JP2011195354A - Method for producing high strength precast concrete - Google Patents

Method for producing high strength precast concrete Download PDF

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JP2011195354A
JP2011195354A JP2010061889A JP2010061889A JP2011195354A JP 2011195354 A JP2011195354 A JP 2011195354A JP 2010061889 A JP2010061889 A JP 2010061889A JP 2010061889 A JP2010061889 A JP 2010061889A JP 2011195354 A JP2011195354 A JP 2011195354A
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concrete
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precast concrete
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JP5373677B2 (en
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Yuji Mitani
裕二 三谷
Goshi Nakazaki
豪士 中崎
Mitsuru Tanimura
充 谷村
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Taiheiyo Cement Corp
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Abstract

PROBLEM TO BE SOLVED: To provide a method for producing high strength precast concrete, which can be efficiently produced by reducing a curing time while ensuring the development of a compressive strength exceeding 130 N/mm.SOLUTION: After a high strength concrete using a binding agent containing low-heat cement and a pozzolan-based fine powder is placed and molded, the concrete is precured at ordinary temperature for 2-4 hours. Then, after the temperature is raised to the maximum of 60-90°C at the rate of 5-10°C/h, and the concrete is kept at the maximum temperature for 3-9 hours, the concrete is cooled to ordinary temperature to be released from the mold.

Description

本発明は、高強度プレキャストコンクリートの製造方法に関するものである。特に、圧縮強度が130N/mmを超える超高強度プレキャストコンクリート部材の製造方法に関するものである。 The present invention relates to a method for producing high-strength precast concrete. In particular, the present invention relates to a method for producing an ultra-high strength precast concrete member having a compressive strength exceeding 130 N / mm 2 .

近年、超高層建築構造物等の用途に用いられるコンクリートとして、圧縮強度80〜120N/mm又はそれ以上の高強度コンクリートが実用化されている。このような高強度コンクリートを用いたプレキャスト部材は、品質管理の行き届いた工場で製造されている。圧縮強度110〜130N/mmクラスの高強度プレキャストコンクリート部材は、コンクリート打設成形後、常温で4〜6時間前養生を行った後、15〜20℃/hの昇温速度で最高温度60〜90℃まで昇温し、最高温度で3〜9時間保持した後、8〜12時間かけて徐冷し、脱型して気中又は水中養生を行うのが一般的である(例えば特許文献1)。前養生時間や昇温速度などにより広い範囲の記載がなされた特許文献も見られるが、いずれの場合も実施例は前記の範囲に収まっている(例えば特許文献2〜4)。 In recent years, high-strength concrete having a compressive strength of 80 to 120 N / mm 2 or more has been put into practical use as concrete used for applications such as super high-rise building structures. Such a precast member using high-strength concrete is manufactured in a factory with good quality control. High strength precast concrete members of compressive strength 110 to 130 N / mm 2 class are subjected to pre-curing at room temperature for 4 to 6 hours after concrete casting, and then a maximum temperature of 60 to 15 ° C./h. The temperature is generally raised to ˜90 ° C., held at the maximum temperature for 3 to 9 hours, then gradually cooled over 8 to 12 hours, demolded, and subjected to air or water curing (for example, Patent Documents). 1). Although patent documents in which a wide range is described depending on the pre-curing time, the temperature rising rate, and the like can be seen, in any case, the examples are within the above range (for example, Patent Documents 2 to 4).

一方、圧縮強度が130N/mmを超えるような超高強度コンクリートでは、凝結始発まで12時間以上かかるため、それまでに昇温を始めると十分な強度が得られないことが知られており、12時間〜2日間の前養生時間が設けられている(例えば非特許文献1、2)。 On the other hand, in ultra-high-strength concrete whose compressive strength exceeds 130 N / mm 2 , it takes 12 hours or more to start setting, so it is known that sufficient strength cannot be obtained by starting the temperature rise until then, A pre-curing time of 12 hours to 2 days is provided (for example, Non-Patent Documents 1 and 2).

最近では、圧縮強度が130N/mmを超える超高強度プレキャストコンクリート部材の需要が高まってきているが、12時間以上の前養生を行う現行の養生方法では、部材の製造方法としては非効率である。 Recently, there is an increasing demand for ultra-high-strength precast concrete members having a compressive strength exceeding 130 N / mm 2 , but the current curing method in which pre-curing for 12 hours or more is inefficient as a method for producing the members. is there.

