ここで説明する作業は、スイス連邦道路庁 (研究プロジェクト AGB2012/010) は部分的に融資されました。我々 は大きく、金融サポートを認めます。

<ol>
	<li>Bertolini, L., Elsener, B., Pedeferri, P., Redaelli, E., Polder, R. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Corrosion of Steel in Concrete: Prevention, Diagnosis, Repair. 2nd edn. , (2013).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Development of an holistic approach to ensure the durability of new concrete construction. , (1997).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Condition+control+and+assessment+of+reinforced+concrete+structures+exposed+to+corrosive+environments.">Condition control and assessment of reinforced concrete structures exposed to corrosive environments.</a> F&#233;d&#233;ration Internationale du B&#233;ton (fib). , (2011).</li><li>Angst, U. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Present+and+future+durability+challenges+for+reinforced+concrete+structures.">Present and future durability challenges for reinforced concrete structures.</a> Mater. Corros. 63 (12), 1047-1051 (2012).</li><li>Angst, U., Elsener, B., Larsen, C. K., Vennesland, &. #. 2. 1. 6. ;. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Critical+chloride+content+in+reinforced+concrete+-+A+review.">Critical chloride content in reinforced concrete - A review.</a> Cem. Concr. Res. 39 (12), 1122-1138 (2009).</li><li>Breit, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zum+Ansatz+eines+kritischen+Chloridgehaltes+bei+Stahlbetonbauwerken.">Zum Ansatz eines kritischen Chloridgehaltes bei Stahlbetonbauwerken.</a> Beton- und Stahlbetonbau. 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Taking, examining and testing in compression.</a> European Committee for Standardization. , (2009).</li><li>Andrade, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Test+methods+for+on-site+corrosion+rate+measurement+of+steel+reinforcement+in+concrete+by+means+of+the+polarization+resistance+method.">Test methods for on-site corrosion rate measurement of steel reinforcement in concrete by means of the polarization resistance method.</a> Mater Struct. 37 (273), 623-643 (2004).</li><li>Angst, U., Vennesland, &. #. 2. 1. 6. ;., Myrdal, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diffusion+potentials+as+source+of+error+in+electrochemical+measurements+in+concrete.">Diffusion potentials as source of error in electrochemical measurements in concrete.</a> Mater Struct. 42 (3), 365-375 (2009).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=European+Standard+EN+14630:+Products+and+systems+for+the+protection+and+repair+of+concrete+structures+-+Test+methods+-+Determination+of+carbonation+depth+in+hardened+concrete+by+the+phenolphthalein+method.">European Standard EN 14630: Products and systems for the protection and repair of concrete structures - Test methods - Determination of carbonation depth in hardened concrete by the phenolphthalein method.</a> European Committee for Standardization. , (2006).</li><li>Gulikers, J., Andrade, C., Kropp, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Testing+and+Modelling+the+Chloride+Ingress+into+Concrete.">Testing and Modelling the Chloride Ingress into Concrete.</a> RILEM Proceedings PRO 19. , (2000).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ASTM+C1084+Standard+Test+Method+for+Portland-Cement+Content+of+Hardened+Hydraulic-Cement+Concrete.">ASTM C1084 Standard Test Method for Portland-Cement Content of Hardened Hydraulic-Cement Concrete.</a> ASTM International. , (2013).</li><li>Boschmann K&#228;thler, C., Angst, U. M., Wagner, M., Elsener, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Image+analysis+for+determination+of+cement+content+in+concrete+to+improve+accuracy+of+chloride+analyses.">Image analysis for determination of cement content in concrete to improve accuracy of chloride analyses.</a> Cem Concr Res. , (2017).</li><li>Angst, U., Wagner, M., Elsener, B., Leemann, A., Nygaard, P. v. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Method+to+determine+the+critical+chloride+content+of+existing+reinforced+structures.">Method to determine the critical chloride content of existing reinforced structures.</a> VSS report no. 677. , (2016).</li><li>Lambert, P., Page, C. L., Vassie, P. R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigations+of+reinforcement+corrosion:+Part+2+-+Electrochemical+monitoring+of+steel+in+chloride-contaminated+concrete.">Investigations of reinforcement corrosion: Part 2 - Electrochemical monitoring of steel in chloride-contaminated concrete.</a> Mater. Struct. 24 (143), 351-358 (1991).</li><li>Angst, U. M., Elsener, B., Larsen, C. K., Vennesland, &. #. 2. 1. 6. ;. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chloride+induced+reinforcement+corrosion:+Electrochemical+monitoring+of+initiation+stage+and+chloride+threshold+values.">Chloride induced reinforcement corrosion: Electrochemical monitoring of initiation stage and chloride threshold values.</a> Corros. 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K., Vennesland, &. #. 2. 1. 6. ;. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chloride+induced+reinforcement+corrosion:+Rate+limiting+step+of+early+pitting+corrosion.">Chloride induced reinforcement corrosion: Rate limiting step of early pitting corrosion.</a> Electrochim Acta. 56 (17), 5877-5889 (2011).</li><li>Boubitsas, D., Tang, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+influence+of+reinforcement+steel+surface+condition+on+initiation+of+chloride+induced+corrosion.">The influence of reinforcement steel surface condition on initiation of chloride induced corrosion.</a> Mater Struct. 48 (8), 2641-2658 (2015).</li><li>Pacheco, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Corrosion+of+steel+in+cracked+concrete+-+chloride+microanalysis+and+service+life+predictions.">Corrosion of steel in cracked concrete - chloride microanalysis and service life predictions.</a> TU Delft. , (2015).</li><li>Li, L., Sag&#252;&#233;s, A. 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著者が明らかに何もありません。

