Moisture Transport in Salt Free and Salt Contaminated Ceramic Bricks

AbstractIn this work the effect of salt contamination on moisture transport parameters - the water vapor permeability and moisture diffusivity is studied for case of ceramic bricks with very low and low hygroscopic ability. The analysis is focused to small salt concentrations, having practically negligible effect on the material porosity but significantly increasing hygroscopic moisture content of the bricks.The simply experiment, consisting in monitoring of isothermal one-dimensional capillary uptake and following drying was carried out for salt free and salt contaminated bricks. Tests were done for two different salt concentrations. The moisture uptake and release during the tests was determined by weighting the samples. The experimental results were compared with numerical simulation of the process of drying. In the simulations, desorption curves, measured from capillary moisture content were used as moisture storage functions. Within the hygroscopic range, moisture transport was specified by water vapor permeability, determined from standard cup measurements. Beyond the hygroscopic range, moisture diffusivity function, obtained from absorption coefficient for water and capillary saturation water content, was used for simulation of moisture transport.On the basis of the comparison, the effect of salt contamination on moisture transport parameters was evaluated. The presence of salt significantly lowered the water vapor permeability by the salt crust formation on the drying surfaces. However, the actual crust formation differed on the particular surfaces and was dependent on the initial moisture content at the surface as well as on the surface roughness

CIB W040: heat, air and moisture transfer terminology: parameters and concepts

This publication compiles the heat, air and moisture transfer terminology existing in books, standards and other reference documents. An introduction is provided and presents the CIB Commission W040 \u2013 Heat and Moisture Transfer in Buildings and summarises the Commission activities since 1969.NRC publication: Ye

Production of anorthite refractory insulating firebrick from mixtures of clay and recycled paper waste with sawdust addition

Production of porous anorthite refractory insulating firebricks from mixtures of two different clays (K244 clay and fireclay), recycled paper processing waste and sawdust addition are investigated. Suitability of alkali-containing-clay, low-alkali fireclay, pore-making paper waste and sawdust in the products was evaluated. Prepared slurry mixtures were shaped, dried and fired. Highly porous anorthite ceramics from the mixtures with up to 30% sawdust addition were successfully produced. Physical properties such as bulk density, apparent porosity, percent linear change were investigated as well as the mechanical strengths and thermal conductivity values of the samples. Thermal conductivities of the samples produced from fireclay and recycled paper waste decreased from 0.25 W/mK (1.12 g/cm 3) to 0.13 W/mK (0.64 g/cm 3) with decreasing density. Samples were stable at high temperatures up to 1100 °C, and their cold strength was sufficiently high. The porous anorthite ceramics produced in this study can be used for insulation in high temperature applications. © 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved