Title: Mechanism of Chloride Ion Adsorption in Cement Hydrates as per Time-Dependent Behavior
Author(s): In-Seok Yoon and Tatsuhiko Saeki
Publication: Materials Journal
Appears on pages(s): 41-53
Keywords: adsorption behavior; AFm phase; Ca/Si ratio; chloride binding; C–S–H phase
The purpose of this study was to explore the mechanism of the interaction between cement hydrates and chloride ions by examining the time-dependent behavior of chloride ion adsorption.
The CH and AFt phases had no role in the adsorption of chloride ions. The AFm phase clearly adsorbed chloride ions rapidly, and the trend was clearly observed over the 20 days of the test period. The ion exchange reaction for adsorption was nearly stopped after 40 days. The C–S–H phase showed an adsorption behavior with three stages, and the trend depended on the Ca/Si ratio. The C–S–H phase showed a complicated adsorption behavior by not only physical adsorption that progressed relatively faster but also by slow
chemical adsorption. The highest chloride adsorption capacity was observed for the C–S–H phase with a Ca/Si ratio of 1.50.