JP3765693B2 - Low environmental impact type high strength concrete - Google Patents
Low environmental impact type high strength concrete Download PDFInfo
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- JP3765693B2 JP3765693B2 JP21322099A JP21322099A JP3765693B2 JP 3765693 B2 JP3765693 B2 JP 3765693B2 JP 21322099 A JP21322099 A JP 21322099A JP 21322099 A JP21322099 A JP 21322099A JP 3765693 B2 JP3765693 B2 JP 3765693B2
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- strength concrete
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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
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/021—Ash cements, e.g. fly ash cements ; Cements based on incineration residues, e.g. alkali-activated slags from waste incineration ; Kiln dust cements
-
- 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
- C04B11/00—Calcium sulfate cements
- C04B11/05—Calcium sulfate cements obtaining anhydrite, e.g. Keene's cement
-
- 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
- C04B2111/00017—Aspects relating to the protection of the environment
-
- 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
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
- C04B2201/52—High compression strength concretes, i.e. with a compression strength higher than about 55 N/mm2, e.g. reactive powder concrete [RPC]
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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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Combustion & Propulsion (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、主に、土木・建築分野において使用される低環境負荷型高強度コンクリートに関する。
【０００２】
【従来の技術】
近年、コンクリートに要求される性能は多様化し、中でもコンクリートの高強度化に関するニーズは益々高まってきている。
一方、環境問題が顕在化してきており、例えば、1997年12月に気候変動枠組条約・第三回締約国会議が京都で開かれ、先進国の温室効果ガス排出量について、法的拘束力のある削減目標を規定した京都議定書が採択された。これに伴い、各産業において二酸化炭素排出量の削減が必要になってきているが、全産業の二酸化炭素排出量に対する土木・建設業の占める割合は極めて大きく、要求性能を満足しつつ、環境負荷の小さなコンクリートの開発が切望されている。
【０００３】
【発明が解決しようとする課題】
高性能コンクリート、特に高強度コンクリートは、製造の際に二酸化炭素排出量が大きいセメントを多量に使用するため、環境負荷の大きいコンクリートであった。又、産業副産物をリサイクルすることは、我が国のように資源の少ない国では、資源の有効利用にもつながり、極めて重要である。
本発明者らは、これらの課題を解決すべく種々の検討を重ねた結果、特定の産業副産物を配合したコンクリートにおいて、高強度で二酸化炭素排出量の小さな低環境負荷型高強度コンクリートとなるとの知見を得て本発明を完成するに至った。
【０００４】
【課題を解決するための手段】
