这里描述的工作部分由瑞士联邦路办公室 (研究项目 AGB2012/010) 资助。我们非常感谢财政支持。

<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. (5), 290-298 (2011).</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+EN14629:+Products+and+systems+for+the+protection+and+repair+of+concrete+structures+-+Test+methods+-+Determination+of+chloride+content+in+hardened+concrete.">European Standard EN14629: Products and systems for the protection and repair of concrete structures - Test methods - Determination of chloride content in hardened concrete.</a> European Committee for Standardization. , (2007).</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+C1152+Standard+Test+Method+for+Acid-Soluble+Chloride+in+Mortar+and+Concrete.">ASTM C1152 Standard Test Method for Acid-Soluble Chloride in Mortar and Concrete.</a> ASTM International. , (2012).</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=SIA+269/2:2011+Erhaltung+von+Tragwerken+-+Betonbau.">SIA 269/2:2011 Erhaltung von Tragwerken - Betonbau.</a> Schweizerischer Ingenieur- und Architektenverein SIA. , (2011).</li><li>Draft, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Draft+recommendation+for+repair+strategies+for+concrete+structures+damaged+by+reinforcement+corrosion.">Draft recommendation for repair strategies for concrete structures damaged by reinforcement corrosion.</a> Mater Struct. 27, 415-436 (1994).</li><li>Broomfield, J. P. <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: Understanding, Investigation and Repair. 2nd edn. , (2006).</li><li>Richartz, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Die+Bindung+von+Chlorid+bei+der+Zementerh&#228;rtung.">Die Bindung von Chlorid bei der Zementerh&#228;rtung.</a> Zement-Kalk-Gips. 10, 447-456 (1969).</li><li>Vassie, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reinforcement+corrosion+and+the+durability+of+concrete+bridges.">Reinforcement corrosion and the durability of concrete bridges.</a> Proc. Inst. Civ. Eng. Part 1. 76, 713-723 (1984).</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=The+steel-concrete+interface.">The steel-concrete interface.</a> Mater. Struct. 50 (2), 143 (2017).</li><li>Polder, R. B., Peelen, W. H. A., Courage, W. M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-traditional+assessment+and+maintenance+methods+for+aging+concrete+structures+-+technical+and+non-technical+issues.">Non-traditional assessment and maintenance methods for aging concrete structures - technical and non-technical issues.</a> Mater. Corros. 63 (12), 1147-1153 (2012).</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=Standard+Test+Method+for+Corrosion+Potentials+of+Uncoated+Reinforcing+Steel+in+Concrete.">Standard Test Method for Corrosion Potentials of Uncoated Reinforcing Steel in Concrete.</a> ASTM International. , (2015).</li><li>Planung, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=SIA+2006:2013+Planung+Durchf&#252;hrung+und+Interpretation+der+Potenzialmessung+an+Stahlbetonbauten.">SIA 2006:2013 Planung Durchf&#252;hrung und Interpretation der Potenzialmessung an Stahlbetonbauten.</a> Schweizerischer Ingenieur- und Architektenverein SIA. , (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=B3:+Merkblatt+f&#252;r+Elektrochemische+Potentialmessungen+zur+Detektion+von+Bewehrungsstahlkorrosion.">B3: Merkblatt f&#252;r Elektrochemische Potentialmessungen zur Detektion von Bewehrungsstahlkorrosion.</a> Deutsche Gesellschaft f&#252;r Zerst&#246;rungsfreie Pr&#252;fung DGZfP. , (2014).</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=B2:+Merkblatt+zur+zerst&#246;rungsfreien+Betondeckungsmessung+und+Bewehrungsortung+an+Stahl-+und+Spannbetonbauteilen.">B2: Merkblatt zur zerst&#246;rungsfreien Betondeckungsmessung und Bewehrungsortung an Stahl- und Spannbetonbauteilen.</a> Deutsche Gesellschaft f&#252;r Zerst&#246;rungsfreie Pr&#252;fung DGZfP. , (2014).</li><li>Soylev, T. A., Fran&#231;ois, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quality+of+steel-concrete+interface+and+corrosion+of+reinforcing+steel.">Quality of steel-concrete interface and corrosion of reinforcing steel.</a> Cem. Concr. Res. 33 (9), 1407-1415 (2003).</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+12504-1:2009+-+Testing+concrete+in+structures.+Cored+specimens.+Taking,+examining+and+testing+in+compression.">European Standard EN 12504-1:2009 - Testing concrete in structures. Cored specimens. 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. Sci. 53 (4), 1451-1464 (2011).</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> RILEM technical committee 235-CTC. , (2015).</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=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. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chloride+corrosion+threshold+of+reinforcing+steel+in+alkaline+solutions+-+Effect+of+specimen+size.">Chloride corrosion threshold of reinforcing steel in alkaline solutions - Effect of specimen size.</a> Corros. 60 (2), 195-202 (2004).</li><li>Angst, U., R&#248;nnquist, A., 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=Probabilistic+considerations+on+the+effect+of+specimen+size+on+the+critical+chloride+content+in+reinforced+concrete.">Probabilistic considerations on the effect of specimen size on the critical chloride content in reinforced concrete.</a> Corros. Sci. 53 (1), 177-187 (2011).</li></ol>

