Advancing industry experience developing and working with next generation lower-carbon materials is part of Amazon's continuous efforts to decarbonize its buildings. As part of this effort, Amazon challenged the design, construction, and material supply teams of the Bellevue 600 project to pilot new materials. The result is a novel near-zero Portland cement concrete that was tested through physical mock-ups and placed in a series of non-structural concrete column encasements in the below-grade garage. The innovative concrete mixture uses sulfated granulated blast furnace slag (GBFS) that replaces the more typical Portland cement, which is the most carbon intensive aspect of producing concrete.