Architectural Ceramics

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Author: Hans-Jürgen Schwarz
Back to Decay Pattern

Abstract

Typical damage patterns are presented and explained.

Decay Pattern of Architectural Ceramics

Ziegelschäden

Salt-induced damage to bricks are common.

Damage to bricks can look like this:

Glazed Architectural Ceramics

The glaze of a glazed building ceramics prevents both the transport of moisture and salts. Often however glaze is crackled, which allows a capillary moisture transport. The Craquelée particularly clear shows an existing salt load, which consequently often leads to the spalling of the glazes.

Some examples of salt-contaminated glazed building ceramics are shown here.

Flaking

• Decay pattern on a brick of the St.Jakobi church in Perleberg
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  Figure 1: The damaged brick shows a scaly surface, which was caused by crystallizing salts.

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  Figure 2: Photo of a thin section in polarized light. The grey parallel crystals are gypsum.

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  Figure 3: Photomicrograph as Fig 2 but with crossed polarisers. It is clearly seen that the plaster is both responsible for the damage and on the other hand, he acts in this case as a kind of glue that holds together the broken brick pieces. With the removal of the original plaster the brick material would be lost.

Back Weathering

• Schäden an einem Gebäude in Lüneburg
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  Figure 4: Salze schädigen einen Formstein

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  Figure 5: Salzschäden wirken unter Oberfläche einer Beschichtung.

Efflorescences

• Efflorescences on Architectural Ceramics
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  Figure 6: Salt on a floor plate

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  Figure 7: Carbonate salts form a crust on a pillar. Cause in this case were a injection with cement slurry

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  Figure 8: Crystallizing salts make the crackles on a glazed tile visible. With time, the salts will damage the glaze.