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THE BRIEFING
Concrete
The Quest for Carbon-Neutral Concrete MIDDLE EAST
Charles K Nmai, President of the American Concrete Institute, shares his thoughts on how the construction industry can work towards meeting carbonneutrality goals through concrete
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August 2022 | MEConstructionNews.com
t’s universally accepted that achieving carbon neutrality must centre around Portland cement and, accordingly, cement organisations such as the Portland Cement Association (PCA), the Global Cement and Concrete Association (GCCA), and the Inter-American Cement Federation (FICEM) have either developed or committed to industry roadmaps for netzero concrete—that is, to fully decarbonise the cement and concrete industry by 2050. These roadmaps involve different strategies and include savings in clinker production, savings in cement and binders, efficiency in concrete production, and efficiency in design and construction— which speaks to the objective of ‘construction productivity’. This includes the decarbonisation of electricity, carbon capture and use/storage,
and the re-carbonation of concrete. Savings in cement and binders and efficiency in concrete production are not new to the industry. Supplementary cementitious materials (SCMs) such as fly ash, slag cement, calcined clay/metakaolin, silica fume, and natural pozzolans are used worldwide, depending on availability, to optimise Portland cement concrete. Other SCMs such as rice husk ash and, in recent years, ground-glass pozzolans are also available regionally. Blending SCMs with Portland cement during the manufacturing process is also not new, though not extensive in North America, where concrete producers typically add SCMs separately, usually as a replacement for Portland cement. The main difference between blending during manufacturing and separate addition is the Portland cement
75%
Portland cement replacement levels of 70 to 75% are being used routinely throughout the United States