即ち、本発明は、フライアッシュセメントと、ｐＨが4.5以下の産業副産物として発生する無水セッコウとを配合し、材齢 56 日の圧縮強度が 60N/mm ２ 以上、炭素排出量の原単位が72kgC/m3以下であることを特徴とする低環境負荷型高強度コンクリートであり、更に産業副産物として発生するシリカ質微粉末を配合してなることを特徴とする該低環境負荷型高強度コンクリートであり、単位セメント量が350kg/m3以下であることを特徴とする該低環境負荷型高強度コンクリートであり、水／セメント比が40％以上であることを特徴とする該低環境負荷型高強度コンクリートであり、断熱温度上昇量が45℃以下であることを特徴とする該低環境負荷型高強度コンクリートである。
【０００５】
【発明の実施の形態】
以下、本発明を更に詳細に説明する。
【０００６】
本発明のコンクリートの炭素排出量の原単位とは、１ｍ3のコンクリートを製造する際に排出される炭素重量を意味し、その単位は（kgC/m3）で表す。コンクリートの炭素排出量の原単位とは、コンクリートを製造する際に使用される材料、即ち、セメント、砂、砂利、混和剤（材）等の炭素排出量の原単位を用い、コンクリート配合から算出する。各材料の炭素排出量の原単位は、LCA（ライフサイクルアセスメント）手法によって算出され定められている。ここで、LCA手法とは、材料を製造する際に、原料の調達、運搬、製造、消費、廃棄に至るまでのライフサイクルにおいて発生する、二酸化炭素の排出量を炭素排出量として表す手法である。土木・建設業で用いられる材料の炭素排出量の原単位は、例えば、（社）土木学会、（社）空衛建築学会、建設省建築研究所、建設省土木研究所等の各学術団体や研究機関によって提案されている。具体例としては、例えば、（社）土木学会地球環境委員会LCA小委員会推奨値によると、普通セメントの炭素排出量の原単位は0.228kgC/kgであり、高炉セメントは0.135kgC/kgであり、砂は0.00154kgC/kg、砂利は砕石の場合は0.00189kgC/kg、採石の場合は0.00154kgC/kgと定められている。フライアッシュセメントの炭素排出量の原単位については、明確に示されているものはないが、セメントクリンカーとフライアッシュの混合割合やフライアッシュの運搬距離、混合に要するエネルギー消費量等から算出することが可能であり、フライアッシュ置換率20%のフライアッシュセメントＢ種の場合、炭素排出量の原単位は、0.190kgC/kgの値を適用することができる。又、産業副産物をリサイクルした場合の炭素排出量は、零と見なされるので、産業副産物を利用することが極めて重要である。
【０００７】
本発明の低環境負荷型高強度コンクリートは、材齢56日の圧縮強度が60N/mm2以上であると共に、前記の（社）土木学会地球環境委員会LCA小委員会推奨値に基づいて算出した炭素排出量の原単位が72kgC/m3以下であることを特徴とする。
【０００８】
本発明の産業副産物として発生する無水セッコウは、JIS R 9101に準じて測定したｐＨが4.5以下であることが好ましく、ｐＨが4.5を超えると良好な強度発現性が得られない。セッコウは二水セッコウ、半水セッコウ及び無水セッコウに大別されるが、本発明では無水セッコウが好ましく、二水セッコウや半水セッコウでは良好な強度発現性は得られない。無水セッコウには、フッ酸製造時に副生する無水セッコウや天然に産出する無水セッコウ等があるが、環境負荷低減のため、産業副産物として発生する無水セッコウを使用することが好ましい。天然無水セッコウは、ｐＨが4.5を超え、炭素排出量も産業副産物の無水セッコウより大きく、本発明の低環境負荷型高強度コンクリートは得られない。
【０００９】
本発明の産業副産物の無水セッコウの粒度は、特に限定されるものではないが、通常、ブレーン比表面積で3000〜10000cm2/gが好ましく、4000〜9000cm2/gがより好ましい。3000cm2/g未満では強度発現性が充分でなく、10000cm2/gを超えても更なる効果の増進が期待できない。又、強度発現性の面から、無水セッコウの平均粒径は、10μｍ以下が好ましい。
【００１０】
本発明の産業副産物の無水セッコウの配合割合は、特に限定されるものではないが、通常、コンクリート配合において10〜50kg/m3の範囲が好ましく、20〜40kg/m3がより好ましい。10kg/m3未満では、強度発現性が充分でなく、50kg/m3を超えて配合しても更なる強度の増進が期待できない。
【００１１】
本発明の産業副産物の無水セッコウに、更に産業副産物として発生するシリカ質微粉末を併用することが強度発現性の面から好ましい。産業副産物として発生するシリカ質微粉末は、特に限定されるものではないが、具体例としては、シリカフュームや溶融シリカを製造する際に発生するシリカダスト、或いは高炉スラグやフライアッシュ等が挙げられる。
【００１２】
本発明の産業副産物のシリカ質微粉末の配合割合については、特に限定されるものではないが、通常、コンクリート配合において無水セッコウとシリカ質微粉末を合わせ、10〜100kg/m3の範囲で配合することが好ましい。10kg/m3未満では、強度発現性が充分でなく、100kg/m3を超えて配合しても更なる強度の増進が期待できない。
