Stone matrix asphalt (SMA) is a gap-graded mix with a high concentration of coarse aggregate which maximizes stone-on-stone contact in the mix and provides for excellent friction characteristics and a very strong pavementlayer that is highly resistant to rutting deformation. The coarse aggregate particles are bound by a thick film of a rich matrix of mineral filler,fibers, and polymerized asphalt that provides for a longer service life by increasing mix durability and fatigue life. SMA has proven very successful in Europe since the 1960s. United States asphalt professionals were first introduced to the mix on a European Asphalt Study Tour in 1990. The first projects in the US were constructed in 1991. Since then, many states inthe US have been using SMA very successfully. In the last 10 years, many civilian airport runways in Europe and over 10 civilian airport runways inChina have used this material with excellent results. USAF experience with SMA began with a test section placed at RAF Lakenheath in 1995. This test section performed remarkably well under aircraft with very high tire pressures, over 300psi. In 1999, SMA (with no grooves) was utilized on the wearing course of the Aviano AB, Italy runway. This runway is providing excellent service to fighters and medium/heavy cargo aircraft. The last inspection, in Sep 2006, shows no rutting deformation or cracking, and its surface is still providing good friction characteristics. Based on the success with the Aviano runway, HQ USAFE used SMA to resurface the Spangdahlem AB,Germany runway in Jun/July 2007. For the covering abstract see ITRD E139491.
Samenvatting