Apparent yield stress measurement in cemented paste backfill

The effect of specimen composition on the apparent yield stress of cemented paste backfill (CPB) is studied using a Brookfield rotational viscometer with vane geometry. The factors that are assessed include binder type and content, selected chemical admixtures (superplasticizers) and pore fluid chemistry (e.g. ionic concentration and pH). The difficulties associated with performing viscosity measurements on high solids content mixtures are addressed. Additionally, the zeta potential of the mine tailings is measured using an electroacoustic spectrometer. The data indicates that particle packing, electrostatic forces and hydration of the cement affect the flow behaviour of CPB.