Corrosion-induced deterioration assessment at steel-concrete interface based on hoop strains measured with distributed fiber optic sensors

Liang Fan, Yi Bao, Genda Chen

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

In this study, distributed fiber optic sensors are applied to measure the hoop strain at the interface of a reinforcing bar and its surrounding concrete due to the expansion of steel corrosion products. The measured strain distributions are used to assess the deterioration condition of the steelconcrete interface. An optical fiber was spirally winded on a steel bar with a 10-mm spacing. The steel bar was embedded in a concrete beam measuring 140 mm × 70 mm × 70 mm. After cured in lime-saturated water for 28 days, the reinforced concrete beam was immersed in 3.5 wt.% NaCl solution for accelerated corrosion under a current density of 500 μA/cm2. While the steel mass loss was determined from the current density based on the Faraday s law, the hoop strain due to the expansion of corrosion products was simultaneously measured from the distributed fiber optic sensor. The time history of the hoop strain shows three stages. In Stage 1, steel corrosion initiated and generated limited corrosion products that filled surrounding pores in the concrete, resulting in very small hoop strains. In Stage 2, corrosion products encapsulated the bar surface and increased the hoop strain. In Stage 3, concrete cracks appeared due to excessive expansion of the corrosion products, and more oxygen and electrolyte were provided for severe corrosion with a dramatic increase of the hoop strains. The measured hoop strains are used to monitor the corrosion condition of steel bars embedded in the concrete.

Original languageEnglish
Title of host publication9th International Conference on Structural Health Monitoring of Intelligent Infrastructure
Subtitle of host publicationTransferring Research into Practice, SHMII 2019 - Conference Proceedings
EditorsGenda Chen, Sreenivas Alampalli
Pages1360-1365
Number of pages6
ISBN (Electronic)9780000000002
StatePublished - 2019
Event9th International Conference on Structural Health Monitoring of Intelligent Infrastructure: Transferring Research into Practice, SHMII 2019 - St. Louis, United States
Duration: 4 Aug 20197 Aug 2019

Publication series

Name9th International Conference on Structural Health Monitoring of Intelligent Infrastructure: Transferring Research into Practice, SHMII 2019 - Conference Proceedings
Volume2

Conference

Conference9th International Conference on Structural Health Monitoring of Intelligent Infrastructure: Transferring Research into Practice, SHMII 2019
Country/TerritoryUnited States
CitySt. Louis
Period4/08/197/08/19

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