JP2533562B2 - Method for preventing cracking of high strength cement hardened product - Google Patents
Method for preventing cracking of high strength cement hardened productInfo
- Publication number
- JP2533562B2 JP2533562B2 JP62223710A JP22371087A JP2533562B2 JP 2533562 B2 JP2533562 B2 JP 2533562B2 JP 62223710 A JP62223710 A JP 62223710A JP 22371087 A JP22371087 A JP 22371087A JP 2533562 B2 JP2533562 B2 JP 2533562B2
- Authority
- JP
- Japan
- Prior art keywords
- strength
- strength cement
- cement hardened
- hardened product
- high strength
- 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.)
- Expired - Lifetime
Links
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、高強度セメント硬化体の打設後に発生する
初期のひび割れを防止する技術に関するものである。Description: TECHNICAL FIELD The present invention relates to a technique for preventing early cracking that occurs after placing a high-strength cement hardened body.
高強度セメント硬化体を製造するに当っては、有機系
又は無機系添加剤を用いることにより、ワーカビリティ
ーを損なわない程度にまで、極力水セメント比を低くす
るのが一般的である（例えば、特公昭57−17871号公
報）。In producing a high-strength cement hardened product, it is common to use an organic or inorganic additive to reduce the water-cement ratio to the extent that workability is not impaired (for example, JP-A-57-17871).
この高強度セメント硬化体はブリージングがほとんど
なく、打設表面の乾燥が他のセメント硬化体に比べて早
く、そのため高強度セメント硬化体の表面には乾燥収縮
による初期ひび割れが生じやすいという欠点を有してお
り、これが硬化体の美観を損なったり、耐久性の低下に
つながったり等の問題点となっている。This high-strength cement hardened product has almost no bleeding, and the drying of the cast surface is faster than other cement hardened products, so that the surface of the high-strength cement hardened product is liable to have initial cracks due to drying shrinkage. This causes problems such as impairing the aesthetics of the cured product and reducing the durability.
そこで、高強度セメント硬化体の初期ひび割れを防止
するために、例えば、打設後早めに硬化体表面への散水
を繰り返すとか、シートを被せて水の蒸発を防ぐとかい
った方法がとられてきたが、大変な手間を要したり、現
場によってはその様な方法がとれないといった欠点があ
った。Therefore, in order to prevent the initial cracking of the high-strength cement hardened body, methods such as repeating watering on the surface of the hardened body early after placing or covering the sheet with water to prevent evaporation of water have been taken. However, there were drawbacks that it required a great deal of work and that such a method could not be taken depending on the site.
更には、硬化体製造時に、各種の無機系又は有機系の
長繊維を含有させて補強するといった方法も採用された
（例えば、特開昭59−58291号公報）。しかし、ヒュー
ム管や推進管等のコンクリート２次製品の製造に際して
は、長繊維を含有させることは可能であるが、屋外で比
較的規模の大きい高強度セメントコンクリートの打設を
する場合、長繊維を使用することは技術的に極めて困難
である。Furthermore, a method has also been adopted in which various inorganic or organic long fibers are incorporated to reinforce the cured product during its manufacture (for example, JP-A-59-58291). However, it is possible to include long fibers in the production of secondary concrete products such as fume pipes and propulsion pipes. However, when placing relatively large scale high-strength cement concrete outdoors, long fibers can be added. Is technically very difficult to use.
従って、この方法も、高強度セメント硬化体の初期ひ
び割れ防止に有効な方法であるとは言えず、問題点とし
て残されている。Therefore, this method cannot be said to be an effective method for preventing initial cracking of the high-strength cement hardened product, and remains a problem.
本発明者は、特定の繊維をセメント組成物中に含有さ
せることにより、前述の問題点である高強度セメント硬
化体の初期ひび割れを防止することができることを知見
して、本発明を完成したものである。The present inventor has found that the inclusion of a specific fiber in a cement composition makes it possible to prevent early cracking of the high-strength cement hardened product, which is the above-mentioned problem, and completed the present invention. Is.
本発明は、引張強度が70kg/mm2以上の短繊維を含有さ
せることを特徴とする圧縮強度が500kgf/cm2以上の高強
度セメント硬化体のひび割れ防止方法。The present invention is a method for preventing cracking of a high-strength cement hardened product having a compressive strength of 500 kgf / cm 2 or more, characterized by containing short fibers having a tensile strength of 70 kg / mm 2 or more.
以下、本発明について詳しく説明する。 Hereinafter, the present invention will be described in detail.
