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Forensic analysis of outdoor exposed legacy samples undergoing corrosion propagation
December 3, 2024 @ 11:30 am - 12:30 pm
Presentation
Forensic analysis of outdoor exposed legacy samples undergoing corrosion propagation
Forensic analysis was performed on outdoor samples that showed cracks. One or more rebars were removed from the selected samples. The outdoor samples have been exposed to seawater wet/dry cycles since 1994. In some cases, the three top rebars were removed, in other cases only one rebar or two rebars were removed. The surface condition upon rebar exposure was recorded by photographing the sample, then the rebars were cleaned by sandblasting the rebars with walnut sand. The cross-section loss as a function of length was measured by using a caliper with conical tip. The pitting factor was calculated using only the sections that showed corrosion, i.e., the non-corroding sections were not included to calculate the average section loss. The percentage average mass loss (η) values were estimated by using the mass of the rebar section rebar embedded with respect to the mass a non-corroding rebar of the same length. The location of the corroding section was not always at the center, in some cases multiple sections were found to be corroding. In some instances, a large corrosion spot (likely by coalescing several smaller ones) was observed. Electrochemical measurements were performed, and typically a set of measurements was performed prior to terminating a rebar. Correlations of rebar potential vs. η, corrosion current density vs. η and resistivity vs. η were prepared and included in here. There is quite a bit of scatter on these three plots suggesting that some rebars had been corroding for a longer time.
Speaker
Francisco J. Presuel-Moreno, PhD
Florida Atlantic University
Dr. Francisco J. Presuel-Moreno is a professor in the Ocean and Mechanical Engineering department at Florida Atlantic University. Dr. Presuel received his PhD from University of South Florida. Dr. Presuel has been conducting research related to concrete durability and topics related to corrosion of reinforcing steel embedded in concrete for 30 years.