JP2005320201A - Cement composition using waste concrete fine powder and method of preparing the same - Google Patents
Cement composition using waste concrete fine powder and method of preparing the same Download PDFInfo
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- JP2005320201A JP2005320201A JP2004139825A JP2004139825A JP2005320201A JP 2005320201 A JP2005320201 A JP 2005320201A JP 2004139825 A JP2004139825 A JP 2004139825A JP 2004139825 A JP2004139825 A JP 2004139825A JP 2005320201 A JP2005320201 A JP 2005320201A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
Description
本発明は、廃コンクリート微粉末を用いたセメント組成物及びその製造方法に係り、老朽化したり、改築のために解体された鉄筋コンクリート構造物等から分離して取り出されたコンクリート塊を破砕処理して所定粒径の微粉末とし、さらに所定の処理を施すことにより、一定の水和自硬性能を有するセメント組成物とその製造方法に関する。 The present invention relates to a cement composition using waste concrete fine powder and a method for producing the same, crushing a concrete block taken out from a reinforced concrete structure that has been aged or dismantled for reconstruction. The present invention relates to a cement composition having a certain hydration self-hardening performance by forming a fine powder having a predetermined particle diameter and further performing a predetermined treatment, and a method for producing the same.
高度経済成長期に建設されたコンクリート構造物が今後、更新時期を迎える。このため、解体された鉄筋コンクリート構造物等から分離して取り出されたコンクリート塊(以下、廃コンクリートと記す。)のリサイクル技術の確立が急務となっており、建築分野を中心として再生骨材の品質を天然骨材なみに高め、構造用骨材として一般のコンクリート構造に再利用するための開発が進められている。 The concrete structure built during the period of high economic growth will soon be renewed. For this reason, it is an urgent task to establish recycling technology for concrete blocks (hereinafter referred to as waste concrete) separated and removed from dismantled reinforced concrete structures. Development is underway to increase the quality of natural aggregates and recycle them into general concrete structures as structural aggregates.
各種の破砕処理装置によって高次処理を行って廃コンクリートから高品質の再生骨材を製造する際、付着したセメント水和物が取り除かれ、セメント硬化物を主体とする多量のコンクリート微粉末が発生する。したがって、廃コンクリートから製造される構造用再生骨材の普及展開にあたり、この二次副産物として発生する微粉末の各分野での再利用が課題であり、各種の適用例が提案されている。 When high-quality recycled aggregates are produced from waste concrete by high-level processing using various crushing equipment, adhering cement hydrate is removed, and a large amount of concrete fine powder mainly composed of hardened cement is generated. To do. Therefore, the reuse of fine powder generated as a secondary by-product in each field is an issue in the widespread development of structural recycled aggregates produced from waste concrete, and various application examples have been proposed.
出願人も、すでにコンクリート資源の有効循環利用を目的として廃コンクリートから高品質の再生骨材を製造可能な「加熱すりもみ法」を採用し、同方法によって得られた微粉末に対しては、地盤固化材料やその他の用途を視野に入れた再利用について検討を進めてきた(特許文献1)。 Applicants have already adopted the “heated surimi method” that can produce high-quality recycled aggregates from waste concrete for the purpose of effective recycling of concrete resources, and for fine powder obtained by this method, Studies have been made on reuse with a view to solidifying materials and other uses (Patent Document 1).
それと並行して、上述の微粉末の固化メカニズムをより正確に把握することにより、その再利用を高めるための研究も進めている。今までに、再生された微粉末が極めて高い粉末度を示すことと、微粉末中のCa(OH)2量が、微粉末の自硬性(強度発現)に関係している点等について確認している(非特許文献1,非特許文献2)。
At the same time, research is underway to increase the reuse of the above-mentioned fine powder by more accurately grasping the solidification mechanism. So far, we have confirmed that the regenerated fine powder shows extremely high fineness and that the amount of Ca (OH) 2 in the fine powder is related to the self-hardness (strength development) of the fine powder. (Non-patent
ところで、既往の研究では、廃コンクリートの微粉末の自硬性に着目し、たとえば地盤改良の主固化材としてのセメントに所定割合の混合比で微粉末を添加し、混合固化材として従来のセメント組成物を用いた場合と同等の強度、剛性等が得られることを確認してきた。しかし、セメント組成物としての代替性を確実なものとするためには、微粉末の再水和メカニズムに着目し、その再水和を促進するような微粉末の再生処理方法の確立が課題となってきている。 By the way, in past research, focusing on the self-hardness of fine powder of waste concrete, for example, adding fine powder at a mixing ratio of a predetermined ratio to cement as the main solidification material for ground improvement, and conventional cement composition as mixed solidification material It has been confirmed that the same strength, rigidity, etc. can be obtained as when using an object. However, in order to ensure the substitutability as a cement composition, focusing on the rehydration mechanism of fine powder, establishing a reprocessing method of fine powder that promotes the rehydration is an issue. It has become to.
