Investigations of accelerated methods for determination of chloride threshold values for reinforcement corrosion in concrete

ABSTRACT

Testing the critical chloride content (C_crit) in laboratory samples or in samples retrieved from structures enhances the understanding of rebar corrosion initiation in concrete and can result in a significant improvement of predicting the residual service life of ageing structures. A possible drawback of test methods for C_crit is that they can be time-consuming. In this work, different accelerated methods for C_crit testing are studied and compared. It is found that the acceleration method influences the test results. The results are discussed with respect to evaluation of existing structures and service life modelling.

KEYWORDS:

• Chloride-induced corrosion
• reinforced concrete
• critical chloride content
• migration
• diffusion
• capillary suction
• acceleration
• test method

Acknowledgments

The authors want to express their sincere appreciation to the Federal Road Administration of Switzerland for the funding parts of this project. For their enthusiasm during the experimental work, the authors want to thank Nicole Felder and Benjamin Weber.

Furthermore, the experimental work at DTI was carried out with much appreciated financial support from the Danish Agency for Institutions and Educational Grants.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Bundesamt für Strassen; Danish Agency for Institutions and Educational Grants.

Notes on contributors

Carolina Boschmann Käthler

Carolina Boschmann Käthler obtained her MSc in civil engineering and PhD at the ETH Zurich (Switzerland). The PhD project comprises different aspects of chloride-induced reinforcement corrosion, including initiation mechanisms, testing methods, and application to engineering structures. Her research interests are mainly the effect of cracks on reinforcement corrosion, the chloride-induced corrosion initiation, and the influence on service life modelling.

Søren L. Poulsen

Søren Lundsted Poulsen is a consultant at the Concrete Centre at Danish Technological Institute, Denmark. He received his MSc degree in geology and PhD degree in natural sciences from Aarhus University, Denmark. His main research interests lie within concrete durability, especially issues related to chloride-induced corrosion initiation and modelling of service life for reinforced concrete structures.

Henrik E. Sørensen

Henrik Erndahl Sørensen is product manager at the Concrete Centre at Danish Technological Institute, Denmark. Henrik received his MSc in Chemical Engineering followed by a PhD in Chloride Penetration into Concrete from the Technical University of Denmark. His research interests and major work fields are durability of concrete structures with extended competences in chloride ingress, reinforcement corrosion, monitoring, field exposure stations, condition assessment, non-destructive testing and modelling.

Ueli M. Angst

Ueli Michael Angst is an assistant professor at the Department of Civil, Environmental and Geomatic Engineering at ETH Zurich, Switzerland. He received his degrees in civil engineering from ETH Zurich (MSc degree) and the Norwegian University of Science and Technology, Trondheim, Norway (PhD degree). His research interests include all aspects related to corrosion and durability of metal-based infrastructures, including sensors, monitoring, NDT, predictive modeling, and corrosion protection methods.