JP2010222166A - Aggregate and method for suppressing shrinkage of cementitious hardened body - Google Patents

Aggregate and method for suppressing shrinkage of cementitious hardened body Download PDF

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JP2010222166A
JP2010222166A JP2009070125A JP2009070125A JP2010222166A JP 2010222166 A JP2010222166 A JP 2010222166A JP 2009070125 A JP2009070125 A JP 2009070125A JP 2009070125 A JP2009070125 A JP 2009070125A JP 2010222166 A JP2010222166 A JP 2010222166A
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aggregate
shrinkage
cementitious
hardened
suppressing
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Hiroyuki Hayano
博幸 早野
Ippei Maruyama
一平 丸山
Atsushi Teramoto
篤史 寺本
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Nagoya University NUC
Taiheiyo Cement Corp
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Taiheiyo Cement Corp
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    • 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
    • C04B18/02—Agglomerated materials, e.g. artificial aggregates
    • C04B18/027—Lightweight 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
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/34—Non-shrinking or non-cracking materials

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

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aggregate for suppressing shrinkage capable of effectively suppressing the shrinkage of a cementitious hardened body, and a cement composition and a cementitious hardened body containing the aggregate. <P>SOLUTION: The aggregate for suppressing the shrinkage of a cementitious hardened body consists of a porous aggregate in which an aqueous salt solution of a concentration at which equilibrium relative humidity at room temperature becomes 50-99% RH is held, and by being mixed in a cementitious hardened body, water is supplied from the aggregate to the cementitious hardened body when the chemical potential of water of the surrounding environment of the aggregate decreases due to the progress of hydration reaction of the cement composition and drying of the cementitious hardened body, and the shrinkage of the cementitious hardened body can be suppressed by this. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

本発明は、セメント質硬化体の収縮抑制用骨材及びセメント質硬化体の収縮を抑制する方法に関する。   The present invention relates to an aggregate for suppressing shrinkage of a hardened cementitious body and a method for suppressing shrinkage of a hardened cementitious body.

モルタル、コンクリート等のセメント質硬化体は、硬化時の自己収縮、又は硬化後の乾燥によってセメントペーストから水分（間隙水）が逸散し、セメント質硬化体の体積が減少する乾燥収縮が生じることがある。これらの収縮量が大きくなると、セメント質硬化体にひび割れが生じてしまい、当該セメント質硬化体を用いた構造物等の耐久性や外観を損ねてしまうおそれがある。   For cementitious hardened bodies such as mortar and concrete, self-shrinkage during hardening or drying (curing water) from the cement paste due to drying after hardening causes drying shrinkage that reduces the volume of the cementitious hardened body. There is. When these shrinkage amounts become large, cracks occur in the cementitious hardened body, which may impair the durability and appearance of structures and the like using the cementitious hardened body.

このような収縮を抑制する方法として、従来、収縮低減剤を混和剤としてセメントに添加する方法や、膨張性混和材をセメントに添加する方法等が知られている（特許文献１参照）。   Conventionally known methods for suppressing such shrinkage include a method of adding a shrinkage reducing agent to the cement as an admixture, a method of adding an expandable admixture to the cement, and the like (see Patent Document 1).

また、水で湿潤し、水分を保持した状態の多孔質骨材を粗骨材及び／又は細骨材の全部又は一部として用い、セメント質硬化体の養生中に骨材から水分をセメントペーストに供給することで、セメント質硬化体の収縮を抑制する方法も知られている。   In addition, the porous aggregate in a state of being wetted with water and retaining moisture is used as all or part of the coarse aggregate and / or fine aggregate, and the moisture is removed from the aggregate during curing of the cementitious hardened body. There is also known a method for suppressing the shrinkage of the cementitious hardened body by supplying to.

なお、セメント質硬化体の収縮を抑制する方法ではないものの、予め水酸化アルカリ水溶液に含浸させた骨材をコンクリートに配合し、骨材から溶出するアルカリ成分によってコンクリートの中性化を抑制する技術も知られている（特許文献２参照）。   Although it is not a method to suppress the shrinkage of the hardened cementitious material, it is a technology that mixes aggregate previously impregnated with an aqueous alkali hydroxide solution into concrete and suppresses the neutralization of the concrete by the alkali component eluted from the aggregate Is also known (see Patent Document 2).

特開２００６−１５１７７２号公報JP 2006-151772 A 特開昭６１−２５１５５２号公報JP-A-61-251552

しかしながら、水で湿潤した状態の多孔質骨材をセメントとともに混練することによってセメント質硬化体を製造しても、混練初期におけるセメント質硬化体中の水分イオン濃度が高くなることで、浸透圧差によって多孔質骨材に保持されている水分がその周囲環境（セメントペースト側）に移動してしまい、セメント質硬化体の乾燥とともに当該水分も逸散してしまう。その結果として、セメント質硬化体の乾燥以前に多孔質骨材から水分がセメント質硬化体に供給されてしまい、セメント質硬化体の収縮を十分に抑制することができないという問題があった。   However, even if a cementitious hardened body is produced by kneading a porous aggregate in a wet state with water together with cement, the water ion concentration in the cementitious hardened body at the initial stage of kneading becomes high, which causes a difference in osmotic pressure. Moisture retained in the porous aggregate moves to the surrounding environment (cement paste side), and the moisture is dissipated as the cementitious hardened body is dried. As a result, there is a problem in that moisture is supplied from the porous aggregate to the cementitious cured body before the cementitious cured body is dried, and the shrinkage of the cementitious cured body cannot be sufficiently suppressed.

