What Is Concrete Spalling?

Concrete spalling is the process where the surface layer of concrete flakes, chips, or cracks away, exposing the underlying material. It is caused by factors like freeze-thaw cycles, moisture absorption, chemical reactions (such as corrosion of steel rebar), and high temperatures. Spalling not only compromises the structure’s appearance but can also lead to reduced structural integrity and safety hazards.

Flaking, chipping, or crumbling surfaces:
The most direct signs of the surface breaking away.

Cracks and holes:
Cracks form as the concrete deteriorates, and subsequent breaks can create holes.

Rust stains:
When the steel rebar inside the concrete corrodes, it expands, creating rust stains on the surface.

Bubbling:
The formation of bubbles on the concrete surface can also indicate spalling.

Freeze-Thaw Cycles:
When water absorbed into the concrete freezes and expands, it stresses the material, causing it to crack and break.

Moisture and Chemical Infiltration:
Moisture, salts (like chlorides), and other chemicals can penetrate the porous concrete.

Rebar Corrosion:
Steel reinforcement rusts and expands when exposed to moisture and chemicals, exerting internal pressure that cracks the surrounding concrete.

Carbonation:
Atmospheric carbon dioxide reacts with concrete, reducing its alkalinity and removing the protective barrier for steel rebar, which then corrodes.

Alkali-Silica Reaction (ASR):
A chemical reaction between the alkaline cement and reactive silica in the concrete can also cause expansion and cracking.

High Temperatures (Fire):
Fire can cause water within the concrete to turn to steam, creating pressure that leads to spalling.

Safety:
Cracking and crumbling concrete can pose a safety risk to building occupants. 

Structural Integrity:
Spalling weakens the concrete, reducing its structural integrity and potentially making the building unstable. 

Aesthetic Damage:
It significantly damages the appearance of the structure. 

Further Deterioration:
Open cracks allow more air, moisture, and chemicals to penetrate, leading to further damage and corrosion, often referred to as concrete cancer.

Click Here To Learn More About Concrete Cancer Repairs