Balance between sulfate and aluminate in cement is important to regulate setting
behaviour and interaction between cement and admixtures. The increasing use of
supplemental cementitious materials (SCM) results in more complex interactions
between cementitious and admixtures. Insufficient sulfate in cementitious system is
one of the common causes of incompatibility problems, such as extended setting time
and slower than expected strength development.
This paper discusses the role and effect of sulfate in improving cementitious and
admixture interaction to optimise the performance of concrete containing SCM
materials. Case studies of concrete field problems are presented to demonstrate that
sufficient sulfate in cementitious is necessary to ensure field performance of concrete
with more robust responses to variation in chemical admixtures.