DESCRIPTION
In forming a watertight concrete structure it is not sufficient to prevent the passage of water through the joints; water must also be prevented from penetrating into the concrete especially penetration due to capillary attraction. The presence of water in hardened concrete can cause corrosion of the reinforcing steel with subsequent spalling. Serious damage may result from the alternate freezing and thawing of concrete containing absorbed moisture. Further, the structure may be chemically attacked in depth if water entering the concrete contains dissolved deleterious matter. All concrete, however well made and placed, contains pores left by the evaporation of the mixing water not taken up in hydration, and will therefore be susceptible to the types of deterioration by reducing the permeability of concrete and by making it water repellent.