そこで、本発明は、セメント質硬化体の収縮を効果的に抑制することのできる収縮抑制用骨材、当該骨材を含むセメント組成物及びセメント質硬化体、並びにセメント質硬化体の収縮を抑制する方法を提供することを目的とする。   Therefore, the present invention suppresses the shrinkage of the cementitious hardened body, the aggregate for suppressing shrinkage that can effectively restrain the shrinkage of the hardened cementitious body, the cement composition containing the aggregate, the hardened cementitious body, and the hardened cementitious body. It aims to provide a way to do.

上記課題を解決するために、本発明は、セメント組成物に配合されることにより当該セメント組成物が硬化してなるセメント質硬化体の収縮を抑制し得る骨材であって、多孔質骨材に、室温における平衡相対湿度が５０〜９９％ＲＨとなる濃度の塩水溶液が保持されてなることを特徴とするセメント質硬化体の収縮抑制用骨材を提供する（発明１）。   In order to solve the above-mentioned problems, the present invention is an aggregate capable of suppressing the shrinkage of a cementitious hardened body formed by hardening the cement composition by being blended with the cement composition, and is a porous aggregate Further, the present invention provides an aggregate for suppressing shrinkage of a hardened cementitious material, characterized in that a salt aqueous solution having a concentration of 50 to 99% RH at room temperature is maintained (Invention 1).

上記発明（発明１）に係る収縮抑制用骨材が室温における平衡相対湿度が５０〜９９％ＲＨとなる濃度の塩水溶液を保持していることで、当該骨材が配合されたセメント組成物を硬化して得られるセメント質硬化体における骨材周囲環境（セメントペースト中）の水分の化学ポテンシャルよりも骨材中の水分の化学ポテンシャルが低い状態になる。そのため、セメント組成物の水和反応の進行やセメント質硬化体の乾燥に伴って骨材周囲環境の水分の化学ポテンシャルが骨材中の水分の化学ポテンシャルよりも低下したときに当該骨材からセメント質硬化体の骨材周囲環境に水分を供給することができるようになる。よって、上記発明（発明１）によれば、当該骨材をセメント組成物に配合することで、得られるセメント質硬化体の自己収縮及び乾燥収縮を効果的に抑制することができる。   The aggregate for suppressing shrinkage according to the invention (Invention 1) holds a salt aqueous solution having a concentration at which the equilibrium relative humidity at room temperature is 50 to 99% RH, whereby a cement composition containing the aggregate is obtained. The chemical potential of moisture in the aggregate is lower than the chemical potential of moisture in the environment surrounding the aggregate (in the cement paste) in the hardened cementitious body obtained by curing. Therefore, when the chemical potential of the moisture in the environment surrounding the aggregate is lower than the chemical potential of the moisture in the aggregate due to the progress of the hydration reaction of the cement composition and the drying of the hardened cementitious material, It becomes possible to supply moisture to the environment surrounding the aggregate of the hardened material. Therefore, according to the said invention (invention 1), the self-shrinkage and dry shrinkage of the obtained cementitious hardened body can be effectively suppressed by mix | blending the said aggregate with a cement composition.

上記発明（発明１）においては、前記塩水溶液が、アルカリ金属の水酸化物の水溶液であるのが好ましく（発明２）、かかるアルカリ金属の水酸化物が、水酸化リチウム、水酸化ナトリウム又は水酸化カリウムであるのが好ましい（発明３）。   In the above invention (Invention 1), the aqueous salt solution is preferably an aqueous solution of an alkali metal hydroxide (Invention 2), and the alkali metal hydroxide is lithium hydroxide, sodium hydroxide or water. Potassium oxide is preferred (Invention 3).

水酸化リチウム、水酸化ナトリウム、水酸化カリウム等のアルカリ金属の水酸化物を所定濃度（室温における平衡相対湿度が５０〜９９％ＲＨとなる濃度）で水に溶解させることで、当該水溶液の化学ポテンシャルを十分に低下させることができるため、上記発明（発明３，４）によれば、セメント質硬化体の収縮を効果的に抑制することができる。また、アルカリ金属の水酸化物の水溶液がセメント質硬化体（セメントペースト）に供給されることから、セメント質硬化体の乾燥による中性化の進行を抑制するという効果も奏し得る。さらに、特に水酸化リチウムを用いた場合には、骨材から溶出するシリカとリチウムイオンとの反応により生成するアルカリシリカゲル（Ｌｉ２Ｏ・ＳｉＯ２，Ｌｉ２Ｏ・２ＳｉＯ２）が膨張性を有しないことから、アルカリシリカ反応を抑制することもできる。 By dissolving alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide in water at a predetermined concentration (concentration at which the equilibrium relative humidity at room temperature is 50 to 99% RH), Since the potential can be sufficiently lowered, according to the inventions (Inventions 3 and 4), shrinkage of the cementitious hardened body can be effectively suppressed. Moreover, since the aqueous solution of an alkali metal hydroxide is supplied to the cementitious cured body (cement paste), an effect of suppressing the progress of neutralization due to drying of the cementitious cured body can also be achieved. Further, particularly when lithium hydroxide is used, alkali silica gel (Li 2 O · SiO 2 , Li 2 O · 2SiO 2 ) produced by the reaction between silica eluted from the aggregate and lithium ions has expansibility. Therefore, the alkali silica reaction can be suppressed.

上記発明（発明１〜３）においては、前記多孔質骨材として、多孔質軽量骨材を用いることができる（発明４）。かかる発明（発明４）によれば、軽量骨材を用いてなる軽量コンクリート等のセメント質硬化体における収縮を効果的に抑制することができる。   In the said invention (invention 1-3), a porous lightweight aggregate can be used as said porous aggregate (invention 4). According to this invention (invention 4), the shrinkage | contraction in cementitious hardened bodies, such as lightweight concrete using a lightweight aggregate, can be suppressed effectively.

