I often meet with prospective property management clients in South Jersey, Delaware, or Eastern Pennsylvania to discuss pavement seal coating. One of their biggest complaints is that the seal coating applications do not last as long in this market as they do in others they manage properties. Their complaint is not unfounded. In fact, it is 100% accurate.
"It's all about the Rock"
To understand why pavement sealers do not last as long in this market as in other surrounding areas, we have to first look at the type of stone used in the asphalt. Southern New Jersey and Delaware do not have quarries with aggregate deposits that are used in the production of hot mix asphalt. Southern New Jersey and Delaware are known for their rich sand deposits in various "sand pits" or simply "pits" (as they are referred to). These sand pits are dredged for high-quality sands, from septic sand to the actual sand used as mineral filler in hot mix asphalt. For this reason, the aggregate (aka: rock) used to make hot mix asphalt is traditionally trucked into this region from quarries in Eastern Pennsylvania.
Several asphalt plants in Southern NJ, Delaware, and Eastern Pennsylvania use an argillite aggregate to manufacture their asphalt. Several large argillite stone deposits in Pennsylvania are mined, processed, and then trucked to asphalt plants in the surrounding area.
I am not a geologist, so I am unfamiliar with why; however, the argillite aggregate seems to oxidize much faster than traditional granite stone used to manufacture asphalt in other parts of New Jersey.
Once argillite begins to oxidize (turn gray), it's next to impossible to get pavement sealer to bond to it.
In my first year in business, I was able to acquire a large national account as a client. The first project they gave me was a property in Voorhees, NJ. When I visited the project to perform the seal coating estimate, I first noticed that the parking lot was only a few years old; however, the asphalt was very gray and smooth. When I approached my supplier (Neyra Industries) and asked them how to proceed, they recommended applying a penetrating primer before seal coating.
I took their advice, and the seal coating application lasted almost 5-years.
The Timing Of When You Sealcoat Is Crucial
If you apply pavement sealer within 18 months of asphalt installation, you typically will not experience bonding issues with pavement sealer. During the first 18 months, the asphalt binder is still coating much of the aggregate. However, once the asphalt begins to show signs of "graying out," you will have bonding issues getting the pavement sealer to adhere in high-traffic areas.
What Is Pavement Priming?
Pavement priming is the process of applying a penetrating primer such as Neyra Poly Prime, Maintenance Inc Oxi-Bond, or Southern Emulsions Tarloc MPC. The primer penetrates down into the asphalt and helps bond the pavement sealer to the asphalt by using the primer as the bonding medium to create a thorough, cohesive bond.
What Happens If You Do Not Apply A Primer To Oxidized Asphalt Before Seal Coating?
Simply put- the pavement sealer will wear off the high traffic areas in under 12 months. The pictures below are of a pavement seal coating project from South Jersey that was not primed before seal coating, and the result was the pavement sealer wore off in less than 12 months.
Does Every Parking Lot In This Region Require Priming For The Pavement Sealer To Last 3 Years?
No. While priming will help create a superior bond between the pavement sealer and the asphalt, it is not required on all seal coating projects. Some asphalt plants in the region use granite stone versus argillite. While granite stone still oxidizes, it does so much slower than argillite. The pictures below show asphalt was installed with two different aggregate types. The white and oxidized asphalt would require priming for the pavement sealer to bond properly.
Is Priming Oxidized Asphalt Before Seal Coating Worth The Additional Expense?
You be the judge. The pictures below show a 5-year-old seal coating job taken in high-traffic areas.
Do you need an evaluation of your current asphalt parking lot to see if it will benefit from priming before asphalt seal coating?
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