JP2000109378A - Lightweight concrete - Google Patents
Lightweight concreteInfo
- Publication number
- JP2000109378A JP2000109378A JP10286215A JP28621598A JP2000109378A JP 2000109378 A JP2000109378 A JP 2000109378A JP 10286215 A JP10286215 A JP 10286215A JP 28621598 A JP28621598 A JP 28621598A JP 2000109378 A JP2000109378 A JP 2000109378A
- Authority
- JP
- Japan
- Prior art keywords
- concrete
- coarse aggregate
- aggregate
- water
- water absorption
- 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.)
- Withdrawn
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- Porous Artificial Stone Or Porous Ceramic Products (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、軽量コンクリート
に関し、特に、高層RCビルの柱や梁等の建築高層素
材、カーテンウォール等の建築非構造部材、鉄道橋や道
路橋等の土木構造物における上部構造及び下部構造等に
適用される超軽量粗骨材を用いたコンクリートであっ
て、高強度となるように低水/セメント比とした軽量コ
ンクリートに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to lightweight concrete, and more particularly to high-rise building materials such as columns and beams of high-rise RC buildings, non-structural members such as curtain walls, and civil structures such as railway bridges and road bridges. The present invention relates to a concrete using ultra-lightweight coarse aggregate applied to an upper structure, a lower structure, and the like, which has a low water / cement ratio so as to have high strength.
【0002】[0002]
【従来の技術】既存の超軽量粗骨材等の軽量粗骨材は吸
水性が高く、該骨材の事前吸水が不十分な状態では、練
混ぜ直後から該骨材がコンクリート中の水を吸水し、打
込み時における作業性が著しく低下する。そのため、既
存の軽量骨材を用いたコンクリートでは作業性を確保す
るため、十分な事前吸水を行った状態で該骨材を使用す
るのが一般的である。2. Description of the Related Art Existing light-weight coarse aggregates, such as ultra-light-weight coarse aggregates, have a high water absorption, and in a state where the pre-absorption of the aggregates is insufficient, the aggregates immediately remove water in concrete immediately after mixing. Water is absorbed and workability at the time of driving is significantly reduced. Therefore, in order to secure workability, it is common to use the existing lightweight concrete in a state where sufficient water absorption has been performed in order to secure workability.
【0003】しかし、これは、初期材齢において、コン
クリートの内部に欠陥を形成させる原因となっている。
つまり、事前吸水した該骨材はコンクリートの硬化過程
においてセメントペースト部に骨材中の含水を供給する
ため、セメントペースト部の組織を膨潤させ、粗大空隙
を生じさせる。[0003] However, this causes a defect to be formed inside the concrete at an early age.
That is, the pre-absorbed aggregate supplies the cement paste portion with water contained in the aggregate during the hardening process of the concrete, so that the structure of the cement paste portion swells to generate coarse voids.
【0004】特に、このような内部欠陥は該骨材とセメ
ントペーストが接する界面部分に生じやすく、セメント
ペーストと骨材間の付着強度の低下、コンクリートの透
水性及び透気性の増大等を引き起こすため、耐久的なコ
ンクリートの製造を困難にしている。In particular, such internal defects are likely to occur at the interface where the aggregate and the cement paste are in contact with each other, causing a decrease in the adhesive strength between the cement paste and the aggregate and an increase in the water permeability and air permeability of the concrete. , Making the production of durable concrete difficult.
【0005】その上、事前吸水した該骨材を用いた場合
には、長期材齢における硬化コンクリートの乾燥収縮が
増大し、構造物にひび割れが発生する一因となってお
り、長期的にもコンクリートの欠陥が増大する傾向とな
っている。[0005] In addition, when the pre-absorbed aggregate is used, the drying shrinkage of the hardened concrete in the long-term age increases, which is one of the causes of the occurrence of cracks in the structure. Concrete defects tend to increase.
【0006】[0006]
【発明が解決しようとする課題】上述のように、軽量粗
骨材の吸水状態が軽量コンクリートの性状に大きな影響
を与えている。そのため、軽量コンクリート製造時にお
いて軽量粗骨材の含水率を管理することは極めて重要で
あるが、その作業は煩雑なものとなっている。従って、
厳密な軽量粗骨材の含水率の管理を行わなくとも、作業
性や耐久性を維持できる軽量コンクリートが望まれてい
る。As described above, the water absorption state of the lightweight coarse aggregate has a great effect on the properties of the lightweight concrete. For this reason, it is extremely important to control the moisture content of the lightweight coarse aggregate during the production of lightweight concrete, but the operation is complicated. Therefore,
There is a demand for lightweight concrete that can maintain workability and durability without strictly controlling the water content of the lightweight coarse aggregate.
【0007】そこで、本発明は、上記従来技術における
問題点に鑑みてなされたものであって、超軽量粗骨材の
使用時の事前吸水の有無及び程度に拘わらず、初期材齢
における内部欠陥を低減することができ、打ち込み時の
作業性と長期的な耐久性をも備えた軽量コンクリートを
提供することを目的とする。Accordingly, the present invention has been made in view of the above-mentioned problems in the prior art, and has been developed in consideration of the internal defect at the initial age regardless of the presence or absence and the degree of prior water absorption at the time of using the ultralight coarse aggregate. It is an object of the present invention to provide a lightweight concrete which can reduce the amount of work, and has workability at the time of driving and long-term durability.
