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Asphalt Could Go Green
by azer | May 29, 2008 at 09:24 pm | 239 views | 2 comments
by hrannsa66
It turns out that the pavement is greener on the other side of the world. Here's an article about cold-mix asphalt - something that has been used extensively for some time in South Africa and may some day be used in North America:
"At U.S. refineries today, there are very mature, establishedspecifications for hot binders - our paving grade asphalts," he said ina statement this week. "But for emulsions, there is no clear agreementon how to define the quality. So, we have emulsions already, but wedon't produce them as much because the specifications aren't as clear."Bahia plans to experiment with adding polymers or plastics to thecold-mix process to make pavement more durable, safer and even quieter.
The big question: Why didn't the United States switch to cold mixeslong ago? We haven't had to, Bahia said, because we've long had awealth of resources that supported the less efficient hot-mix approach.
"In South Africa, they initially decided to go with the low-energyapproach because it can save a lot of money," says Bahia. "Then astheir economy grew, they had to build high-performance roads. Butinstead of switching to hot mixes, they improved their knowledge tobuild better cold mixes."
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May 29, 2008 at 09:24 pm by azer, 239 views, 2 comments
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Comments (2)
at 00:09 on May 30th, 2008
Right on that's great. Our favorite color is now green.
at 12:15 on June 1st, 2008
Is this better than rubber roads? Although they require more heat to produce, not less, roads built of asphalt mixes with crumbed added offer one of the few large-scale applications for recycling rubber tires (hundreds of thousands of them per mile are used). Rubberized asphalt has all the practical benefits of cold-mix asphalt (more durable, quieter, safer, less wear and tear on vehicles -- and passengers). Their added cost is more than recouped by their extreme longevity.
The big question is how they fare in cold weather climates, but Alberta started testing them in 2002. The idea is catching on: California and the UK started trying them out in 2006, and Pennsylvania in 2007. Singapore is planning to check them out, and I've heard that New York and Florida might be too. This method is even being tested for railbeds. Still, most people haven't heard of it.
This type of road was first built in the late 80s. At the time, I read that
the highway maintenance industry made such an outcry, Arizona had
to agree to limit the number of miles constructed per year (even though these thoroughfares -- as predicted -- proved to be very popular). I'm sure plenty other corporate interests are against the idea too. Companies like BASF, which supplied the latex for a the "popcorn" asphalt on a Massachusetts road built last year, would no doubt prefer roads be constructed of something that would create more profit opportunities.
The real problem is that the two ideas will never be objectively compared in our corporate dominated global economy. Whatever industry stands to make the most profit will end up influencing policy decisions, and the public will be presented with a fait accompli.