Impact of physical and physicochemical properties of supplementary cementitious materials on structural build-up of cement-based pastes

Understanding the structural build-up is relevant to new technologies that require workability control, such as 3D concrete printing. The effect of supplementary cementitious materials (SCM) particle size (i.e. specific surface area and particle density) and physicochemical behavior (i.e., chemical reactivity and surface potential) and their interactions with the primary mixture parameters (i.e., water to cement ratio, cement reactivity and SCM replacement) on the structural build up of cementitious paste were studied. The growth of static yield stress with time was used to characterize the structural build up of cementitious pastes. Calorimetric curves were also measured. Results showed that the effect of SCM on structural build up is governed by their particle density and surface potential. The structural build up can be raised by increasing the number of contact points (governed by particle density and w/c), the growth rate of C-S-H bridges (governed by surface potential), or the reactivity of cement.