【００１３】
本発明の低環境負荷型高強度コンクリートの水／セメント比(W/C)は、40％以上が好ましい。40％未満では、フレッシュコンクリートの作業性が著しく悪くなったり、プラスチックひび割れや硬化後の自己収縮によるひび割れが発生し易くなる。
【００１４】
本発明の低環境負荷型高強度コンクリートの単位セメント量は、350kg/m3以下が好ましい。単位セメント量が350kg/m3を超えると、コンクリートの炭素排出量の原単位が大きくなったり、水和発熱量が多くなりコンクリートに熱ひび割れが発生し易くなる。
【００１５】
本発明の低環境負荷型高強度コンクリートの断熱温度上昇量は、45℃以下であることが好ましい。断熱温度上昇量が45℃を超えると、水和発熱によりコンクリートに熱ひび割れが発生し易くなる。
【００１６】
本発明では、減水剤、高性能減水剤、ＡＥ減水剤、高性能ＡＥ減水剤、流動化剤、消泡剤、増粘剤、防錆剤、防凍剤、収縮低減剤、高分子エマルジョン及び凝結調整剤、並びにセメント急硬材、セメント膨張材、ベントナイト等の粘土鉱物及びハイドロタルサイト等のアニオン交換体等のうちの一種又は二種以上を、本発明の目的を実質的に阻害しない範囲で使用することが可能である。
【００１７】
本発明において、コンクリートの混練り方法については、特に限定されるものではなく、それぞれの材料を混練り時に混合しても良いし、予めその一部、或いは全部を混合しておいても差し支えない。混練り装置としては、既存の如何なる装置も使用可能であり、例えば、二軸強制ミキサー、パン型強制ミキサー、遊星型ミキサー、傾胴型ミキサー、オムニミキサー等が挙げられる。
【００１８】
【実施例】
以下、実施例により本発明を詳細に説明する。
【００１９】
実施例１
混和材として使用した、各種セッコウのｐＨを測定した。その結果を表１に示す。又、LCA手法により混和材の炭素排出量の原単位を算出した。但し、産業副産物を使用する場合には、粉砕時に消費した動力より、材料の炭素排出量の原単位を算出した。
【００２０】
＜使用材料＞
混和材ａ：フッ酸製造時に副生する無水セッコウ、比重2.96。ブレーン比表面積5000cm2/gに粉砕、平均粒径10μｍ。粉砕時の動力0.06kwhr/kg。動力の炭素排出量の原単位0.129kgC/kwhrより算出した炭素排出量の原単位0.008kgC/kg。
混和材ｂ：フッ酸製造時に副生する無水セッコウ、比重2.95。ブレーン比表面積5000cm2/gに粉砕、平均粒径8μｍ。粉砕時の動力0.07kwhr/kg。動力の炭素排出量の原単位0.129kgC/kwhrより算出した炭素排出量の原単位0.009kgC/kg。
混和材ｃ：天然無水セッコウ、比重2.96。ブレーン比表面積5000cm2/gに粉砕、平均粒径18μｍ。粉砕時の動力0.17kwhr/kg。動力の炭素排出量の原単位0.129kgC/kwhrより算出した炭素排出量の原単位0.022kgC/kg。
混和材ｄ：天然二水セッコウを約130℃で加熱し半水セッコウとしたもの。比重2.65。ブレーン比表面積5000cm2/gに粉砕、平均粒径12μｍ。加熱時の動力0.15kwhr/kg。粉砕時の動力0.10kwhr/kg。動力の炭素排出量の原単位0.129kgC/kwhrより算出した炭素排出量の原単位0.032kgC/kg。
混和材ｅ：排煙脱硫二水セッコウ、比重2.32。ブレーン比表面積5000cm2/gに粉砕、平均粒径11μｍ。粉砕時の動力0.06kwhr/kg。動力の炭素排出量の原単位0.129kgC/kwhrより算出した炭素排出量の原単位0.008kgC/kg。
＜測定方法＞
比重、ブレーン比表面積：JIS R 5201に準じて測定
平均粒径：レーザ式粒度分布測定装置により測定
ｐＨ：JIS R 9101に準じて測定
【００２１】
【表１】
本発明で使用する産業副産物の無水セッコウのｐＨは、4.5以下であり、天然無水セッコウ、半水セッコウ及び二水セッコウのｐＨは、何れも4.5を超えている。
【００２３】
表２に示す配合のコンクリートを調製し、コンクリートのスランプが18±1.5cmとなるように高性能減水剤を添加し、空気量3.0±1.5%とした。コンクリート物性は、材齢56日における圧縮強度と断熱温度上昇量を測定した。コンクリートの炭素排出量の原単位は、LCA手法により算出した。但し、各材料の炭素排出量の原単位は、土木学会地球環境委員会LCA小委員会推奨値を用いた。又、産業副産物を使用する場合には、粉砕時に消費した動力より、材料の炭素排出量の原単位を算出した。その結果を表２に示す。
【００２４】
＜使用材料＞
シリカ質微粉末Ａ：シリカフューム、産業副産物としてのシリカ質微粉末、比重2.20。ブレーン比表面積200000cm2/g、平均粒径0.2μｍ。
混和材ｆ：混和材ｂ50重量部とシリカ質微粉末Ａ50重量部をブレーン比表面積9000cm2/gに混合粉砕したもの、比重2.58。粉砕時の動力0.08kwhr/kg。動力の炭素排出量の原単位0.129kgC/kwhrより算出した炭素排出量の原単位0.010kgC/kg。