【0008】[0008]
【課題を解決するための手段】本発明者らは、粗骨材と
して特定の超軽量粗骨材を特定の混入量で使用すること
により、上記目的を達成できることを見出した。また、
通常の事前吸水ではなく、予めアルキレンオキサイド重
合物を主成分とする組成物を前記超軽量粗骨材に含ませ
ておくことによって、上記目的がより効果的に達成でき
ることを見出し、本発明を完成させたものである。Means for Solving the Problems The present inventors have found that the above object can be achieved by using a specific ultralight coarse aggregate in a specific mixing amount as a coarse aggregate. Also,
Rather than ordinary pre-absorption, the inventor has found that the above object can be achieved more effectively by including a composition mainly containing an alkylene oxide polymer in advance in the ultralight coarse aggregate, and completed the present invention. It was made.
【0009】請求項1記載の発明は、軽量コンクリート
であって、24時間吸水率が5.0重量%以下及び煮沸
吸水率が10重量%以下、かつ絶乾比重が0.7〜1.
3である超軽量粗骨材を0.3〜0.4m3/m3含み、
単位セメント量が400kg/m3以上、水/セメント
比が40重量%以下であることを特徴とする。The invention according to claim 1 is a lightweight concrete having a 24-hour water absorption of 5.0% by weight or less, a boiling water absorption of 10% by weight or less, and an absolute dry specific gravity of 0.7 to 1.
The ultra-light coarse aggregate is 3 comprises 0.3~0.4m 3 / m 3,
It is characterized in that the unit cement amount is 400 kg / m 3 or more and the water / cement ratio is 40% by weight or less.
【0010】請求項2記載の発明は、前記超軽量粗骨材
の圧壊強度が800N以上であることを特徴とする。The invention according to claim 2 is characterized in that the crushing strength of the ultralight coarse aggregate is 800 N or more.
【0011】請求項3記載の発明は、前記超軽量粗骨材
が、アルキレンオキサイド重合物を主成分とする組成物
を含むこと特徴とする。The invention according to claim 3 is characterized in that the ultra-lightweight coarse aggregate contains a composition containing an alkylene oxide polymer as a main component.
【0012】そして、請求項1記載の発明によれば、2
4時間吸水率が5.0重量%以下及び煮沸吸水率が10
重量%以下、かつ絶乾比重が0.7〜1.3である超軽
量粗骨材を0.3〜0.4m3/m3含み、単位セメント
量が400kg/m3以上、水/セメント比が40重量
%以下の軽量コンクリートであるため、特定の骨材と特
定のコンクリート配合の相乗効果により、該骨材を使用
した軽量コンクリートの作業性が良好となり、軽量コン
クリートの初期材齢における内分欠陥が低減されて耐久
性が向上する。According to the first aspect of the present invention,
4 hours water absorption of 5.0% by weight or less and boiling water absorption of 10%
Wt% or less, and the ultra-light coarse aggregate absolute dry specific gravity is 0.7 to 1.3 include 0.3~0.4m 3 / m 3, the amount of the unit cement 400 kg / m 3 or more, a water / cement Since the concrete is a lightweight concrete having a ratio of 40% by weight or less, the workability of the lightweight concrete using the aggregate is improved due to the synergistic effect of the specific aggregate and the specific concrete composition, and the inner weight of the lightweight concrete at the initial age is reduced. The number of defects is reduced and the durability is improved.
【0013】請求項2記載の発明によれば、前記超軽量
粗骨材のうち圧壊強度が800N以上のものを用いる
が、超軽量粗骨材の圧壊強度が大きい程弾性係数も大き
くなるため、より高強度・高弾性係数の軽量コンクリー
トが得られる。According to the second aspect of the present invention, among the ultralight coarse aggregates, those having a crushing strength of 800 N or more are used, but the elastic modulus increases as the crushing strength of the ultralight coarse aggregate increases. Lightweight concrete with higher strength and higher elastic modulus can be obtained.
【0014】請求項3記載の発明によれば、前記超軽量
粗骨材が、アルキレンオキサイド重合物を主成分とする
組成物を含むため、内部欠陥の低減効果及び作業性を低
下させることなく、効果的に軽量コンクリートの乾燥収
縮を低減させ、長期耐久性を向上させることができる。According to the third aspect of the present invention, since the ultralight coarse aggregate contains a composition containing an alkylene oxide polymer as a main component, the effect of reducing internal defects and the workability are reduced. Dry shrinkage of lightweight concrete can be effectively reduced, and long-term durability can be improved.
【0015】[0015]
【発明の実施の形態】次に、本発明にかかる軽量コンク
リートの実施の形態の具体例について説明する。Next, a concrete example of an embodiment of the lightweight concrete according to the present invention will be described.
