Oil Based Vs. Water Based: The Truth About Modern Pavement Sealers

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In today’s day and age, with a plethora of information channels at our fingertips, it can sometimes be difficult to sift through all that information to find what is relevant and accurate. Those who have ever done a sealcoat on their driveway probably have heard the verbiage “oil based” vs. “water based” sealers casually thrown around by friends, neighbors or contractors they have spoken to. Here are the differences:

Many products are made using raw asphalt, which is an extremely viscous byproduct of the oil refining process, called bitumen. These products are used for a variety of purposes including pavement sealers, paving tack coats, waterproofing, roofing materials, etc. The two main categories of products used in pavement sealers can be classified into “asphalt cutbacks” and “emulsions.”

Asphalt Cutbacks/Gilsonite

These are made with raw asphalt (bitumen) dissolved in petroleum solvents, also called distillates. The amount of solvent added impacts the overall product viscosity and cure rate of the asphalt cutback. The most used solvents include naphtha, gasoline, mineral spirits (paint thinner) and kerosene.

Most commonly, when you hear the term “oil-based sealer,” it is referring to an asphalt cutback sealer used with mineral gilsonite, a naturally occurring form of bitumen that forms in regions of Northern Utah when petroleum solidifies. Compared to refined bitumen, it is extremely brittle and can be crushed into a dark brown powder. A telltale sign that a gilsonite-based sealer has been applied is an extremely shiny and crystallized appearance.

Emulsions

Emulsions are a combination of bitumen, water and an emulsifying agent that helps with colloidal suspension. Emulsions are macroscopically homogeneous and microscopically heterogenous. Sand and additives are agitated into asphalt emulsion sealers prior to application to enhance surface traction, drying and durability.

The Breakdown

Some people in the asphalt industry will refer to asphalt emulsions as a “water-based” sealer to create a negative connotation around it. They will try to sell you by saying that their “oil-based” sealers are superior because they “penetrate the asphalt.” In actuality, when applied to your driveway, the solvent in the material breaks down the existing binder in your asphalt pavement. Once the material is fully cured off, it leaves the asphalt worse off than if nothing had been applied in the first place.

On top of that, the brittle gilsonite has a higher softening point (200 or more degrees) than the natural binder in your asphalt. When applied, it will leave the surface of the pavement extremely brittle once dry. Comparatively, asphalt emulsions fill in the voids of the surface asphalt aggregate to form a protective film, creating a barrier from harmful environmental elements.

Lastly, the released solvents from cutbacks are high in volatile organic compounds (VOCs), which have a negative impact on the environment. As asphalt emulsions cure and harden, harmless water is released into the environment.

As asphalt emulsions continue to improve, they remain the best option to seal and protect your asphalt pavement investment, not “penetrate” it. Don’t be fooled by asphalt salesmen; do your research and ask prospective contractors the right questions on what product will be applied to your driveway.

For more information or to ask questions about your asphalt or concrete driveway, sidewalks and patios, contact TruSeal Asphalt and Concrete at 443-223-9491 or visit www.truseal-asphalt.com.

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