ABSTRACT
In the UK, limestone filler is generally used as the minor constituent for CEM I cements. There has been at least one case in the UK where the change to using a minor constituent coincided with problems of low strength concrete that could not be attributed to changes in the cement strength nor other concreting materials. Whilst it is not proven that the change to using a minor additional constituent was the prime cause of the sudden change in concrete strength, it reinforces the fears that producers hold that there can be changes to cement within the standard that have a significant impact on concrete performance, but are not reflected in the information we are normally supplied with. The UK cement and concrete producers are working together to establish if there are real grounds for concern and, if so, how they can be solved.
