How to Combat Asphalt Pickup Tire
Air Pressure:
Correct pneumatic-tire roller operation begins with checking the air pressure in the tires. Ensuring the air pressure is correct helps a roller operator reduce the possibility f material pickup. If one tire is under-inflated, the lack of pressure will cause the asphalt to bind to the tire instead of the mat.
Warming up Tires:
Another crucial step in proper operation involves warming up the tires to 100°C - 120°C temperature near that of the hot-mix asphalt before applying the roller to the asphalt.If the tires are near the temperature of the asphalt, the petroleum in the asphalt will stay hot enough to act as a lubricant for the rubber tires, much like a release agent.As soon as the tires cool to a temperature below that of the hot asphalt, aggregate will begin to adhere to the rubber.
An appropriate tire temperature can be achieved by first running the roller up and down a compacted surface to begin building heat in the tires. Once this temperature is reached, it is important to keep the roller moving to maintain the heat in the tires. Even if the rest of the equipment in the paving train stops, the pneumatic roller should continue running over the asphalt at 3 to 4 km/h. Pneumatic tires can cool quickly and begin to induce pickup, so it is imperative the operator keeps the roller moving to greatly diminish the chance the problem will occur.
Heat Retention Shields & Cocoa Mats:
Pneumatic-tire roller manufacturers have realised that even with Pavertrend™ and proper roller operation, contractors can still feel the pain from asphalt pickup. In response, manufacturers have developed tools that, when added to the roller, help reduce the occurrence.
Heat retention shields are one of the tools available to alleviate asphalt pickup. These shields consist of a rubberised material that acts as an insulator to keep heat around the tires. Asphalt pickup usually begins on the outside tires of pneumatics, as these tires cool faster because wind is constantly blowing on them. When the tires cool, the hot asphalt is more apt to stick to the rubber. By using heat retention shields, the wind cannot reach the outside tires, keeping the heat from the asphalt mat around them.
Cocoa mats also are available to help eliminate the beginnings of asphalt pickup.These are attached to the roller’s frame and lie against each tire to loosen any aggregate that sticks to the rubber. Since even a small amount of asphalt on the tires will induce more pickup, the use of cocoa mats can help prevent minor build-up from turning into a major problem.
Silicon Based Tires:
Asphalt pickup also continues to diminish thanks to engineering developments in the pneumatic tire industry. Some pneumatic tire manufacturers have taken steps to reduce pickup headaches by developing tires embedded with a silicon-based substance that produces a “non-stick” effect and repels hot asphalt.
With the help of these new tools and technologies as well as old-fashioned roller know how, contractors continue to get a better handle on the problem of asphalt pickup.
Pavertrend™
Improves the quality of the finished product. Allows contractors to focus, rather than wasting their time in solving asphalt pickup issues.
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