Page 212 - Handbook of Thermal Analysis of Construction Materials
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196                            Chapter 5 - Accelerating Admixtures














































                              Figure 5. Possible states of chloride in tricalcium silicate hydrated for different periods.



                                     Collepardi, et al., studied the hydrates formed during the hydration

                              of C S in the presence of calcium chloride. [8][9]  In an autoclaved sample
                                  3
                              containing CaCl ,they detected an exothermic peak in the thermogram that
                                            2
                              was attributed to the chemisorption of chloride on the C-S-H surface and its
                              penetration into the molecular layers of C-S-H.
                                     Compared to the extensive thermal investigations of C S hydration
                                                                                    3
                              in the presence of CaCl , only a limited amount of work has been reported
                                                  2
                              on the effect of calcium chloride on the hydration of C S. Calcium chloride
                                                                            2
                              accelerates the hydration of dicalcium silicate. In the thermograms of C S
                                                                                             2
                              paste hydrated for 1–3 months, lower amounts of calcium hydroxide are
                              formed in the presence of calcium chloride, compared to that hydrated
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