Enhancement of the hydrostatic capillary tension in wet brick green bodies for a reduced susceptibility to cracking during drying

Research project conducted by: Research Alliance of the Brick and Tile Industry reg'd (FGZ) Project number
AiF 15868 N Promoted by
BMWi through the Cologne-based Arbeitsgemeinschaft industrieller Forschungsvereinigungen "Otto von Guericke" e.V. (AiF) Implemented by
Institut für Ziegelforschung Essen e.V. (IZF) Project manager
Dipl.-Ing. Ingo Hofmann

1 Context and problem statement

After shaping, brick green bodies exist as capillary-porous solids, the pores of which are filled with water and which are enclosed by a water sheath. Capillary suction acting on the water sheath holds the brick green body together.

At first, shrinkage compensates for the loss of water associated with drying. However, as the water content diminishes, the coefficient of moisture conductivity also declines. If the drying rate is kept constant, the moisture gradient and, hence, the shrinkage gradient increase. When the tensile yield point is exceeded, tensile...

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