また、本発明は、セメントと、上記発明（発明１〜４）に係るセメント質硬化体の収縮抑制用骨材とを含有することを特徴とするセメント組成物を提供する（発明５）。   Moreover, this invention provides the cement composition characterized by including a cement and the aggregate for shrinkage | contraction suppression of the cementitious hardened | cured material which concerns on the said invention (invention 1-4) (invention 5).

上記発明（発明５）によれば、セメント組成物が上記発明（発明１〜４）に係る収縮抑制用骨材を含有することで、当該セメント組成物を硬化させてなるセメント質硬化体における収縮を効果的に抑制することができる。   According to the said invention (invention 5), the cement composition contains the shrinkage-suppressing aggregate according to the above invention (inventions 1 to 4), so that the shrinkage in the hardened cementitious material obtained by curing the cement composition. Can be effectively suppressed.

さらに、本発明は、上記発明（発明５）に係るセメント組成物を硬化してなることを特徴とするセメント質硬化体を提供する（発明６）。かかる発明（発明６）によれば、収縮が効果的に抑制されたセメント質硬化体を提供することができる。   Furthermore, the present invention provides a cementitious hardened body obtained by curing the cement composition according to the above invention (Invention 5) (Invention 6). According to this invention (invention 6), it is possible to provide a cementitious cured body in which shrinkage is effectively suppressed.

さらにまた、本発明は、少なくともセメントと、骨材と、水とを混練した混練物を硬化させてなるセメント質硬化体の収縮を抑制する方法であって、前記骨材の一部又は全部として、上記発明（発明１〜４）に係るセメント質硬化体の収縮抑制用骨材を用いることを特徴とするセメント質硬化体の収縮抑制方法を提供する（発明７）。   Furthermore, the present invention is a method for suppressing shrinkage of a hardened cementitious material obtained by curing a kneaded material obtained by kneading at least cement, an aggregate, and water, and as a part or all of the aggregate Further, the present invention provides a method for inhibiting shrinkage of a hardened cementitious material (Invention 7), characterized by using an aggregate for suppressing shrinkage of a hardened cementitious material according to the inventions (Inventions 1 to 4).

上記発明（発明７）によれば、セメント質硬化体の製造時に配合される収縮抑制用骨材に保持されている水分（塩水溶液）が、セメント組成物の水和反応の進行又はセメント質硬化体の乾燥に伴って当該骨材からセメントペースト（セメント質硬化体）に供給されることになるため、セメント質硬化体の収縮を効果的に抑制することができる。   According to the said invention (invention 7), the water | moisture content (salt aqueous solution) currently hold | maintained at the aggregate for shrinkage | contraction suppression mix | blended at the time of manufacture of a cementitious hardened body progresses the hydration reaction of a cement composition, or cementum hardening. Since the aggregate is supplied to the cement paste (cured cementitious material) from the aggregate as the body is dried, shrinkage of the cementitious cured material can be effectively suppressed.

本発明によれば、セメント質硬化体の収縮を効果的に抑制することのできる収縮抑制用骨材、当該骨材を含むセメント組成物及びセメント質硬化体、並びにセメント質硬化体の収縮を効果的に抑制することのできる方法を提供することができる。   ADVANTAGE OF THE INVENTION According to this invention, the shrinkage | contraction suppression aggregate which can suppress effectively the shrinkage | contraction of cementitious hardened | cured material, the cement composition and cementitious hardened | cured material containing the said aggregate, and the shrinkage | contraction of cementitious hardened | cured material are effective. Can be provided.

実施例１及び比較例１に係るコンクリートについての無拘束試験結果を示すグラフである。It is a graph which shows the unrestrained test result about the concrete which concerns on Example 1 and Comparative Example 1. 実施例２及び比較例２に係るコンクリートについての無拘束試験結果を示すグラフである。It is a graph which shows the unrestrained test result about the concrete which concerns on Example 2 and Comparative Example 2. FIG. 実施例３及び比較例３に係るコンクリートについての無拘束試験結果を示すグラフである。It is a graph which shows the unrestrained test result about the concrete which concerns on Example 3 and Comparative Example 3. 実施例１及び比較例１に係るコンクリートについての鉄筋拘束試験結果を示すグラフである。It is a graph which shows the reinforcing bar restraint test result about concrete concerning Example 1 and comparative example 1. 実施例２及び比較例２に係るコンクリートについての鉄筋拘束試験結果を示すグラフである。It is a graph which shows the reinforcing bar restraint test result about concrete concerning Example 2 and comparative example 2. 実施例３及び比較例３に係るコンクリートについての鉄筋拘束試験結果を示すグラフである。It is a graph which shows the reinforcing bar restraint test result about concrete concerning Example 3 and comparative example 3.

本発明の実施の形態について説明する。
本実施形態に係るセメント質硬化体の収縮抑制用骨材は、多孔質骨材に、室温における平衡相対湿度が５０〜９９％ＲＨとなる濃度の塩水溶液が保持されてなるものである。 Embodiments of the present invention will be described.
The aggregate for suppressing shrinkage of a cementitious hardened body according to the present embodiment is a porous aggregate in which a salt aqueous solution having a concentration of 50 to 99% RH in equilibrium relative humidity at room temperature is held.

