🕑 Reading time: 1 minuteSurface protection of concrete structural members is necessary to protect the structure from damage due to environmental considerations. Corrosion of reinforcement due to permeability of water / moisture, chemical attack on structural members, structures nearby sea-coast etc. are all responsible for damage to concrete structures. So, surface protection of concrete members becomes necessary to prevent such damages.
Methods of Protecting Concrete Surfaces from Damages and DeteriorationFollowing are the surface protection measures that may be taken to minimize or stop the damage to concrete structures:
Materials for concrete surface protection
(a) The materials used for impregnation, hydrophobation methods for concrete surface protection are:
- Silicon organic solutions
- Siloxanes and
- Silicon resins
- Polymethylmetacrylates (PMMA) and
- Epoxy resins
- Boiled (linseed) oil
- Linseed stand oil and
- Mixture products of boiled (linseed) oil or
- Linseed stand oil with not more than 15% unsaturated organic compounds.
(b) Sealers:In contrast to impregnation and hydrophobation, sealers are more effective is protecting the concrete surface by forming a film on the surface. Sealing of concrete surface is achieved by increasing the applied quantity of an impregnation agent, which tends to form a film, or through the choice of suitable resins. The following plastics are commonly used as sealers for concrete surface:
- Epoxy resins (EP)
- Polyurethane resins (PU)
- Polymethylmetacrylate resins (PMMA); and
- Unsaturated polyester resins (UP)
(c) Coatings:Coatings provides additional protection to concrete surface as compared to sealers. Consideration should also be given to the fact that coatings, as compared to sealers, have an increased resistance to the diffusion of internal moisture. There are two types of coatings used, thin coating and a thick coating. Thin coatings follows the contour of any unevenness of the concrete surface. Thick coatings is used to form as much as possible a plain surface with a thickness of 1mm or larger. Therefore, a thick coating will smooth out any unevenness of the surface.
A good coating materials should have following properties:
- Resistance against chemical attacks,
- Resistance against temperature changes,
- Good adhesion to the surface,
- Sufficient tensile strength and elasticity,
- Sufficient abrasive resistance,
- Capability to bridge cracks; and
- Coefficient of thermal expansion comparable to that of concrete.