Cクリットを決定する提案された実験的プロトコルの成功のための最も重要な手順は、false 腐食の発生や終了効果バーその他の鋼を防ぐための措置を含みます。この点で、最高の結果28屈する発見されたここで報告されたプロトコル中で様々 なアプローチはテストされました。さらにテストでは、このアプローチは、10% 以下に偽開始率を減少させるを可能しました。一方で、これはエポキシ樹脂、鋼棒にコンクリートの塩化物の輸送日数終了かなり増加で露出したコンクリートの表面の国境地帯をコーティングのおかげです。その一方で、高アルカリのセメント系スラリー大幅これらの領域で耐食性を高めます密度の高い原コンクリートの端点に鋼棒の周りを交換する。そのようなシステム、すなわち、塗装、鋼棒にポリマー セメント系材料の層で終わる、他研究29,30でも成功を収めています。
もう一つの重要な側面は、腐食発生の基準です。この基準は、RILEM 技術的委員会 TC 235 Ccrit 31研究室で製造されたサンプルでの測定のための試験方法を推奨することを目的に基づいています。理論的根拠はよく知られているがコンクリートに埋め込まれている偏光されていない鋼の腐食の発症は明確に定義されたインスタント30,32ではなく、時間の長い期間にわたって場所をかかることがあります。鋼は比較的低塩素濃度で腐食を起動ことがありますが、不動態化が発生初期の受動的なレベルへの潜在的な増加によって明らかになる腐食プロセスを維持することができない場合。このような depassivation 不動態化イベントは通常、類似研究30,33,34で観察されます。安定した腐食の時に塩化物濃度は、受動的なレベルからの潜在的な偏差の非常に最初の兆候が明らかになる時間よりも練習のためより適切です。提案基準Ccrit腐食が開始してまた安定に伝搬の塩化物濃度を表しています。
メソッドの制限は、サンプルは、結果35,36に影響がある可能性があります比較的小さなものです。これを打ち消すためには、比較的多くのサンプル (理想的には 10) を使用することをお勧めします。自信のレベルは、実際のテスト地区Ccritの統計的分布に依存します。詳細については、この点では、36を参照を参照してください。追加の制限は実験室の露出の水分条件が実際の構造のものと異なる場合があります。最後に、腐食発生の検出は、潜在性は高炉セメントやその他の硫化物含むバインダーのように、一般に負の場合難しいかもしれません。
我々 の知る限り、これはCcrit定量土木構造物の腐食発生前の段階での最初の方法。腐食劣化が発生する前に特定の構造体や構造部材Ccritを測定する腐食の発生後に得られる定義では、構造から、実証の経験は対照的このメソッドを使用することができます。;結果は、(将来) 腐食の危険性を評価するために、腐食発生 (サービス生活モデリング) までの残り時間を予測するため使用できます。したがって、このメソッド材料機械試験(圧縮強度等)に使用される確立された方法と同様に、テストで使用される可能性があります。
このメソッドは、スイス連邦共和国で異なるコンクリート基盤の数に現在適用されています。これはCcrit構造の統計的分布について厳しく制限5知識を広げるでしょう。さらに、構造、建築材、等、年齢などさまざまな要因の影響を明らかにする、従って土木およびインフラストラクチャ管理の意思決定者に重要な情報を提供します。

