Ready-mixed concrete is by far the most common form of concrete. Ready-mixed refers to concrete that is batched 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.
||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.
||At the end of the life of a structure, all cured concrete waste can be recycled to create new construction materials.
||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).
||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.
||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.
||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.
||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