Spray sealing practice in South Africa

Approximately 80 per cent of South Africa’s surfaced national and provincial road network is covered with a sprayed seal surface, either as the initial surfacing or as a reseal. The sustained significant increase in traffic volumes and traffic loading experienced over the last decade or more has necessitated the increasing use of modified binders and alternative seal types in order to extend the operational limits for such surfacings. This paper will provide an overview of the various seal types used under varying traffic and environmental conditions, the parameters used in the design process, the various component materials and practices used to construct seals.