JP4658362B2 - Manufacturing method for lightweight mortar - Google Patents
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- JP4658362B2 JP4658362B2 JP2001102283A JP2001102283A JP4658362B2 JP 4658362 B2 JP4658362 B2 JP 4658362B2 JP 2001102283 A JP2001102283 A JP 2001102283A JP 2001102283 A JP2001102283 A JP 2001102283A JP 4658362 B2 JP4658362 B2 JP 4658362B2
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Description
【０００１】
【発明の属する技術分野】
本発明は、軽量細骨材を用いた軽量モルタル材に係り、軽量でありながら高い強度を発現するものであり、長期間に亘って劣化せずに大きな強度を保持することのできる耐久性に優れた軽量モルタル材の製造方法に関する。
【０００２】
【従来の技術】
従来、炭酸ガス中でセメント硬化体を養生して、強度の向上を図る技術が知られている。例えば、特開平６−２６３５６２号公報には、セメントと骨材と水を混練して得られるセメント硬化体を成形して、前養生を行ない、脱型した後、所定の期間、炭酸ガス雰囲気中で養生することによって、高強度セメント硬化体を得る技術が開示されている。また、本発明者らにおいては、特願２０００−７０６７７号において、セメント及び必要に応じて配合される無機質粉末に、有機高分子系炭酸化促進剤（例えば、エチレン−酢酸ビニル系エマルション）を含む硬化体を成形して、前養生を行なった後、所定の期間、炭酸ガス中で養生することによって、養生後に達した曲げ強さの最大値を、ほぼそのまま長期間に亘って維持することのできる高曲げ強度で耐久性に優れたセメント系硬化体を得る技術を記載している。
従来の軽量モルタル材並びに軽量コンクリートにおいては、その耐久性を向上させるために、硬化後の軽量モルタル材の空隙率を低減させ、耐久性を向上させる技術が知られている。例えば、特開平１１−１３１８０４号公報には、軽量コンクリートの耐久性向上を目的として、空隙を生成する水量を低減させるために水セメント比を４５％以下に小さくすることで、また、特開平１１−２７８９００号公報には、配合する軽量細骨材として吸水率の低い軽量細骨材を選択して使用することで、硬化後の軽量モルタル材の空隙を低減することが示されている。
【０００３】
【発明が解決しようとする課題】
上記公報には、炭酸ガス養生を行なうと、養生しない場合に比べて、セメント硬化体の曲げ強度が大きくなることが示されている、しかしながら、本発明者らは、炭酸ガス養生を施すと、一時的に最大値に達した軽量モルタル材の曲げ強度が、長期においては時間の経過とともに低下していくことを見出した。
そこで、本発明は、軽量でありながら高強度であるとともに、炭酸ガス養生を施した場合に、曲げ強度の最大値をそのまま長期間保持することのできる耐久性に優れた軽量モルタル材及びその製造方法を提供することを目的とする。
また、いずれも軽量モルタル材並びに軽量コンクリート硬化体の空隙を低減するために水セメント比を小さくしたり、吸水性の低い軽量細骨材を使用する場合、表面層がガラス質状の軽量細骨材を利用する必要があり、使用状況によってはアルカリ骨材反応による軽量モルタル材の硬化体組織の劣化という危険性が避けられない。
【０００４】
【課題を解決するための手段】
本発明者らは、上記課題を解決するために鋭意検討した結果、有機高分子の中に、セメント系軽量モルタル材の炭酸化を促進するものがあること、及びセメントを含む軽量モルタル成形体に促進炭酸化養生を施す前に、成形体の材料として該有機高分子系炭酸化促進剤を配合しておけば、促進炭酸化養生によって軽量モルタル成形体の強度が向上して高い曲げ強度の軽量モルタル硬化体が得られるとともに、最大強度に達した後においても、その強度が時間の経過とともに低下しないことを見出し、本発明を完成した。
【０００５】