作者没有什么可透露的。

为确定C暴击而建议的实验协议的成功最关键的步骤是包括为防止假腐蚀引发和其他钢筋末端效果而采取的措施。在这方面, 对各种方法进行了测试, 其中发现这里所报告的协议能产生最好的结果28。在进一步的测试中, 这种方法允许将假起始率降低到10% 以下。一方面, 这是由于涂层的边界面积的暴露在混凝土表面与环氧树脂, 这增加了运输的长度, 通过混凝土到钢筋两端的钢棒结束。另一方面, 用高密度、高碱性的胶凝浆代替钢筋的两端的原混凝土, 大大提高了这些地区的耐蚀性。这种系统,即, 涂层钢筋结束与一层高分子改性胶凝材料, 已证明成功也在其他研究29,30。
另一个重要的方面是腐蚀起始的标准。此标准基于 RILEM 技术委员会 TC-235, 其目的是建议在实验室31中制造的样本中测试C暴击的检测方法。其基本原理是众所周知, 埋在混凝土中的偏振钢的腐蚀可能会在很长一段时间内发生, 而不是一个定义良好的即时3032。钢可能开始腐蚀在相对地低氯化物集中, 但, 如果这些不能够承受腐蚀过程, 钝化将发生, 变得明显由一个潜在的增量回到最初的被动水平。此类钝化钝化事件通常在类似的研究中观察30,33,34。在稳定腐蚀时测定的氯化物浓度比从被动水平上的潜在偏差的最初迹象变得明显的时间更切合实际。使用所建议的标准, C暴击代表了腐蚀引发的氯化物浓度, 并且稳定地传播。
该方法的一个限制是样本相对较小, 这可能会对结果产生影响35,36。为了抵消这一点, 建议使用相对较高的样本数 (理想情况下为 10)。置信度取决于实际测试区域中的C暴击的统计分布。有关这方面的详细信息, 请参阅参考36。另外一个限制是, 实验室暴露的水分条件可能与实际结构不同。最后, 在潜在的一般为负的情况下, 如在矿渣水泥或其他含硫化物的粘合剂中, 对腐蚀起始的检测可能是困难的。
尽我们所知, 这是第一个在腐蚀开始前的阶段在工程结构中C暴击的方法。对比经验从结构, 是由定义在腐蚀开始以后获得, 这个方法可以用于测量C暴击为具体结构或结构成员在腐蚀之前发生的退化;这样的结果可以用来评估 (未来) 腐蚀的风险, 并预测剩余的腐蚀起始时间 (使用寿命模型)。因此, 这种方法有可能用于材料测试, 类似于用于机械测试的既定方法 (压缩强度,等)
该方法目前适用于瑞士的许多不同的混凝土基础设施。这将扩大对结构中C暴击的统计分布的严重限制的5知识。此外, 它将揭示不同的因素, 如结构的年龄, 使用的建筑材料,等的影响, 从而为土木工程师和 decision-makers 的基础设施管理提供重要的信息。

