluble anhydrous gypsum to the cement is not limited, and it can be added at the time of pulverizing the cement or after the pulverization, or at the time of kneading the cement. It is sufficient that a predetermined amount of hemihydrate gypsum or soluble anhydrite is contained in the cement composition at the time of kneading. In the case where hemihydrate gypsum or soluble anhydrous gypsum is added after the production of cement, the particle size of these is preferably about 3000 to 12000 cm 2 / g.

【００１１】半水石膏または可溶性無水石膏の含有量
は、セメント組成物中、ＳＯ3換算量で１.０〜２.５重
量％、好ましくは、１.５〜２.０重量％が適当である。
但し、セメント組成物中の全ＳＯ3量は１.５〜３.５重
量％となるように調製するのが良い。半水石膏または可
溶性無水石膏の量が１.０重量％より少ないとスランプ
ロスを低減する効果が小さい。一方、半水石膏または可
溶性無水石膏の量が２.５重量％よりも多いと練上り直
後の流動性が大きく低下し、スランプ(フロー)が小さく
なり過ぎて実用に適さない。The content of hemihydrate gypsum or soluble anhydrous gypsum is 1.0 to 2.5% by weight, preferably 1.5 to 2.0% by weight in terms of SO 3 in the cement composition. is there.
However, the total amount of SO 3 in the cement composition is preferably adjusted to 1.5 to 3.5% by weight. If the amount of hemihydrate gypsum or soluble anhydrite is less than 1.0% by weight, the effect of reducing slump loss is small. On the other hand, if the amount of hemihydrate gypsum or soluble anhydrous gypsum is more than 2.5% by weight, the fluidity immediately after kneading is greatly reduced, and the slump (flow) becomes too small, which is not suitable for practical use.

【００１２】各種ポルトランドセメントおよび混合セメ
ントの品質については日本工業規格による基準が設けら
れており、そのなかで石膏含有量は、ＳＯ3量として、
早強性のセメントについては４.５ないし３.５以下、そ
の他の大部分のものが３.０重量％以下に定められてい
る。この規格では石膏の種類は区別されていないが、半
水石膏はセメント混練時の注水により水和して二水石膏
を析出するために流動性が低下し、著しい場合には偽凝
結に至ることが知られている。そのため、従来からセメ
ントの製造工程においては、仕上げ粉砕時のミル内温度
をできるだけ低く保ち、ミル内で二水石膏が脱水して半
水化することを可能な限り抑えるのが一般的である。こ
のような従来のセメントに対して本発明のセメント組成
物は、各種セメントの規格に定められるＳＯ3含有量の
範囲内で、従来は流動性にとって好ましくないとされて
いた半水石膏または可溶性無水石膏を積極的に所定量含
有するようにし、これによりスランプロスを低減させた
ものである。[0012] The standards of Japanese Industrial Standards are established for the quality of various portland cements and mixed cements. Among them, the gypsum content is expressed as SO 3
The fast-strength cement is set to 4.5 to 3.5 or less, and most other cements are set to 3.0% by weight or less. In this standard, gypsum types are not distinguished, but hemihydrate gypsum hydrates due to water injection during kneading cement and precipitates dihydrate gypsum. It has been known. For this reason, conventionally, in the process of producing cement, it has been common practice to keep the temperature in the mill at the time of finish pulverization as low as possible, and to minimize the dehydration and hemihydrate of gypsum in the mill. Such cement compositions of the present invention over conventional cement is in the range of SO 3 content determined for various cement standards, conventional gypsum hemihydrate or soluble anhydrite which has been considered to be undesirable for liquidity Gypsum is positively contained in a predetermined amount, thereby reducing slump loss.