コンクリート中の鉄筋腐食により、コンクリートの塩化物の浸透によって引き起こされる、鉄筋およびプレストレスト コンクリート構造物の早期劣化の最も頻繁な原因である、従っての最も重要な課題の一つを提示土木1,2,3,4。先進国は通常海洋性気候や道路の除氷塩への暴露の数十年の歴史を持つとこの 20 世紀の後半に建てられたコンクリートのインフラを高齢化の大規模な在庫を持っています。確実に腐食のこれらの構造、すなわちリスクの状態を評価することができるという、一般に保守作業の計画とインフラストラクチャ管理のための基礎を形成します。
コンクリート中の塩化物による鉄筋の腐食を管理するためのエンジニア リングの確立されたアプローチ塩化しきい値 (重要な塩分量、 Ccritとも呼ばれます) の値1,5,に基づいています6。 この概念に従って腐食の発生は鋼板の表面コンクリートの塩化物濃度Ccritしきい値を超えるとすぐに発生すると考えられています。したがって、既存の構造の状態を評価して通常残りの寿命の推定が埋め込まれた鉄筋の深さは特に、コンクリートの異なる深さで塩化物含有量を決定するのに頼る。コンクリート7,8のサンプルでこの塩化物の濃度を測定する信頼性の高い標準化されたメソッドの数が存在します。Ccrit結果を比較する腐食リスクの種類と修理対策の範囲を計画評価のための基礎を提供します。ただし、このアプローチには、 Ccritの知識が必要です。
テキストだけでなく、国際規格および推奨事項は、書籍、 Ccrit1,3,9,10,11の規定値。これらは約 0.4% で、通常セメント、長期的な経験に基づく、または初期の重量による塩化研究12,13。ただし、それはよく知られている構造の年齢や露出の歴史と条件1によって使用材料による構造または構造部材のCcritに対して実際の抵抗の影響を強く,5します。 したがって、それは一般に認められた 1 つの構造からの経験は慎重に他の構造体にのみ適用する必要があります。
それにもかかわらず、エンジニア リングの表Cクリット値、実際の構造とは無関係を使用する練習が一般的です。これは、 Ccrit文献の巨大な散布図とCcrit敷地内、5研究室を決定するための信頼性の高い方法の欠乏によって説明できます。耐久性評価の集計のしきい値を使用してのアプローチは、コンクリート構造物の老化の状態評価の構造に関する考慮事項とは対照的です。後者の場合 (鉄筋コンクリート) の構造材料の強度などの機械的性質を決定するための標準化されたテスト メソッドの数が存在する構造物の計算に使用されます。
この作品は、土木構造物から採取したサンプルのCクリティカル率を決定するための実験プロトコルを提案します。アプローチは、掘削部分コンクリート構造物の腐食はまだ開始されませんで鉄筋コンクリート造のコアに基づいています。これらのサンプルは、腐食発生のための条件を検討するために腐食促進試験を受ける場所研究室に転送されます。提案手法の主な利点は、構造とこうして展示実態に関するパラメーター、大きく影響Ccritよく知られている代表ができない数由来のサンプルサンプルの実験室で生産の真似。これは、種類と (若い所熟女サイト生産コンクリートとコンクリート)、コンクリートの年齢の種類や表面の状態、補強鋼使用時と、一般工事、鋼・ コンクリートの特性14をのインターフェイスです。一緒に実験室測定法の精度は、このアプローチは、 Ccrit特定構造体や構造部材の信頼性の決定を許可します。
- Ccritの定数値を使用しての一般的な方法と比較されます - 工学練習で提案されたプロトコルのアプリケーション条件評価の精度と分析モデルの予言する力の強化、残り寿命。今後何十年も15以上構築基盤の改修工事に強い増加が予想の基盤を腐食工学のような改善のための緊急の必要性が生じます。

<table width="651">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="42">
			<td height="42" style="width:216px;height:42px;">Stranded wire</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:245px;">cross section at least 0.50 mm&#178;; ideally copper wire, tin plated</td>
		</tr>
		<tr height="63">
			<td height="63" style="width:216px;height:63px;">Self-tapping metal screw</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:245px;">any suitable self-tapping screw, typically of length 4-5 mm and diameter around 2.5 mm</td>
		</tr>
		<tr height="42">
			<td height="42" style="width:216px;height:42px;">Ring cable lug</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:245px;">suitable to connect screw and cable</td>
		</tr>
		<tr height="63">
			<td height="63" style="width:216px;height:63px;">SikaTop Seal-107</td>
			<td style="width:71px;">Sika</td>
			<td style="width:119px;"></td>
			<td style="width:245px;">two-part polymer modified cementitious waterproof mortar slurry</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Epoflex 816 L</td>
			<td style="width:71px;">Adisa</td>
			<td style="width:119px;"></td>
			<td style="width:245px;">epoxy coating</td>
		</tr>
		<tr height="63">
			<td height="63" style="width:216px;height:63px;">Exposure tank</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:245px;">any suitable tank (e.g. rako box) with a lid;&#160; sufficiently large for exposing the samples</td>
		</tr>
		<tr height="63">
			<td height="63" style="width:216px;height:63px;">Reference electrode</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:245px;">Any stable reference electrode suitable for continuous immersion in sodium chloride solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Tap water</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:216px;height:21px;">Sodium chloride</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:245px;"></td>
		</tr>
		<tr height="105">
			<td height="105" style="width:216px;height:105px;">Data logger</td>
			<td style="width:71px;"></td>
			<td style="width:119px;"></td>
			<td style="width:245px;">any device able to monitor the potentials of all samples vs. the reference electrode at the specified interval (input impedance &#62;10E7 Ohm)</td>
		</tr>
	</tbody>
</table>

experimental protocol to determine the chloride threshold value for corrosion in samples taken from reinforced concrete structures

鉄筋コンクリート インフラ先進国の高齢化は、確実にこれらの構造の状態を評価する方法のための緊急の必要性を課しています。埋め込まれた鉄筋の腐食、劣化の最も頻繁な原因です。構造物の腐食に耐える能力は使用される材料などの要因や、年齢によって強く決まる、頼ることがよく知られているしきい値値で規定された基準や教科書になります。腐食発生 (Ccrit) のこれらの限界値は、明確に状態評価およびサービス寿命予測の精度を制限する特定の構造の実際のプロパティの独立しています。集計値を使用しての練習はCcrit敷地内を確認する信頼性の高い方法と研究室での欠如にたどることができます。
ここでは、個々 の土木構造物や構造部材Cクリットを決定するための実験プロトコルが表示されます。鉄筋コンクリートのサンプル数は、構造から取得され、腐食検査が実行されます。この方法の主な利点は、 Ccrit、代表して真似することはできません鋼コンクリート インターフェイスなどに大きく影響するよく知られているパラメーターに関する実態を保証することサンプルの実験室で生産します。同時に研究所に腐食促進試験はテスト構造体の腐食発生前にCcritの信頼性の決定を許可します。これだけ構造が既に破損している場合の開始、すなわち後の腐食条件の推定を許可するすべての一般的な条件評価方法に比べて大きな利点です。
プロトコルCcritテスト構造の統計的な分布が得られます。これは腐食性、メンテナンス計画に必要な残りの時間の確率的予測モデルのための基礎として機能します。このメソッドは、土木、機械試験に使用される確立された方法と同様の材料試験で可能性のある使用できます。

