What is an Asphalt Road?
An asphalt road is an engineered pavement structure built primarily of Hot Mix Asphalt. Hot Mix Asphalt is the mixing together of quality aggregates (rocks & sand) and asphalt cement (that's the hot, black, sticky stuff) to hold those aggregates together. People commonly use the words "asphalt" and "tar" interchangeably. However, they are not the same and it is important to understand the difference. Tar, is a by-product from the processing of coal and is predominantly used in roofing applications. You'll note the strong odor coming from those operations. Asphalt, is the residual product from the refining of natural petroleum crude oil. A number of products are obtained from a barrel of crude oil. However, after the distillates are removed such as our diesels, kerosene's, and gasoline's, it's the left over asphalt cement that we retain and further refine for use in our Hot Mix Asphalt Pavements. The asphalt is incredibly strong cement, readily adhesive, highly waterproof, and extremely durable. Today's asphalt cements are further refined removing the natural elements that render its fabulous cementing properties and is then put back in a controlled manner. This gives us our "Performance Grade" binders (technical term for asphalt cement) we use today in making our asphalt pavement mixes. What does this mean to the general public? It means the Asphalt Pavements today are engineered with much greater control for consistency in quality and long term performance. It means the pavement will remain stiff in the summer and flexible in the winter for years.
What is Oil and Chip?
This is often referred to as "Chip Seal". A chip seal is a type of surface treatment readily used by smaller townships, counties, and occasionally inner urban applications, to extend the life of an existing, weathered, asphalt pavement. It describes a process in which asphalt is sprayed on the pavement surface and then immediately covered with aggregate chips and rolled. You may have also heard of "Sand Seals" which is basically the same process using sand aggregates. It's economical and provides a waterproof cover.
What are Seal Coats?
A seal coat is a thin asphalt surface treatment using an asphalt material not covered with aggregate. People throughout the industry will still use the term "Seal Coat" when talking about "Chip Seals" so you need to ask specifically what they mean when discussing seal coats. Seal Coats are usually considered a preventative maintenance treatment. It's important to understand that neither, a chip seal or a seal coat, treatment provide for an increase in structural strength in the asphalt pavement. Counties and small townships will use asphalt cement as a method of dust control on rock or gravel roads. After many years of this you'll see where the build-up will actually resemble an "asphalt pavement" and provide a somewhat solid surface for the public. However, it is not and this is one area of public misunderstanding that has formed bad public opinion about the true capabilities of Hot Mix Asphalt Pavements. In other words, just because it's black on top does not mean that its quality Hot Mix Asphalt (HMA).
What is Cold Patching or Cold-Laid Plant Mix?
These are mixes produce in a plant using emulsified or cutback asphalt in order that it can be spread at ambient temperatures. This is material used primarily for emergency road repair (i.e.: pot-hole patching) during the winter/spring months. The cutback or emulsion allows for the material to be stockpiled in the yard and then shoveled into the truck when needed.
What is Blade Mix or Road Mix?
This is the same kind of thing as a cold-laid plant mix except that you mix the aggregates and the cutback or emulsified asphalt on the ground using a road grader or other type of blending equipment.
What is Recycled Asphalt or Recycled Asphalt Pavement (RAP) ?
Recycled asphalt is simply material that has been taken up from an existing asphalt pavement structure. This is done in a number of ways but most commonly is accomplished by the use of a milling machine. The RAP material can then be re-introduced into a new mix as a percent of the aggregate mixture. Hot Mix Asphalt is the most recycled product in America. According to a Federal Highway report, 80.3 Million Tons or 80% of the asphalt pavements removed during resurfacing and/or widening projects each year is recycled. As appose to 3.3 Million Tons of concrete pavements each year. As a matter of fact the amount of Hot Mix Asphalt Pavements recycled each year is 13 times greater than news print and 89 times greater than that of aluminum cans!
