Civil Engineering Reference
In-Depth Information
Figure 19.2
Cumulative evolution of hydration heat in different types of
Portland cement.
similar effect may also be observed in cements containing natural pozzolanas. Most
blended cements that contain fly ash or natural pozzolana in sufficiently high amounts, in
combination with Portland clinker and gypsum, qualify as low-heat cements.
B
elite-rich Portland cement
and
belite cement
possess a low heat of hydration due to
the absence or presence of reduced amounts of tricalcium silicate among their
constituents (Kuba
et al.,
1997; Matsunaga
et al.,
1997; Uchida, 1998). In general, the
amount of released heat decreases with increasing C
2
S content (Matsunaga
et al.,
1997).
At a constant C
2
S content, the ratio of heat of hydration to strength in these cements also
depends on the A/F content in the interstitial phase, and is at a minimum when the
composition of the interstitial phase is close to C
6
AF
2
(Ikabata and Takemura, 1997). The
effects of fineness and SO
3
content on the heat evolution of belite cements are rather
small (Nagaoka
et al.,
1994).
Unlike belite cements,
sulfobelite cements
tend to exhibit a fast initial rate of
hydration heat release, owing to a fast hydration of the C
4
A
3
phase, and do not usually
qualify as low-heat cements.
C
alcium aluminate cement
does not qualify as low-heat cement either, as its heat of
hydration is high (500 k J/kg), and most of it is released within the first few days of
hydration.
REFERENCES
Ikabata, T., and Takemura, H. (1997) Influence of the composition of the interstitial
phase on the hydration properties of belite cements, in
Proceedings 10th ICCC,