【００１３】半水石膏または可溶性無水石膏と共に不溶
性無水石膏(II型無水石膏、以下、単に不溶性無水石膏
と云う)を併用することにより、スランプロス低減効果
を更に高めることができる。また、不溶性無水石膏を併
用することにより、特に高温養生したコンクリート等の
初期強度が向上する。不溶性無水石膏の含有量は、セメ
ント組成物中、ＳＯ3換算量で、０.５〜１.５重量％が
適当である。不溶性無水石膏の量がこれよりも多いと半
水石膏または可溶性無水石膏の含有量が相対的に少なく
なり、規格の全ＳＯ3量の範囲内で必要量の半水石膏ま
たは可溶性無水石膏を含有させることが困難になる。な
お、二水石膏が共存してもなんら問題は無いが、二水石
膏量が多過ぎると、規格の全ＳＯ3量の範囲内で相対的
に半水石膏または可溶性無水石膏の量が制限されるので
好ましくない。The combined use of insoluble anhydrous gypsum (type II anhydrous gypsum, hereinafter simply referred to as insoluble anhydrous gypsum) together with hemihydrate gypsum or soluble anhydrous gypsum can further enhance the effect of reducing slump loss. In addition, the combined use of the insoluble anhydrous gypsum improves the initial strength, particularly of concrete cured at high temperatures. The content of the insoluble anhydrous gypsum is suitably from 0.5 to 1.5% by weight in terms of SO 3 in the cement composition. The amount of insoluble anhydrite is this large, the content of the hemi-gypsum or soluble anhydrite is relatively smaller than the content of hemihydrate gypsum or soluble anhydrite the required amount in the range of total SO 3 content of standards It becomes difficult to make it. There is no problem if gypsum is present, but if the amount of gypsum is too large, the amount of hemihydrate gypsum or soluble anhydrous gypsum is relatively limited within the range of the total SO 3 amount of the standard. This is not preferred.

【００１４】[0014]

【作用】本発明のセメント組成物は、所定量の半水石膏
または可溶性無水石膏を含有することにより、流動性の
経時的な低下(スランプロス)を効果的に抑制したもので
ある。先に述べたように、通常、セメント中に半水石膏
や可溶性無水石膏が存在すると、注水直後に半水石膏や
可溶性無水石膏が水和して二水石膏が急激に析出するた
め流動性が低下し、著しい場合には偽凝結に至ることが
知られている。ところが、高性能減水剤や高性能ＡＥ減
水剤が使用されている場合には、本発明に示すように半
水石膏や可溶性無水石膏が多くなると、練り混ぜ直後に
二水石膏が多量に析出して流動性が低下するものの、こ
の他に石膏から溶出するＳＯ4 2 -イオンによって高性能
減水剤や高性能ＡＥ減水剤はその吸着が抑制され、この
効果は二水石膏の析出によっても失われずに持続するの
で、練り混ぜ後の流動性が保たれ、従って、スランプロ
スが低減する。The cement composition of the present invention contains a predetermined amount of hemihydrate gypsum or soluble anhydrite, thereby effectively suppressing a decrease in fluidity over time (slump loss). As described above, usually, when hemihydrate gypsum or soluble anhydrous gypsum is present in cement, the hemihydrate gypsum or soluble anhydrous gypsum hydrates immediately after water injection and gypsum dihydrate precipitates rapidly, so that the fluidity is reduced. It is known to decrease and, in severe cases, to false setting. However, when a high-performance water reducing agent or a high-performance AE water reducing agent is used, as shown in the present invention, if the amount of hemihydrate gypsum or soluble anhydrite increases, a large amount of gypsum dihydrate precipitates immediately after mixing. Although the fluidity decreases, the adsorption of the high-performance water reducing agent and the high-performance AE water reducing agent is suppressed by SO 4 2 - ions eluted from the gypsum, and this effect is not lost even by the precipitation of gypsum dihydrate. , The fluidity after kneading is maintained, and the slump loss is reduced.

