Title: Chloride Absorption from Concrete Surfaces
Author(s): A. Lammke
Publication: Symposium Paper
Appears on pages(s): 197-210
Keywords: absorption; calcium chlorides; chlorides; concretes; lime
After actual fires with plastic materials involved concrete surfaces are often infested with high chloride concentrations, causing a serious risk of corrosion of the reinforcement. Absorption techniques with lime paste have been recommended to remove chlorides from concrete surfaces. To study this reaction concrete beams with different chloride contents, added as sodium chloride, were cast. The chloride distribution in the concrete before and after lime paste treatment and the chloride content of the used lime were determined analytically. The results show that the lime does not absorb chlorides, and within the concrete, the chlorides are redistributed. Further tests were made to study the rate of chloride absorption from aqueous solutions by lime, acti-vated carbon and ion exchange resins. The amount of absorbed chloride was very low. Corresponding the absorption of chlorides by fresh pastes of different cements and completely hydrated cements was studied. An effect of absorption but much more of chemical bond was shown.