JP3628070B2 - Method for producing hardened concrete or hardened mortar - Google Patents
Method for producing hardened concrete or hardened mortar Download PDFInfo
- Publication number
- JP3628070B2 JP3628070B2 JP14249095A JP14249095A JP3628070B2 JP 3628070 B2 JP3628070 B2 JP 3628070B2 JP 14249095 A JP14249095 A JP 14249095A JP 14249095 A JP14249095 A JP 14249095A JP 3628070 B2 JP3628070 B2 JP 3628070B2
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- Prior art keywords
- concrete
- hardened
- mortar
- fine powder
- aggregate
- 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 - Fee Related
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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
- C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B18/04—Waste materials; Refuse
- C04B18/16—Waste materials; Refuse from building or ceramic industry
- C04B18/167—Recycled materials, i.e. waste materials reused in the production of the same materials
-
- 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
- C04B40/02—Selection of the hardening environment
- C04B40/024—Steam hardening, e.g. in an autoclave
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Civil Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Description
【０００１】
【産業上の利用分野】
本発明は、蒸気養生を行うコンクリート硬化体又はモルタル硬化体の製造方法に関するものである。
【０００２】
【従来の技術】
普通セメントのコンクリートやモルタルの蒸気養生を行う場合には、温度上昇によるひび割れを防止するために、蒸気養生の工程前に前置き時間を充分にとることが必要となる。
この前置き時間を短縮する方法としては、水セメント比を著しく低減させる方法、硬化促進剤および急結剤を添加する方法などが工夫されている。
水セメント比を小さくした超硬練りの混練物の成形法は、通常のコンクリートやモルタルの成形法と比較して、振動時間、締固め時間などを増加させる特別な成形機が必要となる。
また、硬化促進剤および急結剤を添加する方法では、大幅なコストアップとなる。
【０００３】
一方、蒸気養生後のコンクリートやモルタルに対しては、散水養生や水中養生は、設備・コストの面から一般にはほとんど実施されておらず、乾燥養生に近い養生であるため、水中養生を行った場合よりもその強度発現は期待できず、所要強度が得られるのに養生日数が必要とされる。
【０００４】
【発明が解決しようとする課題】
本発明は、上述したような点に鑑みなされたもので、蒸気養生を行ってコンクリート硬化体やモルタル硬化体を製造する際の、蒸気養生前の前置き時間を短縮するとともに、硬化体の強度発現を向上することを目的とするものである。
【０００５】
【課題を解決するための手段】
本発明者らは、上述したような問題を解決するために検討した結果、コンクリート廃材の微粉末に着目した。これは、コンクリート廃材から再生骨材を製造する際に発生する廃棄物である。すなわち、本発明は、セメントと骨材と水を含む混練物を蒸気養生して、コンクリート硬化体やモルタル硬化体を製造する方法であって、混練物中の細骨材の一部を、コンクリート廃材を粉砕し、コンクリート廃材から粗骨材と細骨材に篩い分ける際に発生する粒度が０．３ｍｍ以下のコンクリート廃材の微粉末で、細骨材に対し内割りで０．５〜３０重量％代替するものである。
【０００６】
そして、このコンクリート廃材の微粉末の混入により、フレッシュなコンクリート又はモルタルのブリーディング量を低減でき、コンクリートやモルタルの硬化時間が短くなる。また、蒸気養生後に乾燥養生を受けても、コンクリート廃材の微粉末の混入により、コンクリートやモルタルの圧縮強度の発現が大きくなり、所要強度を得るための養生日数を少なくすることができる。
