The smooth black surface of asphalt is an attractive choice for a driveway. As a low-cost, neutral paving material, it competes with concrete as a popular choice among homeowners. One of the problems with asphalt is its tendency to break apart from intense ultraviolet rays and extreme temperature shifts between summer and winter seasons. Sealants can help relieve this problem, and extend the life of your asphalt driveway.
Coal tar is the most popular type of asphalt driveway sealant. Coal tar is a water-based sealant, with polymers and other additives that provide it with extra strength. Coal tar is the result of the process when coal is baked to produce coke, a type of industrial fuel. Coal tar sealers last longer than asphalt-based sealers, and provide more resistance to oil and gasoline.
Coating your asphalt driveway with an asphalt-based sealer will help protect your driveway and be easier on the environment than coal tar sealers. Asphalt sealers emit lower levels of greenhouse gases known as volatile organic compounds. Asphalt-based sealers are less odorous than coal tar, and are also less irritating to human tissues. One drawback with asphalt-based sealers is that they won't resist petroleum products as well as coal tar sealers do, so are more prone to staining.
Asphalt Fillers and Patches
If you have a pitted asphalt driveway or a series of cracks, you can repair the damage and prevent it from getting worse with fillers and patches. This is usually applied with a caulking gun filled with rubberized asphalt patching material. If the holes are large enough, then it will be necessary to fill them with gravel and cover it with a patch of packaged asphalt, before being tamped down.
Cracks in your asphalt driveway may occur because of wear, contraction and expansion or because of water erosion. It's important to seal the edges of these cracks, because if they're left open to the elements, they'll only grow larger. Sealants will prevent further destruction of the asphalt surface, until you decide to resurface or replace the driveway. Asphalt crack sealers also prevent moisture from entering the base, adding years to your asphalt driveway surface.
Colored Acrylic Sealers
The most expensive sealers are the acrylic asphalt sealers. These products contain no petroleum products, sand or gravel, and are impervious to the damaging impact of air and ultraviolet rays. Acrylic sealers are the ones used on asphalt tennis courts, and can be applied in black, clear, red or green. These are very durable sealers, which only require reapplication around every seven years.