What is stone mastic asphalt (SMA)?
Stone mastic asphalt (SMA) is a gap-graded asphalt mix composed of coarse aggregate, filler, and high binder content, designed to resist rutting and deformation under heavy traffic loads.
Stone mastic asphalt uses a skeleton of stone particles held together by a thick binder film, rather than filling all voids with smaller particles as standard asphalt does. This structure creates a material that resists permanent deformation, particularly rutting caused by repeated wheel loads in commercial areas, car parks, and heavily used access roads.
The mix typically contains a high proportion of coarse aggregate, lime filler, and bitumen binder. This composition allows the asphalt to handle compressive stress without sinking or forming ruts, making it especially suitable for:
- Commercial and industrial car parks
- High-traffic delivery and turning areas
- Bus routes and public access surfaces
- Busy forecourts and hard standings
SMA wears more slowly than conventional asphalt under sustained heavy loads, extending the interval between resurfacing and reducing long-term maintenance costs for car park operators and fleet-intensive businesses. The material also provides good surface grip when properly laid.
Installation requires specialist knowledge to achieve correct density and binder distribution. If you need SMA surfacing for a commercial site in Cheltenham, contact commercial paving providers who have experience with this specification.