【０００７】
コンクリート廃材の微粉末の粒度は、通常の細骨材よりも細かい０．３ｍｍ程度以下が好ましい。
また、この微粉末の使用量は、微粉末が０．３ｍｍ以下の場合、細骨材に対して内割りで０．５重量％未満では効果がなく、３０重量％を越えるとコンシステンシーが悪くなり過ぎるので、細骨材に対して内割りで０．５〜３０重量％が好ましく、特に好ましいのは０．５〜２５重量％である。
また、コンクリート廃材の微粉末の粒度が細かくなると、保水性が高くなるため、その使用量の上限は低くなり、０．１５ｍｍ以下の微粉末を用いた場合には、細骨材に対する微粉末の代替量は、内割りで０．５〜１５重量％が特に好ましい。
【０００８】
なお、本発明で使用するコンクリート廃材の微粉末は、コンクリート廃材を粉砕する際、さらに粉砕したコンクリート廃材から粗骨材と細骨材を篩い分ける際に発生し、従来は廃棄物として処分していたものを有効に活用することができる。
したがって、粒度その他の条件によって使用量は異なるが、廃材の有効利用の観点からは、コンクリート廃材の微粉末を多く使用することが好ましい。
【０００９】
ここで、セメントには、普通、早強、超早強、中庸熱、白色などの各種のポルトランドセメントや、シリカ、スラグ、フライアッシュなどを混合した各種の混合セメントが使用でき、また、各種の蒸気養生コンクリート硬化体や蒸気養生モルタル硬化体に使用されているナフタリンスルホン酸塩ホルマリン縮合物系、メラミンスルホン酸塩ホルマリン縮合物系、ポリカルボン酸系、リグニンスルホン酸塩系、ポリアルキルアリルスルホン酸系、高縮合トリアジン系などの各種のコンクリート混和剤、さらに、シリカヒューム、スラグ、フライアッシュ、石膏などの各種の混和材の併用も妨げない。
【００１０】
【作用】
上記コンクリート廃材の微粉末のコンクリートやモルタルへの作用効果は、次のような理由によるものと推定される。すなわち、コンクリート廃材の微粉末を細骨材の代替で混入したコンクリートやモルタルでは、この微粉末がセメント粒子のフロック構造に進入し、セメントの分散に寄与し、セメントの水和を促進する。
また、このコンクリート廃材の微粉末は、水和したセメント硬化体を含むため、微細な空隙を有しており、練混ぜ水の一部を吸水して、見かけ上の水セメント比を低下させる。そのため、蒸気養生後にコンクリートやモルタルの強度低下を引き起こさない程度の硬さになるまでの前置き時間を短くすることができる。
【００１１】
蒸気養生後、乾燥養生を行った場合には、微粉末の保水性は通常の細骨材よりも大きいため、その微粉中の水分がセメントの水和に寄与し、微粉を混入していないコンクリートやモルタルよりも圧縮強度は増加する。
比較例に用いた硬質砂岩微粉末においては、コンクリート廃材の微粉末のような微細な空隙を有しておらず、ブリ−ディング水の発生は抑制するもののコンクリート廃材の微粉末のような作用は認められない。
【００１２】
【実施例】
次に、本発明の実施例を説明する。
〈使用材料〉
セメント： 秩父小野田（株）製、普通ポルトランドセメント
細骨材： 静岡県小笠産陸砂
粗骨材： 茨城県岩瀬産砕石
高性能減水剤： 花王（株）製、商品名「マイティ１５０」
本発明で使用の微粉末：最大寸法０．１５ｍｍ以下のコンクリート廃材の微粉末
比較例で使用の微粉末：最大寸法０．１５ｍｍ以下の硬質砂岩粉末
【００１３】
表１に示す各種の配合のコンクリートを、ＪＩＳ Ａ １１３８（試験室におけるコンクリートの作り方）に準じて、強制練りミキサーで練混ぜた。
そして、これらを用いて、ＪＩＳ Ａ １１０８（コンクリートの圧縮強度試験方法）に準拠して、φ１０×２０ｃｍの供試体を成形し、２時間および４時間の前置き時間後に蒸気養生（温度上昇速度：１５℃／時間、最高温度：６５℃、保持時間：５時間、徐冷：自然放冷）を行って硬化体を作り、材齢１日および７日（気中養生：２０℃，６０％Ｒ．Ｈ．）でその圧縮強度試験を行った。
結果を表２に示す。
なお、比較例は、コンクリート廃材の微粉末の代わりに硬質砂岩粉末を用いたものである。
【００１４】
【表１】
【表２】
表２に示したように、本発明のように、コンクリート廃材の微粉末を細骨材の一部に代替すると、この微粉末を使用しないコンクリート、あるいは別の微粉末を使用したコンクリートと比較して、強度発現が向上することがわかる。
【００１７】
【発明の効果】
本発明のようにコンクリート廃材の微粉末を使用することにより、コンクリートやモルタルのブリーディング量を減少でき、蒸気養生工程の前置き時間を短縮することができ、蒸気養生工程を短くできる。また、蒸気養生後の圧縮強度が増大し、さらに、保水性が向上するため、蒸気養生後に乾燥養生を行っても圧縮強度の発現が大きい。[0001]
[Industrial application fields]
The present invention relates to a method for producing a hardened concrete body or a hardened mortar body that performs steam curing.
