This report presents results of a series of nondestructive tests to estimate the strength of concrete in a twenty-year-old prestressed bridge girder removed from an interstate overpass. Nondestructive test results were compared with compressive strength tests of cores. In addition, chloride ion concentration of the concrete was analyzed to determine whether corrosion of the bridge reinforcing steel may have occurred. Nondestructive tests included rebound hammer, pulse velocity, Windsor probe, and break-off tests. Included is a review of commonly encountered strength correlations for each of the tests. Of the nondestructive tests, the rebound hammer and pulse velocity tests predicted concrete strength reasonably well with existing correlations. With one major exception, results from chloride ion tests indicated that sections of the bridge with greater exposure to deicing salts had a greater amount of chloride penetration. The exception was a facia girder exposed to incoming traffic. Rain may have had a beneficial effect by washing salt residue from the facia girder. Chloride ion penetration at the leveI of the reinforcing steel for the bridge girders tested was not found to be great enough to expect corrosion.
