The freeze-thaw cycles of winter can damage your asphalt if you don’t take these precautions.
You may have noticed that asphalt work is almost always best done during the warmer months of spring and summer. This is because the binder in the asphalt is liquid at high temperatures (and easier to work), and it hardens in cold weather. In the freezing temperatures of winter, asphalt hardens enough that it becomes brittle. This means that it is easier to break, especially when it is subjected to repeated freeze-thaw cycles.
The Freeze-Thaw Cycle
When water drops below 32 degrees Fahrenheit, it freezes, and when water freezes, it expands. When temperatures rise above 32 degrees again, the water melts again. This is known as the freeze-thaw cycle. This cycle happens several times each winter, and sometimes it even happens every day for a series of days when the temperatures rise during the day and fall at night.
How It Damages Pavement
When this freeze-thaw cycle happens inside a crack or crevice, like in your asphalt lot, the frozen water increases the size of the crack as it expands, since it expands about 10% and exerts a pressure of about 30,000 psi. It is really easy for liquid water to squeeze into any and every crack and drain down to the bottom, where it does the most damage when it freezes. Once the water thaws again, it can leak further down into the now-expanded crack, and do it all over again. Nothing can stop the water from expanding as it freezes, and this expansion is what damages your asphalt from the inside out. Water can also damage pavement from below if it freezes in the subgrade materials. When this happens, the lenses of ice cause the pavement to heave upwards, called frost heave, and break. When the ice melts again, it leaves a void, and the damaged asphalt sinks into it, causing additional damage and potholes.
How To Prevent Further Damage
The best way to protect your asphalt from the dangers of the freeze-thaw cycle is to make sure that your surface has adequate drainage. Your pavement should be sloped so that water drains off, and it should have drain tile piping to prevent frost heave. Once you have your asphalt down, seal any cracks as they appear, or at least seal the surface every 2-3 years. This will keep water from getting into the cracks and causing problems when it freezes and thaws.
Maintenance You Can Trust from PTG Enterprises
If you want to protect your pavement and ensure it has a long lifespan, choose PTG Enterprises for your community sidewalks, parking lots and pavement maintenance needs. We offer commercial concrete, asphalt, masonry, paving, consultation, and survey report services throughout Baltimore, Harford, Anne Arundel, Howard, and P.G. Counties. If you are interested in hearing how we can help you, contact us online or give us a call at (410) 636-8777. For more tips and tricks, be sure to follow us on Facebook, Twitter, YouTube, LinkedIn, and Flickr.
Tags: Asphalt and the Environment, Asphalt Maintenance, Winter asphalt maintenance
