Wednesday, March 30, 2011
The cage of steel rebar inside the concrete handles the tensile forces within the footing, while the concrete takes care of the compressive forces. From a sustainability standpoint, the steel is almost entirely recycled, and the concrete mix includes steel blast furnace slag as a replacement for half the cement that would ordinarily be used. The aggregate and sand that comprise most of the concrete mix are produced locally, to minimize the embodied energy that comes from transporting materials.
One of the steel rebar cages before the pour. The bars in the footing are a smaller diameter (5/8") than the vertical bars in the pedestal (7/8"). I'm sure there's a good reason for that.