FCS Concrete Repairs Pty Ltd are highly specialised in all aspects of concrete restoration, preservation and protection. We are equipped with the latest technology in fluid containment, chemical or contamination exclusion and the rectification of any type of concrete and masonry based structures.
Vast industry experience and a strong professional team enable us to offer our clients premium remedial and preventative solutions across a broad range of projects from multi residential situations right through to high profile multi-million dollar infrastructure especially in the remediation of Concrete Spalling / Cancer.
Concrete Spalling (also referred to as Concrete Cancer because the problem is not visible in the early stages) is the deterioration of reinforced concrete to the extent that cracks and/or red rust appears or concrete breaks away in sections.
The further the process advances so repair becomes more extensive, more difficult and more costly. Early protection and repair is essential.
Concrete Cancer has many causes such as:
Carbonation: This occurs when concrete is exposed to the air allowing air borne chemicals such as carbon dioxide, carbon monoxide, sulphur dioxide etc to penetrate the surface where they react with moisture and calcium hydroxide in the concrete to form calcium carbonate. Calcium Carbonate acts as an acid and neutralises the alkaline property of concrete at the surface and steadily moves towards the internal steel reinforcement. As a result the steel’s only protection against oxidisation is lost and rusting occurs. The steel then expands forcing the surrounding concrete to crack and flake off.
Moisture: When water penetrates cracks in concrete, steel reinforcement inside the concrete element (e.g. beams columns, walls, floor slabs, soffits, balcony slabs, stairs and landings etc) rusts and expands up to seven times in volume forcing the surrounding concrete to degrade and flake off.
Efflorescence: Efflorescence appears as a white deposit of mineral salts on face of concrete walls and/or floors. Efflorescence usually appears in underground car park areas and other subfloor areas. Efflorescence is caused by moisture ingress. As the moisture enters and moves through the wall or floor, it dissolves mineral salts present in the cement. This mineral salt solution eventually finds its way to the surface of the concrete. As the water evaporates, it leaves behind a white deposit of mineral salts on the surface. This is evidence that moisture ingress is occurring from external sources which will inevitably lead to serious breakdown of cement weakening the concrete. Again the alkalinity of the concrete will drop and the internal steel reinforcement will corrode and spalling will occur.
Salt Ingress: Coastal air is laden with chloride ions (from seawater salt). As concrete is porous, it readily allows chloride ions to move easily through the concrete causing nodules of rust on the surface of the steel reinforcement. The rust nodules create internal stresses in the concrete, which result in cracks in the concrete around the affected steel. The cracks expose the steel to even more chloride ion attack thus exacerbating the problem even further and spalling will occur.