セメント(C)：市販普通ポルトランドセメント80重量部と市販フライアッシュ20重量部とを混合して作製したフライアッシュセメントＢ種、比重2.99。炭素排出量の原単位0.190kgC/kg。
水(W)：水道水
砂(S)：新潟県姫川産、比重2.62。炭素排出量の原単位0.00154kgC/kg。
砂利(G)：新潟県姫川産、比重2.64。炭素排出量の原単位0.00189kgC/kg。
高性能減水剤：ポリカルボン酸系市販品
＜測定方法＞
圧縮強度：JIS A 1108、JIS A 1132、JIS A 1138に準じて測定。
断熱温度上昇量：東京理工（株）社製の断熱温度上昇量測定装置を用いて、打設温度20℃の条件で測定。
【００２５】
【表２】
本発明の低環境負荷型高強度コンクリートは、何れも炭素排出量原単位が小さく（72kgC/m3以下）、圧縮強度が高く（60N/mm2以上）、断熱温度上昇量が小さい（45℃以下）ことが示されている。一方、本発明の産業副産物の無水セッコウを配合していない比較例では、何れも本発明の低環境負荷型高強度コンクリートよりも炭素排出量原単位や断熱温度上昇量が大きいか、圧縮強度が低い。
【００２７】
【発明の効果】
本発明により、炭素排出量原単位が小さく、圧縮強度が高く、水和発熱量が小さい等の効果を奏し、環境問題に大きく貢献する低環境負荷型高強度コンクリートを作製することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to a low environmental load type high strength concrete used in the field of civil engineering and construction.
[0002]
[Prior art]
In recent years, the performance required for concrete has been diversified, and in particular, the needs for increasing the strength of concrete have been increasing.
On the other hand, environmental problems are becoming apparent. For example, in December 1997, the Framework Convention on Climate Change and the 3rd Conference of the Parties to the State of Japan were held in Kyoto. The Kyoto Protocol, which stipulates certain reduction targets, was adopted. Along with this, it is necessary to reduce carbon dioxide emissions in each industry, but the civil engineering / construction industry accounts for an extremely large proportion of carbon dioxide emissions in all industries. The development of small concrete is eagerly desired.
[0003]
[Problems to be solved by the invention]
High-performance concrete, particularly high-strength concrete, is a concrete with a large environmental load because a large amount of cement that emits a large amount of carbon dioxide is used during production. In addition, recycling industrial by-products is extremely important in countries with few resources such as Japan, leading to effective use of resources.
As a result of repeating various studies to solve these problems, the inventors of the present invention have become a high-strength concrete with high strength and low CO2 emission in concrete blended with a specific industrial by-product. Obtaining knowledge, the present invention has been completed.