【００１５】なお、ナフタレンスルホン酸塩系の高性能
減水剤に関しては、石膏から溶出するＳＯ4 2-イオンと
競争吸着の関係にあり、高ＳＯ4 2-イオン濃度下でこの
減水剤の吸着が抑制される傾向にあることは最近知られ
るようになったが、これによりスランプロスを低減でき
ることは従来知られていない。また、前述のように、溶
解速度の大きい半水石膏や可溶性無水石膏は二水石膏を
生じて急激に流動性を低下させる作用が著しいので、石
膏の添加によってスランプロスを低減させることも従来
は試みられていない。本発明者等は、このような従来技
術に対して、半水石膏ないし可溶性無水石膏を積極的に
用いることにより、上記減水剤の使用下においてはスラ
ンプロスが低減できることを新たに見い出した。The naphthalenesulfonate-based high-performance water reducing agent has a competitive adsorption relationship with SO 4 2− ions eluted from gypsum, and the adsorption of this water reducing agent under a high SO 4 2− ion concentration. It has recently been known that the tendency is to be suppressed, but it has not heretofore been known that the slump loss can be reduced. In addition, as described above, hemihydrate gypsum and soluble anhydrous gypsum having a high dissolution rate produce dihydrate gypsum and have a remarkable effect of rapidly decreasing fluidity.Therefore, it has also been conventionally possible to reduce slump loss by adding gypsum. Not tried. The present inventors have newly found that the slump loss can be reduced with the use of the water reducing agent by actively using hemihydrate gypsum or soluble anhydrous gypsum with respect to such a conventional technique.

【００１６】また、半水石膏または可溶性無水石膏と共
に不溶性無水石膏が共存すると、スランプロス抑制効果
が一層顕著に得られる。これは、溶解速度の小さい不溶
性無水石膏がＳＯ4 2-イオンを徐々に供給するため、半
水石膏や可溶性無水石膏により高められたＳＯ4 2-イオ
ン濃度の経時的な低下を抑制するものと考えられる。ま
た、不溶性無水石膏を含むことにより、高温養生したコ
ンクリート等の初期強度が向上する。When the insoluble anhydrous gypsum coexists with the hemihydrate gypsum or the soluble anhydrous gypsum, the effect of suppressing slump loss is more remarkably obtained. This is because the insoluble anhydrous gypsum with a low dissolution rate gradually supplies SO 4 2- ions, so that the time-dependent decrease in the SO 4 2- ion concentration enhanced by hemihydrate gypsum and soluble anhydrous gypsum is suppressed. Conceivable. In addition, by including the insoluble anhydrous gypsum, the initial strength of concrete or the like cured at high temperature is improved.

【００１７】[0017]

【実施例】実施例 実験用に試製した低熱ポルトランドセメント、無水石膏
および二水石膏を半水化した半水石膏を用い、表１およ
び２に示す石膏量のセメントを調製し、このセメントに
砂および高性能ＡＥ減水剤を加えてモルタルとし、この
モルタルのフロー試験を実施した。なお、砂には小笠産
陸砂、高性能ＡＥ減水剤にはＮＭＢ社製レオビルドSP-8
Sおよび花王社製マイティ2000WHZを用いた。高性能ＡＥ
減水剤の使用量はセメントに対して２.３重量％であ
る。また、モルタルの配合は、水セメント比０.３およ
び砂セメント比１.４７である。フロー試験は日本工業
規格 JIS R-5201-1992に準じた。ただし、ガラス板を用
い、テーブルの落下運動を伴わない静置フローを測定し
た。この結果を表１および２に示した。なお表１は高性
能ＡＥ減水剤としてレオビルドSP-8Sを使用した場合、
表２はマイティ2000WHZを使用したときの結果である。EXAMPLES low heat Portland cement was Shisei for example experiments, using the hemihydrate gypsum to the anhydrite and gypsum were semi hydrated, prepared plaster of cement shown in Table 1 and 2, sand cement A mortar was prepared by adding a high-performance AE water reducing agent, and a flow test of the mortar was performed. The sand is Ogasa land sand and the high performance AE water reducing agent is NMB Leobuild SP-8.
S and Kao Mighty 2000WHZ were used. High performance AE
The amount of water reducing agent used is 2.3% by weight with respect to the cement. The mortar was mixed with a water cement ratio of 0.3 and a sand cement ratio of 1.47. The flow test conformed to Japanese Industrial Standard JIS R-5201-1992. However, using a glass plate, the stationary flow without the falling motion of the table was measured. The results are shown in Tables 1 and 2. In addition, Table 1 shows the case where Rheobuild SP-8S is used as a high performance AE water reducing agent.
Table 2 shows the results when Mighty 2000WHZ was used.

