in Accordance with BS 8500-1:2015+A2:2019
I have, over the last couple of years, been privileged to be part of Committee B/517 for British Standards, Ltd. which helped to shape the changes for the UK Marketplace for the specification of concrete.
The specifier is offered five ways to specify concrete within the standard specifications for designated, designed, prescribed, standardised prescribed and proprietary concretes.
The latest amendment to BS 8500 allows the use of natural pozzolana, natural calcined pozzolana or high reactivity natural calcined pozzolana as an addition in Portland‐pozzolana, pozzolanic cements and ternary cements, i.e. blends of three types of cementitious binder which include up to 20% limestone fines.
The changes above are based on the assumption that their performance in concrete is similar to PFA and the recommendations for ternary cements are for applications where their use is considered safe and durable.
The recommendations for the use of natural, natural calcined and high reactivity natural calcined pozzolana, as part of cement or combination, are based on the assumption that their performance in concrete is similar to PFA.
The use of ternary blends does not necessarily mean cement blended / inter-ground at the cement producer’s factory. This means you can purchase three different, or more additions if you have the silo capacity, which could not only lower the overall embodied carbon of your concrete but may also increase your commercial margins with certain types of concrete being supplied as a producer.