How Climate Change Affects Asphalt

As the Earth’s climate continually changes, asphalt pavement reflects these changes. How does it change and what can we do about it?

Like it or not, the Earth’s climate is changing. This is hardly something new. Our planet has gone from a geologically super-active inhospitable rock covered in magma and poison gas to the birthplace of life. A few hundred million years ago, the oxygen levels in the air were so high that various species of scorpions could grow to be 2 feet (0.61 m) long. Climate and geological changes have led to massive extinction events, with some eliminating 96% of the planet’s species.

The relatively good weather of the last few thousand years is actually pretty out of character for this planet. Unfortunately, it doesn’t look like it’s here to stay. Severe weather events continue to multiply, landmasses (like the Indian Continental Plate) are subsumed by the Ocean, and our atmosphere’s composition is changing.

This change affects much of our lives, from growing food to the buildings we live in. Here at Reliable Paving, we like to stay on top of how the changes in the world reflect on what we do. So how does climate change affect asphalt paving? What can we do about it?

What does a changing weather/climate have to do with asphalt anyway?

As you probably know by now, weather changes make a big impact on pavement. UV damage runs its course, and it changes according to how much sun hits the asphalt. But the main culprit of weather damage is water. Water gets in porous asphalt and then changes size when the temperature changes. As the water expands and contracts, asphalt does too. Cracks form, the aggregate loosens, and existing problems will get worse. What’s more, is that liquid in the ground underneath the asphalt can cause frost heave, a big change in the asphalt’s surface level. Ok, so weather definitely effects asphalt. But what about climate change?

Climate change is minor over all, so why should it affect pavement?

From 1880 to 2020 the average land temperature has only gone up by about 1 degreeCelsius (3.8° F), and by 2100 it should be up by about 4 degrees Celsius (7.2° F). That’s not so bad right? Well….unfortunately, 75% of the heat increase since 1880 has happened since 1975. The process is only expected to continue to accelerate.

On top of the over-all heating speeding up, we have more extreme weather. Rather than being a graph that simply slowly plods up, climate change results in the weather being more extreme, both in cold and heat. There is an over all trend towards it being more hot, and the heat levels’ extremities worry us plenty. Extreme weather also is an enormous threat, because events such as floods, tornadoes, hurricanes, and high-wind storms can destroy our paving/road infrastructure.

The threat from extreme weather

Extreme weather is climate change’s most immediate threat to most of us. It can destroy crops, homes, businesses, and entire cities (see: New Orleans, Louisiana, and Cedar Rapids, Iowa). Of course, severe weather can also destroy our paving infrastructure. So the question that arises is simple: What can we do about it? It’s neither cost-effective nor safe to have highways, roads, parking lots, and roofing (which also uses asphalt) that gets destroyed every few years.

Tougher asphalt

Changing our asphalt’s aggregate mix and binder is the key issue here. Upgrading the binder increases its durability and lifetime. Same goes for aggregate. However, thanks to the existing infrastructure we have, these changes are expensive. Fortunately, the savings come in as we will spend less on maintenance over the lifetimes of these upgraded asphalts.

Different maintenance methods

Although the maintenance for higher-quality asphalt paving is less expensive, it’s different from the usual. Rather than just checking the asphalt for damage, it’s important to look at the wider area around it. Is this area prone to flooding? Drought? Severe storms with high winds? Is there erosion close enough that will make it to the asphalt in the next decade?

For an in-depth look at dealing with climate change’s effects on asphalt, read this study from the Journal of Industrial Ecology.

The threat from global warming

Urban heat islands

As the planet gets hotter and hotter, asphalt doesn’t help. Especially hot areas in cities are created by black asphalt which absorbs the sun’s energy and traps it, further heating the air above and around it. This phenomenon is known as the Urban Heat Island Effect. Asphalt blacktop disproportionately contributes to it. The long and short of it is that asphalt absorbs heat and makes the surrounding areas much hotter.

Toxic gas

When exposed to extreme heat and sunlight, asphalt also releases air pollution. Asphalt is made with petroleum products. When it gets extremely hot and is exposed to sun, it begins to release gasses normally associated with oil products. These gasses go into the air and become part of what the people who live nearby breathe on a daily basis in the summer. Pollutants released include PM 2.5 (tiny particles that aerosolize and damage lungs) and mixtures of harmful organic compounds. According to Science Advances, asphalt is a major nontraditional source of secondary aerosols. As paved roads make up 20% of the built environment, and asphalt is 45% of roofing, this is a big issue to tackle.

Solutions include using different materials. Recycled plastic can be used in roads and roofing. Asphalt can also be coated white, or with a reflective surface, so it can reflect, rather than absorb sunlight and heat.

Reliable Paving can help you avoid creating an urban heat island

If you have a paving job that needs to get done, but you are concerned about the heat or pollution caused by it, then contact us. We can offer environmentally-friendly solutions to your paving needs. With experience totaling more than 35 years, and a well-trained team of over 200 paving contractors, we can handle any job. When you rely on us, you will learn the meaning of “relentless cooperation.” Get your work done well, get your work done reliably, with Reliable Paving.