ABSTRACT
In 1986 a joint Building Research Establishment (BRE)/British Cement Association (BCA) Working Party agreed a programme of research to investigate the effect on cement and concrete properties of the addition of calcareous fillers to ordinary and rapid-hardening Portland cements. The work programme was divided between BRE and the UK cement manufacturers and work commenced in the summer of 1987. Cements with calcareous additions of 5% and 25% (approximately) by mass were studied. These addition levels were chosen because (i) the European Pre-Standard for cement, ENV 197-1[1] and its earlier drafts which were available at the time that the research programme was established, permit additions of up to 5% of minor additional constituents, including limestone, to all cement types; and (ii) the earlier drafts of ENV 197-1 included a limestone-filler cement with a maximum limestone content of 20%, although at the time of designing the programme it was unclear whether this maximum value would be 20 or 25%, the latter being chosen for this work in order to represent the possible extreme situation.
