Delamination in Reinforced Concrete Delamination - Concrete Delamination of Glulam[1, 2, 3]

Delamination occurs when composite materials begin to separate or break apart. In many cases these separations occur below the surface or in between layers of the material making delamination hard to identify until the material has already been seriously damaged. Delamination is detected by listening to the sound a material makes when it is struck. “Most composites will respond with a loud reverberating sound. A delaminating composite will sound dull on impact, with a low non-reverberating sound [a].”

In layered materials, repeated loading or stresses can cause the bonding agent to fail causing the layers to separate or flake apart [b]. Large changes in temperature and pressure and high humidity also dramatically increase the rate at which the adhesives between layers break down [b].

Delamination can also occur in non-layered composite materials like reinforced concrete. If the reinforcement is not properly protected against corrosion the rebar will oxidize and expand resulting in a separation between the concrete and reinforcement material. Delamination can be avoided in concrete if the mix is poured and cured correctly, most notably during final finishing of the concrete [c].