多孔質骨材は、セメント質硬化体の収縮を効果的に抑制し得る十分量の塩水溶液を保持し得るものであれば特に限定されるものではなく、多孔質粗骨材及び／又は多孔質細骨材を用いることができるが、特に多孔質粗骨材を用いるのが好ましい。多孔質粗骨材は、多孔質細骨材に比して内部に多量の塩水溶液を保持することができ、長期間にわたって水（塩水溶液）を骨材周囲環境に供給することができるため好ましい。   The porous aggregate is not particularly limited as long as it can hold a sufficient amount of salt aqueous solution capable of effectively suppressing the shrinkage of the cementitious hardened body, and the porous coarse aggregate and / or the porous aggregate is not limited. Although fine aggregate can be used, it is particularly preferable to use porous coarse aggregate. The porous coarse aggregate is preferable because it can retain a larger amount of salt aqueous solution in the interior than the porous fine aggregate and can supply water (salt aqueous solution) to the aggregate surrounding environment for a long period of time. .

また、多孔質骨材の空隙率は、３〜６０％であるのが好ましい。多孔質骨材の空隙率が上記範囲内であれば、セメント質硬化体の収縮を効果的に抑制することができる。なお、多孔質骨材の空隙率は、例えば、水銀圧入法等により測定された値である。   The porosity of the porous aggregate is preferably 3 to 60%. When the porosity of the porous aggregate is within the above range, shrinkage of the cementitious hardened body can be effectively suppressed. The porosity of the porous aggregate is a value measured by, for example, a mercury intrusion method.

このような多孔質骨材としては、例えば、岩石を高温加熱処理等に付して得られる人工軽量骨材や、軽石、火山噴火物等の天然軽量骨材等を好適に用いることができるが、これ以外にコンクリート塊を破砕することにより得られる再生骨材等を用いてもよい。   As such porous aggregates, for example, artificial lightweight aggregates obtained by subjecting rocks to high-temperature heat treatment, natural lightweight aggregates such as pumice and volcanic eruptions can be suitably used. In addition to this, recycled aggregate obtained by crushing a concrete block may be used.

セメント質硬化体に使用する材料やその調合、セメント質硬化体の周囲の環境条件、部材寸法等によって当該セメント質硬化体中の温度、相対湿度等は変動し得るが、多孔質骨材に水を含浸させたものを骨材として用いる場合よりも骨材からセメント質硬化体への水分供給を遅らせるために、多孔質骨材に保持させる塩水溶液の種類や濃度を決定する必要がある。具体的には、２０℃における平衡相対湿度が５０〜９９％ＲＨ、好ましくは５０〜９５％ＲＨとなるような塩の種類及び塩水溶液の濃度を決定すればよい。   The temperature and relative humidity in the hardened cementitious material may vary depending on the material used for the hardened cementitious material, its formulation, the environmental conditions around the hardened cementitious material, the dimensions of the members, etc. It is necessary to determine the type and concentration of the salt aqueous solution to be retained in the porous aggregate in order to delay the water supply from the aggregate to the cementitious hardened body compared to the case where the material impregnated with is used as the aggregate. Specifically, the type of salt and the concentration of the aqueous salt solution may be determined so that the equilibrium relative humidity at 20 ° C. is 50 to 99% RH, preferably 50 to 95% RH.

このような観点から、多孔質骨材に保持される塩水溶液としては、水酸化リチウム、水酸化ナトリウム、水酸化カリウム等のアルカリ金属の水酸化物の水溶液を用いるのが好ましい。例えば、５．５質量％ＮａＯＨ水溶液中に人工軽量粗骨材（商品名：太平洋アサノライト）を浸漬させたときの平衡相対湿度は９５％ＲＨであり、同様に９．８質量％ＮａＯＨ水溶液中では９０％ＲＨである。   From such a viewpoint, it is preferable to use an aqueous solution of an alkali metal hydroxide such as lithium hydroxide, sodium hydroxide, or potassium hydroxide as the aqueous salt solution retained on the porous aggregate. For example, when the artificial lightweight coarse aggregate (trade name: Taiheiyo Asanolite) is immersed in a 5.5% by mass NaOH aqueous solution, the equilibrium relative humidity is 95% RH, and similarly in the 9.8% by mass NaOH aqueous solution. Then, it is 90% RH.

また、アルカリ金属の水酸化物のうち水酸化リチウムの水溶液を塩水溶液として多孔質骨材に保持させることで、収縮抑制用骨材から溶出するシリカとリチウムイオンとの反応により生成するアルカリシリカゲル（Ｌｉ２Ｏ・ＳｉＯ２，Ｌｉ２Ｏ・２ＳｉＯ２）が膨張性を有しないため、アルカリシリカ反応を抑制することもできる。 In addition, an alkali silica gel produced by a reaction between silica and lithium ions eluted from the shrinkage-preventing aggregate by holding an aqueous solution of lithium hydroxide as a salt solution in the porous aggregate among alkali metal hydroxides ( Li 2 O.SiO 2 , Li 2 O.2SiO 2 ) does not have expansibility, so that the alkali silica reaction can be suppressed.

本実施形態に係る収縮抑制用骨材の製造方法としては、特に限定されるものではなく、例えば、多孔質骨材を所定濃度の塩水溶液に所定時間（通常、１日以上）含浸させることにより製造することができる。   The method for producing the shrinkage-suppressing aggregate according to the present embodiment is not particularly limited. For example, by impregnating a porous aggregate with a salt solution having a predetermined concentration for a predetermined time (usually one day or more). Can be manufactured.

このようにして得られる本実施形態に係る収縮抑制用骨材は、セメント組成物に配合して用いることができる。これにより、当該セメント組成物から得られるセメント質硬化体の収縮を効果的に抑制することができる。   The shrinkage-suppressing aggregate according to this embodiment obtained as described above can be used by blending it with a cement composition. Thereby, shrinkage | contraction of the cementitious hardening body obtained from the said cement composition can be suppressed effectively.

