Concrete degradation may have various causes. Concrete can be damaged by fire, aggregate expansion, sea water effects, bacterial corrosion, calcium leaching, physical damage and chemical damage (from carbonatation, chlorides, sulfates and distilled water). This process adversely affects concrete exposed to these damaging stimuli.
Carbonatation has two effects: it increases mechanical strength of concrete, but it also decreases alkalinity, which is essential for corrosion prevention of the reinforcement steel. Below a pH of 10, the steel's thin layer of surface passivation dissolves and corrosion is promoted. For the latter reason, carbonation is an unwanted process in concrete chemistry.
The expansion of the corrosion products (iron oxides) of carbon steel reinforcement structures may induce mechanical stress that can cause the formation of cracks and disrupt the concrete structure. If the rebars have been poorly installed and are located too close to the concrete surface in contact with the air, spalling can easily occur: flat fragments of concrete are detached from the concrete mass by the rebars corrosion and may fall down. (Concrete degragation)
Anti-Carb Coating has been formulated to confer long term protective and decorative properties to concrete and masonry surfaces. The micro-porous structure of the coating acts as a barrier to the ingress of Chlorides and Carbon Dioxide and other acid gases, but allows the passage of water vapour from the substrate. The elastometric nature of Anti-Carb Coating ensures good crack bridging properties, in case of structural movement.
Typically used where new and existing concrete and masonry structures require protection from Water, Carbon Dioxide, Sulphur Dioxide, Oxides of Nitrogen, Chlorides, Sulphates and UV radiation. For example in car parks, commercial and industrial buildings, bridges, subways and high rise flats etc.
Some advantages of Anti-Carb Coating are:
- Easy to clean
- Excellent weathering resistance
- Single pack and easy to apply
- Protects substrates form Carbonation
- Highly resistant to freeze/thaw cycling
- Elastic nature with crack bridging properties
- Allows structure to "breathe"
- Water based and non-toxic
- Range of colours available