特開2009−073700号公報JP 2009-073700 A 特開2007−238439号公報JP 2007-238439 A 特開2008−247709号公報JP 2008-247709 A 特開2008−156168号公報JP 2008-156168 A

日本建築学会大会学術講演梗概集(中国)2008年9月,pp.829−830Abstracts of Annual Meeting of Architectural Institute of Japan (China), September 2008, pp. 829-830 日本建築学会大会学術講演梗概集(東北)2009年8月,pp.889−890Abstracts of Annual Meeting of Architectural Institute of Japan (Tohoku) August 2009, pp. 889-890

圧縮強度が130N/mmを超える超高強度プレキャストコンクリート部材を蒸気養生等の高温履歴を与えて促進養生することにより製造しようとするときに、凝結始発までに昇温すると強度低下が起こるため、12時間以上の前養生が必要となり、効率的な製造ができなかった。したがって、十分な圧縮強度を発現することができ、かつ養生時間を短縮して効率的に、圧縮強度が130N/mmを超える超高強度プレキャストコンクリート部材を製造する方法が望まれている。 When trying to produce an ultra-high-strength precast concrete member with a compressive strength exceeding 130 N / mm 2 by giving a high-temperature history such as steam curing to promote curing, the strength decreases when the temperature rises before the initial setting, Pre-curing for 12 hours or more was required, and efficient production was not possible. Therefore, there is a demand for a method of producing an ultra-high strength precast concrete member capable of expressing sufficient compressive strength and efficiently shortening the curing time and having a compressive strength exceeding 130 N / mm 2 .

そこで、上記のような問題点に鑑みて、本発明は、130N/mmを超える圧縮強度の発現性を確保しつつ、養生時間を短縮して効率的に製造することのできる高強度プレキャストコンクリートの製造方法を提供することを目的とする。 Therefore, in view of the above problems, the present invention is a high-strength precast concrete that can be efficiently produced by shortening the curing time while securing the expression of compressive strength exceeding 130 N / mm 2. It aims at providing the manufacturing method of.

上記課題を解決するために、本発明は、低発熱形セメントとポゾラン質微粉末とを含む結合材を用いた高強度プレキャストコンクリートの製造方法であって、コンクリートを打設成形した後、常温にて2〜4時間前養生し、5〜10℃/hの昇温速度で最高温度60〜90℃まで昇温し、最高温度で3〜9時間保持した後、常温まで冷却して脱型することを特徴とする高強度プレキャストコンクリートの製造方法を提供する(請求項1)。   In order to solve the above-mentioned problems, the present invention is a method for producing high-strength precast concrete using a binder containing a low heat-generating cement and a pozzolanic fine powder, and after casting the concrete, 2 to 4 hours before curing, raise the temperature to 5 to 10 ° C./h to a maximum temperature of 60 to 90 ° C., hold at the maximum temperature for 3 to 9 hours, cool to room temperature, and demold A method for producing a high-strength precast concrete is provided.

上記発明(請求項1)によれば、圧縮強度の低下を引き起こすことなく、前養生時間を短縮することができるため、概ね24時間以内の脱型が可能となり、圧縮強度が130N/mmを超える超高強度プレキャストコンクリート部材を効率的に製造することができる。 According to the above invention (Invention 1), since the pre-curing time can be shortened without causing a decrease in the compressive strength, demolding within about 24 hours becomes possible, and the compressive strength is 130 N / mm 2 . The super-high-strength precast concrete member exceeding can be manufactured efficiently.

なお、本発明において「コンクリート部材」には、例えば、細骨材及び粗骨材を含まないセメントペースト部材;少なくとも細骨材を含み、粗骨材を含まないモルタル部材;少なくとも細骨材及び粗骨材を含むコンクリート部材等が含まれる。   In the present invention, the “concrete member” includes, for example, a cement paste member that does not include fine aggregate and coarse aggregate; a mortar member that includes at least fine aggregate and does not include coarse aggregate; at least fine aggregate and coarse aggregate Concrete members including aggregates are included.

本発明によれば、前養生時間の短縮による圧縮強度の低下を引き起こすことなく、130N/mmを超える圧縮強度の発現性を確保しつつ、養生時間を短縮して効率的に製造することのできる高強度プレキャストコンクリートの製造方法を提供することができる。 According to the present invention, it is possible to efficiently produce by shortening the curing time while ensuring the expression of compressive strength exceeding 130 N / mm 2 without causing a decrease in the compressive strength due to the shortening of the pre-curing time. The manufacturing method of the high strength precast concrete which can be provided can be provided.

