EXPERIMENTAL AND THEORETICAL STUDY OF CHLORIDE ION TRANSPORT IN CONCRETE UNDER CYCLIC WETTING AND DRYING

摘要

A series of cyclic test were performed to obtain an understanding of the physicalmechanisms causing the accumulation of chloride in the interior pores of concrete during thedrying and wetting phases of the cycle. The research shows that the rate of chloride transportin concrete under wet and dry cycles is rapider than that in saturated concrete. The resultsshow that chloride ions are carded by water into the concrete under wet and dry cycles,instead of by diffusion. Under wet and dry cycles,the transport rate of the chloride ionsdepends on the duration of the wetting and the drying phases,chloride concentration at thesurface of concrete,the number of cycles,and the difference in moisture contents betweenthat at the end of wetting phase and that of drying phase.