Effect of supplementary cementitious materials on viscosity of cement-based pastes

Assessment of viscosity is important for development of new concrete technologies. In this study, the effect of particle size and type of supplementary cementitious materials (SCM) and their interactions with the main mixture parameters (i.e., cement type, solid volume fraction (phi T), amount of SCM) on the viscosity of cementitious paste is analyzed. It is shown that the effect of particle size on viscosity is better explained by the particle number density than by the specific surface area of the cementitious particles. The viscosity can be increased by increasing 1) the number of contact points, which is governed by phi T and particle number density, or 2) the interparticle force between cementitious particles, which is controlled by the roughness of the cementitious particles and phi T, which affects the zeta potential of the cementitious paste. phi T has a greater effect on viscosity than the particle size and interparticle force of the cementitious particles.