Yong-Qing Chen , Lin-Ya Liu , Da-Wei Huang , Qing-Song Feng , Ren-Peng Chen , Xin Kang
{"title":"Unraveling the Stray Current-Induced Interfacial Transition Zone (ITZ) Effect on Sulfate Corrosion in Concrete","authors":"Yong-Qing Chen , Lin-Ya Liu , Da-Wei Huang , Qing-Song Feng , Ren-Peng Chen , Xin Kang","doi":"10.1016/j.eng.2024.08.001","DOIUrl":null,"url":null,"abstract":"<div><div>The rail transit in sulfate-rich areas faces the combined effects of stray current and salt corrosion; however, the sulfate ion transport and concrete degradation mechanisms under such conditions are still unclear. To address this issue, novel sulfate transport and mesoscale splitting tests were designed, with a focus on considering the differences between the interfacial transition zone (ITZ) and cement matrix. Under the influence of stray current, the ITZ played a pivotal role in regulating the transport and mechanical failure processes of sulfate attack, while the tortuous and blocking effects of aggregates almost disappeared. This phenomenon was termed the “stray current-induced ITZ effect.” The experimental data revealed that the difference in sulfate ion transport attributed to the ITZ ranged from 1.90 to 2.31 times, while the difference in splitting strength ranged from 1.56 to 1.64 times. Through the real-time synchronization of splitting experiments and microsecond-responsive particle image velocimetry (PIV) technology, the mechanical properties were exposed to the consequences of the stray current-induced ITZ effect. The number of splitting cracks in the concrete increased, rather than along the central axis, which was significantly different from the conditions without stray current and the ideal Brazilian disk test. Furthermore, a sulfate ion mass transfer model that incorporates reactivity and electrodiffusion was meticulously constructed. The embedded finite element calculation exhibited excellent agreement with the experimental results, indicating its reliability and accuracy. Additionally, the stress field was determined utilizing analytical methods, and the mechanism underlying crack propagation was successfully obtained. Compared to the cement matrix, a stray current led to more sulfates, more microstructure degradation, and greater increases in thickness and porosity in the ITZ, which was considered to be the essence of the stray current-induced ITZ effect.</div></div>","PeriodicalId":11783,"journal":{"name":"Engineering","volume":null,"pages":null},"PeriodicalIF":10.1000,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Engineering","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2095809924004879","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
The rail transit in sulfate-rich areas faces the combined effects of stray current and salt corrosion; however, the sulfate ion transport and concrete degradation mechanisms under such conditions are still unclear. To address this issue, novel sulfate transport and mesoscale splitting tests were designed, with a focus on considering the differences between the interfacial transition zone (ITZ) and cement matrix. Under the influence of stray current, the ITZ played a pivotal role in regulating the transport and mechanical failure processes of sulfate attack, while the tortuous and blocking effects of aggregates almost disappeared. This phenomenon was termed the “stray current-induced ITZ effect.” The experimental data revealed that the difference in sulfate ion transport attributed to the ITZ ranged from 1.90 to 2.31 times, while the difference in splitting strength ranged from 1.56 to 1.64 times. Through the real-time synchronization of splitting experiments and microsecond-responsive particle image velocimetry (PIV) technology, the mechanical properties were exposed to the consequences of the stray current-induced ITZ effect. The number of splitting cracks in the concrete increased, rather than along the central axis, which was significantly different from the conditions without stray current and the ideal Brazilian disk test. Furthermore, a sulfate ion mass transfer model that incorporates reactivity and electrodiffusion was meticulously constructed. The embedded finite element calculation exhibited excellent agreement with the experimental results, indicating its reliability and accuracy. Additionally, the stress field was determined utilizing analytical methods, and the mechanism underlying crack propagation was successfully obtained. Compared to the cement matrix, a stray current led to more sulfates, more microstructure degradation, and greater increases in thickness and porosity in the ITZ, which was considered to be the essence of the stray current-induced ITZ effect.
期刊介绍:
Engineering, an international open-access journal initiated by the Chinese Academy of Engineering (CAE) in 2015, serves as a distinguished platform for disseminating cutting-edge advancements in engineering R&D, sharing major research outputs, and highlighting key achievements worldwide. The journal's objectives encompass reporting progress in engineering science, fostering discussions on hot topics, addressing areas of interest, challenges, and prospects in engineering development, while considering human and environmental well-being and ethics in engineering. It aims to inspire breakthroughs and innovations with profound economic and social significance, propelling them to advanced international standards and transforming them into a new productive force. Ultimately, this endeavor seeks to bring about positive changes globally, benefit humanity, and shape a new future.