Influence of Sodium Aromatic Sulfonates on the Hydration of Cement

• Published in: Nippon Kagakukai shi (1972) Vol. 1977; no. 2; p. 208
• Main Authors: SAKAI, Etsuro, YAMANAKA, Seiji, DAIMON, Masaki, KONDO, Renichi
• Format: Journal Article
• Language: English; Japanese
• Published: Tokyo Japan Science and Technology Agency 01.01.1977
• ISSN: 0369-4577
• DOI: 10.1246/nikkashi.1977.208

The influence of sodium aromatic sulfonates including two series of anionic surfactants, on the hydration of alite (3 CaO, SiO2 solid solution) and portland cement was studied by means of conduction calorimeter (see Fig.2). And dispersion of cement with anionic surfactants was discussed by means of sedimentation velocity. Amount adsorbed on cement was determined by UV method. Compounds consisting of short hydrophobic chains scarcely affected the hydration of cement (see Table 2). Anionic surfactants retarded remarkably the hydration, and the retarding mechanisms were dependent on the structure of anionic surfactants. Type I anionic surfactants have a hydrophilic group (-SO3Na) at the end of the molecule. Type ii anionic surfactants have hydrophilic groups in the molecule. Surfactants of type I showed the critical amount of addition. The hydration of cement was not retarded when less surfactants were added than the critical amount, but it was strongly retarded when more surfactants were added than the critical amount. On the other hand, in the case of type II, retarding effect became gradually larger with increasing amount of surfactants (see Table 2, Fig.8). It was suggested that surfactants type I, when present more than the critical amount (see Fig.14-(a)), were closely adsorbed on cement particles. And the hydration of cement was inhibited by the close adsorption of type I anionic surfactants. But in the case of type If anionic surfactants, instead of close adsorption, flat adsorption occurred (see Fig.14-(b)). These results were consistent with the results of sedimentation velocity and amount adsorbed (see Fig.10, 12).