Many people look at their parking lot or roads and want to place asphalt to maximize the use and increase property value. What people don’t realize, is there are several different types of asphalt. Below we will list some of the more common ones in use, and where we would recommend they be used. All mixes discussed are talked about without any special restrictions, such as Rap, Air Voids, or Liquid.
13a is a stone-based asphalt. It is a standard mix used for both bases and top courses. It has been used by several cities and counties in their roads and is a good solid all around mix for parking lots. Cost wise it is the lowest, while it holds up over an extended period.
36a is a sand based asphalt the is courser but does turn out smoother. It is used as a top layer of asphalt for walkways and driveways. It is NOT recommended to be used for heavy duty parking lots (lots with a lot of use or heavy truck traffic). This is mix costs on average roughly 5% more but does give a smoother, nicer finish to it because it is made of more “sandier” particles. 36a should NEVER be used as a base grade of asphalt (1st layer of asphalt laid) as it is not durable enough.
3c/4c mixes are used for commercial grade parking lots with lots of heavy truck traffic. Most of the time, these mixtures are laid along with a thicker layer of the mixtures laid. Typically parking lots with 3c/4c mix are laid at no less than 4” thick other parking lots with mixtures above are laid at 3” thick. The 3c mix has been used as a base layer of asphalt in roads also.
Marshall Blend Mixes, which include E mixes and LVSP are newer blends over the past five years.
E mixes are primarily used in roads although some parking lots with 300,000 plus vehicles driving on it per year will use 5E1 as a top layer of asphalt. Cost wise, they are roughly 15% more than a standard 13a mix.
LVSP mixes are the newer replacements for 13a mixes. They are used in parking lots and cost roughly 5% more.
None of these mixes have been around long enough to show that they give better results for increased costs, however, they are what most counties are transitioning to.