Frost Resistance of Marine Concrete in Cold Regions

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1. Scaling Damage Survey of Marine Concrete in HokkaidoEleven concrete structures which were constructed in 1987 were investigated. The main results are as follows. The maximum depth of scaling was 8.6mm, the scaling area became wider with age, and the scaling ratio(the scaling depth multiplied by the scaling area) made rapid progress for the first one or two years after construction.2. Properties of Concrete Exposed to Tidal or Splash Zone for Five or Seven Years.The following were confirmed by the results of exposure test of concrete specimens which were exposed to the Sea of Okhotsk. Marine environment in cold regions has extremely severe conditions for concrete. Concrete which contained silica fume or eight percent air volume show good resistance to scaling.3. Reliability Analysis to Scaling of Concrete Exposed to Splash Zone for 16 Years.Reliability theory for assessing concrete scaling was attempted. The specimens were one cubic meter and were exposed to the Sea of Okhotsk. The following conclusions were drawn. Weible distribution for reliability function conformed to frequency distribution of scaling depth which were not lower than the set-up ratio. The year lapse of fifty percent reliability for scaling at the constant set-up ratio agreed with the measurements.