[0002]
[Prior art]
When steam curing of ordinary cement concrete or mortar is performed, it is necessary to allow sufficient time before the steam curing process to prevent cracking due to temperature rise.
As a method for shortening the pre-treatment time, a method for significantly reducing the water-cement ratio, a method for adding a curing accelerator and a quick setting agent, and the like have been devised.
The molding method of the super-kneaded kneaded material with a reduced water-cement ratio requires a special molding machine that increases vibration time, compaction time, and the like as compared with ordinary concrete and mortar molding methods.
In addition, the method of adding a curing accelerator and a quick setting agent increases the cost significantly.
[0003]
On the other hand, for concrete and mortar after steam curing, sprinkling curing and underwater curing are generally not carried out from the viewpoint of facilities and costs, and are underwater curing because they are close to dry curing. The strength expression cannot be expected more than the case, and the curing days are required to obtain the required strength.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described points, and shortens the pre-treatment time before steam curing when steam curing is performed to produce a hardened concrete body or mortar hardened body, and the strength expression of the cured body is achieved. It aims at improving.
[0005]
[Means for Solving the Problems]
As a result of studies to solve the above-described problems, the present inventors have focused on fine powder of concrete waste materials. This is waste generated when producing recycled aggregate from concrete waste. That is, the present invention is a method for producing a hardened concrete body or a mortar hardened body by steam curing a kneaded material containing cement, aggregate, and water, and a part of the fine aggregate in the kneaded material is mixed with concrete. This is a fine powder of concrete waste with a particle size of 0.3 mm or less that is generated when pulverizing waste material and sieving it into coarse and fine aggregates from concrete waste. % Substitute.
[0006]
And the mixing amount of the fine powder of this concrete waste material can reduce the bleeding amount of fresh concrete or mortar, and the hardening time of concrete or mortar is shortened. Moreover, even if it receives dry curing after steam curing, the expression of the compressive strength of concrete and mortar increases due to the mixing of the fine powder of the concrete waste material, and the number of curing days for obtaining the required strength can be reduced.
[0007]
The particle size of the fine powder of the concrete waste material is preferably about 0.3 mm or less, which is finer than ordinary fine aggregate.
In addition, when the fine powder is 0.3 mm or less, the use amount of this fine powder is not effective if it is less than 0.5% by weight with respect to the fine aggregate, and if it exceeds 30% by weight, the consistency is poor. Therefore, it is preferably 0.5 to 30% by weight and particularly preferably 0.5 to 25% by weight with respect to the fine aggregate.
In addition, when the particle size of the concrete waste fine powder becomes finer, the water retention increases, so the upper limit of the amount of use becomes low, and when a fine powder of 0.15 mm or less is used, the fine powder against the fine aggregate The substitute amount is particularly preferably 0.5 to 15% by weight.
[0008]
In addition, the fine powder of concrete waste used in the present invention is generated when pulverizing concrete waste and when sieving coarse aggregate and fine aggregate from the crushed concrete waste, and conventionally disposed as waste. Can be used effectively.
Therefore, although the amount used varies depending on the particle size and other conditions, it is preferable to use a large amount of fine powder of concrete waste material from the viewpoint of effective use of the waste material.
[0009]
Here, as the cement, various portland cements such as normal, early strength, super early strength, moderate heat, white, and various mixed cements mixed with silica, slag, fly ash, etc. can be used. Naphthalene sulfonate formalin condensate, melamine sulfonate formalin condensate, polycarboxylic acid, lignin sulfonate, polyalkylallyl sulfonic acid used in steam-cured concrete cured bodies and steam-cured mortar cured bodies The use of various admixtures such as silica and high-condensation triazine, and various admixtures such as silica fume, slag, fly ash and gypsum is not hindered.
