The Guardian suggests that concrete is to become such a big issue in terms of cost and environmental impact that petroleum waste will seem friendly and cheap by comparison. First you have to consider the problem:

Cement is one of the most environmentally hazardous materials in the world, adding more carbon dioxide to the atmosphere than the entire weight of the global airline industry. According to the Sustainable Development Commission, 4% of Co2 is caused by aviation. Depending on how conservatively you do the sums, cement-based building materials, including concrete and asphalt, account for between 5% and 10% of all carbon dioxide emissions.

And then, here is a possible solution, proposed by UKM, a partner of Shell, the Anglo-Dutch oil giant that holds the patent to the proposed material:

When crude oil is “cracked” into its components, the top of the refinement process produces petrol, followed by diesel, light fuel oil and then heavy fuel oil. At the bottom of the barrel lies a “fraction” of blackened waste material. It is hard and sticky and of scant economic worth.

“The standard way of dealing with this low-grade oil is to mix it with light fuel oil to make more heavy fuel oil,” says Robinson [director of UKM], sketching a diagram of the process on a notepad. “It gets burnt off and doesn’t have to be treated as a waste. But that burning causes further CO2 emissions that cause global warming. In our wildest dreams we don’t think we will replace concrete. But in certain applications where concrete isn’t as good, like in heavy industrial roads or in salt water environments, we can replace it. That would in itself be fantastic for the environment.”

Something tells me that even if this is a solution to today’s concrete problems (pun intended), it might introduce far greater problems to resolve tomorrow.

I’m no petroleum waste expert, and thus maybe I’m wrong about the future hazards. I guess if nothing else at least we can see Shell trying to solve some of the same issues as those mentioned by worldchanging.org.