In 2009, test strips of a refined coal tar-based sealant (RTS) and an asphalt-based sealant (ABS) were applied in a little-used corner of an asphalt parking lot in Florida. Seven months after application, the ABS strip had already faded significantly and the underlying asphalt seems to be showing through, as shown in these photographs:
The photograph at the top of this post shows the same two strips 7 years after they were applied. The ABS has almost completely disappeared – if it weren’t for the sharp lines of the strip edges against the unsealed asphalt, it would be difficult to tell if the pavement had ever been sealcoated. The RTS has faded somewhat, but is still dark and the underlying asphalt does not seem to be showing through. After almost 7 years, the RTS continues to provide some protection for the pavement.