Stone Matrix Asphalt
Stone-matrix asphalt (SMA) is a gap-graded asphalt pavement designed to improve rut resistance and durability through the use of a stable stone-on-stone skeleton held together by a rich mixture of asphalt cement, along with stabilizing agents such as fibers and/or asphalt modifiers. SMA is primarily used to pave high-volume U.S. interstates and highways, achieving high levels of rutting resistance and durability. In addition to improved durability and rutting resistance, SMAs have very good friction characteristics. They have been shown to be effective in reducing road spray and traffic noise. SMAs have also been successfully used on high-volume urban roadways with heavy bus and truck traffic.