Modeling of pH elevation due to the reaction of saline groundwater with hydrated ordinary Portland cement phases

普通ポルトランドセメントと塩水系地下水との反応によるpH上昇のモデル化

本田 明; 増田 賢太; 中西 博*; 藤田 英樹*; 根岸 久美*

Honda, Akira; Masuda, Kenta; Nakanishi, Hiroshi*; Fujita, Hideki*; Negishi, Kumi*

The pH elevation due to the reaction of saline groundwaters with hydrated ordinary Portland cement phases was modeled. The pH elevation is attributed to hydroxyil ion generation accompanied with the precipitation of Friedel's salt from the reaction of portlandite and hydrogarnet with chloride ions. The pH elevation was confirmed using actual hydrated OPC phases. However, in this case the pH elevation was lower than expected in this case. This deviation can be explained by the residual aluminum, after being consumed as AFt and AFm, not being wholly assigned to hydrogarnet and a better agreement between the thermodynamic calculations and the experimentally measured results can be made assuming a fraction of aluminum is incorporated into the CSH gel phase.