CHLORIDE PENETRATION INTO MARINE CONCRETE IN A SIMULATED AGGRESSIVE ENVIRONMENT

Performance of concrete, in terms of chloride penetration, subjected to severe marine conditions is investigated in a full-scale laboratory exposure test. Two types of concrete, one with ordinary Portland cement alone and the other blended with blast furnace slag cement, cured with different conditions, have been tested. Concrete specimens were exposed to wettingldrymg and heatinglcooling cycles simulating the tidal zone of marine structures with daily temperature variations. This simulates the concrete elements in marine structures exposed to environmental condition of the tropical regions such as Persian Gulf. The effect of "restraint" of thermal strains on the rate of chloride ingress into concrete has been evaluated. The top surfaces of large beams, as "restrained" elements, and small cubes, as "unrestrained" test specimens, are exposed to the chloride environment. The chloride contents in all specimens were measured. Results from this experiment show that temperature variations accelerate chloride penetration substantially. High chloride resistance in slag concrete specimens was observed compared to Portland concrete in the simulated marine environment. While concrete with normal Portland cement was adversely affected by elevated temperature curing, the slag cement concrete was less susceptible to curing conditions, at least under the conditions of the test.