【００１８】表１および表２に示すように、溶解速度の
大きい半水石膏および可溶性無水石膏からのＳＯ3量が
０.６重量％程度では、フロー値の経時的な低下量はあ
まり変わらないが、ＳＯ3量が増加するとフロー値の経
時変化は小さくなり、フローロスが減少する。ただし、
練上がり直後のフロー値は、このＳＯ3量が１.３重量％
を上回ると低下する傾向を示し、特に、２.５重量％を
超えると顕著になった。従って、半水石膏または可溶性
無水石膏の含有量はＳＯ3換算量で１.０〜２.５重量％
が適当であり、１.５〜２.０重量％が好ましい。また、
不溶性無水石膏を併用すると、併用しない場合に比べ、
練上り直後のフローが大きくなる傾向を示すとともに、
フローロスがより減少する。As shown in Tables 1 and 2, when the amount of SO 3 from hemihydrate gypsum and soluble anhydrite having a high dissolution rate is about 0.6% by weight, the decrease in flow value with time does not change much. However, as the SO 3 amount increases, the change over time in the flow value decreases, and the flow loss decreases. However,
The flow value immediately after kneading is that the SO 3 amount is 1.3% by weight.
When the amount exceeds 2.5% by weight, the tendency tends to decrease. Therefore, the content of hemihydrate gypsum or soluble anhydrite is 1.0 to 2.5% by weight in terms of SO 3.
And 1.5 to 2.0% by weight is preferred. Also,
When combined with insoluble anhydrous gypsum,
The flow immediately after kneading tends to increase,
Flow loss is further reduced.

【００１９】[0019]

【表１】 [Table 1]

【００２０】[0020]

【表２】 [Table 2]

【００２１】[0021]

【発明の効果】本発明のセメント組成物は、所定量の半
水石膏または可溶性無水石膏を含むことにより練上り直
後の流動性はやや低下するものの流動性の経時的な低下
(スランプロス)が小さく、優れたスランプロス低減効果
を有する。半水石膏または可溶性無水石膏と共に不溶性
無水石膏を含有させることにスランプロス低減効果は更
に増し、また特に高温養生したコンクリートの初期強度
も同時に向上させることができる。The cement composition of the present invention contains a predetermined amount of hemihydrate gypsum or soluble anhydrite, so that the fluidity immediately after kneading slightly decreases, but the fluidity decreases over time.
(Slump loss) is small and has an excellent slump loss reduction effect. Inclusion of insoluble anhydrous gypsum together with hemihydrate gypsum or soluble anhydrous gypsum further enhances the effect of reducing slump loss, and at the same time can improve the initial strength of concrete cured at high temperatures.

Claims (5)

