26 October 2011 – From The Guardian UK – Cement is to our buildings as corn is to our food supply. Just as corn is an ingredient in countless food products, cement is a building block for much of what is around us: our roads, our buildings, and our bridges. And, as with corn, plenty of cement substitutes promise to make our environment cleaner. But swapping conventional cement for “greener” equivalents is proving to be a tough challenge.
While many companies tout a more sustainable product than the limestone-based cement that dates back to the ancient Macedonians, cement in its current form is here to stay. One reason is logistics – most of us live within 20 miles of a cement plant, which means any drastic change will involve an overhaul of infrastructure, not to mention the massive education that will be required to retrain everyone from truck haulers to civil engineers. As more buildings rise while others are remodelled, the key to sustainable development will be the smart use of this material.
Efficiency and design has a prominent role in developing smarter cement and concrete structures. Less promising are the expectations of cement alternatives that perform well in a laboratory, but not in the concrete jungles of Seoul, Sao Paulo, and Los Angeles. Efficient design can help reduce the cement industry’s global impact, which contributes about five percent of the globe’s total carbon emissions. And yet cement and concrete are materials that offer durability and thermal properties, and can reduce energy and water waste throughout the places in which we live and work.
The holy grail of sustainable cement is for the material to be carbon-neutral or even carbon-negative. Novacem is one company that promises a more viable alternative to conventional portland cement. The UK-based firm’s product has a base of magnesium oxide and magnesium silicates (ie talc). The cement only needs be heated to a lower temperature than conventional cement, which is why Novacem touts its product as a carbon-neutral or even carbon-negative process. Novacem stands behind its twenty years of research and has won a bevy of awards – but its product and those of other companies have yet to scale.
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