【0016】本発明においては、粗骨材として、24時
間吸水率が5.0重量%以下及び煮沸吸水率が10重量
%以下で、絶乾比重が0.7〜1.3である超軽量粗骨
材を使用する。In the present invention, as the coarse aggregate, an ultralight having a 24-hour water absorption of 5.0% by weight or less, a boiling water absorption of 10% by weight or less, and a bone-dry specific gravity of 0.7 to 1.3 is used. Use coarse aggregate.
【0017】ここで、24時間吸水率とは、絶乾状態の
粗骨材を水中に24時間浸漬したときの吸水率を、ま
た、煮沸吸水率とは、絶乾状態の粗骨材を水中で2時間
煮沸したときの吸水率を示し、これらの吸水率は「JI
S A 1134(構造用軽量粗骨材の比重及び吸水率
試験方法)」に準じて測定されたものである。尚、24
時間吸水率は、常圧下で自然吸水させ、主として骨材表
面の気孔性状に影響されやすい指標であるのに対して、
煮沸吸水率は、蒸気圧によって強制的に骨材内部まで吸
水させるため、骨材内部の気孔性状を反映する指標と考
えられる。Here, the term "24-hour water absorption" refers to the rate of water absorption when soaked coarse aggregate is immersed in water for 24 hours. Shows the water absorption when boiled for 2 hours at room temperature.
SA 1134 (Test method for specific gravity and water absorption of lightweight structural coarse aggregate) ". Incidentally, 24
Time water absorption is an index that is naturally affected by natural water absorption under normal pressure and is mainly affected by the pore properties of the aggregate surface,
The boiling water absorption is considered to be an index reflecting the porosity inside the aggregate because the water absorption is forcibly absorbed into the aggregate by the vapor pressure.
【0018】前記超軽量粗骨材は、例えば、黒曜石、真
珠岩等のガラス質原料にSiC等の発泡剤及びベントナ
イト等の粘着材を加えて造粒し、該造粒物を1000〜
1300℃で焼成・発泡させて得られるものである。ま
た、石灰石にベントナイト等の粘着材を加えて造粒し、
該造粒物を1150〜1350℃で焼成・発泡させて得
ることもできる。The ultralight coarse aggregate is granulated by adding a foaming agent such as SiC and an adhesive such as bentonite to a vitreous raw material such as obsidian, perlite, etc.
It is obtained by firing and foaming at 1300 ° C. In addition, limestone is granulated by adding an adhesive such as bentonite,
The granules can also be obtained by firing and foaming at 1150 to 1350 ° C.
【0019】尚、このような性状を有する超軽量粗骨材
としては、市販品として、アサノスーパーライト(商品
名:太平洋セメント(株)製)が挙げられる。As an ultra-lightweight coarse aggregate having such properties, Asano Superlight (trade name, manufactured by Taiheiyo Cement Co., Ltd.) is a commercially available product.
【0020】前記超軽量粗骨材は、外部と連通した気孔
が少なく内部に数μm〜20μm程度の微細な閉気孔が
均一に分布するため、24時間吸水率が5.0重量%以
下及び煮沸吸水率が10重量%以下となり低吸水性を示
す。その結果、コンクリート中の水分をほとんど吸収す
ることなく、良好な作業性を提供できる。The ultralight coarse aggregate has few pores communicating with the outside, and fine closed pores having a size of about several μm to 20 μm are uniformly distributed inside. The water absorption becomes 10% by weight or less, indicating low water absorption. As a result, good workability can be provided without substantially absorbing the moisture in the concrete.
【0021】また、材齢1日までの硬化過程において、
骨材中の含有水分がセメントペースト部に供給されてコ
ンクリートが膨張することもないため、ペースト組織及
び骨材−ペースト間の界面組織が粗になる等、内部欠陥
が形成されることはない。また、硬化後のコンクリート
が長期にわたって乾燥に曝されても、コンクリートから
逸散する水量が少なく、乾燥収縮は小さくなり、耐久的
なコンクリートの製造が可能となる。In the curing process up to one day of age,
Since the water content in the aggregate is not supplied to the cement paste portion and the concrete does not expand, no internal defects such as a coarse paste structure and an interface structure between the aggregate and the paste are formed. Further, even if the hardened concrete is exposed to drying for a long time, the amount of water escaping from the concrete is small, the drying shrinkage is small, and the durable concrete can be manufactured.
【0022】さらに、骨材の事前吸水時間を十分にとっ
た場合でも、その事前吸水過程で骨材内部に吸収される
水量は少なく、また、骨材表面に連通した気孔も少ない
ため、初期硬化過程に骨材からペースト部への水分供給
は生じにくい。従って、事前吸水を行った該超軽量粗骨
材の使用により、内部欠陥の形成及び乾燥収縮の増大を
生じることはない。Furthermore, even if the pre-absorbing time of the aggregate is sufficient, the amount of water absorbed into the aggregate during the pre-absorbing process is small and the number of pores communicating with the surface of the aggregate is small, so that the initial setting During the process, the supply of moisture from the aggregate to the paste portion is unlikely to occur. Thus, the use of the pre-absorbed ultralight coarse aggregate does not cause the formation of internal defects and increase in drying shrinkage.
