The effects of carbonation and drying during intermittent leaching on the release of inorganic constituents from a cement-based matrix

A Portland cement mortar was submitted to cycles of intermittent wetting (IW) in which tank leaching was interspersed with periods of storage in either an inert or a reactive atmosphere. Relative humidity (RH) (23%, 48% and 98%) was maintained during storage to control the drying process. The effects of IW were qualified by comparing flux and cumulative release of matrix constituents (Ca, OH, Na, K and Cl) to that of continuous water saturation. The carbonation process was associated with the degree of drying occurring due to storage. Cumulative release of most major constituents was suppressed in samples storage under 100% CO2 in comparison to the inert atmosphere (100% N-2)Results suggest that accurate long-term performance assessment must account for the potential impact of phenomena associated with IW. (C) 2003 Elsevier Ltd. All rights reserved.