Enhance both the project and contractor’s reputation benefit

By Jeff Winke

In his paper, “Sealcoating Additives–An Overview,” Girish C. Dubey, president of STAR, Inc., Columbus, Ohio, wrote: “Simply defined, additives are materials added to enhance the properties of a product… the materials that are added to boost the performance of sealcoatings, which may be based on refined tar, asphalt or any other resin. ‘The use of additives in sealcoating coincides with the very inception of sealcoatings in the 1960’s. Additives based on specialty latex/rubber polymers have been a part of the FAA specification since the early 1970’s. Over the last few years, there has been a concerted momentum by materials suppliers to offer a class of products and chemicals that are designed specifically to boost the performance of sealcoats. The use of such products, which are called ‘additives,’ have enabled sealcoating professionals to apply sealcoats even in unfavorable ambient conditions and still accomplish optimum performance. Although it may appear that most additives are supplied to make the sealer dry faster, that is only a part of the benefits provided by additives.”

Think about it, sealcoating and the additives that enhance the asphalt pavement coating have been around since Nancy Sinatra recorded “These Boots are made for Walkin’” and one has to wonder if maybe there are lost lyrics about walking all over asphalt. Probably not, but worth a wishful thought.

So, with a 50-some-year history, additives have shown value beyond faster cure time.

“Additives are used in sealcoating for many different reasons; most common is for faster cure time, but that’s not all they do,” stated Adam Wellman with Maintenance Inc., Wooster, Ohio. “Most contractors these days think that that’s the only benefit of using a additive, but they also dramatically increase the durability of all sealers by adding flexibility, fuel and oil resistance, and they increase bonding to the surface of asphalt, as well as helping suspend sand for easier mixing.”

There are primarily three types of pavement sealers. They are commonly known as refined tar-based (coal tar based), asphalt-based, and petroleum-based. All three have their advantages but are typically chosen by the contractors’ preference unless otherwise specified.

“Additives are a very important tool for the contractor to have in their toolbox,” said Shannon Hemsink, development director with Neyra Industries, Cincinnati, Ohio. “Additives are formulated products produced by the sealer manufacturer to enhance the characteristics of the pavement sealer. They are typically composed of latex polymers and other materials.”

Hemsink added: “It is good to use additives when temperatures are below 60 degrees Fahrenheit and when temperatures are above 90 degrees Fahrenheit. In both temperature extremes, the additive can help with proper film coalescence to ensure a durable, long lasting sealcoat.”

Sealcoat additives are also said to help in conditions when there is less than 24 hours of cure time, when weather conditions are less than ideal within 48 hours of application and when application is made late in the day or at night.

“As with anything, additives do have limitations,” Wellman said. “They are never a cure-all if your surface is in really bad shape–some failures are still going to happen. Also, you can put too much additive in your mix which, in my experience, can actually give you the complete opposite result, such as slowing the cure time of your sealcoat. It’s always important to talk to your supplier and get the recommended mix ratios for your application to ensure best results.”

Clearly there are benefits to sealcoat additives. Additives do add to the performance of the pavement being protected.
Some additives act like a drying agent to accelerate the drying and cure time of the sealcoat. “Dry” is when the sealcoat doesn’t transfer to the touch, and “cure” is when all the moisture has been driven out of the sealcoat and it is fully set (adhesive and cohesive strength reaches its strongest point, and the film cannot be re-dissolved in water).

“Considering the myriad of additives available today, it is crucial to understand the basic chemistries and select the ones that will truly enhance the performance of the sealcoating in terms of better flexibility, toughness, fuel/chemical resistance and overall longevity,” stated Dubey.

Dubey described a handful of performance objectives for additives:
1. Fast Drying: Even under “not-so-ideal” weather conditions.
2. Uniform Dry Color: Under shade or direct sun light.
3. Sand/aggregate suspension: Sand/aggregate are used in the sealcoating mix to improve skid resistance, produce uniform texture and fill minor surface defects..
4. Performance improvement: Greater resistance to chemicals, deicing salts, oil, gasoline, or jet fuel. Greater resistance to weather elements such as rain/snow and UV. Improved toughness, flexibility and elongation.
5. Thickening: Boosting the viscosity to suspend large amount of sand or aggregates. Occasionally thickening additives are used to build viscosity for mix designs using excessive amounts of water.

Paving contractors face challenges in placing their asphalt mix. Sealcoating can help in many areas.

“Seal coating additives are specially engineered products that help pavement coatings last longer and bond to the pavement better,” stated Rick Poole, president, Diamond Shield Fortifier, Alexander, Ark. “Seal coating prolongs the life of the pavement, while additives prolong the life of the seal coat. All additives have specific properties which address a particular contractor’s needs. As a result, no single product is a ‘one size fits all’ additive.”

Poole offered an example of an additive that solved a contractor’s customer challenge.

“A local contractor used an active curing additive to seal coat a drive-thru car wash. Car washes present a special challenge due to constant water exposure. This was the contractor’s first job of the year and took place in early March. He knew an additive was needed to help control the cool temps and counteract the decreased amount of sunlight. This was also a ‘must complete now job!’ After some unexpected repair issues, it was already afternoon and the car wash was due to be reopened the very next day. By the time work could be finished, there was only a small amount of sunlight left to dry and cure the sealcoating before the cooler temps of nightfall set in. I went to the car wash once it was opened and was pleased to see that the coating was holding up well to traffic. I am certain this job could have been a disaster if the contractor had not used the active curing additive. The sealcoating alone would not have had time to dry and cure fast enough to meet the demand of returning traffic, without failing. The sealer likely would have washed into the street and gutters and or left unsightly tracking marks marring the roadway and damaging the coating.”

Clearly, the proper use of an additive can provide the kind of results that can help elevate the reputation of the sealcoat contractor above their competition, because the work turns out better, lasts longer, and most importunately makes the customer happier.

In short, additives play a vital role in the sealcoating industry and can make the quality of sealcoating projects better.

Jeff Winke is a business and construction writer based in Milwaukee, Wisconsin. He can be reached through jeff_winke@yahoo.com