THE PENETRATION OF CHLORIDES IN UNCARBONATED AND CARBONATED CONCRETE

An investigation was carried out into the penetration of chlorides in uncarbonated and carbonated concretes made with different cements and cement-additive mixes. The chloride content of the concrete after stor age for one year in a 3% NaCl solution was measured as a function of t he distance from the surface exposed to the action of chlorides. The t ests have shown that there are differences in the way the chloride pen etrates into uncarbonated and carbonated concrete. In carbonated concr etes it takes place substantially more rapidly than in uncarbonated co ncretes. The chloride levels after reaching the equilibrium state are, however considerably lower in the carbonated concretes than in the un carbonated ones. In carbonated concretes the different cements or ceme nt-additive mixes have very little effect on the chloride penetration and chloride level. The chloride levels in uncarbonated concretes clos e to the surface exposed to the chloride solution are larger than valu es obtained mathematically by just assuming that the capillary pore sp ace is filled with the storage solution.