钢筋在混凝土中的腐蚀, 由氯化物通过混凝土的渗透引起, 是钢筋混凝土结构过早退化的最常见原因之一, 因此在土木工程1,2,3,4。工业化国家通常有大量的老化混凝土基础设施的库存, 建于上个世纪下半叶, 因此有几十年的历史, 暴露于海洋气候或道路上使用的除冰盐。能够可靠地评估这些结构的状况,即, 腐蚀的风险, 构成了规划维护工作和基础设施管理的基础。
在混凝土中氯离子腐蚀的管理工程中建立的方法是基于氯化物阈值 (也称为临界氯含量, C暴击)1,5,6. 根据这个概念, 在钢表面的混凝土中氯化物浓度超过了C暴击阈值时, 就认为会发生腐蚀萌生。因此, 评估现有结构的状况和估计剩余的使用寿命通常依赖于确定不同深度的混凝土中的氯化物含量, 特别是在埋入钢筋的深度。有许多可靠和标准化的方法来测量混凝土样品中的氯化物浓度7,8。将结果与C暴击进行比较, 为评估腐蚀风险提供依据, 并对修复措施的类型和范围进行规划。但是, 此方法需要了解C暴击。
不同的国际标准和建议, 以及教科书, 规定的值为C暴击1,3,9,10,11。这些典型地是大约0.4% 氯化物由水泥的重量, 根据长期经验或早期的研究12,13。然而, 众所周知, 对某一结构或结构成员的C的暴击的实际电阻受到使用的材料、结构的年龄和曝光历史和条件的强烈影响1,5. 因此, 人们普遍认为, 一个结构的经验只应谨慎地适用于其他结构。
尽管如此, 使用表格式的C暴击值是常见的工程实践, 与实际结构无关。这可以通过文献中的C暴击的巨大散布来解释, 也没有可靠的方法来确定c暴击on-site 和实验室中的5。在耐久性评估中使用列表阈值的方法与在老化混凝土结构的状态评估中的结构考虑因素是不同的。在后一种情况下, 有许多标准化的测试方法, 以确定机械性能, 如材料的强度, 在结构 (混凝土, 钢筋), 用于计算的结构行为。
在这项工作中, 提出了一个实验协议来确定从工程结构中抽取的样本的C暴击。该方法是基于钢筋混凝土的钻孔芯, 在混凝土结构部分的腐蚀尚未启动。这些样品被转移到实验室, 在那里他们受到加速腐蚀试验, 以便研究腐蚀起始的条件。所提出的方法的主要优点是, 样本从结构中产生, 从而在许多已知的参数中表现出真实的条件, 而这很大程度上影响了C暴击, 不能代表性在实验室生产的样品中模仿。这包括混凝土的类型和年龄 (年轻实验室混凝土与成熟工地生产的混凝土), 建筑时使用的钢筋的类型和表面条件, 以及一般钢-混凝土的性能接口14。与实验室测量方法的准确性一起, 此方法允许对特定结构或结构成员的C暴击进行可靠的确定。
建议的协议在工程实践中的应用将-与使用C暴击的常量值的一般做法相比, 可以提高条件评估的准确性和模型的预测能力, 以分析剩余的使用寿命。在未来的几十年里, 我们所建造的基础设施的维修工程预计将有强劲的增长15 , 这就迫切需要在腐蚀基础设施工程方面进行这种改进。