図 7には、一般的な鋼電位研究室では、塩化物の露出の間に監視が表示されます。両方の例を示す可能性が非常に短い時間内で著しく低下可能性がありますが、腐食プロセス可能性があります継承しないことまだ安定、初期パッシブ レベルに向けて可能性の増加を通じて明らかになります。このプロトコルでは腐食の発生、すなわち露出を停止およびCクリットを決定すると、日時の時間は負電位 (3.5.2 を参照し、を参照してください 10 日間続いてマーク電位差によって定義されます。ディスカッション詳細については)。
安定した腐食の発生が発生するまで数ヶ月をかかることがありますが一般的です。構造からサンプルを採取するとき、これはまた初期塩化物含有量はコンクリート内に既に存在に依存します。これまでの実験のいくつかのケースでは腐食が開始されるまで 1 年以上かかった
Ccrit以上 40 歳スイス アルプスの道路トンネルから 11 検体で測定の例を図 8に示します。すべてのこれらのサンプル 1 2 m2の領域内から撮影した、従っておそらく同じ生産され公開します。この例では、サンプリング時に鋼板の表面塩化物含有量はごくわずかであった。また、中性化フロントは鋼の表面には程遠い。
潜在的な鋼が塩素フリー ソリューションへの露出に強く減った 2 つの例を図 9に示します。これらの特定のケースの 1 つは、サンプルの後 (破壊) 試験中に分かった鋼深さのコンクリートは既に炭酸すること。鋼板の表面水の到着後、腐食プロセス従ってすぐに始めた。鋼の 1 つでその他の場合は、false 腐食の発生が発生しましたバーエンドします。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56229/56229fig1.jpg"> 
図 1.構造と実験室の処理から取られるサンプルの図: ; 鉄筋の埋め込み部分を (、) のコンクリートのコア(b) コンクリート カバー露出側と背面側を水冷式ダイヤモンド切削; 削減(c) 鉄筋の鋼の周りいくつかの具体的を取り外しと高密度モルタル ペーストと後続のエポキシ コーティング; 取り付けによるエンドの保護水平面とコンクリート表面の始終端、(d) のエポキシ塗装。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig1large.jpg" target="_blank">この図の拡大版を表示するのにはここをクリックしてください</a>。
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56229/56229fig2.jpg"> 
図 2.研究室で腐食テストのセットアップの図。これは露出タンクのサンプルの位置を示しています。スペーサーは、サンプル底面から露出ソリューションに連絡先を確保するために使用されます。すべてのサンプルは、各サンプル露出ソリューションに配置参照電極対の電位を測定データロガーに接続されます。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig2large.jpg" target="_blank">この図の拡大版を表示するのにはここをクリックしてください</a>。
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/56229/56229fig3.jpg"> 
図 3.腐食発生条件を示す鋼電位の可能時間進化の図。1 の時点で潜在的なドロップ 150 未満で最初の「パッシブ レベル」から mV が発生します。2 の時点で潜在的なドロップ少なくとも 150 mV が発生すると、不動態化; が続いています。3 の時点で可能性は、少なくとも 150 のドロップ (最大 5 日) 以内に mV が発生し、達成の負の潜在的なレベルは、10 日以上を維持します。Tiniで露出ソリューションからサンプルを撤回します。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig3large.jpg" target="_blank">この図の拡大版を表示するのにはここをクリックしてください</a>。
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/56229/56229fig4.jpg"> 
図 4.切断および腐食の発生の検出後コンクリートのサンプルの分割を示す図。まず、「海溝」は、鋼棒平行に、後方からカットされます。彫刻刀または同様のツールを挿入することによって、矢印によって示されるようにサンプルを分割するトレンチを使用できます。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig4large.jpg" target="_blank">この図の拡大版を表示するのにはここをクリックしてください</a>。
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/56229/56229fig5.jpg"> 
図 5.写真腐食発生後サンプルの分析を示します。(、) の分割、および (b)、錆のスポットは、鋼に表示されます後サンプルの 2 つの半分の表面腐食の発生の後。さまざまなサンプルからの写真。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig5large.jpg" target="_blank">この図の拡大版を表示するのにはここをクリックしてください</a>。
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/56229/56229fig6.jpg"> 
図 6.概略図面を示す腐食発生後塩化物分析のためのサンプリング:分割コンクリート コアのエポキシ コーティング部分の (、) の除去 (紫 = 切断面);(b) 鋼の表面から 2 mm まで表層コンクリートの除去 (紫 = 切断面);(c) 研削深さ間隔 ± 2 mm 深棒鋼の上 (赤 = サンプリング ボリューム)。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig6large.jpg" target="_blank">この図の拡大版を表示するのにはここをクリックしてください</a>。
<img alt="Figure 7" class="xf alt="Figure 7" class=""></img alt="Figure 7" class="xf>igimg"src="/files/ftp_upload/56229/56229fig7.jpg"/> 
図 7.測定された潜在的な対の代表例時間曲線。続く場合があります潜在的な増加 (不動態化) 提案された基準に従って安定した腐食の発生を最後に開始するまで通常顕著な潜在的な低下。(、) の潜在的な負のレベルに安定化 (b) は例可能性が 10 日間の調査期間にわたって減少を続ける場合を示しています。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig7large.jpg" target="_blank">この図の拡大版を表示するのにはここをクリックしてください</a>。
<img alt="Figure 8" class="xfigimg" src="/files/ftp_upload/56229/56229fig8.jpg"> 
図 8.Ccrit 11 サンプル撮影で測定の例内の小さなコンクリート領域以上 40 年から古い道のスイス アルプスのトンネルします。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig8large.jpg" target="_blank">この図の拡大版を表示するのにはここをクリックしてください</a>。
<img alt="Figure 9" class="xfigimg" src="/files/ftp_upload/56229/56229fig9.jpg"> 
図 9.マークされた可能性の例減少すぐに無料の塩化物溶液中の露出にします。1 つの場合、鋼の深さでコンクリートは既に炭酸、こうして到着時に鋼板の表面水の腐食プロセスの開始すぐに、潜在性の急激な減少に 。鋼の 1 つでその他の場合は、false 腐食の発生が発生しましたバーエンドでは、ここより緩やかな潜在的な減少に導いた。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig9large.jpg" target="_blank">この図の拡大版を表示するのにはここをクリックしてください</a>。

