Environmentally conscious homeowners looking to pave their driveway or walkways have a few choices they can choose from. One of those bigger choices is between asphalt and concrete. There are a couple different questions that they may ask themselves during the process. What’s the difference between them? What are the pros and cons of each? Which one is more eco-friendly? How long does each last? What’s the maintenance for each?
What is the Difference Between Asphalt and Concrete?
Asphalt, or bitumen, is a product made from petrochemicals. It can be natural or refined, and when mixed with aggregate makes an excellent pavement material. Concrete is usually made from Portland cement, aggregate, and water. When poured, it hardens to a nearly stone-like toughness. Asphalt pavement is easier to make, generally requires about 20% less energy to produce and construct than other pavements, including concrete.
Why Asphalt is More Eco-Friendly
Though concrete lasts a long time if it’s been properly installed, the problem comes when it is installed in environments that have a freeze-thaw cycle. In this situation, the concrete is subject to heaving and cracking as the water it contains freezes during very cold weather, then thaws out when the weather warms. Concrete can be replaced, but if the damage is extensive, much of the pavement may need to be jackhammered out and replaced, which is both time-consuming and disruptive. Fresh concrete then needs to be poured into the resulting holes, and it takes at least a day or two for the concrete to set. Depending on the weather, it may take even longer than that.
Asphalt can be considered to be a permanent pavement. It is unusual for an entire section of asphalt pavement to suffer enough damage that it must be completely rebuilt the way concrete pavement is. Even if asphalt pavement has reached the end of its working life, all that needs to happen is for the top layer to be removed and a new layer rolled over it. Another difference between asphalt and concrete is that the asphalt sets more quickly than concrete. On a highway, asphalt only needs a few hours to set. After that, it can withstand normal traffic with no physical effects or problems.
Asphalt can also be recycled in ways that concrete can’t. Recycling asphalt can be fairly easy compared to other materials. For example, normal concrete needs to be pounded to rubble and to be reused as more pavement. Asphalt can be made into shingles for roofing and indeed can be used as pavement for another area. It can also be mixed with other materials such as the rubber from old tires. Asphalt is also porous and won’t put out toxic substances into the environment.
Asphalt and concrete are both good for pavements, but asphalt does have the edge when it comes to eco-friendliness. It’s the better material for both saving money and saving the planet.
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