以下、本発明の一実施形態について詳細に説明する。
本実施形態に係る高強度プレキャストコンクリートの製造に用いる結合材は、低発熱形セメントとポゾラン質微粉末とを含むものであり、高強度コンクリート用セメントとして市販されているもの(例えば、太平洋セメント社製:SFPC)を用いることができる。
Hereinafter, an embodiment of the present invention will be described in detail.
The binder used for manufacturing the high-strength precast concrete according to the present embodiment includes a low heat generation type cement and a pozzolanic fine powder, and is commercially available as a cement for high-strength concrete (for example, Taiheiyo Cement Corporation). Manufactured by: SFPC).

上記低発熱形セメントとしては低熱ポルトランドセメント、中庸熱ポルトランドセメント、高炉セメント、フライアッシュセメント、シリカセメント、石灰石微粉末を混合したセメントなどがあげられる。特に、高強度コンクリートの流動性や長期強度発現性に優れる点で、2CaO・SiO含有量が30〜60質量%、3CaO・Al含有量が7質量%以下、3CaO・SiO含有量が50質量%以下のポルトランドセメントを用いることが好ましい。また、上記ポゾラン質微粉末も特に限定されるものではないが、例えば、シリカフューム、シリカダスト、フライアッシュ、火山灰、シリカゾル、沈降シリカ等が挙げられる。一般に、シリカフュームやシリカダストは、その平均粒径が1.0μm以下であり、高強度コンクリート用セメントを調製するに際して粉砕等をする必要がなく、好適に用いることができる。高強度コンクリートの流動性の観点から、ポゾラン質微粉末のBET比表面積は5〜25m/g、特に好ましくは5〜15m/gであり、上記結合材中のポゾラン質微粉末の配合割合は5〜25質量%であるのが好ましい。さらに、上記結合材には、低発熱形セメントに由来する石膏に、さらに石膏を加えて、SO換算で3〜6質量%の石膏を含むことが好ましい。 Examples of the low heat generation type cement include low heat Portland cement, medium heat Portland cement, blast furnace cement, fly ash cement, silica cement, cement mixed with fine limestone powder, and the like. In particular, from the viewpoint of excellent flowability and long-term strength development of high strength concrete, 2CaO · SiO 2 content of 30 to 60 wt%, 3CaO · Al 2 O 3 content of 7 wt% or less, 3CaO · SiO 2 content It is preferable to use Portland cement having an amount of 50% by mass or less. The pozzolanic fine powder is not particularly limited, and examples thereof include silica fume, silica dust, fly ash, volcanic ash, silica sol, and precipitated silica. In general, silica fume and silica dust have an average particle size of 1.0 μm or less, and need not be pulverized when preparing a cement for high-strength concrete, and can be suitably used. From the viewpoint of fluidity of high-strength concrete, the BET specific surface area of the pozzolanic fine powder is 5 to 25 m 2 / g, particularly preferably 5 to 15 m 2 / g, and the blending ratio of the pozzolanic fine powder in the binder Is preferably 5 to 25% by mass. Furthermore, it is preferable that gypsum derived from the low heat-generating cement is further added to gypsum derived from the low heat generation type cement to contain 3 to 6% by mass of gypsum in terms of SO 3 .

上記結合材に、水及び細骨材、並びに所望により粗骨材や各種混和剤を配合して混練し、型枠に打設して養生を行い、高強度プレキャストコンクリートの硬化体を得ることができる。   Mixing and kneading water and fine aggregate, and, if desired, coarse aggregate and various admixtures with the binder, curing it by placing it on a mold, and obtaining a hardened body of high-strength precast concrete it can.

上記水の配合量(水結合材比)は特に限定されないが、結合材の全量に対して9〜20質量%であるのが好ましい。水結合材比が9質量%未満であると、所望の流動性を確保するために減水剤の添加率を増加させる必要があり、それによりコストアップや凝結遅延が生じるおそれがある。また、20質量%を超えると、硬化体の圧縮強度が十分に得られないおそれがある。   The blending amount of water (water binder ratio) is not particularly limited, but is preferably 9 to 20% by mass with respect to the total amount of binder. If the water binder ratio is less than 9% by mass, it is necessary to increase the rate of addition of the water reducing agent in order to ensure the desired fluidity, which may cause an increase in cost and a delay in setting. Moreover, when it exceeds 20 mass%, there exists a possibility that the compressive strength of a hardening body may not fully be obtained.

