During the construction of a wastewater treatment facility in 2007, the wet wells and other basins were coated with a coal tar epoxy. Within a year and a half after commissioning, the plant operators noticed that the coating was delaminating from the walls of several clarifier wet wells. Yet, inspections of the clarifier basins showed no coating failures. This article presents a field and laboratory investigation of coating deterioration as well as repair recommendation.

This paper presents data collected from 25-year-old concrete specimens exposed to tides in excess of 6 m (20 ft) and an average of 100 cycles of freezing and thawing per year at the Marine Exposure Station on Treat Island, ME. Results indicate that the incorporation of fly ash, slag cement, or silica fume and decrease in water-cementitious materials ratio (w/cm) lead to a substantial increase in the resistance to chloride penetration. However, at the same time, concretes with high levels of supplementary cementitious material may also experience greater surface loss and not be suitable for exposure to a harsh marine environment with multiple cycles of freezing and thawing unless w/cm is limited to 0.40 or less.

This article provides a brief review of physical salt attack (PSA) on concrete. PSA is often associated with concrete, stone, or brick elements in contact with wet soil containing dissolved salts (sodium sulfate, sodium carbonate, and sodium chloride or magnesium sulfate, calcium sulfate, calcium chloride, and sodium nitrate). At the evaporation front, a given salt solution becomes supersaturated and the salts crystallize. Crystals that form below the surface (subflorescence) can result in surface scaling.