Watch this Scientific Journal Video about Experimental Protocol to Determine the Chloride Threshold Value for Corrosion in Samples Taken from Reinforced Concrete Structures at JoVE.com

Experimental Protocol to Determine the Chloride Threshold Value for Corrosion in Samples Taken from Reinforced Concrete Structures

高い腐食評価や土木構造物からのサンプルのテストを許可する主な利点と鉄筋コンクリート構造の予測に関連するパラメーターを測定する方法を提案します。これにより鋼コンクリート界面の実態研究所製サンプルの人工物を避けるために非常に重要であります。

鉄筋コンクリート構造物から採取された検体で腐食の塩化しきい値値を決定する実験的プロトコル

The aging of reinforced concrete infrastructure in developed countries imposes an urgent need for methods to reliably assess the condition of these ...

experimental-protocol-to-determine-chloride-threshold-value-for

Research

Education

JoVE Core

JoVE Journal

Civil Engineering

Engineering

Unit 1

Permeability of Concrete

SCIENTISTS IN ACTION

15.2K ビュー.  ETH Zurich. 高い腐食評価や土木構造物からのサンプルのテストを許可する主な利点と鉄筋コンクリート構造の予測に関連するパラメーターを測定する方法を提案します。これにより鋼コンクリート界面の実態研究所製サンプルの人工物を避けるために非常に重要であります。

ビデオ: Experimental Protocol to Determine the Chloride Threshold Value for Corrosion in Samples Taken from Reinforced Concrete Structures

Laboratory Drop Towers for the Experimental Simulation of Dust-aggregate Collisions in the Early Solar System

For the purpose of investigating the evolution of dust aggregates in the early Solar System, we developed two vacuum drop towers in which fragile dust aggregates with sizes up to ~10 cm and porosities up to 70% can be collided. One of the drop towers is primarily used for very low impact speeds down to below 0.01 m/sec and makes use of a double release mechanism. Collisions are recorded in stereo-view by two high-speed cameras, which fall along the glass vacuum tube in the center-of-mass frame of the two dust aggregates. The other free-fall tower makes use of an electromagnetic accelerator that is capable of gently accelerating dust aggregates to up to 5 m/sec. In combination with the release of another dust aggregate to free fall, collision speeds up to ~10 m/sec can be achieved. Here, two fixed high-speed cameras record the collision events. In both drop towers, the dust aggregates are in free fall during the collision so that they are weightless and match the conditions in the early Solar System.

We present a technique to achieve low-velocity to intermediate-velocity collisions between fragile dust aggregates in the laboratory. For this purpose, two vacuum drop-tower setups have been developed that allow collision velocities between &#60;0.01 and ~10 m/sec. The collision events are recorded by high-speed imaging.

原始太陽系におけるダスト凝集衝突の実験的シミュレーションのための研究室のドロップタワー

For the purpose of investigating the evolution of dust aggregates in the early Solar System, we developed two vacuum drop towers in which fragile dust ...

