“It’s about to rain.” It’s a phrase that every road builder dreads. Weather conditions, along with traffic and other elements, acutely affect the ability to prepare a base for asphalt pavement. One way to “weather the storm” is to apply a quality trackless prime coat which will help prevent erosion, water penetration and save time and money.

But first, what is a prime coat?

A prime coat is emulsified asphalt applied to a granular base that prepares the surface for additional asphalt layers by bonding loose material. It also hardens the surface, providing and protecting a better platform for construction. Prime coat creates adhesion between the base and asphalt, forming a waterproof layer that plugs small voids. Think of it as the protection and preparation coat that helps ensure traffic stresses are transferred throughout all layers of the road, elongating the road’s lifespan.

What’s the benefit of using a premium trackless prime coat?

Imagine it’s a beautiful, warm, sunny Monday morning. A paving contractor starts grading the base layer but notices an approaching rainstorm a few hours into the job. The rapid onset of heavy showers can make it challenging to manage the finished base layer without delays. This is a great example of why leveraging a quality trackless prime brings value to contractors.

With a typical prime coat, the contractor would either need to prime and sand the finished base of the construction site, hoping that moisture doesn’t penetrate the subgrade layer, or let it rain on the base and wait days for it to dry out and rework it. Though prime coats provide a waterproof coating, most products require sanding and take 24-72 hours to cure.

What if you had an opportunity to use a trackless asphalt emulsion prime coat with characteristics of a trackless tack and an optimal cure time of fewer than 60 minutes?

(left): Base layer prepared and ready for a prime coat. (right): UltraTack as a prime coat on top of base level.

Premium trackless prime coats

When used as a prime coat, UltraTack® — The Original Trackless Tack®–  cures within 60 minutes. As long as the rain holds off for a bit, a contractor can apply the trackless prime coat according to spec and preserve the progress they have made on that job site, avoiding time delays, sanding costs and rework.

Additionally, cost and time savings can be realized using a trackless tack as a prime and tack coat. Using one product means one supplier, less cleanup, less waiting and coordination. A premium trackless product provides even more time savings because of the quick cure time, cutting the project time down by hours, and sometimes even days. 

UltraTack used as a prime coat on a commercial road.

The good and the not-so-good

Not all prime tack coats are made the same. Many are not considered environmentally friendly, according to the Environmental Protection Agency (EPA). Some prime and tack emulsions contain light hydrocarbons (HCs) that release pollutants into the air when they evaporate. As long as the product is composed of sustainable products with negligible volatile organic compounds (VOCs), such as UltraTack, it can be used for both applications. 

While most studies show real value in using a prime coat, some studies conclude it’s not a necessary step, claiming that a prime coat doesn’t significantly impact the stability and durability of a road construction project.  

At ACAF, The Florida Department of Transportation (FDOT) presented their findings that a prime coat provides a bond between HMA and base course. FDOT also found that pavement damage is more likely to happen at an accelerated rate without a prime coat — fatigue resistance decreased more than 60 percent and subgrade damage resistance decreased more than 80 percent, all of which would contribute to premature failure.

The power of prime

Extend the life of your road, while gaining performance and convenience when using a quality trackless prime. Great roads are built on solid foundations, so be sure to protect them with a premium product like UltraTack.


Leave a Reply

Your email address will not be published. Required fields are marked *