Ready-mixed concrete
Ready-mixed concrete is by far the most common form of concrete.
Ready-mixed refers to concrete that is tached for delivery from a
central plant, instead of being mixed on the job site. Each batch
of ready-mixed concrete is tailor-made according to the specifics
of the contractor.
Sustainability credentials
| CO2 |
Additional cementitious materials and admixtures are used by
most concrete manufactureres to optimised cement content and can
reduce the embodied CO2 of the concrete. Transportation
CO2 is minimal with the average delivery distance of
ready-mixed concrete being 8 kilometres, and 50 per cent of
ready-mixed plants are located at the aggregate extraction
site. |
| Recycling |
At the end of the life of a structure, all cured concrete waste
can be recycled to create new construction materials. |
| Resource depletion |
Every tonne of ggbs or fly ash used in concrete mixes saves
about 1.4 tonnes of raw materials and fossil fuels. Aggregates are
abundant the world over, and the UK has enough aggregate reservs to
last for hundreds of thousands of years at current rates of usage
(i). |
| Waste |
Modern formwork systems and efficient site management minimise
ready-mixed wastage, which is estimated at less than two per cent.
Systems are available to re-use returned ready-mixed concrete and
this does not go to landfill. Concrete buildings can be designed
with less finishes, reducing the associated material waste. |
| Water |
A cubic metre of fresh concrete contains 140 to 190 litres of
water. The use of admixtures can reduce the water content by up to
30 litres per cubic metre. 80 per cent of ready-mixed concrete
already includes water reducing admixtures. |
| Emissions |
All ready-mixed plants have dust suppression systems in
place. |
| Health and safety |
The ready-mixed sector is an increasingly safe place for people
to work, and is working towards a target of reducing injuries per
100,000 direct employees by 13 per cent year on year from 2008
levels. |
| Sustainable formwork |
Formwork suppliers and contractors have responded to the
sustainability agenda by, for example, increasing the number of
re-uses of formwork on site, refurbishing forms with surface
treatment rather than replacing, and using vegetable-based release
agents. |
Source: Concrete Credentials: Sustainability, MPA - The
Concrete Centre, 2010