Nondestructive Evaluation of Fiberglass Wrapped Concrete Bridge Columns

Many in-service concrete bridge decks and columns built before the advent of epoxy coated bars show cracking and spalling of the concrete due to corrosion of the steel reinforcement. In cold regions, the corrosion rate of concrete bridge decks and columns is accelerated by the use of deicing solutions in winter. The corrosion of the steel rebars causes cracking, delamination, and spalling of reinforced concrete structures and increases the cost of rehabilitation and maintenance operations. In Wisconsin (USA), fiberglass wrapping has been used for corrosion protection of reinforced concrete columns. In this methodology, a fiberglass wrap is placed as a barrier between the concrete surface and the surrounding environment and is expected to reduce the detrimental effect of traffic splashing of deicing solutions. This paper describes a study aimed at evaluating the effectiveness of fiberglass wrapping in controlling and reducing the rate of corrosion in bridge concrete columns. Field tests included nondestructive wave propagation and half-cell potential methods. Nondestructive evaluation results were examined and compared to chloride ion (Cl⁻) intrusion measurements. The data show that fiberglass wrapping helps in arresting the chloride ion ingress to the columns, however, it does not help reduce corrosion rates in chloride contaminated concrete columns.