- Ronald Wittmeyer
- February 22, 2014
Deteriorating pavement becomes a constant of winter and spring driving. Driving on a brand new road is always a thrill for the driver and for their car. But broken pavement is a nightmare. When oxygen and water, which constantly bathe the pavement, start to combine with the binder of the pavement, a chemical change begins to take place and the road begins to deteriorate. A combination of this chemical change, ever-changing outdoor conditions and constant use can transform a new road to a crumbling one in the blink of an eye. In a world filled with stunning new advances in technology many wonder why it is that we have not yet figured out how to bring longer life to our roads. In fact, new refining advances are said to be making our asphalt weaker than it used to be, so is there any way that we can reverse this trend of deteriorating pavement?
There are about 2.65 million miles of paved roads running through the United States. A good asphalt road generally lasts around fifteen years including resurfacing and other repairs. According to the Washington Asphalt Pavement Association, the most commonly used paved surface for these roads is known as hot mix asphalt. Other mixes include combinations such as: superpave, asphalt treated base, concrete and hveem mix. These different mixtures offer varied densities, aggregate textures, weights and flexibilities in hopes to reduce deteriorating pavement. Each different mix is specifically designed to stand up to the particular usages of that particular roadway. For instance, densely graded hot mix asphalt is used in locations with high traffic because it can stand up better to the rigors.
To illustrate how different mixes are used together to produce the longest lasting results we can look to the recent reconstruction of the Dan Ryan Expressway. This road is one of the busiest in the country with more than 330,000 vehicles traveling on it every day. The new highway now boasts a 24-inch-deep aggregate sub-base, six inches of asphalt, then 14 inches of concrete, for a total of 44 inches. While this impressive list of materials is rumored to give the road a life of up to 30 years, it cost more than 1 billion dollars to build and will inevitably have to be replaced before we know it. So, is there any way we could make a road like this last longer in order to save bundles of time and money and reduce the deteriorating pavement?
The answer is a yes contingent on whether or not the right procedures are being utilized to reduce deteriorating pavement. Although no magic new mixture yet exists, it is known that the worst practice for extending the life of a road is waiting too long while damage develops. The best way to keep this from happening is to develop a strategic prevention plan that emphasizes the use of fog seals, slurry seals or chip seals which are lab tested based on existing conditions, climate, and traffic loads which can help determine shape, size, moisture content, and placement of replacement materials. The moral of the story is that in the long run it is cheaper for highway maintenance agencies to bear high maintenance costs up front. This decision will inevitably save money over time and keep our roads in better current condition so that we can all enjoy smooth sailing to whatever destination we may choose in hopes of reducing car accidents from potholes.