セメント組成物に配合される収縮抑制用骨材は、セメント組成物に配合される骨材のうちの一部を構成するものであってもよいし、当該骨材の全部を構成するものであってもよい。本実施形態に係る収縮抑制用骨材を骨材のうちの一部として用いる場合、当該収縮抑制用骨材とともに、砂利、砕石、天然・人工軽量粗骨材、再生粗骨材等の粗骨材；川砂、山砂、陸砂、海砂、砕砂、珪砂、天然・人工軽量細骨材、再生細骨材等の細骨材を適宜用いることができる。なお、本実施形態に係る収縮抑制用骨材とともに用いられる粗骨材及び／又は細骨材は、湿潤状態のものであってもよいし、絶乾状態、気乾状態、表乾状態のものであってもよい。   The shrinkage-suppressing aggregate blended in the cement composition may constitute a part of the aggregate blended in the cement composition, or constitute all of the aggregate. May be. When the shrinkage-suppressing aggregate according to the present embodiment is used as a part of the aggregate, together with the shrinkage-preventing aggregate, coarse bones such as gravel, crushed stone, natural / artificial lightweight coarse aggregate, recycled coarse aggregate, etc. Materials: Fine aggregates such as river sand, mountain sand, land sand, sea sand, crushed sand, quartz sand, natural / artificial lightweight fine aggregate, recycled fine aggregate, etc. can be used as appropriate. The coarse aggregate and / or fine aggregate used together with the shrinkage-suppressing aggregate according to the present embodiment may be in a wet state, in an absolutely dry state, in an air dry state, or in a surface dry state. It may be.

上記セメント組成物において配合し得るセメントとしては、特に限定されるものではなく、例えば、普通ポルトランドセメント、早強ポルトランドセメント、中庸熱ポルトランドセメント、低熱ポルトランドセメント、耐硫酸塩ポルトランドセメント等の各種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等の各種混合セメント；都市ゴミ焼却灰及び／又は下水汚泥焼却灰を原料として製造した焼成物の粉砕物と石膏とからなるセメント（普通エコセメント、速硬エコセメント）等が挙げられる。   The cement that can be blended in the cement composition is not particularly limited. For example, various Portland cements such as ordinary Portland cement, early-strength Portland cement, moderately hot Portland cement, low heat Portland cement, sulfate-resistant Portland cement, and the like. ; Various mixed cements such as blast furnace cement and fly ash cement; Cement composed of ground and incinerated ash from municipal waste incineration ash and / or sewage sludge incineration ash (ordinary eco-cement, fast-hardening eco-cement) Etc.

本実施形態に係る収縮抑制用骨材の容積配合量は、セメント質硬化体１ｍ３中、０．２５ｍ３以上であるのが好ましい。 It is preferable that the volume compounding amount of the shrinkage-suppressing aggregate according to the present embodiment is 0.25 m 3 or more in 1 m 3 of the cementitious cured body.

上記セメント組成物を水とともに混練し、セメントペーストを得ることができる。そして、得られたセメントペーストを型枠等に打設し、養生して硬化させることにより、セメント質硬化体を製造することができる。養生方法としては、例えば、気中養生、加温養生、水中養生、蒸気養生、オートクレーブ養生等が挙げられるが、これらに限定されるものではない。   The cement composition can be kneaded with water to obtain a cement paste. And the cementitious hardened | cured material can be manufactured by placing the obtained cement paste in a formwork etc., curing and hardening. Examples of the curing method include air curing, heating curing, underwater curing, steam curing, and autoclave curing, but are not limited thereto.

セメント質硬化体における水セメント比（水結合材比）は、１０〜７０質量％であるのが好ましく、特に２０〜６０質量％であるのが好ましい。   The water cement ratio (water binder ratio) in the hardened cementitious body is preferably 10 to 70% by mass, and particularly preferably 20 to 60% by mass.

本実施形態におけるセメント質硬化体は、必要に応じて、クエン酸等のオキシカルボン酸、リグニンスルホン酸等の凝結遅延剤；リグニン系、ナフタリンスルホン酸系、メラミン系、ポリカルボン酸系等の減水剤、ＡＥ減水剤、高性能減水剤又は高性能ＡＥ減水剤；アルミニウム粉末等の発泡剤；ポリエーテル類、芳香族スルホン酸塩類（アルキルベンゼンスルホン酸塩等）、硫黄含有化合物（高級アルキルエーテル硫酸エステル類等）、天然樹脂類等の界面活性剤（起泡剤）等の各種混和剤を含むものであってもよい。これらの混和剤の配合量は、得られるセメント質硬化体における収縮抑制用骨材が有する収縮抑制効果を妨げない限り、それらの混和剤の配合目的に応じて適宜設定すればよい。   The cementitious hardened body in the present embodiment is, if necessary, an oxycarboxylic acid such as citric acid, a setting retarder such as lignin sulfonic acid; a lignin-based, naphthalene sulfonic acid-based, melamine-based, or polycarboxylic acid-based water reducing agent. Agent, AE water reducing agent, high performance water reducing agent or high performance AE water reducing agent; foaming agent such as aluminum powder; polyethers, aromatic sulfonates (alkylbenzene sulfonate, etc.), sulfur-containing compounds (higher alkyl ether sulfates) Etc.) and various admixtures such as surfactants (foaming agents) such as natural resins. What is necessary is just to set suitably the compounding quantity of these admixtures according to the compounding purpose of those admixtures, unless the shrinkage | contraction inhibitory effect which the aggregate for shrinkage | contraction suppression in the obtained cementitious hardened body has is not disturbed.

