Suction and its use as a measure of moisture contents and potentials in porous materials

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ConferenceInternational Symposium on Humidity and Moisture, Proceedings: 1963, Washington, D.C., USA
Volume4, Chap. 29
Pages245252; # of pages: 8
Subjectporosity; moisture content; vapor pressure; capillarity; capillarimeters
AbstractMany practical problems that arise with the use of materials of a porous nature result from their interaction with water. There is, therefore, a need to describe the moisture status in a more adequate way than on a weight or volume percentage basis. The concept of suction provides a rational method for describing and controlling the moisture status of porous materials, particularly in the high humidity region. In many materials, moisture contents greatly increase with a small change in vapor pressure at relative humidities in excess of 0.95, and accurate measurement and control of vapor pressure directly is often so difficult as to preclude its use. The concept of suction is based on the Kelvin and height-of-capillary rise equations relating the reduction in the vapor pressure over a curved water meniscus in a capillary to the length of the water column this curved meniscus will support. On this scale, a column of water 10,000 cm high is equivalent to a relative vapor pressure of 0.993. The log of this expanded scale based on suction is Schofield's pF. Its ease of determination and control makes it most useful in many studies in which moisture in porous materials is involved. Reference is made to some of the more important work in which it has been employed.
Publication date
AffiliationNRC Institute for Research in Construction; National Research Council Canada
Peer reviewedNo
NRC number8601
NPARC number20375938
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Record identifier3737e2f5-06be-4ccf-b6bc-af323d024f29
Record created2012-07-23
Record modified2016-05-09
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