Why seal asphalt?
In spite of its excellent adhesive and waterproofing properties, asphalt has some serious drawbacks that relate to its chemical makeup. Asphalt is a very complex mixture of thousands of chemicals which are predominantly open chain (aliphatic) in structure with a considerable degree of un-saturation within their molecular structure. The open chain provides easy access to weather, salts, and chemicals to attack and disintegrate the asphaltic molecules. As the asphaltic molecules disintegrate, the asphalt in the pavement loses much of its original properties, such as binding and waterproofing. The first visual sign of this phenomenon is a progressive change in the color of asphalt pavement from rich black to brown to gray. Furthermore, asphalt, being a byproduct of the petroleum distillation process, is easily dissolved by other products that also are derived from petroleum, such as oils, fats, grease, mineral spirits etc. The reason is quite logical: As petroleum, these various products
