What are White Spots in Pavement?

Posted by Judson Burdon on September 22
Posted in Sealcoating

When white spots appear in the pavement, it does not have anything to do with the asphalt sealcoating work. These spots are unavoidable and may appear on any job. It’s important to prepare to educate the customer on this naturally occurring event.

When White Spots Appear in Pavement

Before asphalt sealcoating, the pavement likely looked grey. The color change process for that is oxidation. Regardless, the grey color hid the white spots or at least made them less visible. The spots were still there if they appear in the asphalt sealcoating process.

The asphalt sealcoating process places the white spots in sharp relief. Often, customers will point out these spots and request workers do something about them. It’s the company’s job to explain the white spots in the pavement.

What Causes White Spots in Pavement

Mineral salts are the big cause of white spots in pavement. These salts often exist within soils and may appear dissolved in water. Either way, mineral salts affect the salinity of the soil. Since asphalt, and in particular cracked asphalt, is in direct contact the soil, it has effects. Additionally, ground shifts can force this up through unsealed asphalt cracks.

Another potential salt source is calcium carbonate. This is most notably found in limestone and other rocks with a high calcite content. Limestone is very crumbly and may be present in the surrounding soil. It can also travel quickly due to erosion or in a gravel mixture.

White spot-causing salt is around every day of the year, though concentration may vary. Additionally, location is a huge factor for soil makeup. The parking lot or road may also be subject to extra salt. For example, businesses salt parking lots in wintery locations. These location-specific events contribute to the amount of visible white spots.

What Not to Do

Under no circumstances should workers complete another layer of asphalt sealcoating. It will not solve the issue. Adding another layer of asphalt sealcoating traps the compounds between the two layers. Eventually, white spots will reappear in the exact same pavement location.

Fixing White Spots in Pavement

Time is the best solution for white spots in the pavement. Exposure to the elements will wash the spots away. However, it’s not advisable to force washing, especially around a fresh sealcoating job. Simply reassure the customer that the spots will disappear or fade over time.

White Spot Prevention

No white spot solution is perfect, but companies can reduce the risks. Business customers can bring in asphalt sealing professionals to seal cracks as soon as possible. Doing so creates fewer opportunities for problem compounds to interact with the asphalt.

To begin, the sealing team cleans the area. Then crews widen the crack slightly for a smooth edge and clean the gap up again. Workers finally add a flexible sealant. Following this procedure helps the sealant adhere and can help the patch last longer.

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Judson Burdon created his own asphalt maintenance business out of Montreal, Quebec over 20 years ago. He is now President of Action Seal, where he helps contractors and property owners throughout Canada with their asphalt maintenance equipment and supply needs.

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