すなわち、本発明の軽量モルタル材の製造方法は、セメント及び必要に応じて配合される無機質粉末と、軽量細骨材並びに固形分換算にして上記セメント及び必要に応じて配合される無機質粉末の合計量１００重量部に対して２〜２０重量部の、熱可塑性エマルション、合成ゴムラテックス、再乳化形粉末樹脂、セルロース誘導体及びポリビニルアルコールからなる群より選択される有機高分子系炭酸化促進剤とを含有する成形体を炭酸化養生することを特徴とする（請求項１）。この様にあらかじめセメント等とともに有機高分子系炭酸化促進剤を配合しておくことで、炭酸化養生後も長期間に亘って軽量高強度を維持することができる。ここで、上記軽量細骨材の粒子径は０．１ｍｍ〜１．２ｍｍであり、比重が０．１〜０．９であり（請求項２）、その含有量が上記セメント及び必要に応じて配合される無機質粉末の合計量１００重量部に対して５〜１５０重量部である（請求項３）。上記炭酸化養生は、遅くとも水和材齢１０日以内に開始される必要がある（請求項４）。なお、炭酸化養生の前に、水中養生または湿空養生による前養生を行なうと、さらに強度が向上する（請求項５）。上記セメント及び必要に応じて配合される無機質粉末の合計量中のビーライトの含有率は、５質量％以上である（請求項６）。
【０００６】
【発明の実施の形態】
本発明に用いられるセメントは、水和に伴い水酸化カルシウム並びにケイ酸カルシウム水和生成物が生成するセメントであれば特に限定されず、例えば、低熱ポルトランドセメント（高ビーライト系セメント）、中庸熱ポルトランドセメント、普通ポルトランドセメント、早強ポルトランドセメント、超早強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ポルトランドセメントや、各種低アルカリ形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、フライアッシュセメント等の混合セメント、白色セメント等が挙げられる。普通ポルトランドセメントでは、通常、２５質量％以上、また、早強ポルトランドセメントでは、通常、１５質量％以上のビーライトを含んでおり本発明の効果は十分に得ることが可能である。
中でも本発明の効果（軽量高強度発現性）に優れる点で、低熱ポルトランドセメントや中庸熱ポルトランドセメントが好ましい。低熱ポルトランドセメントでは、通常、４０質量％以上のビーライトを含む。中庸熱ポルトランドセメントは、通常、３０質量％以上のビーライトを含んでいる。
【０００７】
セメントと共に必要に応じて配合される無機質粉末としては、高炉スラグ粉末、フライアッシュ、石灰石粉、硅石粉、シリカフューム、ビーライトを多量に含む天然物や人工物などから選ばれる一種以上からなるものが用いられる。また、コンクリート微粉やセメント系製品等のケイ酸カルシウム系廃材を粉砕した微紛を用いることもできる。
なお、セメントと必要に応じて配合される無機質粉末の合計量中のビーライトの含有率は５質量％以上となるように調整するのが好ましい。該含有率が５質量％以上であると、炭酸化養生した場合、特に優れた高曲げ強度の発現がみられる。
【０００８】
本発明で用いる軽量細骨材としては、特に限定されることはなく、パーライト、シラスバルーン、バーミキュライトや、頁岩、粘土等を焼成・発泡させた人工軽量細骨材や製紙スラッジを焼却して得られるパルプスラッジ（ＰＳ）灰砂等の無機質軽量細骨材、また、スチレンビーズ、塩化ビニル、ポリプロピレン、ポリエチレン、ポリスチレン等の合成樹脂発泡体及びそれらの廃材を利用することができる。
【０００９】
軽量細骨材としては、粒子径が０．１ｍｍ〜１．２ｍｍであり、比重０．１〜０．９程度のものが好ましい。また、本発明における軽量細骨材は、上記２種類以上の軽量細骨材を組み合わせて配合するようにしてもよい。粒子径が０．１ｍｍ未満の軽量細骨材を用いると混練後のモルタルの流動性が低下し成形性が悪化する。一方、１．２ｍｍを超える軽量細骨材を用いると軽量モルタル硬化体の表面性が悪化するため好ましくない。また、比重が０．１未満の軽量細骨材を用いるとモルタル中での浮き上がりが顕著となって硬化体の表面性が悪化し、一方、比重が０．９より大きくなると軽量性の効果が発現しにくくなるため好ましくない。
【００１０】
軽量細骨材の添加量は、セメント並びに必要に応じて配合される無機質粉末１００重量部に対して、５〜１５０重量部で効果がみられるが、実際は、使用する軽量細骨材の比重並びに必要とする軽量モルタル材の比重との関係から適宜定めればよい。該添加量が５重量部未満であると軽量性が得られず、１５０重量部を超えると高コストになるとともに硬化体の弾性率が低くなり、目的の強度性状を得ることができなくなる。軽量細骨材の添加量を軽量モルタル材中の容積割合でみると材料全体の２０％以上を占めるように適宜配合するのが好ましい。
【００１１】
本発明で用いる有機高分子系炭酸化促進剤としては、セメント系軽量モルタル材の炭酸化を促進するものであって、熱可塑性エマルション、合成ゴムラテックス、再乳化形粉末樹脂、セルロース誘導体及びポリビニルアルコールからなる群より選択されるものが用いられる。具体的には、熱可塑性エマルションとしてはアクリル酸エステル、ポリ酢酸ビニル、エチレン−酢酸ビニル系エマルション、スチレン-アクリル酸エステル系エマルション等が、合成ゴムラテックスとしてはスチレンブタジエンゴム等が、再乳化形粉末樹脂としてはポリアクリル酸エステル、エチレン−酢酸ビニル共重合体、酢酸ビニル−ビニルバーサテート（ＶｅｏＶａ）等が、セルロース誘導体としてはメチルセルロース等が挙げられる。
