An asphalt driveway is nothing more than small stones and fine sand or gravel mixed together with black asphalt cement. That asphalt cement is what holds everything together.
When an asphalt driveway is first laid its dark black and smooth. Right from day one the elements are all ready starting to take a toll on your driveways finish. The sun slowly starts to turn, that black finish to a dull gray.
With the changing of the seasons and temperatures your driveway will expand and contract. This expansion and contraction combined with the suns UV rays with cause the asphalt to become more brittle and less flexible. Over time this will cause small hairline type cracks to appear.
Those cracks if left untreated will allow water to seep in and create further damage to the asphalt as well as the foundation below.
A Protective Coating
Sealing your driveway is like sealing your deck or waxing your car. The sealant fills in those tiny cracks and provides a protective layer to the surface of your driveway. This not only protects against water seepage but also from the elements and various automotive fluids.
Motor oil is especially harmful to your driveway as it weakens the bonds in the asphalt cement and leaves the effected area more vulnerable to cracking.