What are the enviromental benefits of using slag cement?

Production of slag cement creates a value-added product from a material—blast furnace slag—that otherwise might be destined for disposal. Not only does the making of slag cement lessen the burden on landfills, but it also reduces air emissions at steel plants through the granulation process (as compared to the traditional air cooling process).  Use of slag cement in concrete reduces the environmental impact of concrete by:

• Reducing greenhouse gas emissions by eliminating approximately one ton of carbon dioxide for each ton of portland cement replaced.
• Reducing energy consumption, since a ton of slag cement requires nearly 90% less energy to produce than a ton of portland cement.
• Reducing the amount of virgin material extracted to make concrete.
• Reducing the “urban heat island” effect by making concrete lighter in color thus reflecting more light and cooling structures and pavements with exposed concrete.

The Environmental Protection Agency recognizes the environmental benefits of using slag cement in concrete.  It has classified slag cement as a “recovered” product under the Resource Conservation Recovery Act (RCRA), and has issued a procurement guideline requiring its specification on most federally-funded projects.