Civil Engineering Reference
In-Depth Information
Martin and Brown investigated the hydration of tetracalcium
phosphate (C
4
P) due to the fact that it is the only calcium phosphate more
basic than hydroxyapatite.
[31]
Its hydration was considered to be conceptu-
ally similar to that of the silicates. The reaction was considered to be
represented by the following equation:
Eq. (9)
3Ca
4
(PO
4
)
2
O + 3H
2
O = Ca
10
(PO
4
)
6
(OH)
2
+ 2Ca(OH)
2
Heat evolution curves for the reaction at 25, 38, 55, and 70°C are presented
in Fig. 33. Heat evolution is undetectable after 5 hours at all temperatures.
Figure 33.
Hydration of Ca
4
(PO
4
)
2
at 25, 38, 55, and 70°C: (
a
) calorimetric rate curves;
(
b
) calorimetric rate of reaction curves.
[30]
