Studies of the Physical Properties of Hardened Portland Cement Paste Part 9. General Summary of Findings on the Properties of Hardened Portland Cement Paste

摘要

Microscopic observation of hardened paste indicates that only Ca(OH)_2 crystals and unhydrated residues of the original cement grains can readily be identified. Other microcrystalline constituents, particularly calcium sulfoaluminate, may be present in small amount but are generally obscured by the abundant "amorphous" constituents. The size and volume of the pores in hardened paste indicate that the solid material is finely subdivided, though the solid units are obviously bonded to each other. If the units were equal spheres, the sphere diameter would be about 140A. Since the computations leading to this figure included the volume of microcrystalline constituents, the units of "amorphous" material must be somewhat smaller than just indicated. The size indicated is definitely in the colloidal size-range. Since a gel is defined as a coherent mass of colloidal material, it follows that the principal constituent of hardened paste is a gel, here called cement gel.