Spray Seals for Airports

Where the establishment of a mobile asphalt plant in a remote location and importation of asphalt quality aggregate is not cost-effective, sprayed sealing is often the only viable airport pavement surface. The threat of loose aggregate being ingested into an aircraft engine drives the design and construction of sprayed seals for airports. The successful adaptation of road sealing techniques to airport pavement application requires modifications to the design and construction of the seal. The design requires high application rates of premium binders to resist the high tyre pressures and wheel loads and to hold the aggregate particles tightly bound. Light aggregate spread rates are also required to prevent aggregate particles from being partially held and then coming loose. It is also common to provide a bitumen emulsion-sand overspray over the seal to lock the aggregate in place. Construction issues that require a different approach include steel drum rolling the uppermost layer and increased rolling effort at the time of construction. Airports with such seals that have been accommodating jet aircraft on a regular basis for some years include Ballina-Byron Airport, Gove Airport, Argyle Diamond Mine Airport and the cross runway at Darwin International Airport