Journal Published Online: 27 January 2016
Volume 39, Issue 2

Single-Point and Multi-Point Water-Sorption Methods for Specific Surface Areas of Clay

CODEN: GTJODJ

Abstract

A single-point water-vapor-sorption method for measuring specific surface area (SSA) from simplified Brunauer–Emmett–Teller (BET) analysis is evaluated for application to natural clayey soils. The approach is predicated on the constraint that the BET C parameter related to surface hydration energy be a relatively large value. Water-vapor-sorption isotherms are obtained for 20 clayey soils along adsorption and subsequent desorption paths between 3 % relative humidity (RH) and 95 % RH. Surface areas calculated using the single-point method at 30 % RH are compared with values from conventional multi-point BET analysis. The average difference between single-point and multi-point SSA values is within 10 %. Correction factors are proposed based on measured BET C values for the suite of soils, and are shown to reduce differences between single-point and multi-point SSA to within 3 %. A simple and inexpensive method involving equilibration of specimens in closed chambers containing saturated MgCl2 solution is proposed and demonstrated.

Author Information

Akin, Idil
Univ. of Wisconsin-Madison, Dept. of Civil and Environmental Engineering, Madison, WI, US
Likos, William
Univ. of Wisconsin-Madison, Dept. of Civil and Environmental Engineering, Madison, WI, US
Pages: 10
Price: $25.00
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Details
Stock #: GTJ20150117
ISSN: 0149-6115
DOI: 10.1520/GTJ20150117