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Materials for Retainer Plates and Their Use for Retentivity Measurements
Author(s) -
Richards L. A.,
Ogata Gen
Publication year - 1956
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1956.03615995002000030002x
Subject(s) - loam , retainer , materials science , suction , ceramic , composite material , geotechnical engineering , environmental science , soil water , geology , soil science , engineering , mechanical engineering
The selection of ceramic materials suitable for use as sample retainer plates is discussed. Methods for measuring the permeability, air‐bubbling pressure, and air‐entry pressure of retainer plates are given. The transfer conductance between retainers and a ceramic suction control surface is satisfactory if the contacting surfaces are reasonably flat and clean. Several tests have consistently indicated, however, that better results are obtained if a capillary contact medium is used when ceramic retainer plates are used on cellulose membranes. The retentivity at high suctions for cores may be significantly different than for air‐dried and fragmented soil. For example, the average 15‐bar percentage for 7 cores of sandy loam soil was 5.96, whereas the average 15‐bar percentage for the soil in these cores after air drying and fragmenting was 5.48, the difference being highly significant. Tests indicate that the water‐release curves for cores of a fine sandy loam soil that were wetted in the field by flood irrigation are the same as when the same cores are wetted to zero suction in the laboratory.