There are many ways to measure the eco-friendliness of various materials and processes. For example, the amount of recycled and reused material employed might be one gauge. Another commonly considered factor is the amount of greenhouse gas emissions caused by the material or processes.
We’ve seen several ways that asphalt pavement is “green,” but we haven’t talked about asphalt’s greenhouse gas emissions. To evaluate the greenhouse impacts of asphalt, we need to understand how these emissions are calculated. Several gases are measured, such as carbon dioxide, nitrous oxide, methane, and hydrofluorocarbon. A paper presented at the 2009 International Conference on Perpetual Pavements shows how asphalt stacks up particularly well. Using methods pioneered by VicRoads, a state authority in Australia, the researchers analyzed the carbon footprint – that is, the amount of carbon released into the air –for asphalt and concrete pavements in typical applications.
The study revealed that the greenhouse emissions from asphalt are only 22-25% the amount caused by a typical concrete pavement (using only virgin materials, not recycled ones, which would improve the number further). A longer-term look (50-year maintenance cycle) reveals a similar trend, with asphalt causing only 30% of the negative emissions concrete causes. This is because the processes used to create concrete involve heating the aggregate and clay to around 1,450°C, causing the production of a great deal of carbon dioxide, which is released into the atmosphere.
As you can see, the use of asphalt pavement over concrete is very helpful in the effort to fight greenhouse gases and protect the environment. When pavement options are considered, protecting the environment is just one more great reason to choose asphalt.
For more information about "green" asphalt and its many benefits, contact the experts at Wolf Paving.