关键词: 稳态测试;剪切模式;动态屈服应力;塑性黏度

Abstract: The steady-state rheological curves of cement paste under different shear protocols were determined by means of RHEORIAB QC rotary viscometer,and the effect of shear protocols on steady-state rheology of cement paste was studied by fitting curves to the modified Bingham rheological model.The results show that: Pre-shearing has little effect on the dynamic yield stress and plastic viscosity of cement paste,when the constant shear rate of the cement paste is less than,equal to,greater than or much greater than the shear resistance of initial structure,the shear stress show trends of keeping the same value after a linear increase,keeping a constant value,decreasing and then keeping constant or increasing slightly and then reaching an equilibrium with time.With the increase of shear rate,the cement pastes show rheological behaviors in turn of shear thinning,Bingham fluid and shear thickening in the intervals of 0.1-100 s-1,100-400 s-1,400-600 s-1 respectively.The range of the shear rate shifts to the shear thinning or shear thickening rate interval,the dynamic yield stress of the cement paste decreases and the plastic viscosity increases.The longer the shear time of a single shear rate is,the smaller the dynamic yield stress and plastic viscosity of the cement paste are.

Key words: steady-state test;shear protocol;dynamic yield stress;plastic viscosity