CHANGE IN CHLORIDE PENETRATION PROPERTIES OF MORTAR DUE TO DEF EXPANSION

Abstract

The objectives of this study were to clarify the characteristic changes in the chloride penetration of mortars with DEF expansion and to investigate the effect of chloride penetration on the acceleration of DEF expansion. Mortar specimens with DEF were immersed in NaCl solutions of different concentrations to evaluate the expansion amount, chloride ion profiles, and pore structure. As a result, a trend toward greater expansion due to DEF was shown when the concentration of the immersed NaCl solution was 3％. For specimens immersed in NaCl solutions for 28days, chloride ions penetrated deeper in the mortar specimens with DEF expansion than in the specimens without DEF expansion. Based on the pore size distribution, capillary pores with diameters ranging from 50nm to 4μm were formed in the specimens with DEF expansion. Therefore, the chloride penetration was probably enhanced by the increase in capillary pores of 50nm to 4μm in diameter associated with DEF expansion.