The liquid sealcoating that is applied to your pavement is a complex formula containing sealant, water, aggregates and any additives needed for the specific job. Silica sand is the type of aggregate that is commonly used, but crushed boiler slag can also be used. Aggregates play a critical role in the quality and durability of the cured sealant. However, some asphalt companies skip this vital ingredient.
Sealcoating: Why Adding An Aggregate Is Important – Why Do Some Contractors Ignore Aggregates?
In simple terms, it is primarily about cost. Purchasing boiler slag or sand reduces the contractor’s profit. The aggregates also take up room in the mix, reducing the amount of square footage that the sealant will cover and cutting into his profit even more. However, the biggest issue — especially for gypsy contractors or novices starting a sealcoating business from their homes — is that the equipment needed to keep aggregates evenly suspended throughout the mix can cost $20,000 or more. Some fly-by-night contractors may try to add aggregates and mix the sealant in a 55-gallon drum, but without the proper agitation, the aggregates will settle to the bottom of the container.
Why Are Aggregates Important?
Aggregates serve multiple functions in the sealcoating mix. A reputable paving contractor knows that the aggregates must be carefully chosen if they are to provide the expected benefits.
• Aggregates enhance traction. Pedestrians will be less likely to slip and potentially suffer an injury. Vehicles will be less likely to skid out of control.
• Aggregates absorb some of the binder, helping the sealant form a strong bond with the pavement.
• Aggregates lend strength to the cured sealant, helping it to resist wear and damage. Sealcoating without aggregates will have a significantly shorter life.
• Aggregates can accelerate the drying time of the freshly applied sealant. Mixes that exclude aggregates will need to contain more water, and this water will need to evaporate for the sealant to dry and cure properly.
• Aggregates help conceal minor imperfections in the surface of the pavement. Hairline cracks and other minor flaws can often become invisible after the sealant cures.
What Qualities Must Aggregates Possess?
The size of the aggregates is classified by a number representing the size of the mesh in a sieve. Aggregates that are too large to pass through the desired sieve are not incorporated into the mix. Regardless of size or type, however, all aggregates should possess the following qualities.
• The aggregates must be free of organic matter, clay, dust or other contaminants.
• The aggregates should be thoroughly washed and dried before they are added to the mix.
• The maximum quantity of aggregates specified by the sealant manufacturer must be carefully observed to avoid sealant that is too rigid or that allows the aggregates to be easily dislodged.
If you need excellence from your sealcoating professional, contact Alpha Paving. We are an Austin based paving company that applies more gallons of sealcoating annually than any other company in the state of Texas. We are a full-service paving company with an impeccable reputation and outstanding references. Our services include street maintenance, asphalt paving and overlays, road construction, asphalt crack sealing, concrete installation, asphalt milling, pavement striping, concrete repairs, parking lot car stops and speed bump installation. To obtain a free quote on your next project, call our office at 512-677-9001 or complete the convenient online form.
