STUDY ON CHLORIDE DIFFUSION PROPERTIES IN FLY ASH CONCRETE

The corrosion of reinforcing bar induced by chloride is the main cause of the properties degradation of concrete structures under chloride erosion environment. At present the vast majority of studies on chloride diffusion properties in concrete take free chloride ions as the object, while the diffusion properties of total chloride ions in concrete are rarely studied. A lot of studies have indicated that fly ash can improve the resistance of concrete to chloride erosion, thus the diffusion properties of free chloride ions and total chloride ions in fly ash concrete were studied by natural diffusion method in this paper, the effect of fly ash content on chloride diffusion properties was investigated, the time-dependence of chloride diffusion coefficient was taken into account, the relationship between the effective chloride diffusion coefficient and the apparent chloride diffusion coefficient was established, which sets the foundation for more scientific prediction of durability life of concrete structures under the chloride erosion environment.