<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

发达国家钢筋混凝土基础设施的老化, 迫切需要对这些结构的状况进行可靠评估的方法。钢筋锈蚀是最常见的降解原因。众所周知, 结构耐腐蚀的能力在很大程度上取决于使用的材料或年龄等因素, 但通常的做法是依赖标准或教科书中规定的阈值。这些阈值的腐蚀启动 (C暴击) 是独立于特定结构的实际属性, 这清楚地限制了条件评估和使用寿命预测的准确性。使用列表值的做法可以追溯到缺乏可靠的方法来确定C暴击on-site 和实验室。
这里给出了一个用于确定单个工程结构或结构构件的C暴击的实验协议。从结构中抽取了一些钢筋混凝土试样, 并进行了实验室腐蚀试验。该方法的主要优点是, 它确保了有关参数的真实条件, 而这是众所周知的非常影响C暴击的, 如钢-混凝土界面, 不能代表性模仿实验室生产的样品。同时, 实验室的加速腐蚀试验允许在测试结构的腐蚀开始之前, 可靠地确定C暴击;这是一个主要的优势比所有的通用条件评估方法, 只允许估计的条件, 腐蚀后启动,即, 当结构已经损坏。
该协议生成测试结构的C暴击的统计分布。这是一个基础的概率预测模型的剩余时间, 以腐蚀, 这是需要的维修规划。这种方法有可能用于民用基础设施的材料测试, 类似于用于机械测试的既定方法。

图 7显示了在实验室氯化物暴露期间监测到的典型钢电位。这两个例子都表明, 电位可能在很短的时间内明显下降, 但腐蚀过程可能还没有稳定传播, 这变得明显通过增加潜在的初始被动水平。在本协议中, 腐蚀起始时间、即、停止曝光的时间和C暴击是由有标记的潜在下降定义的, 后跟10天的负电位 (请参见3.5.2 和讨论有关详细信息)。
这是常见的, 它可能需要几个月, 直到稳定的腐蚀引发发生。这也取决于从结构中抽取样品时, 混凝土中已经存在的初始氯化物含量。到目前为止, 在某些情况下进行的实验, 它花了超过1年, 直到腐蚀开始。
图 8显示了一个C暴击的例子, 该示例是在瑞士阿尔卑斯山的40年以上的公路隧道中采集的11样本中进行测量的。所有这些样本都是从 1-2 m2的区域中抽取的, 因此可能相同地产生和暴露。在这个例子中, 在取样时钢表面的氯化物含量是微不足道的。此外, 碳化锋仍然远离钢表面。
图 9显示了两个例子, 当接触到无氯溶液时, 钢势会明显降低。在其中一个具体事例, 它是在随后 (破坏性) 检查样品发现了混凝土在钢深度已经是碳酸的。当水到达钢表面时, 腐蚀过程便立即开始。在另一种情况下, 在其中一个钢筋末端发生了假腐蚀。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56229/56229fig1.jpg"> 
图 1.从结构中抽取的样品的示意图, 并在实验室中处理: (一个) 与嵌入的钢筋的混凝土芯;(b) 通过水冷式金刚石切割减少外露侧和背面的混凝土保护层;(c) 钢棒端面保护, 方法是将钢筋周围的一些混凝土拆除, 并用密实的水泥浆/砂浆和随后的环氧涂层代替;以及 (d) 在外露混凝土表面的侧面和端面上的环氧涂层。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig1large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56229/56229fig2.jpg"> 
图 2.实验室中腐蚀试验装置的示意图。这显示了样品在曝光槽中的位置。垫片用于确保接触到暴露溶液从底部样品表面。所有样品都连接到一个数据记录器, 测量每个样品与暴露溶液中所放置的参考电极的电位。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig2large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/56229/56229fig3.jpg"> 
图 3.示意图绘制了可能的时间演变的钢势, 说明了腐蚀起始的标准.在1点, 从初始 "被动电平" 发生的电位下降小于 150 mV;在点 2, 一个潜在的下降, 至少 150 mV 发生, 其次是钝化;在点 3, 一个潜在的下降至少 150 mV 发生 (在最大的5天内) 和达到负电位水平持续超过10天。在tini中, 从暴露解决方案中撤回该示例。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig3large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/56229/56229fig4.jpg"> 
图 4.示意图说明了在检测到腐蚀引发后混凝土试样的切割和劈裂.首先, 一条 "沟槽" 从后侧切入, 与钢筋平行。通过插入凿子或类似的工具, 沟槽可以用来分割样品, 如箭头所示。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig4large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/56229/56229fig5.jpg"> 
图 5.照片说明了腐蚀开始后的样品分析。(a) 拆分后试样的两个半部分, (b) 腐蚀开始后在钢表面可见锈迹。来自不同样品的照片。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig5large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/56229/56229fig6.jpg"> 
图 6.示意图说明在腐蚀引发后氯化物分析的取样: (a) 拆分混凝土芯的环氧涂层部分 (紫色 = 切割面);(b) 将混凝土保护层从钢表面移除2毫米 (紫色 = 切割平面);(c) 磨削深度间隔为 2 mm 的钢筋覆盖深度 (红色 = 取样体积)。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig6large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 7" class="xf alt="Figure 7" class=""></img alt="Figure 7" class="xf>igimg "src ="/文件/ftp_upload/56229/56229fig7. jpg 
图 7.已测量的潜在与时间曲线的代表性示例.通常发出的潜在的下降, 随后可能会增加 (钝化), 直到稳定的腐蚀开始根据建议的标准, 最终启动。(a) 显示了在负水平上可能稳定的情况, 并且 (b) 是一个示例, 在10天的研究期间, 潜在的持续下降。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig7large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 8" class="xfigimg" src="/files/ftp_upload/56229/56229fig8.jpg"> 
图 8.示例C暴击在瑞士阿尔卑斯山的40年以上的公路隧道中, 从一个小的混凝土区域内抽取的11样本中进行测量.<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig8large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 9" class="xfigimg" src="/files/ftp_upload/56229/56229fig9.jpg"> 
图 9.当暴露在无氯溶液中时, 有明显电位的例子会立即减少.在一个案例中, 混凝土在钢的深度已经碳化, 因此, 当水到达钢表面, 腐蚀过程立即开始, 导致急剧下降的潜力。在另一种情况下, 在一个钢筋端部发生了假腐蚀, 这导致了一个更渐进的电位下降。<a href="//ecsource.jove.com/files/ftp_upload/56229/56229fig9large.jpg" target="_blank">请单击此处查看此图的较大版本.</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

