The short answer is no. There are different types of asphalt for different purposes and applications. The “mix designs” of asphalt vary from state to state. Each state department of transportation has a standardized specification for different grades of asphalt material. “Surface” asphalt mix from Ohio will be different from “surface” asphalt from Michigan. What is common is that all asphalt “mix designs” fall into three categories: base asphalt, intermediate asphalt and surface asphalt.
“Base asphalt” is typically made with larger stone and has less sand
in the mix designs. The asphalt cement (tar), that binds the material
together, is used in smaller quantities. When the “Base asphalt” is
installed, the surface has a rougher finish to it and is more porous.
“Base asphalt” is typically cheaper than the other two types of material
and is used for projects that require several layers of asphalt.
“Intermediate asphalt” is still made with a larger stone but more
sand and asphalt cement is added to the mix design. The finish texture
is smoother than “Base asphalt” and denser. This type of asphalt is also
used for projects with several layers of asphalt is required. The cost
is more than “base asphalt” but still less than “surface asphalt”.
The final type of asphalt is “surface mix”. This is the finish layer
you see on streets, parking lots, and driveways. This type of material
has smaller stone with the most sand and asphalt cement. This mix
design has the smoothest finish to the surface and looks the best.
Typically, the “surface asphalt” used in streets is the same as what is
used in driveways. This is the most expensive of the three types of
material because of the added asphalt cement used.
That concludes the class today. Test will be next week.