LIFE-CYCLE BENEFITS OF CALCIUM SILICATE REPLACEMENTS

The most universal of all binders, produced in huge quantities worldwi de, is Portland cement. Following introduction in 1824 by Joseph Aspin , it has quite properly enjoyed popular appear with craftsmen, archite cts and engineers for its bonding properties. The manufacture of cemen t relies largely on primary minerals for feedstock and depends heavily on carboniferous fuels for production. Naturally occurring minerals h ave similar properties as a binder and have been used in their own rig ht or as partial replacements for cement. Likewise, secondary products recovered from modern manufacturing or energy production processes al so have the potential to replace in part a proportion of cement. Life cycle analysis of cement production supports the proposition that larg e quantities of fossil fuel and primary minerals are being unnecessari ly used in situations where alternative replacements are available and frequently placed to waste. This paper considers the implications of cement production on a sustainable environment. It argues that, contra ry to some opinions, partial replacement of cement with secondary wast es which have potential cementitious properties can enhance and improv e structures which otherwise would include only Portland cement as the binder. Acceptance of this argument would leave massive quantities of primary minerals untouched and reduce the amount of fossil fuels dema nded of cement production on the present scale. Copyright (C) 1996 Els evier Science Ltd