To investigate the structural build-up of the C 3 A pastes in the presence of the sodium salts, oscillatory time sweeps were performed on a rotational rheometer (MCR 302e, Anton Paar, Austria) at 20 • C. The pastes were tested with a plate-plate geometry (PP25/P2, diameter = 25 mm). Both plates were serrated to prevent wall slippage during the measurements . All measurements were conducted with a gap size of 1.00 mm at a constant shear strain (γ = 10 -4 ) and at a constant angular frequency (ω = 1 rad s -1 ) for 3 h. The chosen strain is within the LVR of the C 3 A model suspensions. The groove on the bottom plate was filled with deionized water, and the measuring geometry was covered with a hood to avoid evaporation during the experiments. The storage modulus (G ′ ) represents the elastic portion of the shear modulus and is proportional to the energy stored when the material is subjected to oscillatory shear.