Galvanized steel critical for SA’s R1tn infrastructure investment plan

Last Updated 1 month ago by Kenya Engineer

Public infrastructure spending over the next three years will amount to more than ZAR 1 trillion, South African Finance Minister Enoch Godongwana announced in his budget speech on 12 March 2025. The spending will focus on three sectors, namely R402 billion for transport and logistics, R219.2 billion for energy infrastructure, and R156.3 billion for water and sanitation.

“The mooted infrastructure investment plan will hopefully be a major fillip for South Africa’s galvanized steel industry and the zinc rich paint suppliers,” comments to Simon Norton, Director of the International Zinc Association (Africa). Infrastructure construction and reinforced concrete, encompassing bridges, buildings, piping, and power transmission towers, relies heavily on steel due to its strength and versatility.

Galvanized steel is used for bridge beams, guardrails, reinforced steel in concrete and other structural components. Continuously galvanized steel sheet is used for roofing, cladding, and hot dip galvanized steel for structural framing. Zinc coatings protect pipes and storage tanks from corrosion, ensuring the safe transport and storage of water and waste water.

Galvanized steel is used for power transmission towers and railway electricity pylons, providing long term protection in harsh environments such as along the South African West coast as well as the South and East Coasts of Southern Africa. It is also used for telecoms towers, ensuring reliable communication infrastructure which does not rust and collapse.

In addition, galvanized steel is used in water treatment and sewage plants, providing resistance to corrosion and wastewater. “This is a key sector for galvanized steel and zinc rich coatings in Southern Africa,” highlights Norton.

However, steel’s vulnerability to corrosion poses a significant challenge, threatening the operational life and safety of these critical structures. To fight this, zinc coatings have emerged as a vital protective measure, offering a double defence mechanism, both a physical barrier and cathodic protection.

Steel, when exposed to water and oxygen, undergoes corrosion, commonly known as rusting. This process weakens the material, leading to structural failures and costly repairs. If infrastructure is exposed to harsh environments, such as in marine or industrial locations, the rate of corrosion accelerates, necessitating effective protective strategies and that’s where zinc comes into its own.

Zinc coatings significantly extend the service life of steel structures, reducing maintenance costs and minimising downtime. Zinc coated steel, particularly batch hot dip galvanized steel, is highly resistant to abrasion, impact, and other forms of mechanical damage.

The long-lasting protection provided by zinc coatings minimises the need for frequent maintenance, recoating and repair. Although the initial cost of zinc coating may be higher than other protective measures such as painting, its long-term durability and reduced maintenance requirements make it a cost-effective solution that far outstrips using only paint. A key technique is to use an organic paint coating over hot dip galvanizing, the so-called DUPLEX SYSTEM, which then provides very long life for steel structures exposed to our harsh South African coastal environment.

Zinc is a naturally occurring element and is totally recyclable. The long service life of zinc coated steel also contributes to sustainability by reducing the need for frequent replacements. “By preventing structural failures and deterioration caused by corrosion, zinc coatings particularly hot dip galvanizing enhance the safety and lifetime of steel and concrete infrastructure,” concludes Norton.