X-Ray Diffraction of Highway Materials, HR-128, 1969

(1969) X-Ray Diffraction of Highway Materials, HR-128, 1969. Transportation, Department of


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X-ray diffraction data during adsorption of water vapor on Na- and Ca-montmorillonites show that interlayer expansion is continuous but nonuniform. X-ray and adsorption isotherm data indicate an ice-like configuration of water molecules is completed with the fourth layer of interlayer water for the Ca-clay; a fifth layer intrudes to give a less ordered structure. Data for the Na-clay indicate a laminar stacking arrangement for up to three layers of interlayer water. The Na-clay adsorbs more than twice as much water and undergoes four times as large a volume change than the Ca-clay. The free energy change during adsorption of water vapor on the Ca-clay is nearly twice that for the Na-clay. Free energy changes with increasing relative pressure reflect interlayer expansion increments.

Item Type: Departmental Report
Keywords: Analysis, Calibration, Curve fitting, Data collection, Diffraction, Methodology, Mineralogy, Samples, X rays
Subjects: Transportation
Transportation > Materials
Transportation > Roads and highways
Transportation > Research
Transportation > Environment
Transportation > Maintenance and preservation
ID Code: 22220
Deposited By: Iowa DOT Library
Deposited On: 27 May 2016 18:21
Last Modified: 27 May 2016 18:21
URI: https://publications.iowa.gov/id/eprint/22220