【0023】前記性状以外の超軽量粗骨材、すなわち、
24時間吸水率が5.0重量%より大きいか煮沸吸水率
が10重量%より大きいものは、内部に粗大な気孔や連
通下気孔を有するため、高吸水性を示す。そのため、作
業性を確保するためには十分な事前吸水を要し、この事
前吸水で生じた多量の含有水分が硬化過程中にコンクリ
ートを膨張させ組織構造を粗にする、すなわち内部欠陥
を生じさせ、さらに硬化コンクリートの乾燥収縮も増大
させるため、好ましくない。[0023] Ultra-light coarse aggregate other than the above properties,
Those having a 24-hour water absorption of more than 5.0% by weight or a boiling water absorption of more than 10% by weight have coarse pores and communicating pores inside, and thus exhibit high water absorption. Therefore, sufficient pre-absorption is necessary to ensure workability, and the large amount of water content generated by this pre-absorption expands the concrete during the hardening process and roughens the structure, that is, causes internal defects. Further, the drying shrinkage of the hardened concrete also increases, which is not preferable.
【0024】尚、本発明で使用する超軽量粗骨材は、絶
乾比重が0.7以上である方が、骨材内部に微細な閉気
孔が形成されており、軽量コンクリートの作業性の向
上、内部欠陥の防止及び乾燥収縮の低減に好適である。
一方、絶乾比重が1.3を超える超軽量粗骨材を使用し
た場合には、コンクリートの軽量化の効果が小さくなる
ので好ましくない。In the ultra-lightweight coarse aggregate used in the present invention, when the absolute dry specific gravity is 0.7 or more, fine closed pores are formed inside the aggregate, and the workability of the lightweight concrete is improved. It is suitable for improving, preventing internal defects and reducing drying shrinkage.
On the other hand, it is not preferable to use an ultralight coarse aggregate having a specific gravity of more than 1.3 because the effect of reducing the weight of concrete is reduced.
【0025】また、超軽量粗骨材の圧壊強度が大きい
程、その骨材の弾性係数も大きくなり、骨材が乾燥によ
るセメントペースト部の収縮を拘束する効果も大きくな
るため超軽量粗骨材の圧壊強度は800N以上のものを
用いることが好ましい。Further, as the crushing strength of the ultralight coarse aggregate increases, the elastic modulus of the aggregate increases, and the effect of restraining the shrinkage of the cement paste portion due to drying of the aggregate also increases. It is preferable to use a crushing strength of 800 N or more.
【0026】また、前記性状を有する超軽量粗骨材にア
レキレンオキサイド重合物を主成分とする組成物を含浸
させて使用することで、内部欠陥の低減効果及び作業性
を低下させることなく、より効果的に乾燥収縮を低減す
ることができる。該組成物の含浸方法としては、常圧下
で該組成物中に浸漬させたり、真空脱気して該組成物中
に浸漬させること等が挙げられる。Further, by using an ultra-lightweight coarse aggregate having the above-mentioned properties impregnated with a composition containing an alkylene oxide polymer as a main component, the effect of reducing internal defects and the workability can be reduced. Drying shrinkage can be reduced more effectively. Examples of the impregnation method of the composition include immersion in the composition under normal pressure, and immersion in the composition after deaeration under vacuum.
【0027】該組成物を含浸した超軽量粗骨材は、練混
ぜ直後から打込み終了までにコンクリート中の水分をほ
とんど吸収することはないため、スランプロスが増大す
ることはない。さらに、骨材に含浸された該組成物は、
骨材の開気孔中に水の場合よりも大きな毛細管張力で保
持されているため、短期間に、言い換えれば硬化過程の
間に、ペースト部へ供給されて構造組織が膨潤すること
はない。その後、硬化コンクリートが長期にわたって乾
燥されるのにともなって、徐々に該組成物がペースト部
へ供給されるようになり、長期材齢におけるコンクリー
トの乾燥収縮をより効果的に低減することができる。[0027] The ultra-lightweight coarse aggregate impregnated with the composition hardly absorbs moisture in concrete from immediately after kneading until the end of pouring, so that slump loss does not increase. Further, the composition impregnated in the aggregate,
Since the capillary is held in the open pores of the aggregate with a larger capillary tension than in the case of water, it is not supplied to the paste portion in a short time, in other words, during the hardening process, and the structural tissue does not swell. Thereafter, as the hardened concrete is dried for a long period of time, the composition is gradually supplied to the paste portion, and the drying shrinkage of the concrete in the long-term age can be more effectively reduced.
【0028】また、本発明で使用するセメントとして
は、普通ポルトランドセメント、早強ポルトランドセメ
ント等のポルトランドセメントや、高炉セメント、シリ
カセメント等の混合セメントが挙げられる。Examples of the cement used in the present invention include portland cement such as ordinary portland cement and early-strength portland cement, and mixed cement such as blast furnace cement and silica cement.