工学

Experimental Protocol to Investigate Particle Aerosolization of a Product Under Abrasion and Under Environmental Weathering

The present article presents an experimental protocol to investigate particle aerosolization of a product under abrasion and under environmental weathering, which is a fundamental element to the approach of nanosafety-by-design of nanostructured products for their durable development. This approach is basically a preemptive one in which the focus is put on minimizing the emission of engineered nanomaterials' aerosols during the usage phase of the product's life cycle. This can be attained by altering its material properties during its design phase without compromising with any of its added benefits. In this article, an experimental protocol is presented to investigate the nanosafety-by-design of three commercial nanostructured products with respect to their mechanical solicitation and environmental weathering. The means chosen for applying the mechanical solicitation is an abrasion process and for the environmental weathering, it is an accelerated UV exposure in the presence of humidity and heat. The eventual emission of engineered nanomaterials is studied in terms of their number concentration, size distribution, morphology and chemical composition. The purpose of the protocol is to study the emission for test samples and experimental conditions which are corresponding to real life situations. It was found that the application of the mechanical stresses alone emits the engineered nanomaterials' aerosols in which the engineered nanomaterial is always embedded inside the product matrix, thus, a representative product element. In such a case, the emitted aerosols comprise of both nanoparticles as well as microparticles. But if the mechanical stresses are coupled with the environmental weathering, the experimental protocol reveals then the eventual deterioration of the product, after a certain weathering duration, may lead to the emission of the free engineered nanomaterial aerosols too.

In this article, an experimental protocol to investigate particle aerosolization of a product under abrasion and under environmental weathering is presented. Results on the emission of engineered nanomaterials, in the form of aerosols are presented. The specific experimental set-up is described in detail.

摩耗の下で環境風化の下で製品の粒子エアロゾル化を調査するための実験プロトコール

The present article presents an experimental protocol to investigate particle aerosolization of a product under abrasion and under environmental ...

Detecting the Water-soluble Chloride Distribution of Cement Paste in a High-precision Way

To improve the accuracy of the chloride distribution along the depth of cement paste under cyclic wet-dry conditions, a new method is proposed to obtain a high-precision chloride profile. Firstly, paste specimens are molded, cured, and exposed to cyclic wet-dry conditions. Then, powder samples at different specimen depths are grinded when the exposure age is reached. Finally, the water-soluble chloride content is detected using a silver nitrate titration method, and chloride profiles are plotted. The key to improving the accuracy of the chloride distribution along the depth is to exclude the error in the powderization, which is the most critical step for testing the distribution of chloride. Based on the above concept, the grinding method in this protocol can be used to grind powder samples automatically layer by layer from the surface inward, and it should be noted that a very thin grinding thickness (less than 0.5 mm) with a minimum error less than 0.04 mm can be obtained. The chloride profile obtained by this method better reflects the chloride distribution in specimens, which helps researchers to capture the distribution features that are often overlooked. Furthermore, this method can be applied to studies in the field of cement-based materials, which require high chloride distribution accuracy.

A protocol for obtaining a water-soluble chloride profile by using a high precision milling method is presented.

セメント ペーストの水溶性塩化物の分布を高精度に検出

To improve the accuracy of the chloride distribution along the depth of cement paste under cyclic wet-dry conditions, a new method is proposed to obtain a ...

Installation Method to Enhance Quality Control for Fiber Reinforced Polymer Spike Anchors

Fiber reinforced polymer (FRP) anchors are a promising way to enhance the performance of externally-bonded FRPs applied to existing structures, as they can delay or even prevent debonding failure. However, a major concern faced by designers is the premature failure of the anchors due to stress concentration. Poor installation quality and preparation of the clearance holes can result in stress concentration that provokes this premature failure. This paper deals with an installation method that aims to reduce the impact of the stress concentration and to provide a proper quality control of the preparation of the drill hole. The method involves three parts: the drilling and cleaning of the holes, the smoothing of the hole edges with a customized drill bit, and the installation of the anchor itself, including the impregnation of the anchor dowel and its insertion. Anchor fans (the free length of the spikes) are then bonded to the external FRP reinforcement. For the end anchorage, and in the case of reinforcements with multiple plies, it is recommended that the anchor fan be inserted between two plies to assist the stress-transfer mechanism. 
The proposed procedure is complemented with a design approach for spike anchors, based on an extensive database. It is proposed that the design follow a number of steps, namely: selection of the anchor diameter and subsequent tensile strength of the connector (that is to say, the anchor before fanning out the free end), evaluation of the reduction in the tensile strength due to bending, provision of enough embedment to prevent slippage failure, and consideration of the number and spacing of anchors for a given reinforcement. In this sense, it should be noted that further research is needed in order to obtain a general expression for the contribution of spike anchors to overall bond strength of FRP reinforcements.

This manuscript presents a method for controlling the quality of installation for spike anchors designed to delay delamination of externally bonded fiber reinforced polymers. The protocol includes the preparation of the drill hole and the insertion process. The most influential parameters on the efficiency of the anchors are discussed.

繊維の品質管理を強化するインストール方法強化ポリマー スパイク アンカー

Fiber reinforced polymer (FRP) anchors are a promising way to enhance the performance of externally-bonded FRPs applied to existing structures, as they ...

