Research Activities: 2003

Phase II of Evaluation and Utilization of the WP4 DewpointPotentia Meter




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Sequential Number


Matching Research Agency

Decagon Devices, Inc.

Principal Investigator

Thomas M. Petry
Professor of Civil Engineering
University of Missouri-Rolla
1870 Miner Circle
Rolla, Missouri, 65409-0030
p(573) 341- 4472
f(573) 341- 4729

Student Involvement

One quarter time graduate student.

Project Objective

Continue to Evaluate the Potential of the WP4 Dewpoint PotentiaMeter for Use in Predicting Expansive Clay Behavior by developing protocols to determine Matric and Osmotic Suction, measuring suction of chemically treated clays and correlating suctions measured with swell potentials.

Project Abstract

(1) Select and Sample Subject Clay Soil(s) to use for Evaluation. (2) Determine the basic physical properties of the subject soil(s). Suggest multiple tests for selected properties to be determined on representative samples. Index Properties: Atterberg Limits, Linear Shrinkage, Grain Size Distribution, Compaction Characteristics, Swell Potential at various water contents. (3) Using both the WP4, determine the water content - soil suction curves for the soil(s). (4) Determine a way(s) to differentiate, through testing, the matric and osmotic suction of the soil(s) at differing water contents, using the WP4. (5) Utilize the WP4 to determine the Total, Matric and Osmotic Suctions for the subject soil(s) after they are chemically treated.

Anticipated Benefits

Provide information about and work to standardize soil suction testing using this device. The result will be that soil suction will be available in less than 24 hours, instead of the current 7 plus days. This will allow geotechnical engineers to more economically and in timelier manner use soil suction for design of transportation facilities. This will potentially reduce the cost of construction of all types of transportation structures and reduce the damage potential of these problematic soils.


Modal Orientation

All transportation facilities


Project Start Date:January 1, 2004
Project End Date:

December 31, 2004


Relationship to other Research/Projects

Continuation from previous study.

Technology Transfer Activities

Final Report and Publications through TRB.

Transportation Research Board Keywords

Expansive soils, clays, soil suction, partially saturated soils.