INFLUENCE OF SALT WEATHERING ON THE PROPERTIES OF CONCRETE

Salt weathering is now known to be as much a widespread problem as corrosion of embedded steel in reinforced concrete structures exposed to aggressive marine environments. A growing shortage of good quality uncontaminated aggregates and mixing water free of chlorides, especially in the coastal regions of the world, means that chlorides may get trapped in the concrete well before it is exposed to hot, marine environments. The integrity and the durable service life of concrete structures under these conditions then very much depend on the ability and performance of salt contaminated concrete to resist further intrusion of chlorides from external sources. The overall aim of this paper is to present some of the critical engineering and durability properties of concrete made with and without slag, and with or without chlorides when exposed to salt laden environments. The tests reported include compressive and flexural strength development, swelling and shrinkage, water and chloride absorption and oxygen permeability after exposure up to 250 days. It is shown that the immediate effect of exposure to such environments is long-term loss of strength, expansive strains, and vulnerability to internal microcracking leading to enhanced permeability and long-term lack of durability of concrete.