This Guide describes basic procedures for surface preparation and application of coatings to concrete surfaces in industrial plants or commercial facilities.
The Guide is pertinent for both new construction and maintenance applications.
This Guide is intended for use by the owner’s representatives and applicators.
Coatings are applied to concrete surfaces to prevent degradation, to maintain appearance and to preserve purity of product contained within a concrete structure.
The major procedures covered in the Guide are surface preparation, coating application, inspection, and safety.
Bug Holes: Small regular or irregular cavities, usually not exceeding 15 mm in diameter, resulting from entrapment of air bubbles in the surface of formed concrete during placement and consolidation.
Concrete: A composite material that consists essentially of a binding medium within which are embedded particles or fragments of aggregate, usually a combination of fine aggregate and coarse aggregate.
Curing Membrane: Materials applied to prevent the moisture in uncured concrete from evaporating too rapidly.
Efflorescence: A white crystalline or powdery deposit on the surface of concrete. Efflorescence results from leaching of lime or calcium hydroxide out of a permeable concrete mass over time by water, followed by reaction with carbon dioxide and acidic pollutants.
Form Release Agents: Compounds such as petroleum oils, waxes, and silicones applied to forms to allow easy removal of forms.
Hydration: The reaction of water with the calcium silicate, aluminate or aluminoferrite components of fine cement grains, necessary for the setting and densifying of concrete. Hydration results in the formation of calcium hydroxide and colloidal gels which occupy a larger volume than the original cement.
Hydrostatic Pressure: The pressure exerted by water at rest.
Laitance: A thin, weak, brittle layer of cement and aggregate fines on a concrete surface. The amount of laitance is influenced by the degree of working or amount of water in the concrete.
Outgassing: The upward and outward emission of air or moisture vapor from concrete.
Surface Porosity: Porosity or permeability at the concrete surface that may absorb vapors, moisture, chemicals, and coating liquids. Small interconnected voids which allow fluids to penetrate an otherwise impervious material.
Surface Hardeners: Compounds applied to a concrete surface to improve hardness, and to decrease permeability.
