Rehabilitation of salt-damaged surfacings with asphalt and crushed stone overlays

Whilst the blistering and cracking of bituminous surfacings damaged by salt crystallization is now rare in southern Africa, it still occurs, and its successful rehabilitation remains difficult. The rehabilitation of severely salt-damaged bituminous surfacings with conventional reseals and thin asphalt overlays has invariably been unsuccessful. This paper describes initial experiments with asphalt overlays on a parking ground and subsequent experience with asphalt on one street, removal and replacement with thick asphalt on one freeway, asphalt overlays on one road and one airport, and with a crushed stone overlay on one road. It is concluded that overlays of asphalt or crushed stone are not cost-effective methods of rehabilitating salt damage if this was their sole purpose, and that even thick overlays are unlikely to be totally successful. Although the damage in all cases was unsightly and alarming, and led eventually to expensive remedial measures, all the pavements carried traffic successfully without any base failures, even in their damaged states.