【００１２】
有機高分子系炭酸化促進剤の添加量は、固形分に換算して、セメント並びに必要に応じて配合される無機質粉末の合計量１００重量部に対して、２〜２０重量部で効果がみられ、好ましくは３〜１５重量部である。該添加量が２重量部未満であると、長期間に亘って強度を保持するのが難しくなり、２０重量部を超えると高コストとなるとともに硬化体の弾性率が低くなり、目的の強度性状を得ることができなくなる。
【００１３】
セメントや軽量細骨材等と共に配合可能な他の材料としては、細骨材、補強用繊維質材料、各種混和剤等が挙げられる。
【００１４】
細骨材は、粗骨材よりも粒子径の小さな骨材であって、例えば、川砂、海砂、山砂、砕砂またはこれらの混合物が挙げられる。細骨材の配合量は、セメント及び必要に応じて配合される無機質粉末の合計量１００重量部に対して、通常、３０〜４００重量部程度であるが、必要とする軽量モルタル材の比重によって適宜定めればよい。
【００１５】
補強用繊維としては、Ｅガラス等のガラス繊維、スラグ繊維、炭素繊維、ビニロン、ポリプロピレン、アクリル、パルプ等の繊維、シリコーンカーバイト繊維、石綿などの各種天然繊維及び合成繊維を挙げることができる。混和剤としては、減水剤、ＡＥ減水剤、高性能減水剤、高性能ＡＥ減水剤、水和促進剤、水和遅延剤、乾燥収縮低減剤、増粘剤等が挙げられる。混和剤の種類及び配合量は、混和剤以外の材料の種類及び配合量や、軽量モルタル材の用途を考慮して、適宜定めればよい。
【００１６】
混練水量は特に限定されるものではないが、好ましくは水セメント比で０．３０〜０．６０である。水セメント比が０．３０未満であると、炭酸化が進行しづらくなることで促進炭酸化による軽量モルタル材の強度増進効果が得られなくなるおそれがあり、０．６０を超えると、強度の低下や耐久性を損うおそれがあるからである。なお、本明細書中では、「水セメント比」とは、「水」の質量（Ｗ）を「セメント及び必要に応じて配合される無機質粉末」の質量（Ｃ）で割った比率（Ｗ／Ｃ）をいう。
【００１７】
各種材料の混練に用いるミキサとしては、特に限定されるものではないが、パンタイプミキサ、二軸ミキサ、オムニミキサ、ホバートミキサ等の慣用のミキサを用いれば良い。
混練方法としては、全ての材料を一括してミキサに投入し混練しても良いし、水、有機高分子系炭酸化促進剤、混和剤以外の材料をミキサに投入して空練りした後に、水等を投入して混練しても良い。
混練後、混練物を所定の型枠に投入する。型枠に投入された混練物に対して、外部振動を加えたり、加圧装置等を用いて加圧成形しても良い。
【００１８】
混練物は、通常、型枠に投入後、通常１〜２日程度で脱型して成形体とし、その後、本発明の養生を行なう。なお、押出成形等のような、型枠を用いずに成形体を得る方法を用いても良い。
促進炭酸化養生は、好ましくは、遅くとも成形体の水和材齢１０日以内、より好ましくは７日以内に開始する。
【００１９】
炭酸化養生は、通常、気中養生として行なわれるが、必要に応じて、湿空あるいは蒸気養生を組み合わせて行なってもよい。
気中養生の場合、成形体は、炭酸ガス（ＣＯ2）濃度が１〜１００％、好ましくは３〜１００％の条件下で促進炭酸化がなされる。促進炭酸化養生時の温度は、特に限定されないが、通常、１０〜８０℃程度である。促進炭酸化養生時の湿度（Ｒ.Ｈ.）は、特に限定されないが、通常、４０〜９０％程度である。
【００２０】
気中あるいは湿空で促進炭酸化養生を行なう場合の養生時間は、炭酸ガス濃度等の諸条件を考慮して定められる。例えば、炭酸ガス濃度１０％、温度２０℃、湿度（Ｒ.Ｈ.）６０％の場合で、４〜１０日程度である。
前述のように、促進炭酸化養生を開始する時期は、遅くとも成形体の水和材齢１０日以内であることが好ましい。これを過ぎると、炭酸化養生の効果が得られ難くなり強度の発現性が遅くなるおそれがある。
【００２１】
本発明では、促進炭酸化養生の前に、水中養生または湿空養生の工程を加えるのが好ましい。水中養生または湿空養生は、通常、脱型直後または成形直後から１〜１０日程度行なわれる。水中養生や湿空養生等の前養生を行なうことにより、促進炭酸化養生による軽量モルタル材の強度をより一層向上させることができる。なお、湿空養生は、通常、湿度（Ｒ.Ｈ.）９０％以上、温度１０〜６０℃程度の雰囲気下で行なわれる。
【００２２】
本発明で用いられる炭酸ガスとしては、市販の二酸化炭素、ドライアイスの他、セメント工場、火力発電所やゴミ焼却場等の燃焼ガスや廃棄ガス等が使用できる。