以上のようにして得られるセメント質硬化体は、本実施形態に係る収縮抑制用骨材が配合されてなるため、セメント組成物の水和反応の進行又はセメント質硬化体の乾燥に伴って骨材周囲環境の水の化学ポテンシャルが収縮抑制用骨材中の水の化学ポテンシャルよりも低下すると、収縮抑制用骨材から水（塩水溶液）がセメント質硬化体に供給されることになる。これにより、セメント質硬化体の自己収縮及び乾燥収縮が効果的に抑制されることになる。   Since the hardened cementitious body obtained as described above is blended with the shrinkage-suppressing aggregate according to the present embodiment, the bone is accompanied with the progress of the hydration reaction of the cement composition or the drying of the hardened cementitious body. When the chemical potential of water in the environment surrounding the material is lower than the chemical potential of water in the shrinkage suppression aggregate, water (salt aqueous solution) is supplied from the shrinkage suppression aggregate to the cementitious hardened body. Thereby, the self-shrinkage and the drying shrinkage of the cementitious hardened body are effectively suppressed.

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.

〔収縮抑制用骨材の製造〕
多孔質骨材としての人工軽量粗骨材（空隙率：５０％，絶乾密度１．２５ｇ／ｃｍ３，商品名：太平洋アサノライト）を乾燥した後、９．８質量％ＮａＯＨ水溶液（２０℃）に１８日間浸漬させて、収縮抑制用骨材を製造した。得られた収縮抑制用骨材におけるＮａＯＨ水溶液の含有率は、１９質量％であった。 [Manufacture of aggregates for shrinkage suppression]
Artificial lightweight coarse aggregate (porosity: 50%, absolute dry density of 1.25 g / cm 3 , trade name: Pacific Asanolite) as a porous aggregate was dried, and then a 9.8 mass% NaOH aqueous solution (20 ° C. ) For 18 days to produce a shrinkage-suppressing aggregate. The content rate of NaOH aqueous solution in the obtained aggregate for shrinkage | contraction suppression was 19 mass%.

〔実施例１〕
得られた収縮抑制用骨材（粗骨材Ｇ）、普通ポルトランドセメント（ブレーン比表面積：３２９０ｃｍ２／ｇ，密度：３．１６ｇ／ｃｍ３，太平洋セメント社製，セメントＣ）、水Ｗ及び山砂（静岡県掛川産，細骨材Ｓ）をミキサに投入して混練し、混和剤として高性能ＡＥ減水剤（製品名：レオビルドＳＰ８ＨＵ，ＢＡＳＦポゾリス社製）を添加してさらに混練してコンクリートを調製した。 [Example 1]
The obtained aggregate for suppressing shrinkage (coarse aggregate G), ordinary Portland cement (Brain specific surface area: 3290 cm 2 / g, density: 3.16 g / cm 3 , manufactured by Taiheiyo Cement Co., Cement C), water W and mountain Sand (from Kakegawa, Shizuoka Prefecture, Fine Aggregate S) is put into a mixer and kneaded. A high-performance AE water reducing agent (product name: Leo Build SP8HU, manufactured by BASF Pozzolith Co., Ltd.) is added as an admixture and further kneaded to concrete. Was prepared.

〔実施例２〕
混和剤として高性能ＡＥ減水剤（製品名：レオビルドＳＰ８ＳＢ，ＢＡＳＦポゾリス社製）を用いる以外は上記実施例１と同様にしてコンクリートを調製した。 [Example 2]
Concrete was prepared in the same manner as in Example 1 except that a high-performance AE water reducing agent (product name: Leobuild SP8SB, manufactured by BASF Pozzolith) was used as an admixture.

〔実施例３〕
混和剤として高性能ＡＥ減水剤（製品名：レオビルドＳＰ８ＳＶ，ＢＡＳＦポゾリス社製）を用いる以外は上記実施例１と同様にしてコンクリートを調製した。 Example 3
Concrete was prepared in the same manner as in Example 1 except that a high-performance AE water reducing agent (product name: Leobuild SP8SV, manufactured by BASF Pozzolith) was used as an admixture.

〔比較例１〕
収縮抑制用骨材（粗骨材Ｇ）に代えて水道水に１５日間浸漬した軽量粗骨材（空隙率：５０％，絶乾密度１．２５ｇ／ｃｍ３，商品名：太平洋アサノライト）を用いる以外は上記実施例１と同様にしてコンクリートを調製した。なお、軽量粗骨材は、含水率を１９％に調整したものを用いた。 [Comparative Example 1]
Lightweight coarse aggregate (porosity: 50%, absolute dry density of 1.25 g / cm 3 , trade name: Pacific Asanolite) immersed in tap water for 15 days instead of shrinkage suppression aggregate (coarse aggregate G) Concrete was prepared in the same manner as in Example 1 except that it was used. In addition, the light coarse aggregate used what adjusted the moisture content to 19%.

〔比較例２〕
収縮抑制用骨材（粗骨材Ｇ）に代えて水道水に１５日間浸漬した軽量粗骨材（空隙率：５０％，絶乾密度１．２５ｇ／ｃｍ３，商品名：太平洋アサノライト）を用いる以外は上記実施例２と同様にしてコンクリートを調製した。なお、軽量粗骨材は、含水率を１９％に調整したものを用いた。 [Comparative Example 2]
Lightweight coarse aggregate (porosity: 50%, absolute dry density of 1.25 g / cm 3 , trade name: Pacific Asanolite) immersed in tap water for 15 days instead of shrinkage suppression aggregate (coarse aggregate G) Concrete was prepared in the same manner as in Example 2 except that it was used. In addition, the light coarse aggregate used what adjusted the moisture content to 19%.

