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?
Axle load, actually. In theory a 1.5-ton car with two axles and a 3-ton truck with four equally loaded axles would cause the same amount of damage. A 1-ton unicycle would cause more damage than the truck.
Note, though, that this is a rule of thumb. A 50-ton tank is still a 50-ton tank even if you manage to make it have fifty tiny axles. But for fairly average motor vehicles under fairly average conditions it’s close enough to be useful for planning.
Surely that’s damage-per-axle? So it’d be two 1.5-ton cars to match the trucks 4 axles
It could be, but I wouldn’t assume that it is.
I remember when calculating bridge wear, we were discussing the truck arriving on the bridge in terms of impact. It could be the damage somehow comes mostly from the first wheels to encounter the material.
As with all equations in civil engineering, it’s not really derived from physics so much as it’s the curve that best fits the data.
It’s kind of interesting in that way, because it’s an implicit declaration that when shit gets really heavy (pun intended), we trust empirical observations more than we trust our own theories of how things work.
I think it’s a great example of coming back to the roots of science in measurement, as a practical humility we must take seriously because everything civil engineers do is high stakes.