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

»1 Breaking strengths of brick green bodies made of clay “A“ measured in the course of 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...

Issue 05/2013

Energy-saving methods of conditioning green brick bodies for low-temperature drying

1 Context and formulation of problem Low-temperature drying is a modified form of open-air drying with the aid of modern plant and control technology. In heavy clay production, the introduction of...

Issue 05/2009

Influence of the inner surface of drying green ceramic products on their moisture-dependent tensile strength

1 Introduction The determination of the pore size distribution by means of mercury penetration porosimetry leads as a secondary result to the specific pore surface a (total pore area) of the dry...

Issue 02/2022

Influence of mineral additives on the drying and sintering behaviour of brick bodies, Part 2

5. Characterization of the dried brick bodies »Table 8 shows the shrinkage, packing density and bending strength of the dried brick bodies. The shrinkage of the basic bodies varies between 7.6 and...

Issue 04/2014

Causes and avoidance of firing-related damage Part 2: Strength-reducing reactions in the heating-up zone from 500 to 800° C

4 Expansion and shrinkage processes In a tunnel kiln firing process for heavy clay products, there should be no mutual contact between the wares to be fired, and all exposed surfaces within and around...

Issue 01/2022

Influence of mineral additives on the drying and sintering behaviour of brick bodies, Part 1

1. Introduction During shaping, the water serves as a sliding agent between the platelet-like clay minerals, rendering the clay plastic. Water is also responsible for the particles sticking to each...