〔比較例３〕
収縮抑制用骨材（粗骨材Ｇ）に代えて水道水に１５日間浸漬した軽量粗骨材（空隙率：５０％，絶乾密度１．２５ｇ／ｃｍ３，商品名：太平洋アサノライト）を用いる以外は上記実施例３と同様にしてコンクリートを調製した。なお、軽量粗骨材は、含水率を１９％に調整したものを用いた。
実施例１〜３及び比較例１〜３のコンクリートの配合を表１に示す。 [Comparative Example 3]
Lightweight coarse aggregate (porosity: 50%, absolute dry density of 1.25 g / cm 3 , trade name: Pacific Asanolite) immersed in tap water for 15 days instead of shrinkage suppression aggregate (coarse aggregate G) Concrete was prepared in the same manner as in Example 3 except that it was used. In addition, the light coarse aggregate used what adjusted the moisture content to 19%.
Table 1 shows the concrete blends of Examples 1 to 3 and Comparative Examples 1 to 3.

Figure 2010222166
Figure 2010222166

〔無拘束試験〕
実施例１〜３及び比較例１〜３のコンクリートを型枠（１００×１００×６００ｍｍ）に打設するとともに、打設したコンクリート内にひずみゲージ（ＫＭ−１００ＢＴ，東京測定器研究所社製）を埋設し、養生して供試体を作製した。なお、実施例１〜２及び比較例１〜２のコンクリートについては、それぞれ温度２０℃において封緘養生をした供試体及び温度２０℃において７日間封緘養生後、温度２０℃、相対湿度６０％の条件下で気中養生した供試体を作製した。また実施例３及び比較例３のコンクリートについては、それぞれ温度２０℃において７日間封緘養生後、温度２０℃、相対湿度６０％の条件下で気中養生した供試体を作製した。そして、コンクリートに埋設したひずみゲージを用いてコンクリート打設直後から無拘束ひずみを測定した。結果を図１〜３に示す。 [Unrestrained test]
Concretes of Examples 1 to 3 and Comparative Examples 1 to 3 were placed on a formwork (100 × 100 × 600 mm), and a strain gauge (KM-100BT, manufactured by Tokyo Keiki Kenkyujo Co., Ltd.) was placed in the placed concrete. Were buried and cured to prepare specimens. In addition, about the concrete of Examples 1-2 and Comparative Examples 1-2, after 20-degree sealing curing at 20 degreeC, the specimen which carried out sealing curing at the temperature of 20 degreeC, respectively, the conditions of temperature 20 degreeC and relative humidity 60% A specimen that was cured under the air was prepared. Moreover, about the concrete of Example 3 and the comparative example 3, the test piece which carried out the curing under the conditions of the temperature of 20 degreeC and the relative humidity of 60% was produced after sealing curing for 7 days at the temperature of 20 degreeC, respectively. And the unconstrained strain was measured immediately after placing the concrete using a strain gauge embedded in the concrete. The results are shown in FIGS.

〔鉄筋拘束試験〕
実施例１〜３及び比較例１〜３のコンクリートを型枠（１００×１００×１０００ｍｍ）に打設するとともに、打設したコンクリート内に鉄筋（Ｄ２２，長手方向長さＬ：１２００ｍｍ）を埋設し、上記無拘束試験と同様の養生条件にて供試体を作製し、鉄筋ゲージを貼付して、コンクリート打設直後から拘束ひずみを測定した。そして、拘束ひずみの測定結果に基づいて応力を算出した。結果を図４〜６に示す。 [Rebar restraint test]
Concretes of Examples 1 to 3 and Comparative Examples 1 to 3 were placed on a formwork (100 × 100 × 1000 mm), and reinforcing bars (D22, longitudinal length L: 1200 mm) were embedded in the placed concrete. A specimen was prepared under the same curing conditions as in the unconstrained test, a reinforcing bar gauge was attached, and the restraint strain was measured immediately after placing the concrete. And stress was computed based on the measurement result of restraint strain. The results are shown in FIGS.

図１〜６に示すように、実施例１〜３の供試体は、いずれも比較例１〜３の供試体よりも収縮ひずみ及び収縮応力が低減されていることが確認された。また、図５に示すように、比較例２の供試体は、材齢５０日において収縮応力が低減しており、ひび割れが生じていることが確認された。さらに、図６に示すように、比較例３の供試体は、材齢５０日において収縮応力が低減しており、ひび割れが生じていることが確認された。このように、比較例２及び３の供試体においては、収縮によるひび割れが生じているのに対し、実施例２及び３の供試体においては、収縮が効果的に抑制されていた。   As shown in FIGS. 1-6, it was confirmed that the specimens of Examples 1 to 3 have reduced shrinkage strain and shrinkage stress as compared with the specimens of Comparative Examples 1 to 3. Further, as shown in FIG. 5, it was confirmed that the specimen of Comparative Example 2 had reduced shrinkage stress at 50 days of age and had cracks. Furthermore, as shown in FIG. 6, it was confirmed that the specimen of Comparative Example 3 had reduced shrinkage stress at 50 days of age and had cracks. Thus, in the specimens of Comparative Examples 2 and 3, cracks due to shrinkage occurred, whereas in the specimens of Examples 2 and 3, shrinkage was effectively suppressed.