この点について、出願人が進めた研究により、廃コンクリートの微粉末を所定温度範囲で加熱処理することで、クリンカーのビーライト(belite,以下C2Sと記す。)の再合成が促進され、C2Sの水和によるC−S−Hの生成およびCa(OH)2量の増加が確認され、水和硬化性を十分発揮するセメント組成物の一種として利用できるとの知見を得た。 In this regard, research conducted by the applicant promoted the resynthesis of clinker belite (hereinafter referred to as C 2 S) by heat-treating the fine powder of waste concrete within a predetermined temperature range. The production of C—S—H and the increase in the amount of Ca (OH) 2 due to the hydration of C 2 S were confirmed, and the knowledge that it can be used as a kind of cement composition exhibiting sufficient hydration curability was obtained.
上記目的を達成するために、本発明は、セメント組成物としてコンクリート廃材の破砕処理により再生骨材とともに得られる微粉末が、加熱処理により再合成したビーライト(C2S)を含有することを特徴とする。このセメント組成物の製造方法として、微粉末を、所定の温度範囲で加熱し、該微粉末内にビーライト(C2S)鉱物を再合成させることを特徴とする。 In order to achieve the above object, the present invention provides that the fine powder obtained together with the recycled aggregate by the crushing treatment of the concrete waste material as a cement composition contains belite (C 2 S) re-synthesized by the heat treatment. Features. As a method for producing this cement composition, fine powder is heated in a predetermined temperature range, and belite (C 2 S) mineral is re-synthesized in the fine powder.
前記加熱処理は、材料温度が500〜750℃となるように加熱されるようにすることが好ましい。 The heat treatment is preferably performed such that the material temperature is 500 to 750 ° C.
本発明によれば、廃コンクリートから再生骨材を製造する際に、発生した微粉末内に、水和硬化性を有するビーライト(C2S)鉱物を再合成し含有させることができ、セメント組成物として再利用することができるという効果を奏する。 According to the present invention, when producing recycled aggregate from waste concrete, hydrated and hardened belite (C 2 S) mineral can be re-synthesized and contained in the generated fine powder. There exists an effect that it can be reused as a composition.
以下、本発明の廃コンクリート微粉末を用いたセメント組成物及びその製造方法の実施するための最良の形態として、以下の実施例について添付図面を参照して説明する。 Hereinafter, the following examples will be described with reference to the accompanying drawings as the best mode for carrying out the cement composition using the waste concrete fine powder of the present invention and the method for producing the same.
[微粉末の加熱処理]
再生骨材製造の最終段階で発生し、バグフィルタ、サイクロン等の公知の集塵機あるいは公知の乾式及び湿式分級機により収集された微粉末は、粒径0.6mm以下、比表面積500cm2/g以上で、この微粉末は、図1に示した作業フローに基づいて加熱され、所定の硬化特性を有するセメント組成物として再生することができる。以下、そのセメント組成物の製造方法の一実施例について説明する。
[Heat treatment of fine powder]
Fine powder generated at the final stage of recycled aggregate production and collected by known dust collectors such as bag filters and cyclones or known dry and wet classifiers has a particle size of 0.6 mm or less and a specific surface area of 500 cm 2 / g or more. Thus, the fine powder is heated based on the work flow shown in FIG. 1 and can be regenerated as a cement composition having a predetermined curing property. Hereinafter, an example of a method for producing the cement composition will be described.