【特許請求の範囲】[Claims] 【請求項１】 ＳＯ3換算量で１.０〜２.５重量％の半
水石膏または可溶性無水石膏(III型無水石膏)を含有さ
せることによりスランプロスを低減したことを特徴とす
るセメント組成物。1. A cement composition characterized in that slump loss is reduced by containing 1.0 to 2.5% by weight of SO 3 in terms of hemihydrate gypsum or soluble anhydrite (type III anhydrite). Stuff. 【請求項２】 半水石膏または可溶性無水石膏(III型無
水石膏)の含有量がＳＯ3換算量で１.５〜２.０重量％で
ある請求項１に記載のセメント組成物。2. The cement composition according to claim 1, wherein the content of hemihydrate gypsum or soluble anhydrous gypsum (type III anhydrous gypsum) is 1.5 to 2.0% by weight in terms of SO 3 . 【請求項３】 半水石膏または可溶性無水石膏(III型無
水石膏)と共に、ＳＯ3換算量で０.５〜１.５重量％の不
溶性無水石膏(II型無水石膏)を含む請求項１または２に
記載のセメント組成物。3. An insoluble anhydrous gypsum (II type anhydrous gypsum) in an amount of 0.5 to 1.5% by weight in terms of SO 3 together with hemihydrate gypsum or soluble anhydrous gypsum (type III anhydrous gypsum). 3. The cement composition according to 2. 【請求項４】 半水石膏または可溶性無水石膏(III型無
水石膏)を、セメントの粉砕時ないし粉砕後、あるいは
セメントの混練時に添加した請求項１、２または３に記
載のセメント組成物。4. The cement composition according to claim 1, wherein the hemihydrate gypsum or the soluble anhydrite (type III anhydrite) is added at the time of pulverizing or after the pulverization of the cement or at the time of kneading the cement. 【請求項５】 不溶性無水石膏(II型無水石膏)を、セメ
ントの粉砕時ないし粉砕後、あるいはセメントの混練時
に添加した請求項３または４に記載のセメント組成物。5. The cement composition according to claim 3, wherein the insoluble anhydrous gypsum (type II anhydrous gypsum) is added during or after pulverizing the cement, or at the time of kneading the cement.
JP9310381A 1997-11-12 1997-11-12 Cement composition having reduced slump loss Pending JPH11147746A (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005336005A (en) * 2004-05-26 2005-12-08 Mitsubishi Materials Corp Method for producing cement composition
JP2013189337A (en) * 2012-03-13 2013-09-26 Tokuyama Corp Method for producing cement
JP2014185040A (en) * 2013-03-21 2014-10-02 Sumitomo Osaka Cement Co Ltd Cement composition
JP2014185041A (en) * 2013-03-21 2014-10-02 Sumitomo Osaka Cement Co Ltd Cement composition
JP2019131416A (en) * 2018-01-29 2019-08-08 太平洋セメント株式会社 Cement composition and method for producing the same
JP2019135209A (en) * 2013-02-18 2019-08-15 ムスタファ オズストゥ Lower heat treated calcium sulfate for early strength cement and general use
JP2020050568A (en) * 2018-09-28 2020-04-02 太平洋セメント株式会社 Cement composition

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58204854A (en) * 1982-05-20 1983-11-29 電気化学工業株式会社 Manufacture of high strength concrete with improved workability and endurability
JPH0986976A (en) * 1995-09-22 1997-03-31 Ube Ind Ltd High fluidity cement composition
JPH10152359A (en) * 1996-11-22 1998-06-09 Ube Ind Ltd High-fluidity cement composition

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58204854A (en) * 1982-05-20 1983-11-29 電気化学工業株式会社 Manufacture of high strength concrete with improved workability and endurability
JPH0986976A (en) * 1995-09-22 1997-03-31 Ube Ind Ltd High fluidity cement composition
JPH10152359A (en) * 1996-11-22 1998-06-09 Ube Ind Ltd High-fluidity cement composition

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005336005A (en) * 2004-05-26 2005-12-08 Mitsubishi Materials Corp Method for producing cement composition
JP2013189337A (en) * 2012-03-13 2013-09-26 Tokuyama Corp Method for producing cement
JP2019135209A (en) * 2013-02-18 2019-08-15 ムスタファ オズストゥ Lower heat treated calcium sulfate for early strength cement and general use
JP2014185040A (en) * 2013-03-21 2014-10-02 Sumitomo Osaka Cement Co Ltd Cement composition
JP2014185041A (en) * 2013-03-21 2014-10-02 Sumitomo Osaka Cement Co Ltd Cement composition
JP2019131416A (en) * 2018-01-29 2019-08-08 太平洋セメント株式会社 Cement composition and method for producing the same
JP2020050568A (en) * 2018-09-28 2020-04-02 太平洋セメント株式会社 Cement composition

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