Research Activities: 2002

Evaluation and Utilization of the WP4 Dewpoint PotentiaMeter




View Report:


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

Student Involvement

One student on partial support, 1/4 FTE total

Project Objective

To fully evaluate the potential of the WP4 Dewpoint PotentiaMeter for use in predicting expansive clay behavior and to submit a standard procedure for its use to ASTM for possible adoption.

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 and the Filter Paper method, determine the water contentâ€"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 and Filter Paper method.
5.Using the subject soil(s), make up large, homogeneous samples to be distributed to test laboratories volunteering to conduct a specified test protocol using the WP4.
6.Synthesize the results of the Round-Robin Testing and provide a report to the participants.
7.Develop a testing protocol and testing standard for the use of the WP4 for measurement of clay soil suction.
8.Submit the testing standard to ASTM committee D-18 for possible adoption.
9.Analyze results of testing and provide project report to funding company.

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 under 24 hours, instead of the current 7 plus days. This will allow geotechnical engineers to more economically and in a more timely manner use soil suction for design of transportation faciltities. 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:
Project End Date:8/31/2003

Relationship to other Research/Projects


Technology Transfer Activities

Final Report and Publications through TRB

Transportation Research Board Keywords

Expansive soils, clays, soil suction, partially saturated soils