上述した仕様に合致した廃コンクリート微粉末は、図示しない収容サイロから所定のロットで、あるいは連続的に加熱部10に供給される。加熱部10は、投入側に所定投入量を調整可能なホッパ11が設けられた公知のスクリューコンベア12を搬送経路とし、その周囲を長手方向に所定範囲を均一温度に加熱可能な加熱装置13が囲むように構成されている。本実施例では、この加熱装置13により、スクリューコンベア12内を通過する微粉末(図示せず)は、500〜750℃の所定の設定温度になるように加熱範囲を搬送され、高温状態にある微粉末1は、外気に触れずに徐冷され排出ホッパ14から直接貯蔵タンク15に収容される。
Waste concrete fine powder that meets the above-described specifications is supplied to the
加熱装置13の熱源としては、所定温度、加熱時間を制御可能な公知の種々の燃焼方式の装置を使用することができる。たとえば従来、汚泥等の焼却炉として利用される公知の流動床式加熱設備(図示せず)を使用することもできる。この種の流動床式加熱設備では、多数の空気噴出ノズルを備えた火床の上に加熱された微粉末が浮き上がった流動層をなして、瞬時に加熱される。このため、燃焼空気と微粉末とが直接接しないため、二酸化炭素によるCa(OH)2の炭酸化が少なく、C2Sの再合成を効率的に実現することができる。
As a heat source of the
また、上述した加熱すりもみ法によって得られた微粉末を再加熱する場合には、再加熱する加熱設備の廃熱を、再生骨材を製造するための加熱すりもみ法の設備の加熱に利用することで既存設備の多機能化を図ることができる。 In addition, when re-heating fine powder obtained by the above-mentioned hot grinding method, the waste heat of the heating equipment to be reheated is used for heating the equipment of the hot grinding method for producing recycled aggregates. By doing so, it is possible to make the existing equipment multifunctional.
以下、微粉末加熱によるC2Sの再合成の効果確認について行った実験について説明する。 Hereinafter, an experiment conducted for confirming the effect of resynthesis of C 2 S by heating fine powder will be described.
(破砕物の加熱処理)
普通ポルトランドセメントに対してW/C=40%セメントペーストを練り混ぜ、φ50mm×100mm の供試体試料を成型し、所定期間の養生後(20℃水中で30日、40℃温水中で60日養生)、40℃恒温槽で1週間乾燥した後、ジョークラッシャで5mm程度以下に破砕し、粉砕物を100〜600℃(100℃刻み)の6ケースの温度設定条件で2時間加熱処理した。
(Heat treatment of crushed material)
W / C = 40% cement paste is kneaded with normal Portland cement, a specimen sample of φ50mm × 100mm is molded, and after curing for a specified period (30 days in 20 ° C water, 60 days in 40 ° C warm water) ) After drying in a 40 ° C. constant temperature bath for 1 week, it was crushed to about 5 mm or less with a jaw crusher, and the pulverized product was heat-treated for 2 hours under the temperature setting conditions of 6 to 100 ° C. (100 ° C. increments).
(試験の内容)
(1)微粉末スラリー試料の作製
上記各ケースの温度で加熱処理した破砕物を、それぞれ振動ミルを用いて、一定条件で微粉砕し、微粉末を製造した。これを用いて、ホバートミキサで微粉末スラリー(W/P=75%)を練り混ぜ、φ50mm×100mm の供試体を成型して、所定の材齢まで20℃の恒温室で湿潤養生した。なお、再水和後の試料の化学分析には、材齢28日の一軸圧縮試験後の供試体を5mm程度以下に破砕し、アセトン処理した後、真空乾燥したものを用いた。
(2)一軸圧縮試験
スラリー硬化体の一軸圧縮試験を、JIS A 1216(土の一軸圧縮試験方法)に準じて材齢28日で行った。
(Examination contents)
(1) Preparation of fine powder slurry sample The crushed material heat-treated at the temperature of each case was finely pulverized under certain conditions using a vibration mill to produce a fine powder. Using this, a fine powder slurry (W / P = 75%) was kneaded with a Hobart mixer, a specimen having a diameter of 50 mm × 100 mm was molded, and wet-cured in a constant temperature room at 20 ° C. until a predetermined age. For chemical analysis of the sample after rehydration, a specimen after a uniaxial compression test on the age of 28 days was crushed to about 5 mm or less, treated with acetone, and then vacuum-dried.
