A Concrete Exploration

As folks have probably figured out, I’m into highways. Every day, driving the van back and forth, I watch the construction on the 405 (yep, I’m from SoCal, so it’s “the 405”… get used to it). I’ve often wondered how much water gets bound up in the concrete, taking away from our drinking water supplies (I also wonder how much cubic footage each year is lost to painting, but I digress). So, I was very interesting in an article today in the New York Times about concrete: how it is made, how different mixes differ, and how folks are modifying the mix to make it more green. The article talks in particular about the I-35W bridge in Minneapolis. One mix, incorporated in wavy sculptures at both ends of the bridge, is designed to stay gleaming white by scrubbing stain-causing pollutants from the air through the addition of titanium dioxide. There are other mixes being used that are attempting to bind carbon in the aggregate. A really interesting read.