本実施形態において使用し得る細骨材としては、特に限定されず、川砂、山砂、陸砂、海砂、砕砂、珪砂等の砂系細骨材;各種スラグ細骨材;各種軽量細骨材;各種重量細骨材;再生細骨材又はこれらの混合物等を用いることができる。   The fine aggregate that can be used in the present embodiment is not particularly limited, and sand-based fine aggregates such as river sand, mountain sand, land sand, sea sand, crushed sand, and quartz sand; various slag fine aggregates; various lightweight fine bones Various weight fine aggregates; recycled fine aggregates or a mixture thereof can be used.

本実施形態において所望により配合され得る粗骨材としては、特に限定されるものではなく、砂利、砕石、各種軽量粗骨材、各種重量粗骨材、各種スラグ粗骨材、再生粗骨材又はこれらの混合物等を用いることができる。   The coarse aggregate that can be blended as desired in the present embodiment is not particularly limited, gravel, crushed stone, various lightweight coarse aggregates, various heavy coarse aggregates, various slag coarse aggregates, recycled coarse aggregates or Mixtures of these can be used.

また、本実施形態において所望により配合され得る各種混和剤としては、特に水の配合量を極めて少なくし(9〜20質量%)、かつ所定のフロー(モルタルフロー、スランプフロー等)を確保するために、減水剤を用いるのが好ましい。なお、減水剤の配合量は、所定のフローを確保し得るように適宜決定すればよい。   Moreover, as various admixtures that can be blended as desired in the present embodiment, in particular, the blending amount of water is extremely small (9 to 20% by mass) and a predetermined flow (mortar flow, slump flow, etc.) is ensured. It is preferable to use a water reducing agent. In addition, what is necessary is just to determine the compounding quantity of a water reducing agent suitably so that a predetermined | prescribed flow can be ensured.

当該減水剤としては、例えば、リグニン系、ナフタレンスルホン酸系、メラミン系、ポリカルボン酸系の減水剤、AE減水剤、高性能減水剤、高性能AE減水剤等が挙げられるが、これらに限定されるものではない。   Examples of the water reducing agent include, but are not limited to, lignin-based, naphthalene sulfonic acid-based, melamine-based, polycarboxylic acid-based water reducing agents, AE water reducing agents, high-performance water reducing agents, and high-performance AE water reducing agents. Is not to be done.

さらに高強度プレキャストコンクリート部材が硬化後に収縮し、ひび割れ、変形等を生じることを防ぐため、収縮低減剤及び/又は膨張材を添加しても良い。その配合量は、収縮を抑える効果が得られるように適宜決定すればよい。当該収縮低減剤としては、例えば、低級アルキレンオキシド付加物系、グリコールエーテル系、ポリエーテル系等が上げられるが、これらに限定されるものではない。当該膨張材としては、例えば、石灰系、エトリンガイト系、石灰−エトリンガイト複合系等が上げられるが、これらに限定されるものではない。   Further, in order to prevent the high-strength precast concrete member from shrinking after curing and causing cracks, deformation, etc., a shrinkage reducing agent and / or an expansion material may be added. What is necessary is just to determine the compounding quantity suitably so that the effect which suppresses shrinkage may be acquired. Examples of the shrinkage reducing agent include, but are not limited to, lower alkylene oxide adducts, glycol ethers, and polyethers. Examples of the inflating material include lime-based, ettringite-based, lime-ettringite-complexed and the like, but are not limited thereto.

本実施形態に係る高強度プレキャストコンクリートの使用材料の投入順序、使用するミキサ、練り混ぜ時間等は特に限定されず、プレキャストコンクリート部材の製造で通常行われている条件を採用することができる。練り混ぜたコンクリートは、鉄筋を配筋された又は無筋の型枠内に打設し、成形する。高強度プレキャストコンクリート部材がパイル、ポール、ヒューム管等の場合には遠心成形を行う。コンクリートの打設成形、遠心成形の方法やスランプフロー等の条件も特に限定されず、通常行われている方法、条件を採用することができる。   The order in which the materials used for the high-strength precast concrete according to the present embodiment are charged, the mixer to be used, the kneading time, and the like are not particularly limited, and the conditions that are normally performed in the production of precast concrete members can be employed. The concrete that has been mixed is placed in a formwork with or without reinforcing bars and molded. If the high-strength precast concrete member is a pile, pole, fume tube, etc., centrifugal molding is performed. Conditions such as concrete casting and centrifugal molding and slump flow are not particularly limited, and usual methods and conditions can be employed.

