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As a leader in highway and municipal road construction backed by more than 70 years of experience, our primary focus for large infrastructure projects is sustainability. Asphalt pavement is 100% recyclable and reusable. When existing roads are milled, screened and recycled at one of our three Central Virginia plants, not only are we saving fuel and cutting emissions, but our new roadways offer the potential for superior performance and a longer road-life span. And we give the same care and attention to large infrastructure projects as we do to our small intricate projects.













Traffic patterns

Effects on existing traffic flow

High percentages of recycled asphalt per ton


Maintenance and durability

Base preparation and structural integrity

Shoulders and lateral support

Water drainage and longevity

Surface options and processes

Extensive project management





In addition to plant mix asphalt pavement or black top, there is another type of pavement performed by S.L.Williamson Co. called Surface Treatment, also known as “tar and chip” or “chipseal.” This type of road surface is used by VDOT on secondary roads that do not have a high traffic volume. Surface treatment is installed by spraying liquid asphalt from a distributor truck on a prepared stone base, covering the liquid asphalt with a layer of crushed aggregate and compacting it with a roller. This is usually done in 2 layers (prime and seal) or 3 layers (prime and double seal). The color and texture of the final surface is determined by the aggregate used on the final two seals.

Aggregate color varies according to its source (i.e. type of rock – granite (grey), basalt (green), and crushed river gravel (light brown). Surface treatment has a “float” of loose gravel on the surface that some think offers a more “rural” and less “urban” feel to the surface. The initial cost is a little less than plant mix. However, the long-term costs are higher as it has to be repeated more frequently — it is about .5 inches thick versus plant mix, which is 2 inches thick. With the decreased thickness compared to plant mix, this surface option is less durable.


RED HILL PLANT    (434) 293-6934

2617 Redhill Road, North Garden, VA 22959

SHADWELL PLANT    (434) 295-4517

2905 Richmond Road, Charlottesville, VA 22902

RUCKERSVILLE PLANT    (434) 985-3394

221 Luckstone Road, Ruckersville, VA 22968

All FOB customers, please contact Deming Massie for material availability, or call (434) 295-6137.

There are a number of types of plant mix produced in each of our plants. The main difference in the types is the maximum size of the largest aggregate in the plant mix, and the various types have specific uses. The sizes and primary uses are as follows:

  • BM-25.0 – This VDOT classification is plant mix that is used for a base course. The designation stands for Base Mix with a maximum size aggregate of 25 millimeters. This type of base asphalt is typically used on highways, streets or areas used by heavy commercial traffic. Base asphalt is covered with Intermediate and Surface plant mix or Surface plant mix alone, depending on the pavement design, which is dictated by the expected traffic load.

  • IM-19.0A or D - This VDOT classification is plant mix that is used for an intermediate course. The designation stands for Intermediate Mix with a maximum size aggregate of 19 millimeters.

  • SM-12.5A or D - This VDOT classification is plant mix that is used for a surface course on a high traffic volume highway . The designation stands for Surface Mix with a maximum size aggregate of 12.5 millimeters. This mix has a slightly rough surface texture. 

  • SM-9.5A or D - This VDOT classification is plant mix that is used for a surface course on most highways, city streets, commercial parking lots and driveways. The SM designation stands for Surface Mix with a maximum size aggregate of 9.5 millimeters. The surface texture is smooth and non-porous.


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