Statistical modelling of the microfiller effect on the rheology of composite cement pastes

Experiments were designed based on a so-called uniform-precision factorial plan to investigate the effect of limestone microfiller replacement of cement on the rheological properties of low w/c ratio super plasticized cement pastes. Cement pastes of different w/b ratios and incorporating various proportions of limestone powder and/or silica fume were assessed in terms of the saturation dosage of super plasticizer using a modified Marsh cone flow time. At a constant flow time, the different cement pastes were further characterized using a coaxial cylinder viscometer, a mini slump test and an induced bleeding test. The flow of mortars corresponding to the various cement pastes were also investigated, and the different rheological tests were compared. The statistical approach used highlighted the micro filler effect on the various rheological characteristics of cement paste, and permitted its modelling over the selected experimental domain.