Asphalt is everywhere in Raleigh: asphalt driveways, asphalt streets, asphalt shingle roofs… Asphalt is one of the most common building materials, but many people don’t know or misunderstand where it comes from. So, let’s take a minute to look at where asphalt comes from, the liquid asphalt, and how it becomes a solid building material
I. What is liquid asphalt?
The term ‘liquid asphalt’ is often used in the industry, and among asphalt paving companies, which can be a bit confusing. Liquid asphalt is more properly called bitumen, because it’s a natural form of petroleum.
Bitumen can be refined out of crude oil, but it also occurs naturally. It’s the heaviest and thickest form of natural petroleum, typically black and extremely sticky. Bitumen has been used as a building material for literally thousands of years. The ancient Egyptians used it as a sealant for boats, and as an all-around waterproofing material for baskets, pots, or even just as an adhesive.
Today, it’s the base material for all refined asphalt products.
II. Turning bitumen into refined asphalt
Refined asphalt – the type used in Raleigh asphalt driveways – is basically a mixture of bitumen mixed with fine gravel along with some oil as a binder/emulsifier. There are three basic ways this can be done.
1 – Heat
Heat is still the most common way of producing refined asphalt, by heating the mixture until it comes together. Hot-mix asphalt creates the strongest of asphalt, but it also uses a lot of energy. So, increasingly, the industry is using lower-energy “warm mixture” asphalt to reduce the environmental impact.
2 – Blending
In some cases, the raw materials can be blended together at lower temperatures by blending it with kerosene, creating a material called cutback bitumen. This can be sprayed directly onto roads and other surfaces.
3 – Emulsifying
Finally, it’s possible to create ‘cold’ asphalt by using a water suspension process to create an emulsion. Since water and petroleum can’t mix, the water never makes its way into the final product.
III. Protecting the environment
Given that asphalt is made directly from petroleum products, does that make it bad for the environment?
The impact is actually far less than you might expect! This is because asphalt is infinitely recyclable – and it is. Asphalt is one of the most-recycled materials in the country, and over 90% of asphalt reclaimed from old projects ends up being used in new construction. The industry is highly aware that petroleum-based production is problematic, and is constantly looking for ways to reduce the need for new bitumen, as well as reducing energy use in production.
Blalock Paving Creates Excellent Asphalt Driveways in Raleigh
If you need a new driveway, walkway, parking lot, or other asphalt feature in Raleigh, turn to Blalock Paving! We’ve been doing excellent work across the area since 1968. Generations of people in the Golden Triangle have trusted us with their asphalt projects, and our customer service is second to none!
Contact us to discuss your next project and get a free quote.