Civil Engineering Reference
In-Depth Information
composition of C-S-H (in terms of C/S ratio) is variable depending on the
time of hydration. At 1 day, the C/S ratio is about 2.0 and 1.4-1.6 after
several years. The C-S-H can take up substantial amounts of Al
3+
, Fe
3+
, and
SO
4
2-
ions.
Figure 5.
Fraction of cement phases hydrated in cement pastes at different times.
Recent investigations have shown that in both C
3
S and portland
cement pastes, the monomer that is present in the C
3
S and C
2
S compounds
(SiO
4
4-
tetrahedra) polymerizes to form dimers, and larger silicate ions as
hydration progresses. The gas liquid chromatographic analysis of the
trimethyl silylation derivatives has shown that anions with 3 or 4 Si atoms
