How Does the Heat in Austin Affect Asphalt Parking Lots?
Asphalt is a very sturdy material, but it is exposed to the elements in the worst ways. In Austin, the element with the most major impact on your asphalt is the sun. Between the hot weather and very long hours of uninterrupted sun exposure, it’s hard to see how your asphalt could not be affected by the sun. Indeed, the heat in Austin presents special challenges for asphalt parking lots, and it is important to understand what could be going on with your asphalt and how it can be corrected. We’ll explain the major impacts of heat and other weather on your asphalt and how it needs to be repaired.
Oxygen and oxidation as a process are behind rust, corrosion, metal displacement and other damaging chemical reactions. While asphalt doesn’t rust, it is still impacted by oxidation. There are strong chemical bonds which make up asphalt and give it strength. Over time, the oxygen in the atmosphere naturally inserts itself into these bonds, breaking them up. When this process happens in metal, it forms rust, and the process itself is sped up by water. In asphalt, it’s sunlight that speeds up the process. The heat from the sun causes the oils in asphalt to combine, become heavier, sink, and leave the surface more vulnerable to oxygen.
Cracks in the Asphalt
As the oils in asphalt become heavier and sink, and as they evaporate into the atmosphere, the asphalt dries up. This makes it more vulnerable to cracking, especially when it is being used regularly and especially by heavy equipment. You’d think that rainy or overcast weather would give asphalt a break from this phenomenon. But, water can initiate cracking and help to dry out your parking lot. As the oils in the asphalt break away, the addition of water only helps the oil leave the binders and other materials in the asphalt. Oil and water don’t mix, so rain or a puddle is an opportunity for the oils to wash away from the pavement. Rain often first initiates the cracking process in cold climates. In hot climates such as Austin, it is the humidity that does this job. When the weather is very humid, water will gather on the surface of the asphalt and give the important oils in it the opportunity to escape.
Raveling is a more serious stage of asphalt damage. Although it can occur after installation if the heat prevents the asphalt from properly compacting—which can happen in Austin, it is more likely that raveling will happen later on. In raveling, the top of the pavement is damaged, and the damage moves progressively downward, turning the asphalt back into loose debris, full of potholes and cracks. Asphalt that is experienced raveling becomes very unstable. Asphalt raveling is caused by long-term traffic and exposure to high outdoor temperatures, both of which can break down the particles in the asphalt binder and cause it to crumble. Tracked vehicles and studded tires can both accelerate this damage. So can snow plows, but you don’t see those very often in Austin. Sometimes dust coatings can accelerate the raveling process. The asphalt binder does its job on the dust, binding with it, instead of properly binding the other asphalt ingredients together. A poor-quality binder may also break down like this without a dust layer.