型枠に打設、成形されたコンクリート成形体は、常温、例えば10〜35℃の温度範囲で2〜4時間前養生を行った後、高温履歴を与えて促進養生を行う。促進養生は、例えば蒸気を用いて、5〜10℃/hの昇温速度で最高温度60〜90℃まで昇温し、最高温度で3〜9時間保持した後、常温まで冷却する。   The concrete molded body cast and molded on the mold is precured for 2 to 4 hours at room temperature, for example, a temperature range of 10 to 35 ° C., and then subjected to accelerated curing by giving a high temperature history. In accelerated curing, for example, using steam, the temperature is increased to a maximum temperature of 60 to 90 ° C. at a temperature increase rate of 5 to 10 ° C./h, held at the maximum temperature for 3 to 9 hours, and then cooled to room temperature.

昇温速度が10℃/hを超えると、高強度プレキャストコンクリート部材の圧縮強度の低下を招くおそれがあり、好ましくない。昇温速度が5℃/hに満たない時は、養生時間の短縮効果が十分に得られないので好ましくない。   If the rate of temperature rise exceeds 10 ° C./h, the compression strength of the high-strength precast concrete member may be lowered, which is not preferable. When the rate of temperature rise is less than 5 ° C./h, the effect of shortening the curing time cannot be obtained sufficiently, which is not preferable.

最高温度及び最高温度での保持時間は、(最高温度)×(保持時間)が、270〜540℃・hとすることが好ましく、450〜500℃・hとすることがより好ましい。(最高温度)×(保持時間)が270℃・hに満たない時は、十分な強度発現が得られないおそれがあり、好ましくない。(最高温度)×(保持時間)が540℃・hを超えるときは、養生時間の短縮効果が十分に得られないので好ましくない。   The maximum temperature and the retention time at the maximum temperature are preferably (maximum temperature) × (retention time) of 270 to 540 ° C. · h, more preferably 450 to 500 ° C. · h. When (maximum temperature) × (holding time) is less than 270 ° C. · h, there is a possibility that sufficient strength expression may not be obtained, which is not preferable. When (maximum temperature) × (holding time) exceeds 540 ° C. · h, the effect of shortening the curing time cannot be obtained sufficiently, which is not preferable.

冷却は、20℃/h以下の降温速度で行うことが好ましい。降温速度が20℃/hを超えると、高強度プレキャストコンクリート部材のひび割れや変形の原因となり、好ましくない。8時間以上の時間をかけて放冷することも可能であるが、脱型間での時間を短縮するため、10〜20℃/hの降温速度で冷却することが好ましい。   Cooling is preferably performed at a temperature lowering rate of 20 ° C./h or less. If the temperature lowering rate exceeds 20 ° C./h, it may cause cracking or deformation of the high-strength precast concrete member, which is not preferable. Although it is possible to cool for 8 hours or more, in order to shorten the time between demolding, it is preferable to cool at a temperature decreasing rate of 10 to 20 ° C./h.

常温まで冷却した高強度プレキャストコンクリート部材は、型枠から脱型する。冷却の途中の、例えば40℃で脱型してもよいが、高温での脱型はやけどなどの危険を伴うとともに、外気温との温度差によりひび割れを生じるおそれがあり、好ましくない。脱型後は、常温で気中養生を行う。脱型は、常温に降温したのち数時間から数日間、常温に放置した後に行っても良い。   The high-strength precast concrete member cooled to room temperature is removed from the mold. The mold may be removed during cooling, for example, at 40 ° C., but the removal at a high temperature is not preferable because there is a risk of burns and there is a risk of cracking due to a temperature difference from the outside temperature. After demolding, perform air curing at room temperature. Demolding may be performed after the temperature is lowered to room temperature and then left at room temperature for several hours to several days.