【0029】減水剤としては、メラミン系、ナフタレン
スルホン酸系、ポリカルボン酸系の減水剤(高性能減水
剤及び高性能AE減水剤を含む)が挙げられる。Examples of the water reducing agent include melamine-based, naphthalene-sulfonic acid-based, and polycarboxylic acid-based water reducing agents (including high-performance water reducing agents and high-performance AE water reducing agents).
【0030】練混ぜ水には、通常用いられる水道水等が
挙げられる。本発明にかかる軽量コンクリートの配合条
件は、単位セメント量が400kg/m3以上、水/セメン
ト比が40重量%以下、超軽量粗骨材量が0.3〜0.
4m3/m3とする。Examples of the mixing water include commonly used tap water and the like. The mixing conditions of the lightweight concrete according to the present invention are as follows: the unit cement amount is 400 kg / m 3 or more, the water / cement ratio is 40% by weight or less, and the ultralight coarse aggregate amount is 0.3 to 0.
4 m 3 / m 3 .
【0031】単位セメント量が400kg/m3より小さい
場合、水/セメント比が40重量%より大きい場合及び
超軽量粗骨材量が0.4m3/m3より大きい場合には、
硬化過程中に膨張をともない、内部欠陥の低減効果が小
さくなるので好ましくない。特に、超軽量粗骨材量が
0.4m3/m3より多い場合には、超軽量粗骨材の浮上
がりが発生し易くなり、コンクリート表面のコテ仕上げ
を困難にするため好ましくない。When the unit cement amount is less than 400 kg / m 3, when the water / cement ratio is more than 40% by weight, and when the ultralight coarse aggregate amount is more than 0.4 m 3 / m 3 ,
This is not preferable because the effect of reducing internal defects is reduced due to expansion during the curing process. In particular, when the amount of the ultra-light coarse aggregate is more than 0.4 m 3 / m 3 , the floating of the ultra-light coarse aggregate is apt to occur, which makes it difficult to finish the iron on the concrete surface.
【0032】また、超軽量粗骨材量が0.3m3/m3よ
り少ない場合には、骨材がペーストの収縮を拘束する効
果が低下し、言い換えれば、コンクリート中に占めるペ
ースト容積が増えて収縮を生じ易くなり硬化コンクリー
トの乾燥収縮が増大すること、及びコンクリートの軽量
化の効果も小さいことから好ましくない。When the amount of the ultralight coarse aggregate is less than 0.3 m 3 / m 3 , the effect of the aggregate to restrain the shrinkage of the paste is reduced. In other words, the paste volume occupying the concrete increases. It is not preferable because shrinkage is likely to occur and the drying shrinkage of the hardened concrete increases, and the effect of reducing the weight of the concrete is small.
【0033】本発明において、コンクリートの練混ぜ
は、従来より使用されているオムニ型ミキサ、パン型ミ
キサ、二軸型ミキサ等により行う。また、練混ぜ方法及
び練混ぜ時間も特に限定されるものでなく、例えば、所
定のコンクリート構成材料を一括してミキサ内に投入し
練混ぜれば良い。In the present invention, the concrete is mixed by an omni-type mixer, a pan-type mixer, a twin-shaft type mixer or the like which has been conventionally used. Also, the kneading method and the kneading time are not particularly limited, and, for example, a predetermined concrete constituent material may be collectively charged into the mixer and kneaded.
【0034】次に、本発明にかかる軽量コンクリートの
実施例について説明する。 (1)使用材料 セメント :普通ポルトランドセメント:太平洋セメント(株)製 水 :水道水 混和剤 :減水剤(レオビルドSP−8S:(株)エヌエムビー製 AE剤(マイクロエア775S:(株)エヌエムビー製 粗骨材含浸物 :A1;テトラガードAS21(主成分;低級アルコールアルキ レンオキシド付加物):三洋化成工業(株)製 A2;ヒビダン(主成分;ポリエーテル):竹本油脂(株) 製 細骨材 :青梅産砕砂 粗骨材 :G1;アサノスーパーライト 太平洋セメント(株)製、圧 壊強度1652N、絶乾比重1.25、24時間吸水 率2.86重量%(3.58容積%)、煮沸吸水率6 .25重量%(7.81容積%) G2;太平洋セメント(株)試作品、圧壊強度1169N、 絶乾比重0.98、24時間吸水率4.78重量%( 4.68容積%)、煮沸吸水率9.05重量%(8. 87容積%) G3;アサノスーパーライト 太平洋セメント(株)製、圧 壊強度821N、絶乾比重0.82、24時間吸水率 4.93重量%(4.04容積%)、煮沸吸水率9. 89重量%(8.11容積%) G4;メサライト、メサライト工業(株)製、圧壊強度53 9N、絶乾比重1.27、24時間吸水率15.8重 量%(20.1容積%)、煮沸吸水率27.9重量% (35.4容積%)Next, an embodiment of the lightweight concrete according to the present invention will be described. (1) Materials used Cement: ordinary Portland cement: manufactured by Taiheiyo Cement Co., Ltd. Water: tap water Admixture: water reducing agent (Reobuild SP-8S: AE agent manufactured by NMB Corporation (Micro Air 775S: coarse manufactured by NMB Corporation) Aggregate impregnated material: A1; Tetraguard AS 21 (main component: lower alcohol alkylene oxide adduct): manufactured by Sanyo Chemical Industries, Ltd. A2: Hibidan (main component: polyether): fine aggregate manufactured by Takemoto Yushi Co., Ltd. : Ome-produced crushed sand coarse aggregate: G1; Asano Super Light, manufactured by Taiheiyo Cement Co., Ltd., crushing strength 1652N, absolute dry specific gravity 1.25, 24-hour water absorption 2.86% by weight (3.58% by volume), boiling Water absorption 6.25% by weight (7.81% by volume) G2: Prototype of Taiheiyo Cement Corp., crushing strength 1169N, absolute specific gravity 0.98, water absorption for 24 hours 4. 