What Changed in BS 8500:2023
BS 8500 is periodically revised as materials, environmental priorities and the understanding of durability move on. The 2023 edition followed BS 8500:2015+A2:2019 and introduced a number of changes; this page explains the broad areas that changed conceptually, without quoting specific old-versus-new numeric limits that should instead be checked directly against the current standard.
Low-carbon, multi-component cements
One significant area of development has been wider recognition of multi-component cements and combinations that use more than one secondary cementitious material together (for example combining fly ash or GGBS with limestone fines), reflecting the push toward lower embodied-carbon concrete without giving up durability performance. See cement and combination designations for how these are specified.
Revised exposure class tables
The exposure class durability limiting values — maximum w/c, minimum cement content and minimum strength class by exposure class and cement type — were also revised. Because these figures change between editions and are cross-referenced against specific cement and combination designations, this site does not reproduce a specific old-vs-new numeric table; see exposure classes and durability and check BS 8500-1’s current tables directly for the figures that apply to your project.
What this means in practice
For a live project, the practical implication is straightforward: confirm which edition of BS 8500 the project specification calls up, and use that edition’s tables and designations rather than assuming an earlier edition’s figures still apply, since a specification written under an older edition may reference designations or limits since revised.
Frequently asked questions
Does this site’s calculator use the 2023 edition?
The calculator works through the underlying EN 206 method and durability-limit concept common to both editions; for the exact current limiting values, BS 8500-1’s current tables should always be checked directly rather than relying on any single source’s fixed table, since editions do change.
Do I need to redesign existing approved mixes because of the 2023 edition?
Not automatically — a mix already approved and in use under an earlier edition’s specification is not automatically invalidated, but a new project specified against BS 8500:2023 should be designed against that edition’s own requirements.
Where can I find the full list of changes?
The British Standards Institution’s own published scope and foreword for BS 8500:2023, and BSI’s change-summary documentation, are the authoritative sources for the complete list of changes between editions.