Migration and formation of an iron rich layer during acidic corrosion of concrete with no steel reinforcement

dc.contributor.authorTaheri, Sen_AU
dc.contributor.authorGiri, Pen_AU
dc.contributor.authorAms, Men_AU
dc.contributor.authorBevitt, JJen_AU
dc.contributor.authorBustamante, Hen_AU
dc.contributor.authorMadadi, Men_AU
dc.contributor.authorKuen, Ten_AU
dc.contributor.authorGonzalez, Jen_AU
dc.contributor.authorVorreiter, Len_AU
dc.contributor.authorWithford, Men_AU
dc.contributor.authorClark, SMen_AU
dc.date.accessioned2024-10-03T06:34:35Zen_AU
dc.date.available2024-10-03T06:34:35Zen_AU
dc.date.issued2021-11-22en_AU
dc.date.statistics2024-10-03en_AU
dc.description.abstractThe present study aimed to study the formation, enrichment, and relocation of iron-rich regions in the corroded area of concrete blocks, made without rebar, subjected to severely corrosive highly acidic conditions. In this work, three different concrete mix designs (a proprietary ready-mixed concrete, and laboratory made mortar and concrete) were corroded under induced accelerated conditions in sulfuric acid solutions at pH 1 for a duration of one to six months, in the absence of reinforcement (i.e. rebar) or iron-oxidizing bacteria. A variety of physicochemical and mechanical techniques were applied to monitor and assess the corrosion progress, and physical and chemical changes in the corroded samples. Results indicated a pronounced presence of iron rich layer (iron oxide/hydroxide) at the border of the corrosion front and the transition zone in all mix designs in the form of a ring. While existing papers in the literature describe the iron coming from the rebar, the only source of mobile iron in this experiment was from the iron oxide (Fe2O3) already in the cement. This zone (in a form of a ring) had an average iron content of 2.0 wt% and moved away from the surface to the center of the samples submerged in a sulfuric acid bath with the increase of immersion time, and it was accompanied by hairline cracks. The movement of this zone was in the same direction as sulfate (from acidic media) ingress and the opposite direction of calcium ion leaching, (Ca leaching). The rate of corrosion, the hardness and the compressive strength of concrete are mostly affected by the concrete mix design, the iron-ring enrichment and relocation had no significant impact on them. Detection of the iron-rich zone is an indication of the depth of corrosion at advanced stages in concrete products. © 2021 Elsevier Ltden_AU
dc.description.sponsorshipThis work was carried out as part of an ARC Linkage (LP160100576) between Sydney Water, Melbourne Water, and Macquarie University. ST would also like to thank Macquarie University for a Macquarie University Research Fellowship (MQRF2018). The Australian Centre for Neutron Scattering at ANSTO, Lucas Heights, is acknowledged for provision of neutron beam time and use of the neutron instrument, DINGO (ANSTO ACNS grant 7388). We thank Professor Bijan Samali, Robert Marshall, and Ali Ghari Zadeh for access to the Structural research and testing laboratory facilities at Western Sydney University. Dr. Chandani Tennakoon from the Independent Cement & Lime is acknowledged for providing cement and concrete material test certificate. We also thank Professor Marjorie Valix, Hee-Chan Jang and William Hadinata Lie from The University of Sydney for providing access to their ICP-AES equipment and helping us collecting data. We thank Mark Tran and Dr. Chao Shen of the Department of Molecular Sciences, Macquarie University, for access to FTIR and SEM facilities and Mr Vahik Avakian from School of Engineering, for access to UTM and microindentation facilities. We thank Dr. Timothy Murphy, Dr. Sean Murray and Manal Bebbington from the Macquarie University GeoAnalytical Unit for their technical support. This work was performed in-part at the OptoFab node of the Australian National Fabrication Facility, utilizing NCRIS and NSW state government funding.en_AU
dc.identifier.articlenumber125105en_AU
dc.identifier.citationTaheri, S., Giri, P., Ams, M., Bevitt, J. J., Bustamante, H., Madadi, M., Kuen, T., Gonzalez, J., Vorreiter, L., Withford, M., & Clark, S. M. (2021). Migration and formation of an iron rich layer during acidic corrosion of concrete with no steel reinforcement. Construction and Building Materials, 309, 125105. doi:10.1016/j.conbuildmat.2021.125105en_AU
dc.identifier.issn0950-0618en_AU
dc.identifier.journaltitleConstruction and Building Materialsen_AU
dc.identifier.urihttp://dx.doi.org/10.1016/j.conbuildmat.2021.125105en_AU
dc.identifier.urihttps://apo.ansto.gov.au/handle/10238/15706en_AU
dc.identifier.volume309en_AU
dc.languageEnglishen_AU
dc.language.isoenen_AU
dc.publisherElsevieren_AU
dc.subjectConcretesen_AU
dc.subjectCorrosionen_AU
dc.subjectIronen_AU
dc.subjectSewageen_AU
dc.subjectSulfuric aciden_AU
dc.subjectExperiment resultsen_AU
dc.subjectBacteriaen_AU
dc.subjectLeachingen_AU
dc.titleMigration and formation of an iron rich layer during acidic corrosion of concrete with no steel reinforcementen_AU
dc.typeJournal Articleen_AU
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