Corrosion damage to reinforced concrete structural members such as foundations, columns, retaining walls, or piles poses a significant threat to structural integrity. Galvanized rebar plays a crucial role in ensuring resilient, futureproof infrastructure in terms of effective protection against corrosion.
Even when other measures are used, such as extra concrete cover or reducing concrete permeability, galvanized rebar enhances safety and reliability. “Addressing corrosion during construction minimises maintenance costs and disruptions,” notes Simon Norton, Director, International Zinc Association (IZA) Africa.
The IZA reports that corrosion damage to reinforced concrete structures in the United States costs an estimated $20 billion a year. This figure is expected to grow by $500 million each year as existing infrastructure continues to age. In South Africa, ageing wastewater works, waterworks and rail infrastructure need to be repaired with galvanized rebar.
“Dealing with corrosion post-construction is costly and disruptive as all or part of the structure needs to be closed periodically for maintenance and repair. Failure to properly address corrosion can also lead to catastrophic structural failures with potentially deadly consequences,” highlights Norton.
Many of these costs and safety issues are avoidable if the potential for corrosion is minimised during construction through proper design and material selection. This is especially critical for the reinforcing steel and the structural steel connectors used to strengthen and join concrete sections.
Corrosion can be managed by reducing concrete permeability through optimal water and cement ratios, appropriate compaction and curing conditions, the use of concrete impregnation methods or membrane-type concrete coatings and by providing a good depth of concrete cover over the rebar.
“All of these measures can delay the corrosion of rebar, but not prevent it. The use of galvanized rebar has real benefits in improving the safety and reliability of reinforced concrete, even when the above measures are used,” says Norton.
Galvanized zinc coatings form an impervious metallic zinc barrier around the steel to isolate the steel surface from the surrounding concrete. This barrier is the first line of defence to protect the steel from corrosion.
The excellent corrosion protection offered by zinc coatings or galvanizing derives from both the low natural corrosion rate of zinc, coupled with its ability to extend protection to adjacent exposed steel areas, an effect known as cathodic protection.
The coating also exhibits strong adhesion to the underlying steel surface due to its unique metallurgical bond that, together with the inherent toughness of a metallic coating, provides superior resistance to mechanical damage. The combination of these features results in a very durable coating, enabling concrete structures to be more tolerant of variability in concrete quality and reinforcement placement.
Material specifiers and product engineers in key end-use markets such as building, construction and transportation are increasingly interested in selecting materials that have the best environmental profile while meeting traditional cost, quality and technical performance criteria.
Measuring the impact and resource requirements associated with zinc production against the impact and the benefits of using zinc during other stages in the product lifecycle show zinc as a very sustainable material. The environmental footprint of galvanized coatings has also been well documented, adds Norton.
“Galvanizing can extend the life of steel and concrete structures to 100 years or more, enabling huge conservation of natural resources by reducing the waste inherent with premature end-of-life. Energy savings are also accrued through minimised maintenance and upkeep,” highlights Norton.
The end-of-life recycling of zinc coated steel also adds to this conservation because energy requirements for remelting steel and recovering the zinc are less than those required for producing the original metals. “The zinc and galvanizing industries understand that environmental and sustainability are integral to their future,” concludes Norton.
Ends
Connect with the International Zinc Association on Social Media to receive its latest news
Facebook: https://bit.ly/3uNP5w7
LinkedIn: https://bit.ly/3uNSAmb
Notes to the Editor
To download hi-res images for this news article, please visit http://media.ngage.co.za and click the International Zinc Association link to view the company’s press office.
About the International Zinc Association (IZA)
The IZA is the only global industry association dedicated exclusively to the interests of zinc and its users. Operating internationally and locally in Africa through the IZA Africa Desk, the IZA helps sustain the long-term global demand for zinc and its markets by promoting such key end uses as corrosion protection for steel and zinc as essential in human health and crop nutrition. IZA’s main programmes are Sustainability & Environment, Technology & Market Development and Communications.
In South Africa, the IZA plays a vital role in establishing the basis for the successful growth of the zinc industry by increasing awareness of zinc and its applications and benefits in key sectors and markets.
International Zinc Association Contact
Simon Norton
Director
IZA Africa
Phone: (021) 788 9980
Cell: 082 831 2924
Email: zinc@iafrica.com
Web: www.zinc.org
Media Contact
Rachel Mekgwe
Senior Account Executive
NGAGE Public Relations
Phone: (011) 867-7763
Cell: 074 212 1422
Email: rachel@ngage.co.za
Web: www.ngage.co.za
- Galvanized rebar ensures resilient future-proof infrastructure_approved
Galvanized rebar ensures resilient future-proof infrastructure_approved -
Galvanized rebar plays a crucial role in ensuring resilient, futureproof infrastructure
Simon Norton, Director of the International Zinc Association (IZA) Africa