本発明でいう高強度セメントとは、通常の水硬性セメ
ントを必須成分とし、必要に応じてこれに高強度混和材
料やその他の混和材料等が任意に含有されているもの
で、特にコンクリートとして使用する場合にその目標圧
縮強度が500kgf/cm2以上になるもののことをいう。The high-strength cement referred to in the present invention is an ordinary hydraulic cement as an essential component, and optionally contains a high-strength admixture material or other admixture material, etc., particularly used as concrete. When it does, the target compressive strength is 500kgf / cm 2 or more.
高強度セメント硬化体とは、高強度セメントに適量の
水を加えて硬化させたものを言う。The high-strength cement hardened product refers to a high-strength cement hardened by adding an appropriate amount of water.
本発明で使用される短繊維は、引張強度が70kg/mm2以
上であれば、その材質は問わない。具体的には、鋼繊
維、耐アルカリガラス繊維及び炭素繊維等の無機繊維や
アラミッド繊維等の有機繊維が該当する。The short fibers used in the present invention may be made of any material as long as the tensile strength is 70 kg / mm 2 or more. Specifically, inorganic fibers such as steel fibers, alkali-resistant glass fibers and carbon fibers, and organic fibers such as aramid fibers are applicable.
引張強度が70kg/mm2より小さいと高強度セメント硬化
体の初期ひび割れを防ぐことが出来ない。If the tensile strength is less than 70 kg / mm 2, it is impossible to prevent early cracking of the high-strength cement hardened product.
短繊維の形状は、繊維長５〜100mm、繊維径は５〜100
0μｍが好ましい。The shape of the short fiber is 5-100 mm, the fiber diameter is 5-100.
0 μm is preferable.
短繊維の含有量は、高強度セメント硬化体に対し0.1
重量％以上、好ましくは0.5〜5.0重量％である。0.1重
量％より少ないと初期ひび割れ防止の効果が十分でな
く、また5.0重量％を越えると初期ひび割れ防止効果に
差異は認められない。The content of short fibers is 0.1 with respect to the high strength cement hardened product.
It is at least wt%, preferably 0.5 to 5.0 wt%. If it is less than 0.1% by weight, the effect of preventing initial cracking is insufficient, and if it exceeds 5.0% by weight, no difference is observed in the effect of preventing initial cracking.
短繊維の含有方法は、高強度セメント中の粉末物質、
例えば水硬性セメントと予め混合しておく方法や高強度
セメントと水を混練する際に同時に添加する方法が好ま
しい。The method of containing short fibers is as follows:
For example, a method of premixing with hydraulic cement or a method of simultaneously adding high-strength cement and water when kneading is preferable.
本発明における高強度セメント中には、高強度混和材
料として、高性能減水剤、流動化剤若しくはその他の分
散剤等、さらには、無水石膏、二水石膏、シリカヒュー
ム、若しくはエポキシ樹脂等が含有されていても、何ら
等問題がないことは言うまでもない。In the high-strength cement of the present invention, as a high-strength admixture, a high-performance water reducing agent, a fluidizing agent or other dispersant, etc., and further contains anhydrous gypsum, gypsum dihydrate, silica fume, or epoxy resin. Needless to say, even if it is done, there is no problem.
以下、実施例により本発明を説明する。 Hereinafter, the present invention will be described with reference to examples.
実施例１〜６ 普通ポルトランドセメント（アンデスセメント（株）
製）、砂・砂利（共に、新潟県姫川産）、高強度混和材
（電気化学工業（株）製、商品名「デンカΣ5000」）、
水並びに第１表に示す各種繊維を第２表に示す配合〜
の通り準備した。次に、普通ポルトランドセメント、
高強度混和材及び短繊維をＶ型混合機を用いて混合し
た。この混合物と砂利、砂を強制練りミキサーに入れ、
空練りしながら、水を加えて３分間練り混ぜた。練り混
ぜ後、直ちに、予め屋外に準備した１×３×0.1mの型枠
内に打設して、そのまま養生を行なった。Examples 1 to 6 Ordinary Portland cement (Andes Cement Co., Ltd.)
Made), sand and gravel (both produced in Himekawa, Niigata Prefecture), high-strength admixture (produced by Denki Kagaku Kogyo Co., Ltd., trade name "Denka Σ5000"),
Mixture of water and various fibers shown in Table 1 shown in Table 2
I prepared for the street. Next, ordinary Portland cement,
The high strength admixture and short fibers were mixed using a V-type mixer. Put this mixture, gravel and sand into a forced kneading mixer,
While kneading the mixture, water was added and the mixture was kneaded for 3 minutes. Immediately after the kneading, the composition was placed in a 1 × 3 × 0.1 m formwork prepared outdoors and cured as it was.