(2) Uniaxial compression test The uniaxial compression test of the slurry hardened body was performed at a material age of 28 days in accordance with JIS A 1216 (soil uniaxial compression test method).
(試験結果)
一軸圧縮試験結果を、図2に示した。同図に示したように、加熱処理温度が500〜600℃の範囲において、微粉末スラリー硬化体の強度が急激に増加することが認められた。この範囲での強度発現の理由としては、500℃以上の加熱でセメントのクリンカー鉱物のうちのC2Sが再合成され、C2Sの水和反応によってC−S−Hが生成されたことに起因していると思われる。好ましい実用的な加熱温度として600〜700℃程度の加熱を行うことで、廃コンクリート微粉末をもとに、「再生セメント」ととも言えるセメント組成物を提供可能なことも確認できた。なお、このセメント組成物は、通常の配合での28日材齢で数N/mm2程度の強度発現が可能であり、セメント単体としての利用の他、左官材料や人工地盤固化材料にも適用可能なことは言うまでもない。なお、加熱温度が750℃を超えると炭酸カルシウムの分解によって遊離石灰の増加が認められるため、上限として750℃程度の加熱条件が適正と思われる。
(Test results)
The results of the uniaxial compression test are shown in FIG. As shown in the figure, it was recognized that the strength of the fine powder slurry hardened body rapidly increased in the heat treatment temperature range of 500 to 600 ° C. The reason for the strength development in this range is that C 2 S of the clinker mineral of cement was re-synthesized by heating at 500 ° C. or higher, and C—S—H was generated by the hydration reaction of C 2 S. It seems to be caused by. It was also confirmed that a cement composition that can be called “recycled cement” can be provided based on the waste concrete fine powder by heating at about 600 to 700 ° C. as a preferred practical heating temperature. In addition, this cement composition can develop strength of several N / mm 2 at the age of 28 days in a normal composition, and can be applied to plastering materials and artificial ground solidification materials in addition to use as a single cement. It goes without saying that it is possible. When the heating temperature exceeds 750 ° C., an increase in free lime is recognized due to the decomposition of calcium carbonate. Therefore, the heating condition of about 750 ° C. is considered appropriate as the upper limit.
1 微粉末
10 加熱部
13 加熱装置
1
Claims (3)
\\ The said heat processing is heated so that material temperature may be 500-750 degreeC, The manufacturing method of the cement composition using the waste concrete fine powder of Claim 2 characterized by the above-mentioned.
\\
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2010143656A1 (en) * | 2009-06-09 | 2010-12-16 | 株式会社竹中工務店 | Hydraulic cement composition |
JP2012012284A (en) * | 2010-06-01 | 2012-01-19 | Ohbayashi Corp | Method for producing hydraulic material, and method for selecting crushed concrete material |
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JPH08198652A (en) * | 1994-11-24 | 1996-08-06 | Mitsubishi Heavy Ind Ltd | Production of regenerated aggregate from cement concrete lump |
JPH10114556A (en) * | 1996-10-09 | 1998-05-06 | Chichibu Onoda Cement Corp | Production of reclaimed cement, and reclaimed cement |
JPH11292602A (en) * | 1998-04-09 | 1999-10-26 | Mitsubishi Materials Corp | Cement-based composition |
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Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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JPH08198652A (en) * | 1994-11-24 | 1996-08-06 | Mitsubishi Heavy Ind Ltd | Production of regenerated aggregate from cement concrete lump |
JPH10114556A (en) * | 1996-10-09 | 1998-05-06 | Chichibu Onoda Cement Corp | Production of reclaimed cement, and reclaimed cement |
JPH11292602A (en) * | 1998-04-09 | 1999-10-26 | Mitsubishi Materials Corp | Cement-based composition |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
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WO2010143656A1 (en) * | 2009-06-09 | 2010-12-16 | 株式会社竹中工務店 | Hydraulic cement composition |
JP2010285302A (en) * | 2009-06-09 | 2010-12-24 | Tokyo Institute Of Technology | Hydraulic cement composition |
JP2012012284A (en) * | 2010-06-01 | 2012-01-19 | Ohbayashi Corp | Method for producing hydraulic material, and method for selecting crushed concrete material |
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