To understand why asphalt sealing is important, it is first important to understand how asphalt ages, when exposed to the weather and elements. When asphalt is originally placed, the asphalt oils keep it soft and flexible for a few years. As the sun, wind and rain age the asphalt, it begins to lose some of it’s flexibility. With time, small hairline cracks begin to appear.
Once the small cracks are present, water will begin to penetrate through the surface and reach the compacted stone base. The asphalt surface is a flexible pavement that is reliant on and receives it’s strength from the underlying base. Once water begins to reach the base layers, it will soften the stone and weaken the asphalt structure. If you live a climate that is subject to freezing temperature, the water will freeze below the surface and expand. Once the ice melts, a sub-surface void will exist. Once vehicles drive over this weakened area, a pot hole will form rather quickly.
Asphalt sealcoat is a liquid emulsion containing a mixture of tar, sand for added traction and durability, and additives that increase the flexibility and chemical resistance characteristics of the sealer. Sealer is applied in a liquid form by spray, brush or squeegee equipment. Because the emulsion contains sand, it is critical that professional sealcoating equipment contains a hydraulic mixing mechanism (paddle) in the bulk tank to keep the sand in suspension.
This liquid sealcoat is designed to fill in and seal small hairline cracks and reduce water intrusion. If larger cracks are present, they should be filled with a hot, rubberized crack filler, prior to application of the liquid asphalt sealer.
A typical commercial sealcoating project begins before the crews arrives at the jobsite. Professional sealcoating materials are purchased at a regional distributor and mixed with the proper amount of sand and fortifying additives. Additionally, the contractor should provide a site phasing map to show what areas will be completed each day. Proper communication is essential to know what areas will be closed on what days. Asphalt sealer is a water based material and it requires time to dry and cure. Depending on temperature, and more important humidity, it may take 24 hours before the pavement can be opened to traffic.
When the crews arrive to the job site, the will usually proceed in a similar sequence to the following. Crews will arrive very early and barricade the effected parking sections. After unloading equipment, they will use forced air blowers and mechanical brooms to remove dust and debris. If there are large cracks, the hot, rubberized tar would be applied next. After the surface is adequately cleaned and any large cracks are filled, they will use wide squeegee brooms to apply sealer along concrete curbs and sidewalks. Once the detailed cut in work is completed, the asphalt sealer will be applied with a hand spray wand using overlapping passes. On larger parking lots, a truck mounted spray bar may be used to apply the asphalt sealer. It is the same concept as the hand wand, but has multiple spray tips to cover larger areas in the same amount of time.
After the first coat of sealcoat is applied and has had time to dry, a second spray coat will be applied. On some high traffic areas, it may be advantageous to spec a third coat in the high traffic areas.
Finally, after all coats of the sealer have sufficiently dried, the pavement markings will be sprayed with high quality traffic paints to create fresh new lines and stencils. Professional grade pavement products will protect your asphalt investment and provide bright, positive curb appeal for your guests.
Manufacturers of Professional Asphalt Sealcoating Materials
NEYRA | SEALMASTER | STARSEAL | GEMSEAL | BREWERCOTE