[0004]
[Means for Solving the Problems]
That is, the present invention blends fly ash cement with anhydrous gypsum generated as an industrial by-product having a pH of 4.5 or less , a compressive strength of 56 days of age is 60 N / mm 2 or more, and the basic unit of carbon emission is 72 kgC. It is a low environmental load type high strength concrete characterized by being less than / m 3 , and further comprising a siliceous fine powder generated as an industrial byproduct. The low environmental load type high strength concrete characterized in that the unit cement amount is 350 kg / m 3 or less, and the water / cement ratio is 40% or more. The low environmental load type high strength concrete, which is a high strength concrete and has a heat insulation temperature increase of 45 ° C. or less.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
[0006]
The basic unit of carbon emission of the concrete of the present invention means the weight of carbon discharged when producing 1 m 3 of concrete, and the unit is represented by (kgC / m 3 ). The basic unit of carbon emissions of concrete is calculated from the concrete mix using the basic unit of carbon emissions of materials used when manufacturing concrete, that is, cement, sand, gravel, admixture (material), etc. To do. The basic unit of carbon emissions of each material is calculated and determined by LCA (life cycle assessment) method. Here, the LCA method is a method for expressing the carbon dioxide emissions generated in the life cycle from raw material procurement, transportation, production, consumption, and disposal as the carbon emissions when producing the material. . The basic unit of carbon emissions of materials used in the civil engineering / construction industry is, for example, various academic organizations such as the Japan Society of Civil Engineers, the Japan Society for Aircraft and Architectural Engineers, the Institute of Construction, the Ministry of Construction Proposed by research institutions. As a specific example, for example, according to the recommended value of the LCA Subcommittee of the Japan Society of Civil Engineers, the basic unit of carbon emissions of ordinary cement is 0.228 kgC / kg, and the blast furnace cement is 0.135 kgC / kg. Yes, sand is defined as 0.00154kgC / kg, gravel is defined as 0.00189kgC / kg for crushed stone, and 0.00154kgC / kg for quarrying. The basic unit of carbon emissions of fly ash cement is not clearly indicated, but it should be calculated from the mixing ratio of cement clinker and fly ash, the transport distance of fly ash, the energy consumption required for mixing, etc. In the case of fly ash cement type B with a fly ash substitution rate of 20%, a value of 0.190 kgC / kg can be applied as the basic unit of carbon emission. Moreover, since carbon emissions when recycling industrial byproducts are considered to be zero, it is extremely important to use industrial byproducts.
[0007]
The low environmental load type high strength concrete of the present invention has a compressive strength of 60 N / mm 2 or more at the age of 56 days, and is calculated based on the recommended value of the LCA subcommittee of the Japan Society of Civil Engineers Global Environment Committee. The basic unit of carbon emissions is 72kgC / m 3 or less.
[0008]
Anhydrous gypsum generated as an industrial by-product of the present invention preferably has a pH measured according to JIS R 9101 of 4.5 or less. If the pH exceeds 4.5, good strength development cannot be obtained. Gypsum is roughly classified into two-water gypsum, half-water gypsum and anhydrous gypsum. In the present invention, anhydrous gypsum is preferable, and good strength expression cannot be obtained with two-water gypsum and half-water gypsum. Anhydrous gypsum includes anhydrous gypsum produced as a by-product during the production of hydrofluoric acid and naturally produced anhydrous gypsum, but it is preferable to use anhydrous gypsum generated as an industrial by-product in order to reduce environmental impact. Natural anhydrous gypsum has a pH exceeding 4.5 and carbon emissions are larger than that of industrial gypsum anhydrous gypsum, and the low environmental load type high strength concrete of the present invention cannot be obtained.
[0009]
The particle size of the anhydrous gypsum industry byproduct of the present invention, but are not particularly limited, is preferably 3000~10000cm 2 / g in Blaine specific surface area, 4000~9000cm 2 / g is more preferable. If it is less than 3000 cm 2 / g, strength development is not sufficient, and if it exceeds 10000 cm 2 / g, further enhancement of the effect cannot be expected. From the standpoint of strength development, the average particle size of anhydrous gypsum is preferably 10 μm or less.
[0010]
The blending ratio of the anhydrous gypsum as an industrial by-product of the present invention is not particularly limited, but is usually preferably in the range of 10 to 50 kg / m 3 and more preferably 20 to 40 kg / m 3 in the concrete blending. If it is less than 10 kg / m 3 , strength development is not sufficient, and even if it exceeds 50 kg / m 3 , further enhancement of strength cannot be expected.
[0011]
It is preferable from the viewpoint of strength development that the anhydrous gypsum as an industrial by-product of the present invention is further used in combination with siliceous fine powder generated as an industrial by-product. The siliceous fine powder generated as an industrial by-product is not particularly limited, and specific examples include silica dust generated when silica fume and fused silica are produced, blast furnace slag, fly ash, and the like.
[0012]
The blending ratio of the siliceous fine powder of the industrial by-product of the present invention is not particularly limited. Usually, anhydrous gypsum and siliceous fine powder are combined in the concrete blending and blended in the range of 10 to 100 kg / m 3. It is preferable to do. If it is less than 10 kg / m 3 , strength development is not sufficient, and even if it exceeds 100 kg / m 3 , further enhancement of strength cannot be expected.
