Friday, November 29, 2013

sustainable cement ??!?

At various sustainability events I have attended over the past while, I have been surprised to see sponsorship by the Cement Association of Canada.

A quick check of their website reveals this to be a new focus. “The cement and concrete industry is committed to being a proactive partner in addressing the challenges of mitigating and adapting to climate change,” said Michael McSweeney, president and CEO of the Cement Association of Canada. “We are in an age of massive re-investment in our basic infrastructure in Canada, and this presents an enormous opportunity to both mitigate climate change through reduced CO2 emissions as well as prepare ourselves for the changes in our climate that are already underway."


I was reminded of all of this today when I read an article in the Financial Times, On a mission to rescue concrete from its brutal reputation.

When the MuCEM museum opened in Marseille last year, what it was made out of stirred almost as much interest as its displays on European and Medit­er­ran­ean civilisations.
Its elaborate latticework exterior, the columns supporting the exhibition spaces and the spectacular, 115m-long unsupported bridge linking the museum to the city’s Fort Saint-Jean were all made with concrete.The building is about as far as you can get from the lumpen, environmentally unfriendly image usually evoked by crumbling Soviet-era apartment blocks and choked urban road networks.
“You can use concrete for your house because it is beautiful,” declares Bruno Lafont, chief executive of Lafarge, the French company that made the concrete for the MuCEM building.
You might expect a bit of gloss from the head of a group that sits in France’s CAC 40 index alongside companies such as LVMH, arch purveyor of luxury and elegance.
But Mr Lafont has put his company’s money where his mouth is. Lafarge, a world leader in the unglamorous business of cement, aggregates and concrete, spends €120m a year on developing new ways of using these gritty materials. It says its R&D centre just outside Lyon is the world’s biggest research facility for construction materials.
France has a long tradition in concrete. Modern cement, the essential ingredient, was invented by the French and British 200 years ago; a pioneer of reinforced concrete was Joseph Monier, a 19th-century French gardener who wanted to make stronger flowerpots; Le Corbusier was a trailblazer of “brutalist” architecture using concrete.
Many countries – those that suffer from earthquakes, for example – appreciate the robust qualities of concrete. But it has to battle against rival materials. “We need to compete with wood, steel and brick and show that we can have good results,” says Mr Lafont.
Developing “ultra high-performance” concrete – dense, fibre-reinforced and smooth-surfaced – of the type used by architect Rudy Ricciotti for MuCEM is a key task at Lyon.
But it is only one of a number of projects. In one workshop, engineers test cement-laced mud bricks being developed for housebuilding in Malawi, where traditional burnt-clay bricks have been banned because making them is detrimental to the local environment.
Tests are under way on concrete made with biomass, which is four times lighter than concrete made with traditional aggregates. Water-permeable road surfacing, self-levelling concrete and pollution-absorbing concrete for tunnels and car parks are all being worked on by Lafarge boffins.
“Concrete is a dumb material but there is lots of science behind it and that’s why I love it,” says Christophe L√©vy, a director at the Lyon centre.
Much of the challenge is to reduce the environmental impact of concrete. Mr Lafont says construction overall (not just with concrete) accounts for 40 per cent of all carbon dioxide emissions: “We are part of the problem, but we can be part of the solution.”
A core issue is reducing the energy used in making cement by firing limestone and clay at 2000C. Cement remains essential to making concrete. “Nobody has found anything simpler or cheaper to glue stones together,” says Mr Lafont.
New processes, lower quantities of raw materials and recycling are all part of an effort by Lafarge to reduce carbon emissions per tonne of concrete by a third by 2020 compared with 1990 levels.
That way, concrete can compare favourably with other materials, Mr Lafont insists. And it can secure a broader reputation for making beautiful buildings, from small houses to soaring tower blocks – and cutting-edge museums.

To read the article in the Financial Times click here. You can register to read 8 articles free every month.

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