I'd never thought about it like that before- you're absolutely right, and that doesn't even include the manufacturing of it. Still, cement seems like a preferable alternative to, say, asphalt or something.

One thing they're doing with concrete that seems pretty innovative to me- even though I believe it's been around about 15 years- is permeable concrete. You basically pour and screed a concrete mixture with a ridiculous proportion of large aggregate (and a good amount of several admixtures), and when you're done you have something you can drive on just fine, but it allows water to filter through- even screens some impurities.

Of course, you have to keep it really clean, and it's easy to mess up- but still very intriguing, and much more friendly.