Portland Cement Gets Greener

[This image shows a rotating cement kiln used in the manufacture of Portland cement. The scale is deceiving. Note the small human figures standing on the facility floor toward the bottom right of the image.]

The Portland Cement Association (PCA) is in the later stages of spearheading changes to the formulation of portland cement according to the ASTM C 150 standard. By allowing the inclusion of up to 5 percent ground limestone, PCA estimates annual enivironmental benefits including:

• Reduction in raw materials use of 1.6 million tons
• Reduction in energy use of over 11.8 trillion BTUs
• Reduction in carbon dioxide emissions of over 2.5 million tons
• Reduction of cement kiln dust of over 190 thousand tons

According to PCA's November 13, 2003 press release, the proposed changes will result in a 2.6 percent reduction in carbon dioxide emissions per ton of product, part of PCA's longer-term goal to reduce such emissions by 10 percent between 1990 and 2020. PCA also claims to have reduced energy consumption in the manufacture of portland cement by 33 percent since 1975.

More Information:
The manufacture of portland cement is discussed on pages 469 - 471 of the textbook. Issues of sustainability in concrete construction are discussed on pages 472 - 473.
PCA's Cement Basics page provides information on the formulation of portland cement, blended cement, and hydraulic cement, and provides links to additional related topics.