As described in the final report, this study developed and evaluated in the laboratory a multi-parameter corrosion monitoring system for existing reinforced concrete structures in chloride-laden service environments. The study improved and validated the SwRI corrosion sensor prototype for use in the concrete corrosion monitoring system; developed algorithms for quality control and interpretation of the sensor data; made viable recommendations to implement the corrosion monitoring system for existing DOT inventories of RC bridges; and delivered a deployable prototype corrosion sensing system for DOTs to continue field evaluations. The performance and reliability of the SwRI corrosion sensor were confirmed by the benchmark test in simulated concrete pore solutions. However, once active corrosion is initiated and a great amount of chloride is present, the multi-electrode array sensor (MAS) probe may no longer serve as a good tool to predict the corrosion rate of rebar unless more research is conducted to establish such prediction or correlation. The performance and reliability of the SwRI corrosion sensor were also confirmed by embedding it in a paste specimen, while some issues with firmware and possibly graphite reference probe were identified. While more research is needed, the paste specimen test also imply that the MAS probes, Cl probes and pH probes all have great potential to work properly under a reasonably low electric field.
For reinforced concrete (RC) structures, reinforcement corrosion induced by chloride contamination is a leading cause of structural damage and premature degradation. Concern is the greatest in coastal and northern states where these structures are exposed to marine environments or deicing salts respectively, such as in the State of Oregon. Currently, ODOT conducts labor-intensive corrosion surveys of its coastal bridges to determine the timing and type of remedial action required for them. There are limited sensor options that can be effectively deployed on older, existing structures to monitor, detect and diagnose corrosion. The goal of this research is to develop a reliable, cost-effective corrosion monitoring system for existing ODOT RC structures. To this end, specific research objectives include: 1) improving and validating a corrosion sensor prototype for use in the concrete corrosion monitoring system; 2) developing algorithms for quality control and interpretation of the sensor data; 3) making viable recommendations to implement the corrosion monitoring system for existing ODOT inventory of reinforced concrete bridges; and 4) delivering a deployable prototype corrosion sensing system for ODOT to continue the field evaluation. The corrosion monitoring system is expected to include an integrated sensor that can be easily embedded into existing RC structures and conduct continuous monitoring, a web-based wireless data communication and acquisition system, and a software program that analyzes the sensor data for quality control and risk assessment purposes.
The objective of this research is to develop a deployable, prototype corrosion sensing system for existing ODOT reinforced concrete structures.
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