This is a special section of the British Cement Association's
website. It has been set up to help anyone who
received concrete made with cement from Lafarge Cement UK's
Westbury Works in Wiltshire between September 2002 and December
2004 and is concerned that it needs checking.
Lafarge has discovered that the alkali levels in its cement
during this period were higher than the declared
mean alkali levels used by concrete producers in creating their mix
designs. As a result a number of ready-mixed concrete producers
inadvertently supplied non-conforming concrete to customers in the
South West of England.
After completing a detailed investigation to identify what
happened, Lafarge has confirmed that this incident was isolated to
Westbury Works and solely related to the reporting of alkali
levels. Quality reporting and cross-checking systems were
strengthened in all plants to ensure that such an incident cannot
The true alkali data for the period was documented and has
been made available. The company has been
working with the ready-mixed concrete producers to whom it supplied
Westbury cement during the period, sharing all technical data and
meeting its responsibilities in dealing with the problem.
What problems could high
alkali cement cause?
Concrete is inherently alkaline. However,
in certain conditions, high levels of alkali have been linked to
the development of damaging alkali silica reaction (ASR) to an
extent that it causes the concrete to expand and
crack. For damaging ASR to occur, all of the
following factors must be present: high levels of alkali in the
concrete; reactive aggregates; and the presence of moisture.