【００２３】
【実施例】
［実施例１〜１１、比較例１〜６］
以下のように４×４×１６ｃｍのモルタル硬化体を作製し、所定の養生を施した後、促進炭酸化養生条件下で、経時的に比重及び曲げ強さを測定した。また、比重の異なる配合での強度性状を比較するために比強度（＝曲げ強さ／比重）を求めた。
モルタル硬化体の作製方法は、ＪＩＳ Ｒ５２０１に準拠した。軽量モルタル硬化体の養生条件は、型枠内に混練物を投入後、脱型するまでの１日間を、湿空養生（２０℃、湿度（Ｒ.Ｈ.）９０％以上）とし、その後、水中養生または促進炭酸化養生（２０℃、湿度（Ｒ.Ｈ.）６０％、炭酸ガス濃度１０％）またはそれらの組み合わせとした。
促進中性化試験は、セメント系軽量モルタル材の強度の耐久性を評価するために実施したものである。具体的には、高炭酸ガス濃度下（２０℃、湿度（Ｒ.Ｈ.）６０％、炭酸ガス濃度１０％）における曲げ強さの経時変化を測定した。
【００２４】
（１）材料
セメント系軽量モルタル材を作製するために、以下の材料を用いた。
▲１▼セメント
（Ｎ）普通ポルトランドセメント
（Ｌ）低熱ポルトランドセメント（ビーライト含有率５１％）
▲２▼無機質粉末：石灰石粉（ブレーン比表面積：４,５００ｃｍ2／ｇ）
▲３▼軽量細骨材：パーライト（アサノパーライト社製、商品名：「硬質パーライト：
ＫＰ」）、絶乾比重：０．８６、粒子径0.４〜1.2mm，吸水率：約１５％
▲４▼骨材（細骨材）：ＪＩＳ Ｒ５２０１標準砂
▲５▼有機高分子系炭酸化促進剤（ポリマーエマルション）
（Ａ）エチレン−酢酸ビニル（ＥＶＡ）系エマルション（電気化学工業社製、商品名：「８３ＰＬＤ」）
（Ｂ）スチレン−アクリル酸エステル（ＰＡＥ）系エマルション（日本エヌエスシー社製、商品名：「ＧＦ１Ｔ」）
▲６▼混練水：水道水を使用
【００２５】
（２）配合割合及び養生条件
各材料の配合割合（重量部）及び養生条件は、表１の通りである。なお、表１中の「養生条件」は、型枠内で１日間湿空養生を施した後、脱型し、その後に行なった養生方法及び期間を記載したものである。
【００２６】
【表１】
（３）実験結果
▲１▼実施例１〜４、比較例１〜２
実施例１〜４及び比較例１〜２の軽量モルタル材について、曲げ強さ及び比重を測定するとともに、これらの促進中性化を行なった結果を表２に示す。なお、曲げ強度比とは、促進中性化試験材齢１０週後の供試体の曲げ強さを養生後の供試体の曲げ強さで除したものである。
【００２８】
【表２】
表２から、促進炭酸化養生を行なった軽量モルタル材においては、水中養生によって得られた軽量モルタル材に比べて、養生後の曲げ強さが大きく、それを比重で除した比強度も大きいことから、促進炭酸化養生を行なうことで軽量でありながら高い曲げ強さを得ることができることがわかる。また、促進中性化試験材齢１０週後の曲げ強さと養生後の曲げ強さとの比である曲げ強度比においても、促進炭酸化養生を行なった供試体においては、養生後の曲げ強さを保持していることがわかる。
【００３０】
▲２▼実施例５〜１１、比較例３〜６
実施例５〜１１及び比較例３〜６の軽量モルタル材について、曲げ強さ及び比重を測定するとともに、これらの促進中性化を行なった結果を表２に示す。なお、これらの配合中には、有機高分子系炭酸化促進剤を添加している。
【００３１】
表２から、有機高分子系炭酸化促進剤を添加した軽量モルタル材においては、促進炭酸化養生を行なうことで、大きな比強度が得られることがわかる。また、促進中性化試験材齢１０週後の曲げ強さと養生後の曲げ強さとの比である曲げ強度比においても、促進炭酸化養生を行なった供試体においては、養生後の曲げ強さを維持していることがわかる。
【００３２】
【発明の効果】
本発明の製造方法により得られる軽量モルタル材は、軽量でありながら高い強度発現性を有し、その後、長期間に亘ってその強度が低下することなく維持できるので、軽量高強度で耐久性の優れたセメント系軽量モルタル製品として有望である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lightweight mortar material using a lightweight fine aggregate, which expresses high strength while being lightweight, and is capable of maintaining a large strength without deterioration over a long period of time. The present invention relates to a method for producing an excellent lightweight mortar material.