上述した本実施形態に係る高強度プレキャストコンクリートの製造方法によれば、前養生の短縮による強度低下を引き起こすことなく、概ね1日の養生で脱型できるため、効率的な高強度プレキャストコンクリート部材の製造が可能となる。   According to the manufacturing method of the high-strength precast concrete which concerns on this embodiment mentioned above, since it can demold by the curing | curing for 1 day, without causing the strength fall by shortening of precuring, efficient high-strength precast concrete member Manufacture is possible.

以上説明した実施形態は、本発明の理解を容易にするために記載されたものであって、本発明を限定するために記載されたものではない。したがって、上記実施形態に開示された各要素は、本発明の技術的範囲に属する全ての設計変更や均等物をも含む趣旨である。   The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

以下、実施例及び比較例を挙げて、本発明をさらに詳細に説明するが、本発明は下記の実施例等に何ら限定されるものではない。   EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further in detail, this invention is not limited to the following Example etc. at all.

〔コンクリート組成物の配合〕
低発熱形セメントとポゾラン質微粉末とを含む高強度コンクリート用セメントC(太平洋セメント社製,製品名:SFPC)、細骨材S(砕砂,密度:2.56g/cm、吸水率:1.30%)、粗骨材G(砕石,密度:2.64g/cm,実績率:59%,粗骨材最大粒径:10mm)、高性能減水剤SP(BASFポゾリス社製,製品名:SP−8HU)及び水W(水道水)を材料として用い、表1に示す配合に従って、コンクリート組成物を作製した。
[Composition of concrete composition]
Cement C for high-strength concrete containing low exothermic cement and pozzolanic fine powder (manufactured by Taiheiyo Cement, product name: SFPC), fine aggregate S (crushed sand, density: 2.56 g / cm 3 , water absorption: 1 .30%), coarse aggregate G (crushed stone, density: 2.64 g / cm 3 , actual rate: 59%, coarse aggregate maximum particle size: 10 mm), high-performance water reducing agent SP (manufactured by BASF Pozzolith, product name) : SP-8HU) and water W (tap water) were used as materials, and concrete compositions were prepared according to the formulation shown in Table 1.

Figure 2011195354
Figure 2011195354

[コンクリートの養生]
上述のようにして得られたコンクリート組成物をJIS−A1132に規定される型枠に詰め、封緘状態で表2に示す温度履歴で蒸気養生を行った。20℃に降温した後は、そのまま放置し、材齢7日(養生開始から168時間)で型枠から脱型し、圧縮強度試験に供した。
[Concrete curing]
The concrete composition obtained as described above was packed in a mold defined in JIS-A1132, and steam curing was performed with a temperature history shown in Table 2 in a sealed state. After the temperature was lowered to 20 ° C., it was left as it was, removed from the mold at a material age of 7 days (168 hours from the start of curing), and subjected to a compressive strength test.

Figure 2011195354
Figure 2011195354

[圧縮強度の測定]
上述のようにして得られたコンクリート供試体(実施例1、2、比較例1、2)について、JIS−A1108に準拠して圧縮強度を測定した。
結果を表3に示す。
[Measurement of compressive strength]
The compressive strength was measured according to JIS-A1108 for the concrete specimens (Examples 1 and 2 and Comparative Examples 1 and 2) obtained as described above.
The results are shown in Table 3.

Figure 2011195354
Figure 2011195354

表3に示すように、前置き3時間、昇温速度20℃/hの比較例1では、凝結始発前に高温に達するために硬化に異常を生じ、十分な圧縮強度が得られないが、前置き3時間であっても昇温速度が5〜10℃/hの実施例1、2では、十分な前置き時間(12時間)をとった比較例2と同等の圧縮強度が得られた。昇温速度が5〜10℃/hの範囲であれば、凝結始発前に昇温しても硬化に異常を生じることなく強度発現性が得られるものと考えられる。   As shown in Table 3, in Comparative Example 1 where the heating rate was 20 ° C./h for 3 hours in the introduction, the temperature reached a high temperature before the start of condensation, so that the curing was abnormal and sufficient compression strength was not obtained. Even in 3 hours, in Examples 1 and 2 in which the rate of temperature increase was 5 to 10 ° C./h, a compressive strength equivalent to that in Comparative Example 2 in which a sufficient preliminary time (12 hours) was taken was obtained. If the rate of temperature increase is in the range of 5 to 10 ° C./h, it is considered that strength development can be obtained without causing abnormality in curing even if the temperature is increased before the start of condensation.

