The use of the cementitious ash in building products as total or partial replacement for Portland cement results in reduced carbon dioxide emissions that would otherwise result form the manufacture of Portland cement. In addition to avoided carbon dioxide emissions from calcining of limestone to make Portland cement and the burning of fossil fuels to provide the energy needed to make Portland cement, use of the sorbent components tends to increase the efficiency of energy production from burning of coal, further reducing greenhouse emissions from the burning of fossil fuel to produce energy.