valhalla360 wrote:
So if Asphalt is such a horrible material, why is it that around 80% of paved road miles are asphalt.
Cost. If the city/states would spend the money to use better materials for roads, the people that scream about leaving kids public debt would come more unhinged than normal. The idea of leaving kids roads that can be used for decades can't fit between the ears.
Keep in mind Portland Cement Concrete requires burning a lot of fuel to make the cement...leaving behind more asphalt cement from the left overs of a barrel of crude oil to let's not pretend it's a "greener" alternative.
Yes, it takes a lot of fire to make Portland. More than what it takes to heat asphalt to pave the same distance? IDK. But I know all that burning is in 1 location, then the product hauled out to be mixed near where used. 1 stack emissions can be monitored better than when the burning is happening anyplace want to set a portable plant.
Late '90s the local Portland was bought out, and up graded. It burns a lot of utility supplied NG, I'm sure. Also burns over 300 tons a week of ground up tires. Dozens of vans of plastic unloaded for fuel every day. And the old quarry across the highway, turned into a sanitary landfill has a 8 inch line to feed the methane most landfills vent into the burner.
Can you source these tests that show oil leaches out from asphalt? Cars leaking oil onto the pavement can do that but particularly for old asphalt concrete, the vast majority of light oils that would be subject to leaching out are long gone. That's the biggest problem with old asphalt...all that remains after 30yrs are the solids, so it doesn't make a very effective binder.
First I heard of asphalt leaching, a local construction company bought a big chunk of ground, with the idea of using as a waste fill until up above water level of '93. For about 10 years, dumped a lot of concrete buildings, dirt, tear out from utility repairs, even a few crossover in there. City found oil in the public well, traced back to that field. Spent a bunch of money with a couple of excavators working under city supervision, digging down to virgin ground, sorting asphalt out, and refilling the trench. For the last decade I worked asphalt was added to brush, lumber trash leaves sign of what can't be dumped.
The other problem is you have far less control over the quality of the aggregate (sand & gravel). With asphalt concrete, the aggregate is typically more important than the binder.
This is true about Portland as well.
