Concrete shedding is a process of degradation or peeling off of concrete, which can be identified by common signs such as cracking, crumbling, rust stains, bubbles in concrete or cement plaster, and leaks in the ceiling and walls. Not only is it an unattractive sight, but it can also be dangerous in terms of falling debris or tripping hazards. If left unchecked, the shedding will tend to accelerate and spread, making the structure unstable. Therefore, it is important to take timely action to prevent further damage. The easiest way to check if the concrete is flaking is to hit the visibly weak areas with a hammer.
If the hammer head bounces, the compressive strength of concrete is good. However, if the hammer indents and pulverizes the surface, then it means that the concrete is not solid and should be removed. The symptoms of concrete shedding are flaking, chipping, and large pieces missing from the surface, exposing the aggregate of coarse, rocky concrete. The peeling of concrete is a result of chemical and physical processes that occur within the concrete itself.
It can be caused by a number of factors such as improper mixing of concrete or environmental conditions like freeze-thaw cycles. When timely removal of compromised sections is required, a common method is to chip the defective concrete with a hammer, jackhammer, concrete breaker or other impact tool. For new concrete, applying a penetrating waterproofing sealant 28 days after laying and every few years thereafter can help prevent peeling. Deicing chemicals should be avoided as they only aggravate already stressed concrete by allowing more water to migrate into it, increasing the size and depth of shedding failures when freezing occurs. To repair and revitalize concrete surfaces that suffer from peeling or other issues such as stains and light corrosion due to the elements, a concrete coating can be used.
This will help restore the surface and prevent further damage.