Asphalt 101: How Much Do You Need & What Type to Use?
Asphalt 101: A Guide to Your Paving Project
Whether you're a seasoned road builder or a homeowner planning a new driveway, understanding the material you're working with is the key to success. Asphalt—also known as blacktop, bitumen, or Tarmac—is a versatile and durable choice, but planning a project requires more than just a plan. You need to know how much to order and which type is right for the job.
This guide will walk you through the essentials of asphalt, turning your project plan into a confident purchase order.
First Things First: Calculating How Much Asphalt You Need
The most common question we hear is, "How much blacktop do I need?". The answer depends on your project's area (length and width) and the desired thickness (depth).
The process is straightforward:
- Calculate the Volume: First, you determine the total volume of the space you need to fill. The formula is
Length × Width × Depth. - Convert to Weight: Next, you multiply that volume by the standard density of asphalt (around 145 lbs per cubic foot) to find the total weight in pounds.
- Convert to Tons: Finally, since asphalt is sold by the ton, you divide the total pounds by 2,000.
While it's good to know the math, doing it by hand is unnecessary. Our free tool handles all the conversions for you instantly.
>> Get an Instant Tonnage Estimate with Our Free Asphalt Calculator <<
Pro Tip: It's a wise industry practice to order 5-10% more asphalt than your calculation suggests. This small buffer accounts for any unevenness in the sub-grade and prevents the costly problem of running out of material before the job is done. If our calculator suggests 10 tons, ordering 10.5 tons is a safe bet.
Asphalt Basics & Why It's Used Everywhere
Asphalt is a sticky, black, and highly viscous petroleum product. In construction, it's rarely used alone. Instead, it acts as a binder that is mixed with aggregates like gravel, sand, and crushed rock to create asphalt concrete. Its popularity for paving projects isn't an accident; it offers several key benefits:
- Durability: It creates a strong, resilient surface that can withstand heavy traffic and harsh weather for 20+ years with proper maintenance.
- Water Resistance: Asphalt is excellent at repelling water, which is why it's used for everything from roads to roofing and pipe coatings.
- Recyclability: Asphalt is one of the most recycled materials in the United States. Old pavement can be reclaimed and reused, offering significant environmental and cost savings.
- Safety & Comfort: It provides a smooth, quiet ride with high traction and low glare.
Not All Blacktop is the Same: Common Types of Asphalt
Choosing the right type of asphalt is crucial, as each is designed for different conditions and climates. The main difference lies in the temperature at which it's produced.
Hot Mix Asphalt (HMA)
This is the most common type used for paving in North America. The asphalt binder is heated to high temperatures (around 300°F / 150°C) to make it fluid for mixing and application. HMA creates a strong, dense, and weather-resistant surface ideal for everything from major highways to residential driveways. The density used in our calculator most closely matches this type.
Warm Mix Asphalt (WMA)
As the name suggests, WMA is produced and applied at lower temperatures than HMA. This reduces fuel consumption and emissions during production, making it a more environmentally friendly choice. It's an excellent option for paving in cooler weather or for overnight projects where faster cooling times are needed.
Driveway Mix / Cold Patch Asphalt
This mix is often designed for smaller-scale projects or repairs. Cold patch asphalt can be applied directly from the bag without any heating, making it perfect for filling potholes or patching small areas. While it's convenient, it is not as durable as a hot-mix application for a full surface.
Porous Asphalt
This specialized mix is designed with fewer fine particles, allowing water to drain directly through the pavement into a stone bed below. This eliminates the need for separate drainage systems and reduces stormwater runoff. It's a more expensive but highly effective solution for environmentally sensitive areas.
A Note on Units: Ton vs. Tonne
In the world of construction, precision matters.
- A Ton (or Short Ton) is an imperial unit used primarily in the U.S., equal to 2,000 pounds.
- A Tonne (or Metric Ton) is used by most of the world and is equal to 1,000 kilograms (approximately 2,204.6 pounds).
Our calculator works in Tons (U.S.), which is the standard for purchasing materials from American suppliers. Always confirm which unit your supplier is using to avoid confusion.
Now, with a solid understanding of the material and the right calculations in hand, you're ready to tackle your paving project with confidence.