8% by weight (4.68% by volume), boiling water absorption 9.05% by weight (8.87% by volume) G3; manufactured by Asano Superlight Taiheiyo Cement Co., Ltd., crushing strength 821N, absolute dry specific gravity 0.82, Water absorption rate for 24 hours 4.93% by weight (4.04% by volume), boiling water absorption rate 9.89% by weight (8.11% by volume) G4; Mesalite, manufactured by Mesalite Industry Co., Ltd., crush strength 539N, absolutely dry Specific gravity 1.27, 24-hour water absorption 15.8% by weight (20.1% by volume), boiling water absorption 27.9% by weight (35.4% by volume)
【0035】各粗骨材の表面及び割裂した破断面を電子
顕微鏡を用いて調べた結果を以下に示す。 G1;内部に5〜10μm程度の気孔が均一に分布。 G2;内部に5〜15μm程度の気孔が均一に分布。 G3;内部に5〜20μm程度の気孔が均一に分布。 G4;表面に連通した気孔が多く、30μm以上の粗大
気孔も認められる。The results of examining the surface of each coarse aggregate and the fractured fracture surface using an electron microscope are shown below. G1: pores of about 5 to 10 μm are uniformly distributed inside. G2: pores of about 5 to 15 μm are uniformly distributed inside. G3: pores of about 5 to 20 μm are uniformly distributed inside. G4: Many pores communicated with the surface, and coarse pores of 30 μm or more were also observed.
【0036】尚、粗骨材の絶乾比重及び吸水率は、「J
IS A1134(構造用軽量粗骨材の比重及び吸水率
試験方法)」に準じて、圧壊強度は「JIS Z884
1(造粒物−強度試験方法)」に準じ、骨材径が14±
1mmのものを測定した。The absolute specific gravity and the water absorption of the coarse aggregate are as described in "J.
According to IS A1134 (Test method for specific gravity and water absorption of lightweight coarse aggregate for structure), the crushing strength is defined by JIS Z884.
1 (granulated material-strength test method) "
One mm was measured.
【0037】(2)配合条件及び練混ぜ 表1に示す割合で各材料をパン型ミキサ(0.1m3)
に投入し、2分間練混ぜて軽量コンクリートを調整し
た。粗骨材は、絶乾状態及び事前吸水した状態で使用
し、事前吸水は、絶乾骨材を24時間水中に浸漬する
か、絶乾骨材を2時間水中で煮沸することで行った。(2) Mixing conditions and kneading Each material was mixed in the ratio shown in Table 1 in a pan-type mixer (0.1 m 3 ).
And mixed for 2 minutes to prepare lightweight concrete. The coarse aggregate was used in an absolutely dry state and in a state in which water was previously absorbed. The pre-absorption was performed by immersing the absolutely dry aggregate in water for 24 hours or boiling the absolutely dry aggregate in water for 2 hours.
【0038】また、アルキレンオキサイド重合物の含浸
は、絶乾骨材を該組成物中に24時間浸漬するか、絶乾
骨材を真空脱気して該組成物中に30分間浸漬すること
で行った。尚、同表に示す配合のコンクリートは練り上
がり時のスランプ及び空気量を、各々18±1.5c
m、5.0±1.0%の範囲とした。The impregnation of the alkylene oxide polymer can be carried out by immersing the bone-dried aggregate in the composition for 24 hours or by evacuating the bone-dry aggregate in a vacuum and immersing it in the composition for 30 minutes. went. In addition, the concrete of the composition shown in the same table, the slump and air volume at the time of kneading, each 18 ± 1.5c
m, a range of 5.0 ± 1.0%.
【0039】同表において、実施例No.1〜15が本発
明にかかる軽量コンクリートである。尚、比較例No.1
〜3は、既存の軽量骨材を使用したもの、比較例No.4
及びNo.5は、各々粗骨材料が少ないものと多いもの、
比較例No.6及びNo.7は、いずれも水/セメント比が高
いもの、比較例No.8及びNo.9は、いずれもセメント量
が少ないものである。In the same table, Examples Nos. 1 to 15 are lightweight concretes according to the present invention. In addition, Comparative Example No. 1
No. 3 to No. 3 using the existing lightweight aggregate, Comparative Example No. 4
And No. 5 were those with less and more coarse bone material, respectively.
