New approach needed for forecasting corrosion within bridges, concrete structures

The most common cause of degradation and failures of reinforced concrete structures is chloride-induced corrosion of its embedded steel. This is an urgent problem that requires immediate attention.

All existing models to forecast the performance of reinforced concrete structures exposed to chloride environments are based on an underlying concept of a chloride threshold.

Researchers from Switzerland, the United States, Canada, and Norway advocate for a paradigm change in the science of forecasting damage to reinforced concrete structures.

The international group of scientists met and discussed the flaws in using the chloride threshold concept for forecasting corrosive gasses. Changing is needed to address the growing challenges of aging structures losing function and potentially collapsing, greenhouse gas emissions, and the economy at large.

TheCorrosion of steel within concrete is a complex phenomenon.

When exposed to salts, such as seawater or road salts, the concrete can become porous and the chloride ion can reach the steel. At some point, the protective passive layer will be destroyed. Depending on the exposure conditions, it can be a faster or slower process.

Steel corrosion within concrete is a process that is rarely separable into phases. The researchers say the focus should be on the time and space-variant rate from the moment steel is placed within concrete until it reaches the end of its service life.

A multiscale, multidisciplinary approach is needed to achieve this. Scientific research should evolve away from the chloride threshold concept.

Despite huge amounts of research, no clear threshold could be found, and the influencing factors are complex.

More information: Beyond the chloride threshold concept for predicting corrosion of steel in concrete, Applied Physics Reviews (2022). aip.scitation.org/doi/10.1063/5.0076320 Journal information: Applied Physics Reviews Citation: New approach needed for forecasting corrosion within bridges, concrete structures (2022, March 29) retrieved 29 March 2022 from https://phys.org/news/2022-03-approach-corrosion-bridges-concrete.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.