Mineral Products Association Ltd (MPA), Hanson Cement, Building Research Establishment, Forterra Building Products
• Up to 60% reduction in CO2 emissions vs CEM I (the market leader) • New cements have been demonstrated for use in all concrete applications • UK standards to be updated to include the new cements
Construction, cement, concrete
Cements for UK concrete applications generally consist of two main components which are usually Portland cement (CEM I) with limited quantities of either fly ash*, GGBS** or limestone powder. The scientific literature has shown that cements can work better if more than two main components are used. In this project, cements with three main components were developed: CEM I-fly ash-limestone powder, and CEM I-ggbs-limestone powder. Not only can cements with more than two components work better in concrete, there is also the opportunity to improve energy efficiency and to reduce embodied carbon vs. single component (CEM I) and two component cements (CEM II and CEM III).
As the target application for the new cements is concrete, extensive testing was completed on laboratory concrete mixes containing the new cements. The tests investigated mechanical strength and shrinkage as well as resistance to carbonation, chlorides, sulfates, freezing/thawing and alkali silica reaction. The project successfully demonstrated that the new cements require less fly ash or GGBS to achieve performance compared with reference cements. Finally, a precast demonstration and installation was completed to demonstrate the suitability of the new cements for factory-produced concrete elements.
Currently 79% of the UK cement market sales is CEM I, with a total market of 10 million tonnes per annum. Of the new cements trialled in the project - one has a CO2 profile 60% lower than CEM I. If fully deployed this would result in a reduction in direct emissions from cement production of over 4 million tonnes of CO2 every year. On completion of the testing, the cements will need adoption and deployment.
MPA recommendations have been put to the British Standards Institution to include these new cements in the UK concrete standard (BS 8500), to help designers, specifiers, contractors and the wider construction sector reduce emissions related to the use of concrete.
The project was funded through the IEEA programme which supports the development of innovative technologies that will help industry reduce energy consumption and cut carbon emissions. It focuses on innovations with large potential cross-sector energy and carbon reduction impact - either new technologies or established technologies applied to new sectors. Over £15 million in public and private funding has been committed to develop solutions through partnerships between technology developers and industrial companies willing to test technologies on-site. The programme is funded by the UK government (BEIS) and managed by the Carbon Trust, with support from Jacobs.