Comparative Examples No. 6 and No. 7 all have a high water / cement ratio, and Comparative Examples No. 8 and No. 9 all have a low cement amount.
【0040】[0040]
【表1】 [Table 1]
【0041】(3)評価 初期内部欠陥 ・初期材齢の体積変化 軽量コンクリートの打込み終了直後からの体積変化を
「(社)日本コンクリート工学協会自己収縮研究委員会
セメントペースト、モルタルおよびコンクリートの自
己収縮および自己膨張試験方法(案)」に準じて測定し
た。尚、打込み直後の供試体を基長とし、材齢24時間
後まで測定した。この測定により、収縮ひずみやごく僅
かな膨張ひずみが発生する場合には、内部欠陥が形成さ
れず、大きな膨張ひずみが発生する場合には、内部欠陥
が形成されるものと判断できる。(3) Evaluation Initial Internal Defects ・ Volume Change of Initial Age The volume change of the lightweight concrete immediately after the completion of the injection of the concrete is referred to as the self-shrinkage of cement paste, mortar and concrete by the Japan Concrete Institute Association of Self-Shrinkage Research Committee. And self-expansion test method (draft) ". In addition, the specimen immediately after the injection was used as the base length, and the measurement was performed up to 24 hours after the material age. From this measurement, it can be determined that an internal defect is not formed when a contraction strain or a very slight expansion strain is generated, and that an internal defect is formed when a large expansion strain is generated.
【0042】・粗骨材−ペースト間の界面性状 上記の体積変化測定が終了したコンクリート供試体内部
から、試料片を取り出して粗骨材−ペースト間の界面の
SEM像観察を行い、その界面性状を、◎:骨材表面に
内部欠陥はほとんど認められない、×:骨材表面の広範
囲にわたって内部欠陥の厚い相が存在している、によっ
て判断した。Interfacial Properties between Coarse Aggregate and Paste A sample piece was taken out of the concrete specimen after the above volume change measurement was completed, and an SEM image of the interface between the coarse aggregate and the paste was observed. And ◎: Almost no internal defects were observed on the surface of the aggregate, ×: A thick phase of internal defects was present over a wide range of the surface of the aggregate.
【0043】作業性及び耐久性 ・スランプロス 練混ぜ直後と練混ぜ終了から1時間経過後の軽量コンク
リートのスランプを「JIS A1101(コンクリー
トのスランプ試験方法)」に準じて測定し、作業性低下
の指標としてスランプロスを算出した。Workability and durability Slump loss The slump of lightweight concrete is measured according to "JIS A1101 (Slump test method for concrete)" immediately after kneading and one hour after the end of kneading, to reduce workability. Slump loss was calculated as an index.
【0044】・表面仕上げ性 コンクリート表面をコテ仕上げする際の作業性を◎:極
めて良好、○:良好、×:不良、によって判断した。Surface finishability The workability in ironing the concrete surface was evaluated as ◎: extremely good, :: good, ×: poor.
【0045】・乾燥収縮 上記内部欠陥の低減効果の判定試験に用いた供試体を材
齢24時間で脱型し、材齢14日まで水中養生(20
℃)した後、恒温恒湿室(20℃、60%)にて乾燥し
た。乾燥中における長さ変化の測定は、「JIS A1
129(モルタル及びコンクリートの長さ変化試験方
法)」に準じて行った。Dry Shrinkage The specimen used in the test for determining the effect of reducing the internal defects was demolded at a material age of 24 hours, and cured in water (20 days) until the material age was 14 days.
° C), and then dried in a constant temperature and humidity chamber (20 ° C, 60%). The measurement of the length change during drying is described in “JIS A1
129 (Method of testing length change of mortar and concrete) ".
【0046】[0046]
【表2】 [Table 2]
【0047】同表により明らかなように、実施例No.1
〜15の本発明にかかる軽量コンクリートは、初期材齢
で大きな膨張を生じることがなく、粗骨材−ペースト間
の界面性状も良好であり、初期内部欠陥を生じないもの
と判断できる。また、実施例No.6及びNo.13〜15の
ように、アルキレンオキサイド重合物を主成分とする組
成物を含んだ超軽量粗骨材を使用した場合には、初期内
部欠陥を生じさせることなくより効果的な乾燥収縮の低
減も可能となっている。As is clear from the table, Example No. 1
Lightweight concretes according to the present invention of Nos. 1 to 15 do not cause significant expansion at the initial age, have good interfacial properties between the coarse aggregate and the paste, and can be judged as having no initial internal defects. Also, as in Examples No. 6 and Nos. 13 to 15, when an ultralight coarse aggregate containing a composition containing an alkylene oxide polymer as a main component is used, an initial internal defect may occur. It is also possible to reduce drying shrinkage more effectively.
