Page 260 - Handbook of Thermal Analysis of Construction Materials

Section 6.0 - Phosphonates 241

(HEDP), diethylenenitramine pentamethylene phosphonic acid (DTMP),
and their corresponding sodium salts were added to cement and cement
compounds in small amounts of 0.03–0.09% in order to study their
retarding action. Conduction calorimetry and DSC techniques were
applied. [30]

Figure 13. Influence of 0.1% glucose (G), sodium gluconate (NG), and lignosulfonate high
or poor in sugar acids (LSA and LS respectively) on C S hydration.
3

A phosphonate-based admixture, ATMP (amino trimethylene
phosphonic acid) in amounts of 0.03–0.05%, was added to C S and C A at
3
3
a w/s ratio of 1.0 and the heat, developed with time, was followed by
conduction calorimetry. [31] Phosphonic acid affects the hydration of C S
3
(Fig. 14). The reference C S produced a maximum exothermic peak with a
3
heat equivalent to 5.32 cals/g/h at 8.5 hours. Addition of phosphonic acid
reduced the amplitude of the peak, delayed the occurrence of the peak, and
also modified the appearance of the peak. About 1.79 cals/g /h of heat was
developed at 11.5 hours with the addition of 0.03% phosphonic acid, and,
at a dosage of 0.04%, an exothermal peak occurred at 31 hours with a heat
production of 1.41 cals/g/h. At 0.05% addition, there was practically no
heat produced even up to 72 hrs.