America’s roads have been in a pretty poor condition for a long time, with plenty of potholes and cracks that drivers all across the country have to try and navigate around, or drive over and have their vehicles severely damaged. This is largely due to the way they were built – by pouring asphalt over compacted dirt, instead of concrete, which is why they get damaged very easily. They require a lot of maintenance, which is expensive. The shape of roads and highways in the U.S. has deteriorated even further due to the lack of investment in transportation infrastructure over the past 50 years.
Virtually all potential solutions to this problem cost a lot of money, and many states are struggling to get the funding to maintain and fix their roads properly. An experiment that is being conducted by Magdy Abdelrahman, an associate professor of civil and environmental engineering at North Dakota State University, might provide a more cost-effective and efficient solution. He has come up with an idea of using old tires for building new roads and fixing existing ones. The experiment that Dr. Abdelrahman is doing is funded by the National Science Foundation.
Considering that about 300 million tires are discarded in the United States annually, according to the EPA, and often end up on improvised tire dumps, which has many environmental impacts, Dr. Abdelrahman thought that they could be used for other purposes that wouldn’t create any environmental concerns.
He is working with so-called crumb rubber, which is basically recycled rubber from passenger car and truck scrap tires, and consists of uniform granules, that are created by either cryogenic processing or ambient grinding. He believes that this component can be mixed with road materials that are being used currently and improve them, and preserve the asphalt on existing roads. “It’s very durable. We mix it with different materials and in different percentages, and in different conditions, to find the best ways to add rubber to asphalt,” Abdelrahman said about crumb rubber. He added that pavement performance can be improved by using rubber as asphalt binder, which as he claims, can result in longer lasting surfaces, and can lower road noise.
When rubber is added to asphalt, it becomes more flexible, preventing cracks, which are otherwise the biggest factor contributing to the deterioration of road surfaces, as they allow water to get under the asphalt and damage it.
This would reduce maintenance costs in the long run, easing the burden on transportation budgets in many states around the country. At the moment, there are a few states that use asphalt rubber for road construction, including Arizona, California, Florida, South Carolina, New York, and Texas, to name a few.
Dr. Abdelrahman will also try to determine how the mixture of asphalt and crumb rubber will be affected by the addition of other components, and whether they would harm the soil or the ground water. He said that it’s very important for them to make sure that the additives improve the rubberized road technology, and make it more environmentally-friendly.