Production of Single Tracks of Ti-6Al-4V by Directed Energy Deposition to Determine the Layer Thickness for Multilayer Deposition

Directed Energy Deposition (DED), which is an additive manufacturing technique, involves the creation of a molten pool with a laser beam where metal powder is injected as particles. In general, this technique is employed to either fabricate or repair different components. In this technique, the final characteristics are affected by many factors. Indeed, one of the main tasks in building components by DED is the optimization of process parameters (such as laser power, laser speed, focus, etc.) which is usually carried out through an extensive experimental investigation. However, this sort of experiment is extremely lengthy and costly. Thus, in order to accelerate the optimization process, an investigation was conducted to develop a method based on the melt pool characterizations. In fact, in these experiments, single tracks of Ti-6Al-4V were deposited by a DED process with multiple combinations of laser power and laser speed. Surface morphology and dimensions of single tracks were analyzed, and geometrical characteristics of melt pools were evaluated after polishing and etching the cross-sections. Helpful information regarding the selection of optimal process parameters can be achieved by examining the melt pool features. These experiments are being extended to characterize the larger blocks with multiple layers. Indeed, this manuscript describes how it would be possible to quickly determine the layer thickness for the massive deposition, and avoid over or under-deposition according to the calculated energy density of the optimum parameters. Apart from the over or under-deposition, time and materials saving are the other great advantages of this approach in which the deposition of multilayer components can be started without any parameter optimization in terms of layer thickness.

In this research, a rapid method based on melt pool characterization is developed to estimate the layer thickness of Ti-6Al-4V components produced by directed energy deposition.

多層成膜の層の厚さを決定する指向性エネルギー蒸着法による Ti 6al-4 v の単一トラックの生産

Directed Energy Deposition (DED), which is an additive manufacturing technique, involves the creation of a molten pool with a laser beam where metal ...

Optimized Sealing Process and Real-Time Monitoring of Glass-to-Metal Seal Structures

Residual stress is an essential factor to keeping the hermeticity and robustness of a glass-to-metal seal structure. The purpose of this report is to demonstrate a novel protocol to characterize and measure residual stress in a glass-to-metal seal structure without destroying the insulation and hermeticity of sealing materials. In this research, a femto-laser inscribed fiber Bragg grating sensor is used. The glass-to-metal seal structure that is measured consists of a metal shell, sealing glass, and Kovar conductor. To make the measurements worthwhile, the specific heat treatment of metal-to-glass seal (MTGS) structure is explored to obtain the model with best hermeticity. Then, the FBG sensor is embedded into the path of sealing glass and becomes well-fused with the glass as the temperature cools to RT. The Bragg wavelength of FBG shifts with the residual stress generated in sealing the glass. To calculate the residual stress, the relationship between Bragg wavelength shift and strain is applied, and the finite element method is also used to make the results reliable. The online monitoring experiments of residual stress in sealing glass are carried out at different loads, such as high temperature and high pressure, to broaden functions of this protocol in harsh environments.

Key procedures to optimize the sealing process and achieve real-time monitoring of the metal-to-glass seal (MTGS) structure are described in detail. The embedded fiber Bragg grating (FBG) sensor is designed to achieve online monitoring of temperature and high-level residual stress in the MTGS with simultaneous environmental pressure monitoring.

ガラスから金属へのシール構造の最適化されたシールプロセスとリアルタイムモニタリング

Residual stress is an essential factor to keeping the hermeticity and robustness of a glass-to-metal seal structure. The purpose of this report is to ...

Artificial Thermal Ageing of Polyester Reinforced and Polyvinyl Chloride Coated Technical Fabric

Architectural fabric AF9032 has been subjected to artificial thermal ageing to determine changes of the material parameters of the fabric. The proposed method is based on the accelerated ageing approach proposed by Arrhenius. 300 mm x 50 mm samples were cut in the warp and fill directions and placed in a thermal chamber at 80 &#176;C for up to 12 weeks or at 90 &#176;C for up to 6 weeks. Then after one week of conditioning at ambient temperature, the samples were uniaxially tensioned at a constant strain rate. Experimentally, the parameters were determined for the non-linear elastic (linear piecewise) and viscoplastic (Bodner&#8211;Partom) models. Changes in these parameters were studied with respect to the ageing temperature and ageing period. In both cases, the linear approximation function was successfully applied using the simplified methodology of Arrhenius. A correlation was obtained for the fill direction between experimental results and the results from the Arrhenius approach. For the warp direction, the extrapolation results exhibited some differences. Increasing and decreasing tendencies have been observed at both temperatures. The Arrhenius law was confirmed by the experimental results only for the fill direction. The proposed method makes it possible to predict real fabric behavior during long term exploitation, which is a critical issue in the design process.

Here, we simulate accelerated thermal ageing of technical fabric and see how this ageing process influences the mechanical properties of the fabric.

ポリエステル強化およびポリ塩化ビニルコーティング技術織物の人工熱老化

Architectural fabric AF9032 has been subjected to artificial thermal ageing to determine changes of the material parameters of the fabric. The proposed ...

