Effect of metakaolin on chloride binding in lime-based composites

Abstract

The determination of chloride binding isotherms for two different types of lime-based composite materials containing metakaolin is presented in this paper. The experiments are performed on small specimens with defined shape so that the effect of the porous structure is respected. Also, the experiment with crushed samples as in the original procedure by Tang and Nilsson is done for the sake of comparison and the differences analyzed. It is concluded that the chloride binding capacity of lime-based materials depends critically on the size of the sample. Therefore, the result obtained by the original Tang and Nilsson method can be considered as a certain upper limit to the real chloride binding capacity.