Single 6.4 mm (0.25 in.) post-tensioning wires failed in a parking garage in the southern portion of the United States. Several failed wires were removed and the lengths were examined for signs of corrosion using SEM metallography. The scans showed localized shallow pitting, and chloride was detected in some of the pits. The test also revealed an initial crack that was probably caused by hydrogen embrittlement. Since no chloride was detected on the fracture surface, and none was detected in the overlying concrete, the corrosion appears to have begun prior to the wires' placement in the concrete.

Some corrosion processes in the presence of chlorides, for steel embedded in concrete, are described and illustrated with the aid of scanning electron microscope EDXA data. Observations made of failure surfaces of reinforcements removed from the concrete beams after being subjected to sinusoidal load fluctuations at 6.7 Hz in air, 3% NaCl solution, and natural sea water are described. Reinforcement types studied included: hot-rolled mild steel bar, hot-rolled alloyed high strength bar, cold-worked high strength bar, galvanized bar of all these three types, nickel-clad bar and epoxy-coated bar.