Research conducted by both The Asphalt Institute and The National Center For Asphalt Technology (NCAT) have scientifically proven that sealcoating will greatly preserve and thereby, extend the life of hot mix asphalt pavements. High quality sealants such as our “GEM SEAL” product will produce these results in the following ways:

  • Prevents surface water from penetrating older, more porous pavements, which have become weathered or cracked.
  • Coats and bonds loose aggregate particles in the pavement surface, which occurs as part of the normal wear process.
  • Slows oxidation by protecting the surface from the sun’s ultra violet rays, which dry out the asphalt’s natural oils and binders causing premature cracking.
  • Helps to resist the damaging effects of automotive leaks and spills such oil, gasoline, and other chemicals.
  • Restores your pavement’s original satiny black finish, enhancing your home or business’ curb appeal.

Currently there are two types of sealants, which are practical for residential and commercial application. They are asphalt emulsion and coal tar emulsion.  These are referred to by industry professionals as “off road use” products. There are a number of other sealants manufactured today, but they are exclusively for “on road use” and are not cost effective for residential and commercial applications.

So, what is the difference between asphalt emulsion and coal tar emulsion? Without getting into a highly technical discussion on chemistry; plain and simply coal tar emulsion is a superior product. It is the product of choice by the professional asphalt contractor. It provides the best level of protection and service life to the customer’s pavement at a sensible cost.

Coal tar emulsion is also the only type of sealant that is assigned a “Federal Specification”. These designations (RP-355e, ASTM D5727, FAA P-625, P-627, P-630, and P-631) make it the only type of sealant that is approved by the Federal Aviation Administration for use on airport runways.  With this information available, why would any professional asphalt contractor use another product?

Obviously, coal tar emulsion is the best sealcoating product available today, but only when used properly by the professional asphalt contractor. There are two factors, which will affect the performance of the coal tar emulsion sealant.

The first factor is what is referred to in the industry as “mix design”. When coal tar sealant is purchased from the manufacturing facility it is in a concentrate form. The professional asphalt contractor is responsible for the “mix design”. The “mix design” is comprised of three primary components. The coal tar concentrate, water, and sand.

The technically correct “mix design” for coal tar emulsion sealant is (75%) sealant concentrate, (25%) water, and approximately (2) pounds of sand per gallon of mixed sealant. These are the specifications as determined by the manufacturers of these products and must be followed for maximum product performance.

The correct “mix design” is also required to comply with the “Federal Specification” as approved by the Federal Aviation Administration for use on airport runways. When the proper “mix design” is not followed, the product just does not yield the optimal performance, which any customer deserves.

The second factor affecting sealant performance is application method. The sealant can be applied manually by brush/squeegee or spayed on with commercial type application equipment. No matter what method is used though, the sealant must be dispensed from a tank that has an agitation system. The sealant is an emulsion and it must be mixed frequently, or it simply will fail to perform.

Coal tar emulsion must also be applied in two coats. One heavy coat is just not the same as two lighter coats. To get effective surface coverage and optimal results, the manufacturers of these products prescribe a two coat application procedure. If you don’t get two coats, then you are not getting an effective “seal”.

There is one other product that we frequently see applied to hot mix asphalt pavements in this area and therefore, must be mentioned. That product is oil based and is generically referred to as “gilsonite”. “Gilsonite” is not a pavement sealer, but instead a pavement rejuvenator.

“Gilsonite” is formulated to effect the pavement in a completely different manner than a “true sealant” such as Gem Seal coal tar emulsion. “Gilsonite” penetrates through the surface of the pavement and helps to restore its resiliency by “rehydrating”. There are some advantages to applying a “gilsonite rejuvenator”, but they do not compare to the effectiveness and advantages of a “true sealant” like Gem Seal coal tar emulsion.

Coal tar emulsion forms an impervious, flexible membrane on the surface of the pavement, which offers the greatest form of protection against the elements and other adverse factors. It will also be more attractive than the “gilsonite rejuvenator” for an extended period of time because it stays on the surface, whereas the “gilsonite rejuvenator” seeps down into the pavement. After just a few months, the “gilsonite rejuvenator” is usually not even visible. Your pavement will look worn and gray again.

These are the facts regarding sealcoating. After understanding the available choices; the decision should be very simple. If you want to extend the life of your pavement and make it look new again; then choose a professional asphalt contractor like Advantage Asphalt, LLC for your next sealcoating project. We are committed to utilizing the best product available and applying it with the proper equipment to meet the highest industry standards.