Steel House C60: Construction Info
GGBS and its Environmental Credentials
The Global demand for construction products is vast and each
year about 1.4 billion tonnes of Portland cement is manufactured
globally. Portland cement is the most energy intensive component
of concrete and contributes to about 50% of its CO2 emissions.
Portland cement production involves burning a source of calcium
carbonates (such as limestone), silica and alumina (such as
clay) in a kiln at a temperature of about 14000C. This involves
the burning of fossil fuels and also CO2 is liberated as the
Calcium Carbonate decomposes. The global average of the amount
of CO2 produced per 1 tonne of Portland cement manufactured
is also about 1 tonne and this equates to about 7% of global
CO2 emissions.
Ground Granulated Blastfurnace Slag is a by-product of the
Iron industry and is produced at the blastfurnace. The molten
slag is rapidly quenched in water and then is ground into
a fine cementitious powder. Modern steelworks rely on a steady
supply of high quality iron. The quality of the iron and the
blastfurnace slag are interdependent. The composition of the
iron particularly with regard to minor elements is monitored
closely by measuring the chemistry of the blastfurnace slag.
The process of recovering and producing one tonne of ground
granulated blastfurnace slag powder produces approximately
0.1 tonne of CO2.
GGBS is a latent hydraulic material and when combined with
Portland cement, it hydrates in much the same way as Portland
cement, forming products such as Calcium Silicate Hydrates
that bind the aggregates together to form concrete. With care,
suitable concrete mixes can contain 70% ggbs: 30% Portland
cement, drastically reducing the embodied energy of the finished
concrete structure. ggbs is off-white in colour and considerably
lightens the colour of the resulting concrete, producing an
aesthetically pleasing creamy colour, which many architects
prefer.
Further info Hanson/Appleby/Civil&Marine:
http://www.civilandmarine.com/pages.en/
Steel frame fabrication: Factory
visit by members of the team to Stoneguard 18/19 November.
Below: Underfloor Heating Layout |
