Eco-cement

Eco-Cement is a brand-name for a type of cement which incorporates reactive magnesia (sometimes called caustic calcined magnesia or magnesium oxide, MgO), another hydraulic cement such as Portland cement, and optionally pozzolans and industrial by-products, to reduce the environmental impact relative to conventional cement.

Energy Requirements

Ordinary Portland cement requires a kiln temperature of around 1450°C. The reactive magnesia in Eco-Cement requires a lower kiln temperature of 750°C [Smith, P: "Architecture in a Climate of Change", page 206. Elsevier, 2005, ISBN 0750665440] , which lowers the energy requirements, and hence the use of fossil fuels and emission of carbon dioxide (CO₂).

CO₂ Sequestration

Eco-Cement sets and hardens by sequestering CO₂ from the atmosphere and is recyclable. The rate of absorption of CO₂ varies with the degree of porosity and the amount of MgO. Carbonation occurs quickly at first and more slowly towards completion. A typical Eco-Cement concrete block would be expected to fully carbonate within a year.

Waste Utilisation

Eco-Cement is able to incorporate a greater number of industrial waste products as aggregate than portland cement as it is less alkaline. This reduces the incidence of alkali-aggregate reactions which cause damage to hardened concrete. [Swamy, R: "The Alkali-silica Reaction in Concrete", page 46. Taylor & Francis, 1992, ISBN 0216926912] Eco-Cement also has the ability to be almost fully recycled back into cement, should a concrete structure become obsolete.

References

Bibliography

*cite book
last = Wu
first = H. C.
title = Advanced civil infrastructure materials. Science, mechanics and applications
publisher = Routledge
date = 1999
*cite book
last = Day
first = K. W.
title = Concrete Mix Design, Quality Control and Specification
publisher = Cambridge, Woodhead
date = 2006
*Citation
last = Owen
first = Dyer
title = A rock and a hard place
newspaper = The Guardian
year = 2003
date = May 28
url = http://www.guardian.co.uk/society/2003/may/28/guardiansocietysupplement3

External links

* [http://www.abc.net.au/tv/newinventors/txt/s1296184.htm ABC New Inventors Segment (Real Player)]
* [http://www.exn.ca/dailyplanet/view.asp?date=4/21/2003 Discovery Channel (Canada) on Eco-Cement (Windows Media Player)]
* [http://www.tececo.com/document.appraisals.php Independent appraisals of the technology]
* [http://www.fastcompany.com/magazine/127/a-devilish-green-angel.html?page=0%2C0 Alternative to low-carbon Eco-cement: Making cement while sequestering carbon from the atmosphere] , Issue 127, July 2008; Retrieved 2008-07-20.