Advanced Self-Healing Asphalt Reinforced by Graphene Structures: An Atomistic Insight

Graphene can improve the self-healing properties of asphalt with high durability. However, the self-healing behaviors of graphene-modified asphalt nanocomposite and the role of incorporated graphene are still unclear at this stage. In this study, the self-healing properties of pure asphalt and graphene-modified asphalt are investigated through molecular dynamics simulations. Asphalt bulks with two crack widths and locations for graphene are introduced, and the molecular interactions among asphalt components and the graphene sheet are analyzed. The results show that the location of graphene significantly affects the self-healing behaviors of asphalt. Graphene near the crack surface can greatly accelerate the self-healing process by interacting with the aromatic molecules through &#960;-&#960; stacking, while graphene at the top area of the crack tip has a minor impact on the process. The self-healing process of asphalt goes through the reorientation of asphaltene, polar aromatic, and naphthene aromatic molecules, and the bridging of saturate molecules between crack surfaces. This in-depth understanding of the self-healing mechanism contributes to the knowledge of the enhancement for self-healing properties, which will help to develop durable asphalt pavements.

Graphene-modified asphalt nanocomposite has shown an advanced self-healing ability compared to pure asphalt. In this protocol, molecular dynamics simulations have been applied in order to understand the role of graphene in the self-healing process and to explore the self-healing mechanism of asphalt components from the atomistic level.

グラフェン構造によって強化された高度な自己修復アスファルト:原子論的洞察

Graphene can improve the self-healing properties of asphalt with high durability. However, the self-healing behaviors of graphene-modified asphalt ...

Modeling and Experimental Analysis of the Single-Shaft Coaxial Motor-Pump Assembly in Electrohydrostatic Actuators

An electrohydrostatic actuator (EHA) can be the most promising alternative compared with the traditional hydraulic servo actuators for its high power density, ease of maintenance, and reliability. As the core power unit that determines the performance and service life of the EHA, the motor-pump assembly should simultaneously possess a wide speed/pressure range and a high dynamic response.
This paper presents a method to test the performance of the motor-pump assembly through simulation and experimentation. The flow output characteristics were defined through simulation and analysis of the assembly at the beginning of the experiment, leading to the conclusion of whether the pump could meet the requirements of the EHA. A series of performance tests were conducted on the motor-pump assembly via a pump test bench in the speed range of 1,450-9,000 rpm and the pressure range of 1-30 MPa.
We tested the overall efficiency of the motor-pump assembly under various working conditions after confirming the consistency between the test results of the flow output characteristics with the simulation results. The results showed that the assembly has higher overall efficiency when working at 4,500-7,000 rpm under the pressure of 10-25 MPa and at 2,000-2,500 rpm under 5-15 MPa. Overall, this method can be utilized for determining in advance whether the motor-pump assembly meets the requirements of EHA. Moreover, this paper proposes a rapid test method of the motor-pump assembly in various working conditions, which could assist in predicting EHA performance.

We built a simulation model to evaluate pump flow characteristics and performance of the single-shaft coaxial motor-pump assembly in electrohydrostatic actuators and investigate the overall efficiency in a wide set of working conditions of the motor-pump assembly experimentally.

電気油圧アクチュエータにおける単軸同軸モータポンプアセンブリのモデリングと実験解析

An electrohydrostatic actuator (EHA) can be the most promising alternative compared with the traditional hydraulic servo actuators for its high power ...

Co-localizing Kelvin Probe Force Microscopy with Other Microscopies and Spectroscopies: Selected Applications in Corrosion Characterization of Alloys

Kelvin probe force microscopy (KPFM), sometimes referred to as surface potential microscopy, is the nanoscale version of the venerable scanning Kelvin probe, both of which measure the Volta potential difference (VPD) between an oscillating probe tip and a sample surface by applying a nulling voltage equal in magnitude but opposite in sign to the tip-sample potential difference. By scanning a conductive KPFM probe over a sample surface, nanoscale variations in surface topography and potential can be mapped, identifying likely anodic and cathodic regions, as well as quantifying the inherent material driving force for galvanic corrosion.
Subsequent co-localization of KPFM Volta potential maps with advanced scanning electron microscopy (SEM) techniques, including back scattered electron (BSE) images, energy dispersive spectroscopy (EDS) elemental composition maps, and electron backscattered diffraction (EBSD) inverse pole figures can provide further insight into structure-property-performance relationships. Here, the results of several studies co-localizing KPFM with SEM on a wide variety of alloys of technological interest are presented, demonstrating the utility of combining these techniques at the nanoscale to elucidate corrosion initiation and propagation.
Important points to consider and potential pitfalls to avoid in such investigations are also highlighted: in particular, probe calibration and the potential confounding effects on the measured VPDs of the testing environment and sample surface, including ambient humidity (i.e., adsorbed water), surface reactions/oxidation, and polishing debris or other contaminants. Additionally, an example is provided of co-localizing a third technique, scanning confocal Raman microscopy, to demonstrate the general applicability and utility of the co-localization method to provide further structural insight beyond that afforded by electron microscopy-based techniques.

Kelvin probe force microscopy (KPFM) measures surface topography and differences in surface potential, while scanning electron microscopy (SEM) and associated spectroscopies can elucidate surface morphology, composition, crystallinity, and crystallographic orientation. Accordingly, the co-localization of SEM with KPFM can provide insight into the effects of nanoscale composition and surface structure on corrosion.

ケルビンプローブ力顕微鏡と他の顕微鏡および分光法との共局在化:合金の腐食特性評価における選択されたアプリケーション

Kelvin probe force microscopy (KPFM), sometimes referred to as surface potential microscopy, is the nanoscale version of the venerable scanning Kelvin ...