Late last month, the U.S. Senate defeated the radical Climate Stewardship Act, whose measures aimed at reducing carbon dioxide emissions from industry stood to have far-reaching, negative impact on domestic portland cement production. Sponsored by Sen. John McCain (R-AZ) and Joe Lieberman (D-CT), the bill (S.139) proposed limits on the amount of CO₂ gas that could be emitted in power-generating and industrial operations that rely heavily on coal. As noted here in August, portland cement production is a major source of CO₂ emissions, with the gas generated in equal quantities by a) coal combustion for the pyroprocessing needed to form clinker; and b) calcining, the preheating phase in which carbon content is removed from limestone and other raw kiln feed. Climate Stewardship envisioned a market-based “cap and trade” system, where credits would be issued to allow fixed volumes of CO₂. Those credits could then be traded among cement companies and other gas sources.

Staff from the Portland Cement Association's Washington, D.C., office note that the cement industry opposes any legislation that would effectively cap domestic powder output. As an alternative to McCain-Lieberman's extreme measures — which assume that reduced greenhouse gas emissions will curtail the onslaught of global warming — cement companies have enlisted in the Bush Administration's Climate Vision program. During the 2003 Greenbuild International Conference and Expo (Nov. 12-14, Pittsburgh), PCA Environment and Energy Committee Chairman Thomas Chizmadia is scheduled to review the industry's CO₂ emission-reduction strategy and Climate Vision commitment. Chizmadia, who serves as vice president of communications and public affairs for Dundee, Mich.-based Holcim (US) Inc., will concentrate on PCA's proposal to allow the addition of up to 5 percent ground limestone in ASTM C 150 product — the subject of a year-long balloting among Committee C01 on Cement members.

The committee crosses a range of producer, specifier, user and academia interests tied to cement and concrete. In routine balloting, members review matters like a change of wording for a certain standard. More decisive measures — i.e., water-cement ratio or compressive-strength thresholds — are typically balloted after years of field- and lab-test data collection. Ballot measures can also reflect impending modifications among specifying agencies or other groups writing standards or defining field practice, most notably American Association of State Highway and Transportation Officials and American Concrete Institute.

On behalf of an industry challenged with reducing CO₂ emissions and harmonizing product standards to promote global trade, PCA outlined its ground limestone proposal during December 2002 C01 meetings. That lead to subcommittee and full committee balloting, whose results are scheduled for release next month.

C01 members weighing the rationale behind PCA's proposal have found more than technical arguments. The proposal is solidly founded from an engineering standpoint, as it evidences comparable performance — on both durability and physical property scales — of concrete specimens cast from mixes with ground limestone-bearing portland cement versus pure powder. From the standpoint of economy — another criteria in ballot measures — the C 150 provision would lead to production savings in domestic cement. It could likewise mean more competitive pricing on powder processed in Canada and European countries whose standards have allowed ground limestone additions for a decade or more.

Committee C01 probably has limited experience responding to directives of federal government agencies with little or no ties to construction; by technical and scientific protocol, some members might not like the mix of politics and standards development. But, the committee and the construction professionals who reference C 150 in day-to-day work should recognize that PCA's ground limestone proposal is rooted in places like Washington, D.C., and foreign cities hosting summits on global climate change — not Skokie, Ill.

e-mail: dmarsh@primediabusiness.com