Civil Engineering Reference
In-Depth Information
Figure 2.
DTA and XRD data for a Secar 71 paste hydrated at 10°C for 24 hours.
[1]
Carboaluminate phases (e.g., C
4
A
-
H
11
) can form when hydration
takes place in normal atmospheres. The presence of this phase is indicated
by a DTA peak in the region 180-200°C, which can overlap with the peak
due to the presence of C
2
AH
8
. A shoulder may be present for the phase
present in the lesser amount.
Figure 3 is a plot of various DTA thermograms (Secar, Alcoa CA,
Secar + C
-
) depicting the presence of C
2
AH
8
and C
4
A
-
H
11
. Thermograms
for pastes to which CaCO
3
had been added are included in Fig. 3. Supple-
menting Fig. 3 are bar graphs indicating the relative amounts of the phases
determined by XRD.
