There are a variety of different asphalt compounds available to those looking to replace a road, driveway, or even the pavement for an entire neighborhood, but one particular mix that stands out from the rest is a compound known as stone matrix asphalt. Also called stone mastic asphalt, or simply SMA, this iteration of asphaltic cement was designed in Germany in the 1960s for the purpose of preventing permanent degradations in asphalt-paved roadways. It has since seen a meteoric rise to prominence in the asphalt industry as one of the most wear-resistant compounds available. This article outlines what exactly goes into the production of SMA, as well as a few of the advantages of stone matrix asphalt and a few scenarios where it is most appropriate.
How It's Made
Stone matrix asphalt is manufactured with the same equipment used to manufacture hot-mix asphalt and other common asphalt compounds. The distinction between making other compounds and stone-matrix asphalt, however, concerns the list and proportion of ingredients.
Stone mastic asphalt contains significantly more aggregates in the mix than other asphalt compounds. Specifically, stone matrix asphalt is composed of roughly 80% aggregate, in addition to other fillers, as well as a binder such as bitumen. Excess bitumen concentrations improve the formula's overall flexibility. The aggregate portion of the compound is comprised of large, coarse stones that strengthen the formula after it has cured. Fiber additives are also included for elasticity, and the mix must be maintained at a certain temperature to avoid damaging the fibers, and by extension the integrity of the asphalt.
The primary advantage of stone mastic asphalt is its resistance to wear from heavy traffic. Stone matrix asphalt compounds are extremely resilient to rutting and permanent deformations, i.e., potholes. This makes it a superior choice for heavily traveled stretches of road, be it a highway or a busy downtown boulevard. In fact, studies have shown that stone matrix asphalts wear up to 40% better than hot-mix and warm-mix varieties. The high binder content in SMA mixes also translates to better 'aging' over the life of the road, which also means fewer maintenance calls for high-traffic areas. SMA is also a prime candidate for pavement in colder climates as it holds up very well in cold temperatures relative to other asphalt compounds.
In all, stone matrix asphalt is one of the most wear-resistant types of asphalt paving available and is a great choice for any stretch of roadway that is heavily and frequently traveled. For more information about asphalt paving, contact Lakeridge Paving Company.