A driveway sealer protects your driveway from wear and tear caused by vehicles and the natural outdoor elements that lead to cracking and chipping. Two types of sealers are available for use on asphalt driveways -- oil based and water based. Which one is best is a matter of debate. Both have their pros and cons, and each is inherently different.
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Water-based sealers are either coal-tar emulsions or asphalt emulsions. An asphalt emulsion is simply asphalt suspended in water. Coal-tar emulsions are a bit more complicated and a byproduct of the steel industry. Also suspended in water, coal-tar sealers have a completely different structure than the asphalt they protect. Oil-based driveway sealers are petroleum-based products that combine asphalt rejuvenators, or asphaltic chemicals, in an oily suspension.
A major difference between water-based and oil-based driveway sealers is how they work. While water-based or acrylic sealers form a protective layer on top of the driveway, oil-based sealers go one step further. Oil-based driveway sealers penetrate the surface, forming a flexible bond that decreases the likelihood that contraction and expansion throughout the winter months will result in cracking. While this in no way means that water-based sealers are ineffective, lack of suppleness may require reapplication more often than with oil-based sealers.
Despite their good performance, oil-based sealers have some big drawbacks. Unlike water-based driveway sealers, oil-based varieties have a longer cure time and distinct odor that is quite strong and often lingers in the air for days after the sealing is complete. Oil-based sealers also contain VOCs, or volatile organic compounds, which pollute the environment. In fact, some states have banned the use of oil-based driveway sealers because of their hazardous nature. Water-based varieties are more environmentally friendly.
The proper disposal of oil-based driveway sealer is dependent on whether it is in a solid or liquid state. Leftover oil-based driveway sealer does not go out with the household trash. Because of its makeup, a local or commercial hazardous waste facility is best equipped to handle permanent disposal. Leftover water-based driveway sealer can go out with the regular household garbage if left to dry first. In the same respect, oil-based driveway sealers can also go out with household trash as long as they are in a dry state.