They can boost protection, performance

By Jeff Winke

Sealcoating applied to a new, freshly paved, rich black asphalt pavement surface provides a sustainable layer of protection. Adding additives to sealcoat formula can enhance its power while also tweaking elements of its performance.

As Mark McLeod, president & CEO of Maintenance Inc., Wooster, Ohio, creatively described it: “When you wake up in the morning for work, what do you want your pavement sealer to do today? I liken pavement sealer to coffee, If you want it sweet, you add sugar, if you want it creamy, you add cream. but without the sugar and cream it’s just black coffee! All additives have a purpose in pavement sealers.”

Pavement sealer additives hold importance. “In addition to boosting the overall performance properties of sealcoatings, additives enable contractors to accomplish certain objectives,” stated Girish C. Dubey, president, STAR, Inc., Columbus, Ohio. “For example, sealcoat additives can provide fast, and uniform drying under not-so-ideal-cure condition. Additives can use sand and aggregates in larger amounts to ensure uniform textured appearance and can provide thickening for proper application, as well as various other performance needs.”

The benefits of additives outstrip any concerns about cost.

“Additives key benefits vastly outweigh any cost of post added additives,” stated McLeod. “Every additive has been formulated and tested and contractor proven with additional performance measurements compiled over decades of applications. The benefits discussed with hundreds and hundreds of professional pavement maintenance contractors center around issues of wind, rain, heat, cold, and the thickness and thinness of the application, so weather is a major concern with pros in our field.”

In addition to resistance to water and weather elements, additives can provide resistance to chemicals that can include deicing salts, gasoline, oil, jet fuel.

Dubey also added there can be the performance improvement of abrasion resistance, and providing flexibility, and toughness.

Sealcoat additives are used to ensure faster drying time.

“A sealcoat additive can reduce drying time by 25-30% and ensure uniform drying even under ‘not-so-ideal’ conditions,” Dubey stated. “You also can achieve a uniform dry color under shade or direct sunlight.”

Sealcoat additives have been around since sealcoating was devised back in the 1960s.

“Additives offer so many benefits, in so many ways, that not offering the option to use in a sealcoating bid may be a disservice in the sense that the property owner would be deprived of a better return on their pavement investment dollars,” Dubey said. “Sealcoating systems should be presented to property owners with full delineation of cost and benefits, namely longevity, protection and preservation of asphalt, safety, and value, which can be easily established with the use of additives.”

McLeod agreed: “Not informing contractors what additives can do and what they are for, is a major disservice because they are available! Education is key!
“We can go on and on with all the additive application benefits for professional and new startup companies. It gives the contractor peace of mind knowing they applied a spec. material fortified with a post added additive on their customer’s parking lot that will allow the contractor to get on the parking lot sooner for line marking and thus opening much sooner for traffic than without an additive added to the pavement sealer. This means the contractor can do more work, faster, and make more money!”

Clearly, additives save production time.

“Notwithstanding the performance enhancement, fast drying additives alone, have enabled the contractor’s faster turnaround on sealcoating projects,” Dubey said. “The jobs like sealcoating in early spring and late fall, night time sealcoating, applying under not-so-ideal conditions are done with the use of additives. Performing some of these sealcoating jobs was considered unthinkable before the advent of specialty additives.”

Most additives are made with polymers and specialty chemicals. They are commonly formulated as water dispersible products. The ability of additive in performance enhancement depends on the type of polymer used to make it. It is important to understand the benefits of choosing the right additive for the sealcoating job.

According to Dubey additives can be categorized as follows:

  • Performance boosting additives: They are designed to improve the overall performance of the sealcoating in terms of better overall longevity, flexibility, toughness, resistance to water, salt, and petro-chemicals. Such additives are based on rubber polymers and have been a part of most performance-based specifications, e.g., FAA, ASTM, etc.
  • Fast drying additives: Even under unfavorable drying/weather conditions, these can speed up the drying time thereby reducing labor cost and allowing traffic to open sooner on the surface.
  • Uniform Dry Color: These additives help in uniform drying of sealcoating even under sun or shade. Thus, resulting in a uniform dry color.
  • Thickening: Such additives are commonly used to suspend large amounts of sand, and or where the sealer has been excessively diluted with water.

Besides thickening the sealer, they do not contribute much to sealer performance. Generally, thickeners introduce permanent water sensitivity in the cured sealer film, therefore, should be used with caution. The problem is that sometimes they are used to thicken a “watered down” sealer, thus putting down an inferior product, which most likely will show premature wear. Sealer performance is driven by what stays on the pavement (dry film thickness), after the full cure.

Sealcoat additives fortify the sealer film by reducing surface tension and by adding flexibility, which helps to prevent raveling and moisture damage. Additives thus extend the life of a sealcoating. They also can give the sealer the deep black color desired in a freshly sealed pavement.