Page 251 - Handbook of Thermal Analysis of Construction Materials

232 Chapter 6 - Retarding and Water Reducing Admixtures

G = C-S-H
H and H 2 = first and second peaks for C AH and C AH 8
1
2
13
4
H =C AH
3 3 6
CH = Ca(OH) 2
CC = CaCO
3
Figure 8. Influence of sodium carbonate (NLS) and sodium lignosulfonate + sodium
carbonate (NC) on the paste hydration of C S (80%)-C A (20%).
3 3

2.7 Cement-Lignosulfonate-Water System

Thermal investigations have shown that the rate of hydration of
C A and the inter-conversion of ettringite to the low monosulfoaluminate
3
in the C A-CaSO •2H O-CLS-H O system, and hydration of individual
3
2
4
2
cement phases C AF, C S, and C S are all retarded by lignosulfonates.
4 3 2
Thus, it is expected that the rate of hydration of cement should also be
retarded by the addition of lignosulfonates.