[0002]
[Prior art]
Conventionally, a technique for improving strength by curing a cemented body in carbon dioxide gas is known. For example, in JP-A-6-263562, a hardened cement obtained by kneading cement, aggregate, and water is molded, precured, demolded, and then in a carbon dioxide atmosphere for a predetermined period. A technique for obtaining a high-strength cement hardened body by curing with the use of is disclosed. In addition, in the present inventors, in Japanese Patent Application No. 2000-70677, an organic polymer carbonation accelerator (for example, ethylene-vinyl acetate emulsion) is contained in cement and inorganic powder blended as necessary. After the cured body is molded and pre-cured, the maximum bending strength achieved after curing is maintained for almost a long time by curing in carbon dioxide gas for a predetermined period. A technology for obtaining a cement-based cured body having high bending strength and excellent durability is described.
In the conventional lightweight mortar material and lightweight concrete, in order to improve the durability, the technique of reducing the porosity of the lightweight mortar material after hardening and improving durability is known. For example, Japanese Patent Laid-Open No. 11-131804 discloses that the water cement ratio is reduced to 45% or less in order to reduce the amount of water that generates voids for the purpose of improving the durability of lightweight concrete. No. -278900 discloses that the light-weight mortar material after hardening is reduced by selecting and using a light-weight fine aggregate with a low water absorption rate as the light-weight fine aggregate to be blended.
[0003]
[Problems to be solved by the invention]
The above publication shows that when carbon dioxide curing is performed, the bending strength of the hardened cement body is increased as compared to the case where curing is not performed, however, the present inventors perform carbon dioxide curing, It was found that the bending strength of the lightweight mortar material that temporarily reached the maximum value decreased with time in the long term.
Therefore, the present invention is a lightweight mortar material excellent in durability and capable of maintaining the maximum bending strength as it is for a long time when subjected to carbon dioxide curing while being light weight and high strength, and its production It aims to provide a method.
In both cases, when the water-cement ratio is reduced to reduce the voids in the lightweight mortar material and the cured lightweight concrete, or when a lightweight fine aggregate with low water absorption is used, the surface layer is a glassy lightweight fine bone. It is necessary to use the material, and depending on the use situation, there is an unavoidable risk of deterioration of the cured body structure of the lightweight mortar material due to the alkali aggregate reaction.
[0004]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventors have found that there are organic polymers that promote carbonation of cement-based lightweight mortar materials, and lightweight mortar molded bodies containing cement. If the organic polymer type carbonation accelerator is blended as a material of the molded body before the accelerated carbonation curing, the strength of the lightweight mortar molded body is improved by the accelerated carbonation curing, and the light weight has high bending strength. A mortar hardened body was obtained, and even after reaching the maximum strength, it was found that the strength did not decrease with time, and the present invention was completed.
[0005]
That is, the method for producing a lightweight mortar material of the present invention is a total of the cement and the inorganic powder blended as necessary, the light fine aggregate, and the cement and the inorganic powder blended as necessary in terms of solid content. 2 to 20 parts by weight of organic polymer carbonation accelerator selected from the group consisting of thermoplastic emulsion, synthetic rubber latex, re-emulsified powder resin, cellulose derivative and polyvinyl alcohol with respect to 100 parts by weight The molded product contained is carbonated and cured (Claim 1). Thus, by blending an organic polymer carbonation accelerator together with cement or the like in advance, it is possible to maintain light weight and high strength over a long period even after carbonation curing. Here, the light-weight fine aggregate has a particle diameter of 0.1 mm to 1.2 mm, a specific gravity of 0.1 to 0.9 (Claim 2), and the content thereof is the cement and, if necessary, It is 5-150 weight part with respect to 100 weight part of total amounts of the inorganic powder mix | blended (Claim 3). The carbonation curing needs to be started at the latest within 10 days of hydration material age (Claim 4). In addition, when pre-curing by underwater curing or wet air curing is performed before carbonation curing, the strength is further improved (Claim 5). The content of belite in the total amount of the cement and, if necessary, the inorganic powder is 5% by mass or more (Claim 6).
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The cement used in the present invention is not particularly limited as long as it is a cement that generates calcium hydroxide and calcium silicate hydrated products upon hydration. For example, low heat Portland cement (high belite cement), moderate heat Portland cement such as Portland cement, normal Portland cement, early-strength Portland cement, ultra-high-strength Portland cement, sulfate-resistant Portland cement, Portland cement such as various low alkali type Portland cement, blast furnace cement, silica cement, fly ash cement Such as mixed cement, white cement and the like. Ordinary Portland cement usually contains 25% by mass or more, and early-strength Portland cement usually contains 15% by mass or more of belite, so that the effects of the present invention can be sufficiently obtained.
