The Concrete Industry Sustainable Construction Strategy and the annual performance report is helping to put concrete manufacturers at the forefront of the construction industry’s efforts to get to grips with issues such as embodied energy, resource efficiency and BIM. Ecobuild 2015 sees the publication of the concrete industry’s 7th performance report, containing the collected data for 2013. While it demonstrates that progress has been considerable, it is recognised that there remains no room for complacency.
The original initiative focused more on those aspects of sustainability that were within the concrete industry’s control – in other words, the cradle-to-factory-gate impacts of production. In 2012, in response to the European Commission’s drive towards greater resource efficiency, the UK concrete industry broadened its sustainability strategy to include the material’s impact after it had left the factory. Now, it has extended it still further with the launch of a series of resource efficiency action plans (REAPs) in partnership with WRAP and the brick industry, involving close collaboration with stakeholders, contractors and those responsible for projects to the very end of service life. With the objective to deliver a more holistic approach to measuring and demonstrating whole-life product stewardship.
The action plans highlight how far the concrete industry has travelled since 2008, but this shouldn’t detract from its success in achieving the strategy’s initial goals set for 2012. The initial focus was on reducing the amount of carbon dioxide emitted for every tonne of concrete produced. The reduction in concrete’s embodied CO2 has seen the 1990 figure fall by 22%, from 103 kg of CO2 per tonne of concrete to 79.7 kg. The target for 2020 is to reduce this figure to 71.8 kg of CO2 per tonne of concrete, which equates to a 30% reduction from the 1990 baseline.
Because concrete is a mix of materials, its CO2 emissions are affected by both production, from processes such as cement manufacture, and embodied energy from transportation and a range of other criteria. The embodied CO2 emissions can be further lowered by local sourcing or by using cementitious additions derived from other industries in the concrete mix. These include flyash from power stations and ground granulated blast furnace slag (GGBS) from the iron and steel industry. In 2013, 28.6% of all cementitious materials used were byproducts; the target for 2020 is 35%.
There is also an opportunity to use recycled materials in concrete. This can be either directly, as recycled aggregate, or indirectly, such as the ferrous metal reused in the manufacture of most steel reinforcement. Environmental rating schemes such as BREEAM encourage the use both of aggregates that have previously been used, and of secondary aggregates such as granulated slag.
The proportion of recycled or secondary aggregates used in concrete production is around 6% by mass, according to Guy Thompson. “Environmentally, it is preferable to use recycled aggregates as close as possible to their origin as their embodied CO2 value can exceed that of virgin materials if they are transported by more than about 10 miles by road. Secondary aggregates, such as stent from the china clay industry in Cornwall, have a much lower transportation CO2 as this is usually achieved by rail or ship, allowing them to be moved over much longer distances at the same or lower impact.”
The concrete industry is currently investing in generic Environmental Product Declarations (EPDs) and BIM guidance, to help designers harness the sustainability credentials of concrete on a credible basis from the earliest design stage of building and infrastructure projects. The Mineral Products Association published the first in 2013, declaring the lifecycle environmental impact of UK-produced cement. This has paved the way for the production of generic EPDs for precast concrete products and for ready-mixed concrete, which will provide designers, contractors and clients with a sound basis for project environmental or carbon assessments.
The 7th performance report will be launched on 3 March 2015 at Ecobuild and will be available to download from the 1 March from www.sustainableconcrete.org.uk.
Posted by Louise Fordham
Read the article online at: https://www.worldcement.com/special-reports/26022015/uk-concrete-industry-commitment-reaps-benefits-408/