[0013]
The water / cement ratio (W / C) of the low environmental load type high strength concrete of the present invention is preferably 40% or more. If it is less than 40%, the workability of fresh concrete is remarkably deteriorated, and plastic cracks and cracks due to self-shrinkage after curing tend to occur.
[0014]
The unit cement amount of the low environmental load type high strength concrete of the present invention is preferably 350 kg / m 3 or less. If the amount of cement exceeds 350 kg / m 3 , the basic unit of carbon emissions from concrete will increase, or the amount of heat generated by hydration will increase, making it easier for cracks to occur in concrete.
[0015]
The amount of heat insulation temperature rise of the low environmental load type high strength concrete of the present invention is preferably 45 ° C. or less. When the heat insulation temperature rise exceeds 45 ° C., thermal cracking is likely to occur in the concrete due to hydration heat generation.
[0016]
In the present invention, a water reducing agent, a high performance water reducing agent, an AE water reducing agent, a high performance AE water reducing agent, a fluidizing agent, an antifoaming agent, a thickening agent, a rust preventive agent, a defrosting agent, a shrinkage reducing agent, a polymer emulsion and a coagulation In the range which does not substantially impede the purpose of the present invention, one or more of the modifier, cement rapid hardening material, cement expansion material, clay minerals such as bentonite and anion exchangers such as hydrotalcite, etc. It is possible to use.
[0017]
In the present invention, the concrete kneading method is not particularly limited, and the respective materials may be mixed at the time of kneading, or a part or all of them may be mixed in advance. . As the kneading apparatus, any existing apparatus can be used, and examples thereof include a biaxial forced mixer, a pan-type forced mixer, a planetary mixer, a tilted barrel-type mixer, and an omni mixer.
[0018]
【Example】
Hereinafter, the present invention will be described in detail by way of examples.
[0019]
Example 1
The pH of various gypsum used as an admixture was measured. The results are shown in Table 1. In addition, the basic unit of carbon emissions of admixtures was calculated by the LCA method. However, when using industrial by-products, the basic unit of carbon emissions of materials was calculated from the power consumed during grinding.
[0020]
<Materials used>
Admixture a: anhydrous gypsum by-produced during hydrofluoric acid production, specific gravity 2.96. Crush to a Blaine specific surface area of 5000 cm 2 / g, average particle size 10 μm. Power during grinding is 0.06kwhr / kg. Basic unit of carbon emission calculated from 0.129kgC / kwhr of carbon emission of motive power 0.008kgC / kg.
Admixture b: anhydrous gypsum by-produced during hydrofluoric acid production, specific gravity 2.95. Crush to a Blaine specific surface area of 5000 cm 2 / g, average particle size 8 μm. Power of pulverization 0.07kwhr / kg. The basic unit of carbon emission calculated from the basic unit of carbon emission of motive power 0.129kgC / kwhr 0.009kgC / kg.
Admixture c: natural anhydrous gypsum, specific gravity 2.96. Crush to a Blaine specific surface area of 5000 cm 2 / g, average particle size 18 μm. Power of grinding 0.17kwhr / kg. Basic unit of carbon emissions calculated from 0.129kgC / kwhr of carbon emissions of motive power 0.022kgC / kg.
Admixture d: A natural dihydrate gypsum heated at about 130 ° C. to make a half water gypsum. Specific gravity 2.65. Crush to a Blaine specific surface area of 5000 cm 2 / g, average particle size 12 μm. Power during heating 0.15kwhr / kg. Power during grinding is 0.10kwhr / kg. The basic unit of carbon emissions calculated from the basic unit of carbon emissions of motive power 0.129kgC / kwhr.
Admixture e: Flue gas desulfurization dihydrate gypsum, specific gravity 2.32. Crush to a Blaine specific surface area of 5000 cm 2 / g, average particle size 11 μm. Power during grinding is 0.06kwhr / kg. Basic unit of carbon emission calculated from 0.129kgC / kwhr of carbon emission of motive power 0.008kgC / kg.
<Measurement method>
Specific gravity, Blaine specific surface area: Measured according to JIS R 5201 Average particle size: Measured with a laser particle size distribution measuring device pH: Measured according to JIS R 9101
[Table 1]
The pH of the anhydrous gypsum as an industrial by-product used in the present invention is 4.5 or less, and the pH of natural anhydrous gypsum, half-water gypsum, and dihydrate gypsum is all over 4.5.
