Hygrothermal performance of building materials and products. Determination of water absorption coefficient by partial immersion

2003 ◽  
Keyword(s):  
Absorption Coefficient ◽  
Water Absorption ◽  
Building Materials ◽  
Water Absorption Coefficient ◽  
Partial Immersion ◽  
Hygrothermal Performance

Ermittlung der Kapillartransportkoeffizienten mineralischer Baustoffe aus dem w-Wert / Estimating the capillary transport coefficients of mineral building materials from the water absorption coefficient

1997 ◽  
Vol 3 (3) ◽  
pp. 219-234
Author(s):  
M. Krus ◽  
A. Holm ◽  
Th. Schmidt
Keyword(s):  
Absorption Coefficient ◽  
Water Absorption ◽  
Building Materials ◽  
Transport Coefficients ◽  
Capillary Transport ◽  
Water Absorption Coefficient ◽  
Standard Material ◽  
Moisture Balance ◽  
Computer Calculations ◽  
Building Components

Abstract Computer calculations are of increasing importance for the assessment of moisture balance in building components, since modern calculation methods achieve good agreement with measurements. A broader application of these methods is hampered, however, by the laborious measurements needed to determine the capillary transport coefficients essential for the calculations. A new method is therefore presented which allows to estimate the coefficients from wellknown standard material properties (free capillary saturation, practical moisture content and water absorption coefficient). These coefficients are sufficient for estimative assessment of the moisture balance of many materials, as is demonstrated by comparison of suction profiles calculated in this way and measured profiles.

Salt Degradation in Stone of Old Buildings

2013 ◽  
Vol 334-335 ◽  
pp. 337-342
Author(s):  
João M.P.Q. Delgado ◽  
V.P. de Freitas
Keyword(s):  
Relative Humidity ◽  
Absorption Coefficient ◽  
Water Absorption ◽  
Air Temperature ◽  
Experimental Work ◽  
Building Materials ◽  
Soluble Salts ◽  
Water Absorption Coefficient ◽  
Major Mechanism ◽  
Mechanism Of Degradation

The crystallization of soluble salts is a major mechanism of degradation of some building materials, including stone. This mechanism of deterioration is based on the pressure exerted by the formation of salt structures in porous materials, with increased volume and is dependent on the type of salts involved and the size and arrangement of pores. When the pressure exceeds the internal strength of the material, and particularly when the salt formations undergo cycles of crystallization and dissolution in response to fluctuating levels of humidity, the deterioration of materials typically becomes apparent. It is therefore essential to understand the phenomenon of crystallization and dissolution of salts, i.e., to know the conditions of crystallization of each salt, depending on relative humidity and air temperature. For this purpose we developed an experimental work, using four samples of stone (one limestone and three granites), which consists, initially, to study the variation of the water absorption coefficient with and without soluble salts.

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