Laboratory and field performance comparison of dense graded and stone mastic asphalt as a runway surface

Abstract

ABSTRACT Ungrooved stone mastic asphalt (SMA) provides an alternate to grooved dense graded asphalt (DGA) as a runway surface. To be verified as suitable in this application, SMA must provide similar or better asphalt surface performance, compared to DGA, and must achieve regulated aircraft skid resistance requirements. A pilot runway resurfacing project provided the basis for this laboratory and field comparison of ungrooved SMA to grooved DGA as a runway surface. Laboratory performance testing demonstrated adequate and comparable deformation, fatigue and moisture resistance of SMA, while the quality assurance records indicated acceptable asphalt production. The construction records indicated that SMA had a lower air void content in the compacted layer, which can only provide a more durable surface. Most importantly, the aircraft skid resistance of SMA exceeded that of grooved DGA, based on surface macro-texture and wet friction measurements. It was concluded that SMA performed equal to or better than DGA, particularly with regard to surface texture and wet friction and it is recommended that airports consider ungrooved SMA as a runway surface in the future. The demonstration project should also be monitored in the future, to verify the long-term performance of SMA, compared to the DGA.