Replace Portland Cement To Reduce Greenhouse Gasses

Portland cement in concrete can be replaced with fly ash and other recycled materials.  Since manufacture of Portland cement is a high CO2 emitter, this is doubly useful, in that it reduces greenhouse gas as well.  Optional statements reading "Replace as much Portland cement as possible with fly ash, ground granulated blast furnace slag, silica fume, or rice hull ash as is consistent with ACI recommendations" have been added to the main concrete sections, including 033000, 034100, 034113, 034500, and 034713.  In addition, the LEED Credit Summary and LEED Certification Procedures sections have been modified to include these options.