Different Types of Asphalt
Is all asphalt created equally? Kind of. There are a few different commonly used asphalt in Columbus OH. More important than the specific asphalt type is the standard of quality. There are multiple asphalt plants in Central Ohio. Luckily there is also a standard. The ODOT-approved mix is a must. ODOT-approved asphalt is asphalt that has been approved by the Ohio Department of Transportation and has been tested to meet their standards. If a company doesn’t use ODOT-approved asphalt, don’t use them. You are not getting a good product.
What Is In Asphalt?
Asphalt is a combination of three different materials. Sand, AC (Liquid asphalt), & Aggregate. Sometimes RAP (Recycled Asphalt Product) is used as the aggregate but ODOT limits this to 20% of the mix. Asphalt is made of a combination of these materials but there are a few differences with each type of asphalt.
#301 Binder
#301 Asphalt, commonly known as a binder course, is a less refined product. The variation of the aggregate is wider in this mix. The larger stone in the mix makes it have a little rougher finish. This allows for #301 binder to be cheaper than 448 Type 2 or 448 Type 1 asphalts. This doesn't mean it is lower quality. #301 is still an ODOT-approved asphalt. This asphalt is used as a base asphalt. For example, say you are paving 8 inches of asphalt. An example of a scope for this might be 5" of #301 binder, 1 1/2 inches of 448 Type 2, and 1 1/2 inches of 448 Type 1. When building an asphalt parking lot, #301 binder is a useful tool for saving customers money without sacrificing quality.
448 Type 2 - Intermediate Asphalt
448 Type 2 Asphalt is commonly known as intermediate course asphalt. This material is very similar to #301 Binder asphalt. It is slightly more refined than #301 asphalt but less refined than 448 Type 1. #301 & 448 Type 2 asphalt are commonly interchangeable.
448 Type 1 - Surface Asphalt
448 Type 1 is commonly known as surface asphalt or top course asphalt. This asphalt mix design is more refined than #301 Asphalt or 448 Type 2 asphalt. It has more refined aggregate and slightly more sand for a smoother finish.
Asphalt mix designs vary from state to state. These mix designs are typical of ODOT mix designs. If you are in another state besides Ohio, check your local Department of Transportation for your local mix designs. If you have additional questions about asphalt, please feel free to reach out.