これは、実施例２及び３のコンクリート中の水分が逸散した後に、収縮抑制用骨材中の水分が当該骨材からコンクリートに供給されたことで、コンクリートの収縮を抑制できたものと考えられる。   This is because the moisture in the aggregate for suppressing shrinkage was supplied from the aggregate to the concrete after the moisture in the concrete of Examples 2 and 3 was dissipated, so that the shrinkage of the concrete could be suppressed. It is done.

〔圧縮強度試験〕
実施例１〜３及び比較例１〜３のコンクリートにつき、ＪＩＳ−Ａ１１０８に基づいて材齢７日において圧縮強度試験を行った。
結果を表２に示す。 [Compressive strength test]
About the concrete of Examples 1-3 and Comparative Examples 1-3, the compressive strength test was done in the age of 7 days based on JIS-A1108.
The results are shown in Table 2.

Figure 2010222166
Figure 2010222166

表２に示すように、実施例１〜３のコンクリートは、比較例１〜３のコンクリートと略同等の圧縮強度を示した。この結果から、収縮抑制用骨材からコンクリートに供給されるＮａＯＨ水溶液がコンクリートの圧縮強度に与える影響はほとんどなく、コンクリートの収縮を効果的に抑制し得ることが確認された。   As shown in Table 2, the concretes of Examples 1 to 3 exhibited substantially the same compressive strength as the concretes of Comparative Examples 1 to 3. From this result, it was confirmed that the NaOH aqueous solution supplied to the concrete from the aggregate for suppressing shrinkage has little influence on the compressive strength of the concrete and can effectively suppress the shrinkage of the concrete.

Claims (7)

セメント組成物に配合されることにより当該セメント組成物が硬化してなるセメント質硬化体の収縮を抑制し得る骨材であって、
多孔質骨材に、室温における平衡相対湿度が５０〜９９％ＲＨとなる濃度の塩水溶液が保持されてなることを特徴とするセメント質硬化体の収縮抑制用骨材。 An aggregate capable of suppressing shrinkage of a hardened cementitious material formed by hardening the cement composition by being blended with the cement composition,
An aggregate for inhibiting shrinkage of a hardened cementitious material, characterized in that a porous aqueous solution holds a salt aqueous solution having a concentration of 50 to 99% RH at room temperature. 前記塩水溶液が、アルカリ金属の水酸化物の水溶液であることを特徴とする請求項１に記載のセメント質硬化体の収縮抑制用骨材。   The aggregate for suppressing shrinkage of a hardened cementitious material according to claim 1, wherein the salt aqueous solution is an aqueous solution of an alkali metal hydroxide. 前記アルカリ金属の水酸化物が、水酸化リチウム、水酸化ナトリウム又は水酸化カリウムであることを特徴とする請求項２に記載のセメント質硬化体の収縮抑制用骨材。   The aggregate for suppressing shrinkage of a hardened cementitious material according to claim 2, wherein the alkali metal hydroxide is lithium hydroxide, sodium hydroxide or potassium hydroxide. 前記多孔質骨材が、多孔質軽量骨材であることを特徴とする請求項１〜３のいずれかに記載のセメント質硬化体の収縮抑制用骨材。   The said porous aggregate is a porous lightweight aggregate, The aggregate for shrinkage | contraction suppression of the cementitious hardening body in any one of Claims 1-3 characterized by the above-mentioned. セメントと、請求項１〜４のいずれかに記載のセメント質硬化体の収縮抑制用骨材とを含有することを特徴とするセメント組成物。   A cement composition comprising cement and an aggregate for suppressing shrinkage of a hardened cementitious material according to any one of claims 1 to 4. 請求項５に記載のセメント組成物を硬化してなることを特徴とするセメント質硬化体。   A cementitious hardened body obtained by curing the cement composition according to claim 5. 少なくともセメントと、骨材と、水とを混練した混練物を硬化させてなるセメント質硬化体の収縮を抑制する方法であって、
前記骨材の一部又は全部として、請求項１〜４のいずれかに記載のセメント質硬化体の収縮抑制用骨材を用いることを特徴とするセメント質硬化体の収縮抑制方法。 A method of suppressing shrinkage of a hardened cementitious material obtained by curing a kneaded material obtained by kneading at least cement, aggregate, and water,
The method for suppressing shrinkage of a hardened cementitious material, comprising using the aggregate for suppressing shrinkage of a hardened cementitious material according to any one of claims 1 to 4 as a part or all of the aggregate.
JP2009070125A 2009-03-23 2009-03-23 Aggregate and method for suppressing shrinkage of cementitious hardened body Pending JP2010222166A (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61251552A (en) * 1985-04-27 1986-11-08 ナショナル住宅産業株式会社 Aggregate for concrete
JPS6418951A (en) * 1987-07-11 1989-01-23 Shimizu Construction Co Ltd Light-weight aggregate concrete
JPH04260646A (en) * 1991-02-13 1992-09-16 Fujikawa Kenzai Kogyo Kk Mortar composition
JP2006143501A (en) * 2004-11-17 2006-06-08 Taiheiyo Material Kk Aggregate, method of manufacturing the same, and mortar/concrete for spraying

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61251552A (en) * 1985-04-27 1986-11-08 ナショナル住宅産業株式会社 Aggregate for concrete
JPS6418951A (en) * 1987-07-11 1989-01-23 Shimizu Construction Co Ltd Light-weight aggregate concrete
JPH04260646A (en) * 1991-02-13 1992-09-16 Fujikawa Kenzai Kogyo Kk Mortar composition
JP2006143501A (en) * 2004-11-17 2006-06-08 Taiheiyo Material Kk Aggregate, method of manufacturing the same, and mortar/concrete for spraying

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