The ACCI undertook a three-year research program sponsored by the Sydney Harbour Tunnel (SHT) Holdings Ltd on corrosion of steel reinforcement in concrete in marine environments. This program has been extended for another twelve months with additional financial support from the SHT.

This research investigates the micro-cell and macro-cell mechanisms and the rate of reinforcement corrosion in concrete crack zones in seawater. From the initial findings, the crack width was found to have insignificant influences on the macro-cell corrosion rate in the crack zone, and the phenomenon of corrosion spreading away from the crack zone was identified probably for the first time with electrochemical evidence. Research is also in progress on the microcell corrosion rate of reinforcement in concrete in seawater, which is found to be very different to steel without concrete cover in seawater.

Several papers have been published from this research and further information is available by contacting Z.T. Chang at the ACCI (02 9385 0408).