Coupled moisture and salt transport in bulding materials: theoretical and experimental treatments

conference paper

English

Coupled moisture and salt transport in building materials is analyzed both theoretically and experimentally. First, basic models of moisture and salt transport in building materials are described with an emphasis to simplest and most complicated solutions. Then, material parameters related to moisture and salt transport in building materials are analyzed and basic measurement techniques for their determination are shown. Finally, an experimental analysis of coupled water and chloride transport in cement mortar in the conditions of one-sided sodium chloride-in-water solution uptake is presented. Moisture diffusivity is determined as function of moisture content and chloride diffusion coefficient as function of chloride concentration using two methods commonly used for analysis of moisture profiles, namely the double integration method and the Matano method. It is observed that water transport is much faster than chloride transport, and water transport in the initial time period is for the chloride solution faster and in later times slower than for distilled water. The observed differences in the calculated apparent values of moisture diffusivity and chloride concentration coefficients are attributed to the fact that Cl- and Na+ ions are adsorbed on the pore walls faster than water molecules. This effect can be included into mathematical models using ion binding isotherms.

salt, concrete, transport, moisture

ČERNÝ, R., PAVLÍK, Z., ROVNANÍKOVÁ, P.

2002

1. 1. 2002

Praha

1

16

16