Effect of Sea Salts on Structural Concrete in a Tidal Environment

Abstract

SummaryStructural concrete exposed to the tidal/splash zone of marine environments is always subjected to ambient external, as well as internal, action of seawater over its entire lifespan. The environmental loading causes maximum damage to structural concrete in the tidal/splash zone of marine environments where it experiences the concentrated effect of salt ions found in seawater in presence of atmospheric oxygen, carbon dioxide and other harmful gases. The gradual penetration of sea salt ions and the formation of expansive/leachable compounds leads to cracking, spalling and even structural distress. This paper presents a part of a durability study on the effect of sea salts on structural concrete exposed to simulated tidal/splash zone marine conditions over a period of one year. The concrete specimens cast from two different grades of concrete were exposed to seawater of different concentration under submerged, alternate wetting-drying and atmospheric state of exposure in a controlled humidity and temperature environment. Using accelerated test techniques, the deteriorative effects were measured by studying visual appearance, weight and volume change, compressive strength, permeability and stress-strain characteristics, and x-ray diffraction patterns of salt-attacked concrete specimens. The test data provide useful information regarding the durability of structural concrete exposed to the tidal/splash zone of marine environments.