THE EFFECT OF MECHANICAL PRESSURE ON THE IMBIBITIONAL AND DRYING PROPERTIES OF SOME CERAMIC CLAYS,I*

A number of ceramic clays in the plastic condition were held between water-permeable pistons under mechanical pressure of from 200 to 20,000 pounds per square inch in contact with water at atmospheric pressure until equilibrium was reached; the water in the pistons was removed by compressed air, the pressure released. and the moisture content, density, drying shrinkage, and other properties of the clays determined. In every case, the moisture content and drying shrinkage decreased with increasing pressure and with some clays at high pressures expansion occurred on drying. Rather complete data are given for a number of clays and their theoretical and practical significance is discussed.