Selecting a Good Asphalt Driveway

Asphalt Driveways

Asphalt is a popular surfacing material for roads, parking lots, highways and walking trails. Your driveway is a valuable part of your home and what your visitors, friends, neighbors and family see everyday. Driveway appeal or “curb appeal” can enhance the value of your home and provide a greater resell value. As a homeowner paying close attention and knowing the process asphalt driveway development will allow you to ask pertinent questions to your contractor.

Newly constructed asphalt pavements have a rich, oily, black color from the liquid asphalt cement (binder).

In the early stage, applying a seal coat within 90 days to 365 days from the installation date will prevent future cracking and ensure long-term performance of your driveway, including saving 50-60% of your investment.

What is the Asphalt Paving Process for Driveways?

Asphalt is poured on your driveway, compacted using a heavy rolling machine and subsequently cooled. This process creates the your curb driveway. The asphalt mix poured onto your driveway arrives as Hot Mix Asphalt (HMA) and is manufactured at an offsite asphalt facility. The Hot Mix Asphalt (HMA) is made from a combination of roughly 95% aggregates (various stones, sand, gravel) and binded or fused together using 5% liquid asphalt cement. A dump truck delivered the HMA (Hot Mix Asphalt) to a paving machine, where a hopper consistently surfaces the HMA onto your driveway.

Asphalt comes in different grades, such as softer asphalts used in colder climates and harder asphalts used in warmer climates.

What is my Driveway Asphalt Made Of?

Asphalt is made from a combination of liquid asphalt cement (the binder) and aggregates (crushed rocks, sand, gravel).

What is a Binder or Liquid Asphalt Cement?

Liquid asphalt cement (a petroleum product) is the glue (binder) that holds the aggregates (various types of crushed rocks, gravel, sand) together and functions as a scaffold and strength for the hot asphalt mix (HMA).

Why Are Binders Important?

When speaking with your driveway pavement contractor, selecting a high-quality asphalt binder is the key factor in a solid driveway. From 1987 to 1992, the US invested $50 million into the Strategic Highway Research Program (SHRP) to develop the most advanced asphalt binder grading system. The Performance Graded (PG) System was borne out of this effort.

The PG grading system focuses on asphalt binder properties being determined by expected climatic conditions as well as time and aging considerations. The PG system uses various tests to measure the physical properties of the binder related to their performance in extreme temperatures and time.

Asphalt binders that are used in different regions must pass certain tests at specific temperatures and climates. For example binders used in the Sonoran Desert of California/Arizona/Mexico would have different properties than one used in the Alaskan tundra.

What are Aggregates?

In a simple sense, aggregates are crushed and screened rocks and fines. Aggregate rocks range from granite and sandstone to river gravel. Aggregates are screened for size, surface texture (coarse or fine), and angularity (rounded or fractured faces). Longer or rounded fine aggregate rocks are avoided since they do not provide the durability and can lead to HMA (Hot Mix Asphalt) rutting. Particles in various sizes utilizing coarse and fine aggregate angularity* (FAA) provide the best strength and durability for your driveway. The hardest and most angular are used for the top layer or surface. Using aggregates with multiple fractured faces creates optimal friction and skid resistance for your pavement.