For C-S-H precipitates, transmission electron microscopy was conducted to characterize the morphology of the precipitates. During the titration experiments, a 5 µL aliquot of the suspension was removed at the point of maximum calcium concentration, i.e., at the onset of nucleation. The time of sample collection was also varied. Later sample removal, however, leads to strongly agglomerated C-S-H particles whose primary structure can not be meaningfully characterized by TEM. After removal from the titration solution, the sample was directly deposited on a carbon-coated TEM grid (Carbon Film 300 Mesh, Copper, Sigma-Aldrich), and the excess water was immediately removed by blotting with filter paper. The samples were analyzed using a JEM 1400 plus microscope (JEOL) equipped with a LaB 6 electron gun.