EVALUATION OF LONGITUDINAL STEEL IN ILLINOIS CRC PAVEMENTS

A follow-up investigation was made of several CRC pavements constructed within Illinois to determine the extent of corrosion occurring on the longitudinal reinforcement at transverse cracks. The effect of crack width, depth of reinforcement, slab thickness, type of reinforcement, infiltration of water and foreign matter, bond between concrete and steel, and D-cracking were studied to determine their influence on the progression of corrosion. The initial investigation was carried out during 1970. During the present study an analysis was made of 147 cores removed from 12 experimental pavements throughout the State for an intensive study on the behavior of a variety of CRC pavement designs. Of the cores removed from the experimental pavements, 42.2 percent showed no evidence of active steel corrosion, 52.4 percent indicated slight pitting to moderate pitting and 5.4 percent showed advanced rusting with a marked reduction in cross-sectional area or fracture of the reinforcing steel. The findings indicate that steel corrosion has progressed with the passage of time (from 1970 to 1979) but, at this stage, its effect on the pavement performance is minimal and the steel does not appear to be a potential problem with pavements designed in accordance with the present criteria. Of the parameters investigated, crack width and depth of reinforcing steel appear to be the only significant factors influencing the progression of corrosion. (FHWA)