Sustainability is more than simply about carbon, and this is recognised in codes and assessment tools. However CO2 emissions, associated with materials, manufacture, construction, operation and end of use, is an important parameter and the cement and concrete industry is investing hugely in developing and enabling construction solutions that reduce whole life CO2 emissions as well as embodied CO2.
Buildings: CO2 emissions associated with operation is by far the most significant of the 5 stages material, manufacture, construction, operation and end of use. Operational emissions in buildings are being reduced by improving insulation and air tightness. As these improve, the role of thermal mass becomes more significant. In commercial buildings the operational CO2 savings achieved by thermal mass can offset any additional material embodied CO2 in only 6 years. In low rise housing, the offset period is 11 years according to independent research done by Arup when comparing a lightweight semi detached house with a similar one of masonry construction.
This good news does not mean the industry is complacent, and successful efforts have been made to reduce the embodied CO2 of concrete.
Infrastructure: CO2 emissions
associated with the running of trains, flow of traffic or
distribution of utilities is generally of greater significance than
the construction itself. For example the concrete safety barrier
down the central median of UK highways contributes to
CO2 reductions primarily through the avoidance of
congestion arising from lane closures associated with cross-over
accidents and barrier repair and maintenance. Its long life means
annualised embodied CO2 is low. For more
information on embodied CO2.