The need
From roof tiles and patio slabs to structural beams and columns, concrete is the basis for many construction applications and its use is growing. According to the International Energy Agency, global cement demand by 2050 will be between 3.69 - 4.4 billion tonnes.

Cement manufacture is also responsible for around 5% of CO2 emissions. Increased pressure on manafacturers from government and consumers to reduce carbon emissions across all industrial sectors means there is a drive towards finding sustainable alternatives to current processes.

The results
With funding from the Technology Strategy Board, a British consortium led by sustainable buildings consultancy BRE, has developed new materials, based on ‘Alkali activated ash’ (AAA) binders that set and bind concrete together. These ‘low carbon binders’ can be used in concrete products such as tiles and pavers and offer significant benefits, including 70% fewer carbon emissions compared with traditional cement. As well as improved durability and strength, AAA is produced from readily available waste or by-products such as ash materials, which would otherwise end up in landfill.

The new binders are unlikely to fully replace traditional Portland cement but they will provide a cost-effective and alternative choice in concrete products where low environmental impact gives the concrete producer a competitive advantage. If widely adopted, the new binders offer the public benefits of reduced CO2 emissions, diversion of industrial waste from landfill to beneficial re-use, and the creation of a new low carbon concrete industry for the UK.

The project has produced reliable data on how to produce the binders on an industrial scale; has created prototype concrete products with 30% less CO2 impact, and has sufficient critical mass to move the new technology towards commercialisation. Similar products are being developed in Australia but the UK is at the forefront of the new technology in Europe. Those behind the project estimate that these new concrete products could be on the market by 2015.

Next steps
A new research project, which started in 2009 with support from the Technology Strategy Board, aims to improve cost and performance and to extend applications into ready-mixed and re-inforced concretes, for example, foundations for buildings. Barriers to the uptake of AAA technology and the requirements of consumers are also being explored.

Innovation Results : Low carbon future for concrete

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