Asphalt used on road surfaces are byproducts from fossil fuel. With the ultimate goal of eliminating the use of fossil fuel to combat climate change, are there any good alternatives for road surfaces? I don’t think I’ve ever heard of a viable replacement of asphalt in the works, or even a plan to replace it in any environmental discussions before. At least, not enough for me to notice.
Extented question would be: what are some products derived from fossil fuel that are used in everyday life, but still lack viable alternatives you don’t see enough discussions about?
Climate change isn’t caused by just using fossil fuels to make a product, it’s caused by burning fossil fuels releasing greenhouse gasses, (primarily carbon dioxide and methane), into the environment.
Asphalt is a problematic material, but not so much because it’s made from oil. It’s problematic because we burn fossil fuels to harvest the raw crude and to generate the energy needed to refine crude into asphalt. The carbon in the asphalt itself remains sequestered there and doesn’t contribute to the greenhouse effect as long as it isn’t burned later.
If we figured out how to extract crude and generate the vast amount of energy needed to manufacture asphalt without actually burning fossil fuels we’d eliminate the vast majority of asphalt’s impact on climate change.
In fact it’s been shown in a lab that it’s possible to make asphalt from CO2. It’s currently cost prohibitive to do so, but in theory asphalt could be part of the solution to climate change.
Now Asphalt does have other environmental issues, like leaching toxic chemicals into the soil and water table and the fact that it’s usually black which absorbs more the sun’s radiation than almost anything else which would reflect more of the sun’s energy back out into space. But those problems aren’t necessarily solved by using non-petroleum based bioasphault, nor are they unsolvable with bitumen based asphalt.
About 20% of a barrel of oil gets made into products like plastics or foam, that’s not what’s causing climate change. What causing climate change is the 80% that gets refined and burned for cheep energy. So it’s less “Just stop oil” and more “Just stop burning oil”
Thank you for the very detailed answer!
Bioasphalts can be made from all sorts of non-petroleun renewable resources, including food wastes and sewerage effluent: https://en.m.wikipedia.org/wiki/Bioasphalt
I think the main challenge now will be determining the ideal mix of ingredients that best suit the purpose of the asphalt.
Good to know! Thanks!
Also another factor is heavy vehicles. I don’t have the article or video, but I remember hearing that a majority of road damage comes from heavy vehicles. I believe the video was also comparing roads to Rome roads where it wasn’t that they were built better (although volcanic ash did help) it’s that horses and people are way less heavy than the 3,000+lb vehicles we have going almost 24/7.
Less road damage would mean less containments/pollution and less need for repair. So the future might be seeing more public transit and more rail transit for materials/products which would mean wherever we need to add more road or re do sections we would replace it with the greener option or potential normal asphalt since it wouldn’t need to be touched for another 20,30,40+ years.
that a majority of road damage comes from heavy vehicles
Specifically, wear and tear on the road surface scales with the fourth power of vehicle weight.
As a worked example, this means that if we compare a 3-ton cargo van and a 1½-ton sedan, the cargo van weighs twice as much as the sedan, but it does sixteen times as much damage to the road.
Wow, it makes sense but definitely not good at all
Asphalt is really highly recycled (though I’m sure at a high energy cost), so at least we have that going for us.
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It currently takes about 3 to 6 cubic meters of gas to make 1 ton of asphalt. It doesn’t really matter if that’s new or recycled, and doesn’t include mining and transporting the materials.
If we eliminate the use of fossil fuel to combat climate change, our agricultural output will drop enormously and a significant fraction of humanity will starve to death.
I think if you‘re driven to find non-fossil road pavement strategies, you should refocus your efforts on finding non-fossil sources of nitrogen for fertilizer.
Food is way more fundamental than roads, and it’s far more heavily reliant on fossil fuels.
Well this thread is a discussion on alternatives and what you think are not talked about enough, so thanks for informing about fertilizers. I certainly didn’t know that they were also reliant on fossil fuel.
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Brick.
Yellow brick
Trains
I mean, I’m all for more public transportation (seriously, wtf America?). But in reality, there is still a need for public roads for things like buses in places where subway stations aren’t viable, and also for logistics (construction materials, mail, Amazon deliveries, your Uber eats, etc.)
You forget that many people live in areas where passenger rail infrastructure is not economically (or practically) viable. I, for one, pity the grain truck that has to drive over an unpaved road.
Wooden cart.
What ruins the asphalt is the weight of vehicles, and in car-free places, you can see 30+ year old asphalt without potholes or cracks with only minor damage or repairs. If it weren’t for the sun making the asphalt pale, you wouldn’t know it isn’t a recently paved street.
By reducing the number of cars in cities and towns in favour of bicycles and rail, and putting stricter restrictions on the weight of the vehicles, we can make asphalt last WAY longer.
Also, some modern asphalts are more durable than older ones, but I don’t know the specifics.
Modern farm fertilizers are all made with ammonia which is produced with natural gas. Apparently Yara,a Norwegian company, is trying to replace the fossil fuel with solar power. Source
Of course you could also use manure or compost as fertilizer, but only some of the few small farmers would probably be willing to since it is harder and therefore more costly.
The green alternative to Asphalt existed before Asphalt in the form of Rail Roads. “Green Asphalt” also exists and is currently used for walking trails and biking trails, though it consists of recycled plastic and rubber, so technically it isn’t “asphalt.”
Solar Roadways has been trying to make it work for a while, but I think they will end up being a project better geared for driveways or parking lots or bicycle highways rather than replacing asphalt roads, just based on the enormous amount of issues they’ve had in the past in trying to shield and protect the lighting elements.
It could still do a lot of good even in the more limited applications, though, so I’m still hoping for their eventual success, even if it ends up being on a smaller scale than what their initial goal was.
The ground up corpses of the recently deceased.
Kind of a brain dead question. We have much bigger sources of pollution and Asphalt is heavily recycled. We don’t have to replace everything that uses oil, just the heaviest offenders.
