Specifier Remedial Technology
Contractor Duratec Australia
Sector Commercial
Date 2021
Products
- Fosroc Renderoc HB40 Plus
- Fosroc Dekguard S
- Fosroc Nitoproof 510
Over 24,000 litres of Fosroc Renderoc HB40 Plus provided a concrete remediation solution to revitalise this carpark and ensure its safety for drivers and vehicles for years to come.
To complete the solution, Dekguard S was applied over the entire soffit area for corrosion protection and Nitoproof 510 was used on the internal walls to resist dampness.
Concrete remediation restores harbourside carpark
In Kirribilli NSW, this harbourside yacht club carpark boasts an exclusive spot, offering ground floor and top deck parking. Constructed in the 1960s, the ground floor in particular was showing its age, with significant concrete cracking and spalling.
Concrete repair challenges revealed
“When the facility was built, insufficient concrete was used to cover the steelwork. As a result, there was rusting steel in the overhead soffits and spalling concrete. This is unsightly and also hazardous because it can lead to cracking and steel corrosion,” explains Fosroc NSW Specification Manager, Gary Bennett.
Concrete corrosion and carbonation had also occurred.
“Due to the carpark’s location close to the water, it is prone to salt deposition on the surfaces, which corrodes the concrete if it’s not properly protected,” Gary explains.
Meanwhile, carbonation had broken down the cement in the concrete and repair mortars.
“This is a particular issue in carparks given the heavy vehicle use. They are exposed to high carbon dioxide and carbon monoxide emissions.”
Expert specification advice
An assessment of the carpark’s ground floor and top deck by specifiers and project managers, Remedial Technology Pty Ltd, revealed significant concrete cracking and spalling.
Remedial Technology reached out to Fosroc ANZ for assistance with a concrete remediation plan. The ground floor specification needed to prolong the carpark’s lifespan and improve its amenity.
“Each area of the carpark came with its own challenges,” explains Gary. “We sat down with the Remedial Technology team to fully understand the structure, and to get a complete picture on access, environment and any other stakeholders such as local residents.”
Restoring cover with high build, high strength solution
To tackle the low concrete cover to the reinforcing bars at the soffit, contractors Duratec Australia undertook a breakout of the concrete behind the reinforcement using hydro-demolition. They cleaned the steel to bright metal condition using grit blasting.
Approximately 24,000 litres of Renderoc HB40 Plus repair mortar was applied to restore the concrete to its original profile and achieve an additional 12mm of cover to provide extra cover to the embedded reinforcing bars.
Renderoc HB40 is a high strength, abrasion resistant repair mortar. Its high build formulation means fewer product applications are required, while its high resistivity provides increased durability.
“To reduce dust and keep noise levels down, Remedial Technology settled on hydro-blasting to remove the damaged concrete and wet spray mortar application,” Gary says. "Wet spray allows this high build product to go on even faster. It's very efficient."
Extra protection
Providing extra corrosion protection, Dekguard S was applied over the entire concrete soffit area. It is a high performance solution to resist the carbonation caused by carbonic acid – the result of moisture combining with carbon dioxide and carbon monoxide.
A Dulux Acratex render was used to protect the columns and external walls, while Nitoproof 510 was applied to the internal brickwork walls. This moisture barrier coating restricts the passage of dampness through concrete, brick and masonry substrates.
“The carpark sits adjacent to residential homes. The damp proofing properties of Nitoproof 510 means moisture won’t come through from the bricks on the other side of the carpark,” explains Gary, who attended the site several times to check on Fosroc product application and provide on-the-spot advice to the contractors as needed.
“It was such an interesting project, and we have a great relationship with the very experienced Duratec Australia team who were applying Fosroc products.”
This yacht club carpark is now ready to serve its members and their vehicles for many years to come.
Find out more
Download, print and share this case study.
Download our Concrete Repairs brochure to find the right concrete repair products for your remediation requirements.