打設２日後の高強度セメント硬化体の表面状態を観察
し、初期ひび割れの有無を調べた。また５φ×10cmの円
供試体を作製し、標準養生を行なって、材令28日の圧縮
強度を測定した。The surface state of the high-strength cement hardened body 2 days after the casting was observed and examined for the presence of initial cracks. Further, a circular test piece of 5φ × 10 cm was prepared, and standard curing was performed to measure the compressive strength on the 28th day of the material.
これらの結果を第３表に示した。 The results are shown in Table 3.
実施例７〜８ 第２表に示す配合、について、短繊維を予め混合
することなく、強制練りミキサーでの練り混ぜ時に、全
ての材料を同時に投入して練り混ぜた。その後は、実施
例１〜６と同様に試験を行った。Examples 7 to 8 With respect to the formulations shown in Table 2, all the materials were simultaneously added and kneaded at the time of kneading with a forced kneading mixer without previously mixing short fibers. After that, the test was performed in the same manner as in Examples 1 to 6.
これらの初期ひび割れ状況と圧縮強度の結果を第３表
に示した。Table 3 shows the results of these initial cracking conditions and compressive strength.
比較例１〜３ 第２表に示す配合〜について、実施例１〜６と同
様の試験を行なった。これらの初期ひび割れ状況と圧縮
強度の結果を第３表に示した。Comparative Examples 1 to 3 The same tests as in Examples 1 to 6 were performed on the formulations shown in Table 2. Table 3 shows the results of these initial cracking conditions and compressive strength.
〔発明の効果〕 本発明の方法を用いることにより、乾燥収縮による初
期ひび割れが発生しない美観の優れた、耐久性のある高
強度セメント硬化体を得ることができる。 [Effects of the Invention] By using the method of the present invention, it is possible to obtain a durable and high-strength cement hardened product which is excellent in aesthetics and in which initial cracks due to drying shrinkage do not occur.
Claims (1)
せることを特徴とする圧縮強度が500kgf/cm2以上の高強
度セメント硬化体のひび割れ防止方法。1. A method for preventing cracking of a high-strength cement hardened product having a compressive strength of 500 kgf / cm 2 or more, which comprises containing short fibers having a tensile strength of 70 kg / mm 2 or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62223710A JP2533562B2 (en) | 1987-09-07 | 1987-09-07 | Method for preventing cracking of high strength cement hardened product |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62223710A JP2533562B2 (en) | 1987-09-07 | 1987-09-07 | Method for preventing cracking of high strength cement hardened product |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6469541A JPS6469541A (en) | 1989-03-15 |
| JP2533562B2 true JP2533562B2 (en) | 1996-09-11 |
Family
ID=16802452
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62223710A Expired - Lifetime JP2533562B2 (en) | 1987-09-07 | 1987-09-07 | Method for preventing cracking of high strength cement hardened product |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2533562B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6962201B2 (en) | 2003-02-25 | 2005-11-08 | Halliburton Energy Services, Inc. | Cement compositions with improved mechanical properties and methods of cementing in subterranean formations |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CL2009000371A1 (en) * | 2008-03-03 | 2009-10-30 | United States Gypsum Co | Cementitious composition, containing a continuous phase that results from the curing of a cementitious mixture, in the absence of silica flour, and comprising inorganic cement, inorganic mineral, pozzolanic filler, polycarboxylate and water; and use of the composition in a cementitious panel and barrier. |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53138422A (en) * | 1977-05-11 | 1978-12-02 | Asahi Chemical Ind | Formed product of fiberrreinforced cement |
| JPS5788050A (en) * | 1980-11-18 | 1982-06-01 | Teijin Ltd | Fiber reinforced cement moldings |
| JPS60186448A (en) * | 1984-02-29 | 1985-09-21 | 東洋紡績株式会社 | Fiber reinforced cement product |
| JPS62202846A (en) * | 1986-02-27 | 1987-09-07 | 三菱石油株式会社 | Manufacture of carbon fiber reinforced cement structure |
-
1987
- 1987-09-07 JP JP62223710A patent/JP2533562B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6962201B2 (en) | 2003-02-25 | 2005-11-08 | Halliburton Energy Services, Inc. | Cement compositions with improved mechanical properties and methods of cementing in subterranean formations |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6469541A (en) | 1989-03-15 |
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