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Materials Science at Oregon State University

Chlorides in Concrete: Allowable Limits, Threshold Values, and Corrosion Degradation

Date: Thursday, Jan 26th
Presenter: Prof. David Trejo, OSU Civil and Construction Engineering

Abstract


Chlorides are present in almost all constituent materials used to make concrete. Because these chlorides can result in corrosion of the steel reinforcement, most state highway agencies (SHAs) and specification writing organizations limit the amount of chlorides that can be included in the fresh concrete. This is referred to as the allowable chloride limit, CA. However, a review of current specifications indicate a wide range of published CA limits (in fact, several orders of magnitude difference). These chlorides influence the time to corrosion of the steel reinforcement and can significantly reduce to service life of reinforced concrete structures if present in higher quantities. This presentation will present how chlorides in fresh concrete can influence the time to corrosion, will present challenges and on-going research associated with challenges in current specifications, and will discuss needs and on-going research for developing a methodology for setting CA limits.

Bio:
David Trejo, PhD, PE (CA), is Professor and Hal D. Pritchett Endowed Chair in the School of Civil and Construction Engineering at Oregon State University (OSU). Professor Trejo earned his BS, MS, and PhD from the University of California at Berkeley. He has about 8 years of experience in the construction industry, with several years assessing and managing the development and construction of various infrastructure projects. His research focuses on the design and development of materials and systems for efficient construction, while at the same time being resilient and durable. Dr. Trejo has published over 100 publications and maintains an active research program. His research projects have led to development of new materials, systems, and processes and have included development of new, corrosion resistant and high-strength steels, development of precast overhang systems for safe, rapid, and durable bridge construction, risk assessment and performance modeling of segmental, post-tensioned bridges exhibiting strand corrosion, development of refractory materials for NASA’s launch complex, modeling and performance assessment of glass fiber-reinforced polymer (GFRP) concrete reinforcement for use in bridges, and several others.