Review of stone mastic asphalt as a high-performance ungrooved runway surfacing

Abstract

Australian runways are typically surfaced with grooved Marshall-designed dense graded asphalt (DGA). Grooving is undertaken to avoid aircraft skidding incidents during wet weather, as well as satisfying regulatory requirements. Closure of these grooves is a common distress at Australian airports and increases the risk of aircraft hydroplaning. However, there are alternative surface materials to grooved DGA that are employed internationally on runways. Of these, stone mastic asphalt (SMA) has demonstrated comparable or better performance characteristics than DGA, and can satisfy regulated surface texture requirements without the need for grooving. Locally, SMA has been implemented successfully for heavy-duty roads, but use as an airport surface in Australia has been limited, with only two trials undertaken on taxiways and aprons. Further research is required to develop an SMA specification, based on experience on Australian roads, and the international experience on airfields. Verification is also required to confirm that SMA mixtures achieve the Australian airport asphalt performance requirements, as well as the regulated surface texture limits, to confirm suitability as an ungrooved runway surface for Australian airports.