Of these, low heat Portland cement and moderately hot Portland cement are preferred because they are excellent in the effect of the present invention (light weight and high strength). Low heat Portland cement usually contains 40% by weight or more of belite. Medium heat Portland cement usually contains 30% or more by weight of belite.
[0007]
As the inorganic powder blended with the cement as necessary, there are those composed of one or more kinds selected from blast furnace slag powder, fly ash, limestone powder, meteorite powder, silica fume, natural products and artificial materials containing a large amount of belite. Used. Further, fine powder obtained by pulverizing calcium silicate waste materials such as concrete fine powder and cement-based products can also be used.
In addition, it is preferable to adjust so that the content rate of the belite in the total amount of the inorganic powder mix | blended with cement as needed may be 5 mass% or more. When the content is 5% by mass or more, particularly excellent high bending strength is exhibited when carbonized.
[0008]
The lightweight fine aggregate used in the present invention is not particularly limited, and is obtained by incinerating pearlite, shirasu balloon, vermiculite, artificial lightweight fine aggregate obtained by firing and foaming shale, clay, or paper sludge. Inorganic light-weight fine aggregates such as pulp sludge (PS) ash sand, synthetic resin foams such as styrene beads, vinyl chloride, polypropylene, polyethylene, and polystyrene, and waste materials thereof can be used.
[0009]
The lightweight fine aggregate preferably has a particle diameter of 0.1 mm to 1.2 mm and a specific gravity of about 0.1 to 0.9. Moreover, you may make it mix | blend the lightweight fine aggregate in this invention combining the said 2 or more types of lightweight fine aggregate. When a lightweight fine aggregate having a particle diameter of less than 0.1 mm is used, the flowability of the mortar after kneading is lowered and the moldability is deteriorated. On the other hand, if a lightweight fine aggregate exceeding 1.2 mm is used, the surface properties of the lightweight mortar hardened body deteriorate, which is not preferable. In addition, when a lightweight fine aggregate having a specific gravity of less than 0.1 is used, the float in the mortar becomes prominent and the surface property of the cured body is deteriorated. On the other hand, when the specific gravity is greater than 0.9, the light weight effect is obtained. Since it becomes difficult to express, it is not preferable.
[0010]
The addition amount of the lightweight fine aggregate is effective at 5 to 150 parts by weight with respect to 100 parts by weight of the cement and the inorganic powder blended as necessary. What is necessary is just to determine suitably from the relationship with the specific gravity of the required lightweight mortar material. If the addition amount is less than 5 parts by weight, light weight cannot be obtained, and if it exceeds 150 parts by weight, the cost is increased and the elastic modulus of the cured body is lowered, so that the desired strength properties cannot be obtained. It is preferable that the amount of the light fine aggregate is appropriately blended so that it accounts for 20% or more of the entire material in terms of the volume ratio in the light weight mortar material.
[0011]
The organic polymer-based carbonation accelerator used in the present invention is to accelerate the carbonation of a cement-based lightweight mortar material, and includes thermoplastic emulsion, synthetic rubber latex, re-emulsified powder resin, cellulose derivative, and polyvinyl alcohol. Those selected from the group consisting of: Specifically, acrylic ester, polyvinyl acetate, ethylene-vinyl acetate emulsion, styrene-acrylate emulsion, etc., are used as thermoplastic emulsions, and styrene-butadiene rubber, etc., is used as a synthetic rubber latex. Examples of the resin include polyacrylic acid ester, ethylene-vinyl acetate copolymer, vinyl acetate-vinyl versatate (VeoVa), and examples of the cellulose derivative include methyl cellulose.
[0012]
The amount of the organic polymer carbonation accelerator added is 2 to 20 parts by weight in terms of solid content and 100 parts by weight of the total amount of cement and inorganic powder blended as necessary. Preferably 3 to 15 parts by weight. If the added amount is less than 2 parts by weight, it will be difficult to maintain the strength over a long period of time, and if it exceeds 20 parts by weight, the cost will be high and the elastic modulus of the cured product will be lowered, and the desired strength properties will be obtained. You will not be able to get.
[0013]
Other materials that can be blended together with cement, lightweight fine aggregates, etc. include fine aggregates, reinforcing fibrous materials, various admixtures and the like.
[0014]
The fine aggregate is an aggregate having a particle diameter smaller than that of the coarse aggregate, and examples thereof include river sand, sea sand, mountain sand, crushed sand, or a mixture thereof. The amount of fine aggregate is usually about 30 to 400 parts by weight with respect to 100 parts by weight of the total amount of cement and inorganic powder blended as necessary, but depending on the specific gravity of the required lightweight mortar. What is necessary is just to determine suitably.
