Resource Efficiency

Performance indicator

There are significant volumes of by-product materials such as ground granulated blastfurnace slag (GGBS) and fly ash that can act as part of the cementitious binder in concrete. These materials have a lower embodied carbon than cement and can also influence the appearance and performance of concrete.

Additional cementitious materials

The amount of additional cementitious materials as a proportion of total cementitious materials


Additional Cementitious materials


This indicator is influenced by the types of concrete required for the market, which influences the appropriate replacement rates of cement. The 2020 target is 35%.


In 2014, 26.2% of the total cementitious materials used were

additional cementitious materials.

Recycled/secondary aggregates

The use of recycled/secondary aggregates as a proportion of total aggregates used


Recycled/Secondary Aggregates

Depending on the application and the type of concrete there is often an opportunity to incorporate recycled aggregates previously used in other projects and secondary aggregates that may be by-products from other processes.


The specification of recycled and secondary aggregates is a balance of resource efficiency, transportation CO2 and the implications on mix design. Consequently, these aggregates should be used in concrete production where it is technically and environmentally beneficial to do so.


The proportion in concrete has risen slightly in recent years to over 7% by mass. In 2014 around 28% of all aggregates in GB were recycled or secondary, far above levels elsewhere in Europe.


Recycled concrete, as well as being used as an aggregate, is often used at the source of demolition, as part of sub-structures and external landscaping for a new development. For more information download Specifying Sustainable Concrete and Concrete and BREEAM from The Concrete Centre at

Recycled steel reinforcement

Steel reinforcement manufacturing BAR members used approximately 91% of recycled ferrous metal waste as a proportion of the raw materials consumed in their electric arc furnaces (EAF). The BAR members who are reinforcement

fabricators used 95% EAF material in producing and supplying rebar for use in concrete.


These indicators are part of the Materials section of the report and 2020 Commitments. An update on our Materials 2020 Commitments.