Asphalt Coatings

Asphalt is a black sticky material that is used mainly in road constructions by combining it with aggregate materials or in roofing as a waterproofing material. Basically asphalt is a by product of the destructive distillation of coal or the fractional distillation of petroleum. It is a viscous semi solid and is a composed of saturated and unsaturated hydrocarbons with more than 150 atoms in their molecules. Asphalt coatings, also known as asphalt seal coatings, are used to coat the asphalt thus enabling it to be preserved effectively for a long time. Asphalt coatings are highly recommended on asphalt pavements and asphalt driveways.

Reasons for Applying Asphalt Coatings

Asphalt coatings are necessary on asphalt roads and pavements because of a drawback regarding the unsaturated nature of the hydrocarbons that constitutes asphalt. This open chain nature of the hydrocarbons renders it prone to attack by substances such as weather and chemicals. Thus it loses its inherent waterproofing and binding properties while also loosing its dark black color in the process. The discoloration is in fact one of the first visual signs of the decomposition of asphalt. Motor oil, grease etc. also dissolves asphalt. Thus asphalt coatings are a necessity to preserve the properties of asphalt and prevent it from being rendered useless.

Functions and Usefulness

The main advantage asphalt coatings provide are an enormous extension to the lifetime of the asphalt coating. Asphalt coatings are of two types – based on refined coal tar and those based on asphalt usually in the form of an emulsion. Seal coating material properties are usually different manufacturer to manufacturer as no two seal coatings have the properties of both coal tar and asphaltic emulsions and are manufactured with particular uses in mind.


Asphalt coatings prevent the asphalt from aging and prevent water from collecting in the pores of the asphalt as water in the asphalt pores can literally destroy an asphalt surface especially in areas where the winters are cold enough for the water to freeze. The coatings also prevent the asphalt from disintegrating due to the motor oil grease and other chemicals. As the asphalt does not lose its binding properties, the strength of the road is retained and it can support traffic properly for many years to come. In short, asphalt coatings act as waterproofing agents preventing water from entering the pores, filling agents as well as protecting the asphalt from ultraviolet rays of the sun and grease and other chemicals thus improving its lifespan by a long time.

Things to be kept in Mind

There are certain things that are to be kept in mind while considering while applying asphalt seal coating to any asphalt surface: