Page 218 - Handbook of Thermal Analysis of Construction Materials

Section 2.0 - Calcium Chloride 201

The development of heat produced by the addition of calcium
chloride on portland cement Type I from different plants shows significant
variations (Fig. 9). This is due to the differences in the fineness and
chemical composition of cement.

Figure 9. The effect of CaCl on the heat development in four Type I cements.
2

Ramachandran and Feldman [15] compared the rate of hydration of
cement in the presence of calcium chloride by following the amount of
Ca(OH) , non-evaporable water, or heat development. Calcium chloride, in
2
amounts of 0, 1, 2, and 3.5%, was added to cement at w/s ratios of 0.25 and

0.40. Hydration was followed from a few minutes to thirty days.There was
good correlation between the non-evaporable water content and heat
development. It was also observed that cement containing 3.5% hydrated to
the greatest extent in the early periods, but lower amounts of calcium
hydroxide were formed at this dosage. This was explained by the formation
of C-S-H with a higher ratio in such a cement. It was also concluded that the
hydration kinetics cannot be accurately studied by the estimation of lime,
especially at a lower w/c ratio.
Calcium chloride also accelerates the rate of hydration of Type II,
IV, and V cements but only marginally that of Type II, a high early strength
cement.