Descaling, also known as peeling or flaking, is the detachment of small particles of cement paste from the surface of a finished slab. This is a common problem that occurs when water trapped in the concrete goes through multiple freeze-thaw cycles. Chipping is a term used to describe areas of concrete that have cracked and delaminated from the substrate. It is usually caused by corrosion of embedded steel reinforcing bars or steel sections, freeze-thaw cycles, the expansive effects of the alkaline silica reaction, or exposure to fire.
Chipping can have far-reaching consequences in terms of health and safety, structural integrity and asset value. De-icing chemicals only aggravate already stressed concrete by allowing more water to migrate into concrete, increasing the size and depth of husking failures when freezing occurs. Excess water content in concrete mixing can also lead to chipping. Concrete peeling affects a wide variety of structures, including concrete framed buildings, multi-storey car parks, bridges, jetties, tanks and ponds.
An additional consideration is that both delamination and descaling offer greater air and water access to the reinforcing steel within that member; thus creating a corrosion cycle and increased access of corrosive elements, which exacerbates the process with each subsequent cycle. If you encounter chipped concrete and are not sure how old the concrete is or how and when it was poured, consider contacting a structural engineer or similar professional to come and assess the structural integrity of the surface. Specially formulated resurfacing products like Rapid Set NewCrete (available from The Home Depot) make it quick and easy for homeowners to tackle chipping on their own, without having to hire a contractor.