我们提出了一种方法来测量的参数, 这是高度相关的腐蚀评估或预测钢筋混凝土结构, 主要优势, 允许测试的样品从工程结构。这确保了在钢-混凝土界面的实际条件, 这是至关重要的, 以避免实验室制造的样品的工件。

测定钢筋混凝土结构试样腐蚀的氯化物阈值的试验规程

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 次观看.  ETH Zurich. 我们提出了一种方法来测量的参数, 这是高度相关的腐蚀评估或预测钢筋混凝土结构, 主要优势, 允许测试的样品从工程结构。这确保了在钢-混凝土界面的实际条件, 这是至关重要的, 以避免实验室制造的样品的工件。

视频: 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.

实验室落塔的粉尘聚集在碰撞早期太阳系的实验模拟

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 ...

科研

工程学

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.

实验协议来调查产品的粒子雾化在耐磨和环境下风化

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.

高精度水泥浆水溶氯分布的检测

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.

提高纤维增强聚合物穗锚质量控制的安装方法

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.

用定向能沉积法生产 Ti-6Al-4V 层厚度的单车道多层沉积

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.

玻璃到金属密封结构的优化密封工艺和实时监控

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.

聚酯增强和聚氯乙烯涂层技术织物的人工热老化

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.

石墨烯结构增强的先进自愈合沥青：原子学见解

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.

静电静压执行器中单轴同轴电机泵组件的建模与实验分析

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.

开尔文探针力显微镜与其他显微镜和光谱学共定位：合金腐蚀表征中的选定应用

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