Asphalt and Carbon Sequestration

Greenhouse gasses and carbon dioxide

If you are a little bit familiar with the greenhouse effect, you probably know how it works and what the main culprit is. In case you don’t, here’s a quick breakdown: heat gets trapped in the atmosphere according to the level of greenhouse gas currently present. More greenhouse gasses equals more heat trapped. The heat builds up and the climate gets hotter over all.

Carbon comes from natural and human causes. All decaying material, especially plant matter, releases carbon. That is the biggest factor in adding carbon to the atmosphere. Usually it is added as CO2, or carbon dioxide. Now carbon dioxide itself isn’t so bad, and is a natural part of the Earth’s environment. Humans, and nearly every other animal breathes in oxygen, and breathes out CO2. However, it is currently being overproduced, and this is one of the main factors worsening climate change.

Slash and burn deforestation creates enormous quantities of decaying biomatter that in turn makes vast amounts of carbon dioxide. Industry also belches out carbon dioxide on…well, and industrial scale. Cargo shipping alone accounts for about 3% of the whole world’s CO2 emissions. Factories do their damage by releasing tons (literally) of CO2, and other worse gasses, like methane. Finally, agriculture also releases vast amounts of greenhouse gasses. Carbon dioxide isn’t even the worst one, methane, nitrous oxide, and fluorinated gases are much worse. However, carbon is our focus because it accounts for over 81% of greenhouse emissions.

So what does this have to do with asphalt?

Asphalt plays a big role in carbon sequestration. What is that? It means removing carbon out of the atmosphere and putting it somewhere where it won’t get back out. This in turn reduces carbon’s greenhouse effect, and reduces the effects of climate change. There are two ways to do this right now.

  • Biologic carbon sequestration. This is the storage of atmospheric carbon in vegetation, both land-based and aquatic. The carbon is stored in roots, tree trunks, and the bodies of plants. This is useful, as much vegetation also breathes C02 and helps filter air in general.
  • Geologic carbon sequestration. This is the process of storing C02 in underground geological formations. The carbon dioxide is pressurized until in liquid form, then stored in rock formations. It fits well into porous formations, and can even be used for oil and gas extraction.

This is where asphalt comes into the picture.

Asphalt and the environment

We’ve already mentioned how asphalt is actually not nearly as harmful to the environment as one might think, and how it’s improving its footprint over time. Asphalt is primarily something called aggregate. Aggregate is what it sounds like- a collection of small stones, crushed rock, and little, hard things. It is all kept together by a glue. This glue, or binder, is an oil product. Now, the oil industry is famously bad for the environment. Extraction is awful for local ecologies, and accidents can result in crude oil covering huge swathes of the ocean and land. Fortunately, asphalt is mostly recycled, seriously reducing the need for new oil products. This in turn decreases carbon emissions from extraction. Future carbon is also not but into the atmosphere by the extracted oil later being burned.

But how does asphalt sequester carbon?

The first and main way, is by covering a surface. A surface covered in asphalt has that asphalt trapped inside of it. One thing people may not know about plants is that during the night, their roots absorb oxygen and they expel carbon dioxide. This means that the soil can become loaded with that carbon gas, which gets released into the atmosphere. With asphalt covering the surface of the soil, that gas stays underground. It may seem a bit extreme, but the more of the Earth’s surface we cover in asphalt paving, the more carbon we keep out of the air.

So we should pave as much of the Earth over as possible right? Well…it would have some pretty bad effects in the short run. In the long run though, a 100% paved planet would have a very stable, predictable climate.

Fortunately, asphalt has a few other tricks up its sleeve.

Asphalt-porous carbon

New developments in paving technology have led to more porous types of asphalt. This asphalt works just like underground porous rocks that hold carbon. This new material can capture carbon and store over 100% of its weight in carbon. When it is applied to high pressures, of 30 times the atmospheric pressure at sea level, it absorbs CO2. What this means is that it can be used underground at “wellheads.” Wellheads are places where carbon is released in large tubes, often from factories and other big polluters. When the material is released from the pressure, it releases the carbon. This enables it to be “pumped” so that the CO2 can be liquidized and brought to permanent storage. This cheap and easy-to-use material was discovered by Rice University, and you can read all about the specifics here.

The possibilities are endless. Parking lots and roads could be paved with asphalt-porous carbon. It then absorbs underground emissions, preventing thousands of tons of CO2 from entering the air we breathe.

Find out what else asphalt and pavement can do

At Reliable Paving, we believe in more than just doing the best job we can for you. We want to do our work, efficiently, cleanly, and in a way that benefits as many as possible. We make sure to stay on top of the best, most resource-efficient ways to pave and lay asphalt. We are paving contractors with a purpose – unrelenting good service, and a mission to be greener, more efficient, and the best we can be. Contact us today to learn about our environmentally-friendly paving methods, and what we can do for you.