STUDY ON DURBILITY OF ANTI-WASHOUT CONCRETE UNDER MARINE ENVIRONMENT

In recent years, structures made with anti-washout concrete under marine environment have been increasing. However, the durability of such structures is not yet clarified. Therefore, in order to understand the durability of reinforced concrete made with anti-washout concrete, exposure tests were carried out under a marine environment for ten years. The reinforced concrete specimens prepared with anti-washout concrete containing either silica fume or ternary low heat cement were exposed to marine atmosphere and underwater. Investigations were focused on the variation of concrete quality, concentration chloride ion and corrosion of reinforcement. From test results, the compressive strength of anti-washout concrete is similar to reference concrete in ordinary structures. The carbonation depth of the anti-washout concrete made without silica fume admixture is lower than that of reference concrete. At the distance of 2 cm from the surface of underwater cast concrete of the chloride ion concentration is sufficient to corrode the reinforcement of any concrete. After 10 years of exposure to marine environment, that of reference concrete is from 5 to 10 times that of anti-washout concrete. Therefore, the anti-washout concrete is durable under marine environment and it is possible to design for durability in the same way as for normal concrete.