A Green Concrete Jungle? Why Green Cement Is Paving The Future

martin pennels says December 4, 2012

the current practice of using cementitious additives does very little to actually reduce the CO2 emissions from cement and unfortunately HAS to be considered one of the greatest examples of green washing currently on the market.
the processes involved in creating these “waste” products are equally damaging. iron ore smelting process simply heats limestone to 1400deg instead of 1800deg for cement production. many of the CO2 claims are based upon these “waste” products being zero rated for emissions. because the feedstock mix is now being specifically being tailored for the waste to be used as a cementitious additive the EU now no longer considers them waste and should be termed by-products (nobody would consider cream a waste product of skimmed milk production)
however we look at (or indeed the cement industry looks at it ) adding high energy and high emission by-products to cement does not solve or reduce the problem and absolutely does not warrant the title of green cement.
also the produced amounts of these by-products is so low in countries like the uk that we can never supply enough without resorting to imports from large steel producing countries.
my concern is that the marketing of such products is actually spearheading an attempt to increase the use of cement and concrete on the basis that it is now “green”
high energy and emission materials will never be part of the solution. reduction in their impacts is a benefit but elimination of their use HAS except in absolutely necessary applications must be the longer term goal. in spite of these developments cement related CO2 emissions continue to rise even during a worldwide downturn in construction.
if anyone requires more detailed info this was actually part of my masters thesis and I can supply referenced data if necessary

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