For the past 200 years most of the world’s concrete has been made with ordinary Portland cement.
However, this involves heating limestone to 1,450 C, which both releases and creates a significant amount carbon dioxide – estimated at up to 8% of all man-made carbon dioxide emissions.
Carbon capturing cement
A promising new alternative to Portland cement has emerged over the past decade in the form of reactive magnesium cements, invented by Australian scientist John Harrison. The naturally occurring magnesium carbonate is heated to just 750 C and, more importantly, sets and hardens by taking carbon dioxide out of the atmosphere.
This new ‘green’ material is still very much at the research and development stage, but recent production trials of concrete blocks in the UK have made it a major step towards commercial reality. The results of these trials are reported in the latest issue of the ICE Construction Materials journal.
Greener and stronger
According to lead author Martin Liska of Cambridge University, ‘The compressive strength values reached by the reactive magnesia blocks were higher, in some cases much higher, than those of their corresponding Portland cement blocks.’
Find out more
For more information please contact the ICE Proceedings editor Simon Fullalove on +44 (0)20 7665 2448 or at editor@ice.org.uk.