[0015]
Examples of the reinforcing fibers include glass fibers such as E glass, slag fibers, carbon fibers, vinylon, polypropylene, acrylic, pulp, and other natural fibers such as silicone carbide fibers and asbestos, and synthetic fibers. Examples of the admixture include water reducing agents, AE water reducing agents, high performance water reducing agents, high performance AE water reducing agents, hydration accelerators, hydration retarders, drying shrinkage reducing agents, and thickeners. The type and blending amount of the admixture may be appropriately determined in consideration of the type and blending amount of materials other than the admixture and the use of the lightweight mortar material.
[0016]
The amount of kneading water is not particularly limited, but is preferably 0.30 to 0.60 in terms of water cement ratio. If the water-cement ratio is less than 0.30, it is difficult to promote carbonation, so that the effect of promoting the strength of the lightweight mortar material by accelerated carbonation may not be obtained. If the water-cement ratio exceeds 0.60, the strength decreases. This is because there is a risk of damaging the durability. In the present specification, “water cement ratio” means the ratio (W / weight) obtained by dividing the mass (W) of “water” by the mass (C) of “cement and inorganic powder blended as necessary”. C).
[0017]
A mixer used for kneading various materials is not particularly limited, and a conventional mixer such as a pan type mixer, a biaxial mixer, an omni mixer, a Hobart mixer may be used.
As a kneading method, all the materials may be put into a mixer all together and kneaded, or after materials other than water, organic polymer carbonation accelerator, admixture are put into a mixer and kneaded, Water or the like may be added and kneaded.
After kneading, the kneaded product is put into a predetermined mold. An external vibration may be applied to the kneaded material put into the mold, or pressure molding may be performed using a pressure device or the like.
[0018]
The kneaded product is usually removed from the mold after about 1 to 2 days to form a molded product, and then subjected to curing according to the present invention. In addition, you may use the method of obtaining a molded object, such as extrusion molding, without using a formwork.
The accelerated carbonation curing preferably starts at the latest within 10 days, more preferably within 7 days of the hydrated material age of the molded body.
[0019]
Carbonation curing is usually performed as an air curing, but may be performed in combination with wet air or steam curing as necessary.
In the case of air curing, the molded body is subjected to accelerated carbonation under a condition where the carbon dioxide (CO 2 ) concentration is 1 to 100%, preferably 3 to 100%. Although the temperature at the time of accelerated carbonation curing is not specifically limited, Usually, it is about 10-80 degreeC. The humidity (RH) during accelerated carbonation curing is not particularly limited, but is usually about 40 to 90%.
[0020]
The curing time when the accelerated carbonation curing is performed in the air or in the wet air is determined in consideration of various conditions such as carbon dioxide concentration. For example, when the carbon dioxide concentration is 10%, the temperature is 20 ° C., and the humidity (RH) is 60%, it is about 4 to 10 days.
As described above, it is preferable that the accelerated carbonation curing is started at the latest within 10 days of the hydrated material age of the molded body. If this is exceeded, the effect of carbonation curing may be difficult to obtain, and the strength development may be delayed.
[0021]
In this invention, it is preferable to add the process of underwater curing or wet air curing before accelerated carbonation curing. Underwater curing or wet air curing is usually performed for about 1 to 10 days immediately after demolding or immediately after molding. By performing precuring such as underwater curing and wet air curing, the strength of the lightweight mortar material by accelerated carbonation curing can be further improved. In addition, wet air curing is normally performed in the atmosphere (at about 10-60 degreeC) of humidity (RH) 90% or more.
[0022]
As the carbon dioxide gas used in the present invention, in addition to commercially available carbon dioxide and dry ice, a combustion gas, a waste gas, etc., such as a cement factory, a thermal power plant, and a garbage incinerator can be used.
[0023]
【Example】
[Examples 1-11, Comparative Examples 1-6]
A 4 × 4 × 16 cm mortar cured body was prepared as described below, subjected to predetermined curing, and then measured for specific gravity and bending strength over time under accelerated carbonation curing conditions. In addition, specific strength (= bending strength / specific gravity) was determined in order to compare strength properties with blends having different specific gravities.
The manufacturing method of the mortar hardened body was based on JIS R5201. The curing condition of the lightweight mortar cured body is a wet-air curing (20 ° C., humidity (RH) 90% or more) for one day after the kneaded material is put into the mold and then demolded. Underwater curing or accelerated carbonation curing (20 ° C., humidity (RH) 60%, carbon dioxide concentration 10%) or a combination thereof.
The accelerated neutralization test was conducted to evaluate the durability of the strength of the cementitious lightweight mortar material. Specifically, the time-dependent change in bending strength was measured under a high carbon dioxide gas concentration (20 ° C., humidity (RH) 60%, carbon dioxide gas concentration 10%).
[0024]
(1) Materials The following materials were used to produce cement-based lightweight mortar materials.
