Limestone filler/cement ratio effect on the flow behaviour of a SCC cement paste

The effect of cement substitution by limestone filler on the steady and transitory rheological behaviours of a fresh self-compacting cement paste has been studied. An absolute rheometer has been used to measure rheological parameters. Whereas a small proportion of limestone filler (< 3% w/w) favours the self-compacting behaviour, higher concentrations of this additive modify the system to convert it into a conventional paste. The thixotropy study has been made just after contact of the cement with water during the first 10 min. The cement hydration masks the reversible effects when the tests last more than this time limit. An exponential growth fits the evolution with time of the structure built at rest. The microstructure build-up rate parameter does not show dependence with the limestone filler concentration. The microstructure break-down rate parameter slightly increases with the limestone filler concentration.