以上の結果から、低発熱形セメントとポゾラン質微粉末とを含む結合材を用いた130N/mm超クラスの高強度プレキャストコンクリートの製造において、常温での前養生を3時間程度としても、昇温速度を5〜10℃/hの範囲とすることにより、十分な強度発現性を保ちながら、養生時間の短縮が図られることが判明した。 Based on the above results, in the production of high strength precast concrete of 130 N / mm 2 and higher class using a binder containing low exothermic cement and pozzolanic fine powder, even if the pre-curing at room temperature is about 3 hours, It has been found that by setting the temperature rate in the range of 5 to 10 ° C./h, the curing time can be shortened while maintaining sufficient strength.

本発明の高強度プレキャストコンクリートの製造方法は、圧縮強度が130N/mmを超える超高強度プレキャストコンクリート部材の効率的な製造方法として有用である。 The method for producing high-strength precast concrete of the present invention is useful as an efficient method for producing an ultra-high-strength precast concrete member having a compressive strength exceeding 130 N / mm 2 .

Claims (1)

低発熱形セメントとポゾラン質微粉末とを含む結合材を用いた高強度プレキャストコンクリートの製造方法であって、
コンクリートを打設成形した後、常温にて2〜4時間前養生し、5〜10℃/hの昇温速度で最高温度60〜90℃まで昇温し、最高温度で3〜9時間保持した後、常温まで冷却して脱型することを特徴とする高強度プレキャストコンクリートの製造方法。
A method for producing high-strength precast concrete using a binder containing low heat-generating cement and pozzolanic fine powder,
After casting and molding concrete, pre-cured at room temperature for 2 to 4 hours, heated to a maximum temperature of 60 to 90 ° C. at a temperature increase rate of 5 to 10 ° C./h, and held at the maximum temperature for 3 to 9 hours. Then, it cools to normal temperature and demolds, The manufacturing method of the high strength precast concrete characterized by the above-mentioned.
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KR101943037B1 (en) 2018-02-14 2019-01-28 (주)한필이엔지 Composition for high strength concrete panel and high strength concrete panel for inner or outer wall of building prepared by using the same
JP2019055489A (en) * 2017-09-20 2019-04-11 株式会社ピーエス三菱 Method for producing precast concrete member
KR102199937B1 (en) * 2019-10-02 2021-01-07 아세아시멘트(주) High performance mortar composition for large area panels
JP2021154552A (en) * 2020-03-26 2021-10-07 住友大阪セメント株式会社 Method to suppress micro-delamination of precast concrete product, device to suppress micro-delamination of precast concrete product, and manufacturing method of precast concrete product
CN114436573A (en) * 2022-02-17 2022-05-06 浙江瑞腾建筑新材料有限公司 High-strength corrosion-resistant concrete and preparation method of prefabricated part thereof

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JP2002249386A (en) * 2001-02-20 2002-09-06 Shimizu Corp Method for high temperature steam curing of concrete product
JP2007238439A (en) * 1998-08-24 2007-09-20 Denki Kagaku Kogyo Kk Cement composition, concrete and method of producing concrete hardened body using the same

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JPH09174532A (en) * 1995-12-26 1997-07-08 Takenaka Komuten Co Ltd Manufacture of pca plate and production equipment of pca plate used therefor
JP2007238439A (en) * 1998-08-24 2007-09-20 Denki Kagaku Kogyo Kk Cement composition, concrete and method of producing concrete hardened body using the same
JP2002249386A (en) * 2001-02-20 2002-09-06 Shimizu Corp Method for high temperature steam curing of concrete product

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019055489A (en) * 2017-09-20 2019-04-11 株式会社ピーエス三菱 Method for producing precast concrete member
KR101943037B1 (en) 2018-02-14 2019-01-28 (주)한필이엔지 Composition for high strength concrete panel and high strength concrete panel for inner or outer wall of building prepared by using the same
KR102199937B1 (en) * 2019-10-02 2021-01-07 아세아시멘트(주) High performance mortar composition for large area panels
JP2021154552A (en) * 2020-03-26 2021-10-07 住友大阪セメント株式会社 Method to suppress micro-delamination of precast concrete product, device to suppress micro-delamination of precast concrete product, and manufacturing method of precast concrete product
CN114436573A (en) * 2022-02-17 2022-05-06 浙江瑞腾建筑新材料有限公司 High-strength corrosion-resistant concrete and preparation method of prefabricated part thereof

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