Saturday, September 15, 2012

Asphalt

I take asphalt for granted, most of the time.

Summer is the season for road work, when asphalt gets ripped up and replaced. Following the detours prompts a slight awareness that roads in upstate New York are not at all like stone Roman roads. Roman roads were and are obviously bumpy, but capable of function for centuries with little maintenance.  New York asphalt roads have the winter disease of pothole-making as well as the unnamed summer disease where the asphalt softens up and ripples downhill in slow motion. The New York asphalt roads don't live as long as as a stone Roman road. But I hardly think of that factor in the usual course of errands in a car.

What gives a yet greater pause for awareness are parking lots, vast parking lots. Each has been created from those molecules of crude oil that are too branched or long-chain to be convenient for combustion or making plastics. The sheer volume of parking lots is a piece of evidence of how much petroleum has been drawn from the earth.  The roads I see only a bit at a time, but the dimensions of a big-box store parking lot gets to me.  I have to wonder how many people are like me, casting a fleeting glimpse at the vastness of the parking lot before ducking into the more manageable almost cosy dimensions of a car interior.

As the world consumes more difficult deposits of petroleum, the cost of new asphalt mix has jumped. This is somewhat counter-intuitive, as the bitumen from tar sands is dense like asphalt.

I hope to update this post over time as I find more statistics about asphalt, and explore the consequences to earth covered by asphalt.  How do street trees get enough air and water to their roots when only a little neck of open soil is left around their trunks?  The rest of their root system is largely under concrete or asphalt.





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