What is the Difference Between Delamination and Spalling?

Delamination and spalling are two types of crack extensions related to particle physics and material failure. The key difference between them lies in the way they occur:

• Delamination: This refers to areas having poor or no bonding between adjacent layers. It occurs by crack extension along a plane parallel to the surface, generally at the film/substrate interface. Delamination can be detected by tapping the concrete with a hammer, which will produce a hollow sound if the area is delaminated.
• Spalling: This refers to the formation of fragments of a material that are broken off a larger solid body. Spalling involves the subsequent propagation of the crack through the film, usually via brittle rupture mechanisms. Spalls are areas where concrete has broken away from the main structure, often influenced by external forces such as tire loads, temperature changes, and ice jacking.

In summary, delamination occurs by crack extension at the film/substrate interface, while spalling occurs as a subsequent propagation of the crack through the film. Both phenomena are related to material failure and can have significant consequences for the structure and safety of buildings and other constructions.

Comparative Table: Delamination vs Spalling

The following table highlights the differences between delamination and spalling:

Key differences between delamination and spalling include:

• Delamination occurs by crack extension, while spalling occurs as a subsequent propagation of the crack through the film.
• Delamination usually happens at the film/substrate interface, whereas spalling occurs through the propagation of the crack through the film.
• Delamination and spalling are terms related to particle physics and refer to two types of crack extensions.

In the context of concrete, delamination is the separation of the paste layer at the surface, resulting in an unbonded concrete layer between it and the slab body. Concrete spalling, on the other hand, is the breakdown of concrete via natural weathering and/or chemical reaction, compromising the concrete and potentially exposing rebar.