[0023]
Concrete with the composition shown in Table 2 was prepared, and a high-performance water reducing agent was added so that the slump of the concrete would be 18 ± 1.5 cm, so that the air amount was 3.0 ± 1.5%. As for the physical properties of concrete, the compressive strength and the heat insulation temperature rise at the age of 56 days were measured. The basic unit of carbon emissions from concrete was calculated using the LCA method. However, the basic unit of carbon emissions of each material was the value recommended by the Japan Society of Civil Engineers Global Environment Committee LCA Subcommittee. In addition, when using industrial by-products, the basic unit of carbon emissions of materials was calculated from the power consumed during pulverization. The results are shown in Table 2.
[0024]
<Materials used>
Siliceous fine powder A: Silica fume, siliceous fine powder as an industrial by-product, specific gravity 2.20. Blaine specific surface area 200,000 cm 2 / g, average particle size 0.2 μm.
Admixture f: 50 parts by weight of admixture b and 50 parts by weight of siliceous fine powder A mixed and ground to a Blaine specific surface area of 9000 cm 2 / g, specific gravity 2.58. Power of grinding is 0.08kwhr / kg. Basic unit of carbon emission calculated from the basic unit of carbon emission of power 0.129kgC / kwhr. 0.010kgC / kg.
Cement (C): Fly ash cement type B produced by mixing 80 parts by weight of commercially available ordinary Portland cement and 20 parts by weight of commercially available fly ash, with a specific gravity of 2.99. The basic unit of carbon emissions is 0.190kgC / kg.
Water (W): Tap water sand (S): Himekawa, Niigata Prefecture, specific gravity 2.62. The basic unit of carbon emissions is 0.00154kgC / kg.
Gravel (G): Himekawa, Niigata Prefecture, specific gravity 2.64. Basic unit of carbon emissions is 0.00189kgC / kg.
High performance water reducing agent: Polycarboxylic acid commercial product <Measurement method>
Compressive strength: Measured according to JIS A 1108, JIS A 1132, and JIS A 1138.
Adiabatic temperature rise: Measured using an adiabatic temperature rise measuring device manufactured by Tokyo Riko Co., Ltd. at a casting temperature of 20 ° C.
[0025]
[Table 2]
The low environmental impact type high-strength concrete of the present invention has a low carbon emission basic unit (72 kgC / m 3 or less), a high compressive strength (60 N / mm 2 or more), and a small adiabatic temperature rise (45 ° C.). The following) is shown. On the other hand, in the comparative examples in which the anhydrous gypsum of the industrial by-product of the present invention is not blended, the carbon emission basic unit and the adiabatic temperature rise amount are larger than those of the low environmental load type high strength concrete of the present invention, or the compressive strength is higher. Low.
[0027]
【The invention's effect】
According to the present invention, it is possible to produce a low environmental load type high strength concrete that has effects such as a small carbon emission basic unit, a high compressive strength, and a low hydration calorific value and contributes greatly to environmental problems.
Claims (5)
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| CN103496920A (en) * | 2013-09-25 | 2014-01-08 | 厦门市建筑科学研究院集团股份有限公司 | Foam concrete block as well as production method thereof |
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| KR20060123031A (en) * | 2004-03-17 | 2006-12-01 | 덴끼 가가꾸 고교 가부시키가이샤 | Cement Admixtures, Cement Compositions, Mortars and Concrete |
| FR2943662B1 (en) * | 2009-03-24 | 2015-01-16 | Lafarge Sa | CONCRETE WITH LOW CLINKER CONTENT |
| CN102041869B (en) * | 2009-10-16 | 2014-08-06 | 孙凯 | Mixed gypsum wallboard |
| CN102503198B (en) * | 2011-11-08 | 2013-06-05 | 海南蓝岛环保产业股份有限公司 | Composite green mud coal ash for concrete |
| CN102503199B (en) * | 2011-11-08 | 2013-06-05 | 海南蓝岛环保产业股份有限公司 | Compound coal ash for concrete |
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| CN103496920A (en) * | 2013-09-25 | 2014-01-08 | 厦门市建筑科学研究院集团股份有限公司 | Foam concrete block as well as production method thereof |
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