The International Zinc Association (IZA) has urged South Africa’s public and private sectors to accelerate the use of zinc-based corrosion protection technologies as the country works to revive its deteriorating infrastructure. According to Simon Norton, Director of IZA Africa, zinc offers some of the most effective and longest lasting solutions for extending the lifespan of steel and reinforced concrete structures.
“Design engineers and civil engineers can choose to use zinc for the corrosion protection of steel in different formats, namely hot dip galvanizing, zinc thermal spray or by using zinc rich paints,” notes Simon Norton, Director of IZA Africa. “In South African deep mines and at coastal regions, all concrete steel rebar should be hot dip galvanized to ensure long concrete life in these structures.”
Norton notes that many of the country’s steel assets are now failing because they were never hot dip galvanized, inadequately coated, or have been allowed to deteriorate without adequate maintenance. Concrete structures are also showing advanced ageing due to the corrosion of the reinforcing steel, which results in cracking and spalling.
“Zinc remains one of the most powerful and versatile tools for rehabilitating steel and concrete infrastructure,” highlights Norton. “Where possible, deteriorated steel should be removed and hot dip galvanized. If this is not achievable, zinc metal spray, zinc aluminium metal spray or high-quality zinc-rich paints can be applied to provide robust and long-term corrosion protection once the surfaces have been correctly prepared.”
Norton explains that rehabilitation begins with a thorough inspection by civil or corrosion consultants who assess the environment, materials and level of degradation. Only then can an appropriate zinc-based system be specified.
“A hot dip galvanizer performs the galvanising process once a qualified corrosion expert has evaluated the steel structure and designed a rehabilitation plan. This ensures that clients receive the right technical advice and the right form of zinc protection,” says Norton.
The use of zinc is equally important for anchor systems used in civil engineering applications. If steel anchors are set into reinforced concrete slabs, hot dip galvanizing is typically the first choice. Where galvanizing is not feasible, zinc rich paints provide an acceptable but less durable alternative. For anchors embedded in soil, a detailed soil corrosivity assessment must be undertaken.
“In corrosive soils, steel anchors should be hot dip galvanized and then coated with a tough bitumastic layer,” notes Norton. “Alternatively, an organic zinc-rich paint can be applied and then overcoated with bitumastic material. This ensures durability even in aggressive environments.”
Looking ahead, Norton says the future uptake of zinc in South Africa’s construction sector depends heavily on national policy direction. “The potential for zinc use in South Africa is enormous, particularly in construction, mining and rail infrastructure,” he says.
“Underground mining environments are hot, dusty, and often exposed to corrosive mine water. Zinc-based coatings that are duplex coated can dramatically extend the life of steel used in these settings. The same applies to rail systems, which could be revitalised through improved management and investment.”
Prior to 2011, South Africa used around 129 000 tons of refined zinc a year. Over the past five years, this average has declined to about 60 000 tons of refined zinc per annum. “If government policy becomes more focussed and demands action, we could see major growth and a surge in zinc consumption which would strengthen infrastructure for decades to come,” argues Norton.
However, Norton cautions that one of the biggest challenges is a widespread lack of understanding of zinc’s value within the civil and consulting engineering professions. “There is still too much ignorance about the power of zinc as an anti-corrosion solution,” he points out.
“Education efforts made in earlier decades have slowed due to changes in the consulting engineering landscape. Many larger firms have left South Africa, and smaller firms now require extensive support,” says Norton. IZA Africa’s mandate is to address this through seminars, webinars, and high-quality publications, but much more needs to be done.”
Norton emphasises that engineers working near coastal environments should be especially mindful of corrosion risks. “If you are designing within 10 km of the coast, you should be specifying galvanized rebar in concrete, hot dip galvanized bolts, hot dip galvanized steel in atmospheric exposure, and duplex coating systems to extend service life,” he adds. “Engineering personnel should also attend corrosion engineering seminars and IZA training sessions to fully understand best practice.”
IZA Africa continues to promote zinc as a critical material for building long-lasting, resilient, and sustainable infrastructure. The organisation encourages engineering professionals, government departments, and asset owners to engage with corrosion consultants and incorporate zinc-based protection technologies from the start of every project lifecycle.