[0010]
[Action]
The effect of the above-mentioned concrete waste material on the concrete and mortar is presumed to be as follows. That is, in concrete or mortar in which fine powder of concrete waste is mixed in place of fine aggregate, this fine powder enters the flock structure of cement particles, contributes to cement dispersion, and promotes cement hydration.
Further, since the concrete waste fine powder contains a hydrated cement hardened body, it has fine voids and absorbs a part of the mixed water to lower the apparent water cement ratio. For this reason, it is possible to shorten the time required for the pre-treatment time until the hardness of the concrete or mortar does not cause a decrease in strength after steam curing.
[0011]
When dry curing is performed after steam curing, the water retention of fine powder is greater than that of ordinary fine aggregate, so the moisture in the fine powder contributes to the hydration of the cement and the concrete does not contain fine powder. Compressive strength increases more than mortar.
The hard sandstone fine powder used in the comparative example does not have fine voids like the fine powder of concrete waste, and the action like the fine powder of concrete waste is suppressed although the generation of bleeding water is suppressed. unacceptable.
[0012]
【Example】
Next, examples of the present invention will be described.
<Materials used>
Cement: Chichibu Onoda Co., Ltd., ordinary Portland cement fine aggregate: Coarse aggregate from Ogasa, Ogasa, Shizuoka Prefecture: High-performance water-reducing agent from Iwase, Ibaraki, trade name "Mighty 150"
Fine powder used in the present invention: fine powder of a concrete waste material having a maximum size of 0.15 mm or less. Fine powder used in a comparative example: hard sandstone powder having a maximum size of 0.15 mm or less.
Concretes having various blends shown in Table 1 were kneaded with a forced kneading mixer according to JIS A 1138 (how to make concrete in a test room).
And using these, in accordance with JIS A 1108 (concrete compressive strength test method), a specimen of φ10 × 20 cm was molded, and after 2 hours and 4 hours of pre-curing time, steam curing (temperature rise rate: 15 C./hour, maximum temperature: 65 ° C., holding time: 5 hours, slow cooling: natural cooling) to produce a cured product, and age 1 day and 7 days (air curing: 20 ° C., 60% R.C.). H.) was subjected to the compressive strength test.
The results are shown in Table 2.
In the comparative example, a hard sandstone powder is used instead of the fine powder of the concrete waste material.
[0014]
[Table 1]
[Table 2]
As shown in Table 2, when the fine powder of the concrete waste is replaced with a part of the fine aggregate as in the present invention, it is compared with the concrete not using this fine powder or the concrete using another fine powder. It can be seen that the strength expression is improved.
[0017]
【The invention's effect】
By using the fine powder of concrete waste material as in the present invention, the amount of bleeding of concrete and mortar can be reduced, the pre-treatment time of the steam curing process can be shortened, and the steam curing process can be shortened. Moreover, since the compressive strength after steam curing is increased and the water retention is improved, even if dry curing is performed after steam curing, the expression of compressive strength is large.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14249095A JP3628070B2 (en) | 1995-05-17 | 1995-05-17 | Method for producing hardened concrete or hardened mortar |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14249095A JP3628070B2 (en) | 1995-05-17 | 1995-05-17 | Method for producing hardened concrete or hardened mortar |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08310849A JPH08310849A (en) | 1996-11-26 |
| JP3628070B2 true JP3628070B2 (en) | 2005-03-09 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14249095A Expired - Fee Related JP3628070B2 (en) | 1995-05-17 | 1995-05-17 | Method for producing hardened concrete or hardened mortar |
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| Country | Link |
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| JP (1) | JP3628070B2 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6648962B2 (en) * | 2001-09-06 | 2003-11-18 | W. R. Grace & Co.-Conn. | Micro-granulose particulates |
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| Publication number | Publication date |
|---|---|
| JPH08310849A (en) | 1996-11-26 |
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