【0048】一方、比較例No.1〜3及びNo.5〜9の場
合には、初期材齢で大きな膨張を生じ、粗骨材−ペース
ト間の界面に内部欠陥が観察された。比較例No.2〜4
の場合には、粗骨材の含水量が多いことや粗骨材量が少
ないことにより800×10 -6以上の大きな乾燥収縮ひ
ずみが発生した。また、比較例No.5の場合には粗骨材
の浮き上がりにより、表面のコテ仕上げ性が低下した。On the other hand, in Comparative Examples Nos. 1-3 and Nos. 5-9,
Large expansion at early age, coarse aggregate-pace
Internal defects were observed at the interface between the substrates. Comparative Examples No. 2 to 4
In this case, the water content of the coarse aggregate is high or the amount of coarse aggregate is low.
800 × 10 -6Bigger drying shrinkage
Sudden occurrence has occurred. In the case of Comparative Example No. 5, coarse aggregate
The surface finish of ironing on the surface was reduced due to the rise of.
【0049】[0049]
【発明の効果】以上説明したように、請求項1記載の発
明によれば、超軽量粗骨材使用時の事前吸水の有無及び
程度に拘わらず、作業性が良く、初期材齢における内分
欠陥を低減することができ、耐久性の高い軽量コンクリ
ートを提供することができる。As described above, according to the first aspect of the present invention, the workability is good regardless of the presence or absence and the degree of prior water absorption at the time of using the ultra-lightweight coarse aggregate, and the inner part at the initial age is improved. Defects can be reduced and lightweight concrete with high durability can be provided.
【0050】請求項2記載の発明によれば、上記効果に
加え、より高強度・高弾性係数の軽量コンクリートを提
供することができる。According to the second aspect of the invention, in addition to the above effects, it is possible to provide a lightweight concrete having a higher strength and a higher elastic modulus.
【0051】請求項3記載の発明によれば、上記効果に
加え、より効果的に軽量コンクリートの乾燥収縮を低減
することができ、長期的にも耐久性に優れた軽量コンク
リートを提供することができる。According to the third aspect of the present invention, in addition to the above-described effects, it is possible to more effectively reduce the drying shrinkage of the lightweight concrete, and to provide a lightweight concrete excellent in durability for a long term. it can.
───────────────────────────────────────────────────── フロントページの続き Fターム(参考) 4G012 LA15 PA07 PB33 PC14 4G019 LA02 LB02 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4G012 LA15 PA07 PB33 PC14 4G019 LA02 LB02
Claims (3)
煮沸吸水率が10重量%以下、かつ絶乾比重が0.7〜
1.3である超軽量粗骨材を0.3〜0.4m3/m3含
み、単位セメント量が400kg/m3以上、水/セメ
ント比が40重量%以下であることを特徴とする軽量コ
ンクリート。1. A 24-hour water absorption rate of 5.0% by weight or less, a boiling water absorption rate of 10% by weight or less, and an absolute dry specific gravity of 0.7 to less.
The ultra-light coarse aggregate is 1.3 includes 0.3~0.4m 3 / m 3, the amount of the unit cement 400 kg / m 3 or more, the water / cement ratio is equal to or more than 40% by weight Lightweight concrete.
以上であることを特徴とする請求項1記載の軽量コンク
リート。2. The crushing strength of the ultralight coarse aggregate is 800N.
The lightweight concrete according to claim 1, characterized in that:
イド重合物を主成分とする組成物を含むこと特徴とする
請求項1記載の軽量コンクリート。3. The lightweight concrete according to claim 1, wherein the ultralight coarse aggregate contains a composition containing an alkylene oxide polymer as a main component.
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Application Number | Priority Date | Filing Date | Title |
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JP10286215A JP2000109378A (en) | 1998-10-08 | 1998-10-08 | Lightweight concrete |
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Family
ID=17701473
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008184350A (en) * | 2007-01-29 | 2008-08-14 | Sumitomo Osaka Cement Co Ltd | Drying shrinkage reduction method of concrete using high water absorption regenerated aggregate |
JP2015059772A (en) * | 2013-09-17 | 2015-03-30 | 住友大阪セメント株式会社 | Concrete core degradation evaluation method |
JP2017114697A (en) * | 2015-12-21 | 2017-06-29 | 川田工業株式会社 | Manufacturing method of high-early-strength light weight concrete |
JP2019048421A (en) * | 2017-09-11 | 2019-03-28 | 太平洋セメント株式会社 | Method of producing concrete |
-
1998
- 1998-10-08 JP JP10286215A patent/JP2000109378A/en not_active Withdrawn
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2008184350A (en) * | 2007-01-29 | 2008-08-14 | Sumitomo Osaka Cement Co Ltd | Drying shrinkage reduction method of concrete using high water absorption regenerated aggregate |
JP2015059772A (en) * | 2013-09-17 | 2015-03-30 | 住友大阪セメント株式会社 | Concrete core degradation evaluation method |
JP2017114697A (en) * | 2015-12-21 | 2017-06-29 | 川田工業株式会社 | Manufacturing method of high-early-strength light weight concrete |
JP2019048421A (en) * | 2017-09-11 | 2019-03-28 | 太平洋セメント株式会社 | Method of producing concrete |
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