Aquagalv is a low VOC zinc silicate coating from Dulux Protective Coatings formulated specifically to provide heavy-duty galvanic corrosion protection to exposed steelwork in harsh coastal environments.
Steelwork exposed to coastal atmospheres can be protected using a number of methods. According to the Australian Standard AS/NZS 2312, ‘Guide to the protection of structural steel against atmospheric corrosion by the use of protective coatings’, superior galvanic corrosion protection is offered by the use of inorganic zinc silicates or zinc rich epoxy coatings in high corrosivity areas.
A waterborne inorganic zinc silicate coating, Dulux Aquagalv complies with AS/NZS 2312 for long term corrosion protection, comparing very favourably with other forms of galvanic corrosion protection such as hot dip galvanising. Very importantly, at less than 10g of VOC per litre, Aquagalv is also a low environmental impact solution.
Dulux also offers several zinc-rich primers as cost-effective alternatives. Though they comparatively have a higher VOC content than Aquagalv, these primers offer many advantages to eco savvy specifiers. The Zincanode range assures excellent galvanic corrosion protection, has virtually no HAP emissions, requires no chemical pre-treatments, is chromate- and lead-free, and can be applied and cured at room temperature.
Exposed steelwork in dry, sheltered and inland areas are subject to a very low corrosivity environment, which means lower film builds and/or fewer coats are more than sufficient for long-term protection.
On the other hand, concrete structures are designed to avoid the need to protect steel against corrosion. A concrete structure contains almost as much steel as an equivalent-sized steel structure. However, the embedded steel is only protected against corrosion by the surrounding concrete as long as the concrete remains highly alkaline, and protected from salts. Concrete, when exposed to the increasing acidity of rain and atmospheric pollution in coastal developments, readily neutralises, allowing the concrete reinforcement to corrode and expand in volume, forcing cracks and deterioration of the concrete in a common phenomenon called spalling.