(1) Cement (N) Ordinary Portland cement (L) Low heat Portland cement (Belite content 51%)
( 2 ) Inorganic powder: Limestone powder (Blaine specific surface area: 4,500 cm 2 / g)
(3) Lightweight fine aggregate: Perlite (manufactured by Asano Perlite, trade name: “Hard perlite:
KP "), absolute dry specific gravity: 0.86, particle size 0.4-1.2 mm, water absorption: about 15%
(4) Aggregate (fine aggregate): JIS R5201 standard sand (5) Organic polymer carbonation accelerator (polymer emulsion)
(A) Ethylene-vinyl acetate (EVA) emulsion (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: “83PLD”)
(B) Styrene-acrylic ester (PAE) emulsion (manufactured by NSC Japan, trade name: “GF1T”)
(6) Kneaded water: Uses tap water
(2) Mixing ratio and curing conditions Table 1 shows the mixing ratio (parts by weight) and curing conditions of each material. The “curing conditions” in Table 1 describe the curing method and the period of time after performing wet-curing curing for 1 day in the mold and then demolding.
[0026]
[Table 1]
(3) Experimental results (1) Examples 1-4 and Comparative Examples 1-2
Table 2 shows the results of measuring the bending strength and specific gravity of the lightweight mortar materials of Examples 1 to 4 and Comparative Examples 1 and 2, and performing these accelerated neutralizations. The bending strength ratio is obtained by dividing the bending strength of the specimen after 10 weeks of accelerated neutralization test material by the bending strength of the specimen after curing.
[0028]
[Table 2]
From Table 2, the lightweight mortar material that has undergone accelerated carbonation curing has a higher bending strength after curing than the lightweight mortar material obtained by underwater curing, and the specific strength obtained by dividing it by specific gravity. Thus, it can be seen that high bending strength can be obtained while being lightweight by performing accelerated carbonation curing. In addition, in the test specimen subjected to accelerated carbonation curing, the flexural strength after curing was also applied to the bending strength ratio, which is the ratio between the bending strength after 10 weeks of accelerated neutralization test material and the flexural strength after curing. It can be seen that
[0030]
(2) Examples 5 to 11 and Comparative Examples 3 to 6
Table 2 shows the results of measuring the flexural strength and specific gravity of the lightweight mortar materials of Examples 5 to 11 and Comparative Examples 3 to 6, and performing these accelerated neutralizations. In addition, the organic polymer type carbonation accelerator is added in these compounding.
[0031]
From Table 2, it can be seen that a light mortar material to which an organic polymer carbonation accelerator is added can obtain a large specific strength by performing accelerated carbonation curing. In addition, in the test specimen subjected to accelerated carbonation curing, the flexural strength after curing was also applied to the bending strength ratio, which is the ratio between the bending strength after 10 weeks of accelerated neutralization test material and the flexural strength after curing. It can be seen that
[0032]
【The invention's effect】
The lightweight mortar material obtained by the production method of the present invention has a high strength expression while being lightweight, and thereafter can be maintained without a decrease in strength over a long period of time. It is promising as an excellent cement-based lightweight mortar product.
Claims (6)
Priority Applications (1)
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|---|---|---|---|
| JP2001102283A JP4658362B2 (en) | 2001-03-30 | 2001-03-30 | Manufacturing method for lightweight mortar |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001102283A JP4658362B2 (en) | 2001-03-30 | 2001-03-30 | Manufacturing method for lightweight mortar |
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| JP4658362B2 true JP4658362B2 (en) | 2011-03-23 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP3910141B2 (en) * | 2002-12-26 | 2007-04-25 | 和元 橋詰 | Construction method for insulation |
| JP5193556B2 (en) * | 2007-10-16 | 2013-05-08 | 昭和電工建材株式会社 | Method for producing hydraulic molded body |
| JP5083966B2 (en) * | 2007-12-29 | 2012-11-28 | 太平洋マテリアル株式会社 | High fluidity lightweight mortar composition |
| JP4822373B1 (en) * | 2010-12-17 | 2011-11-24 | 中国電力株式会社 | Carbonation curing equipment, carbonized concrete manufacturing method and carbon dioxide fixing method |
| JP5856891B2 (en) * | 2012-03-29 | 2016-02-10 | 株式会社エーアンドエーマテリアル | Manufacturing method of inorganic board |
| JP2012131235A (en) * | 2012-04-09 | 2012-07-12 | Showa Denko Kenzai Kk | Method for producing hydraulic molded article, hydraulic molded article, fire-resistant two-layer pipe, and joint therefor |
| JP6887375B2 (en) * | 2015-04-28 | 2021-06-16 | 株式会社クラレ | Fiber-containing carbonated roof tile and its manufacturing method |
| US11254028B2 (en) | 2019-05-20 | 2022-02-22 | Saudi Arabian Oil Company | Systems and processes for accelerated carbonation curing of pre-cast cementitious structures |
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| JPS52115828A (en) * | 1976-03-25 | 1977-09-28 | Ibigawa Electric Ind Co Ltd | Production method of curing material through coal carbonation |
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| JP2002293601A (en) | 2002-10-09 |
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