TEMPERATURE EFFECTS ON DIELECTRIC CONSTANT DETERMINED BY TIME DOMAIN REFLECTOMETRY

The Purdue TDR Method developed by Siddiqui and Drnevich in 1995, determines gravimetric water content of soil and considers soil density and type through the use of two soil-specific parameters. Much construction with soils of marginal quality requires that stabilizers such as lime, cement, and fly ash be mixed into the soil. In some cases, fly ash is used by itself as a structural fill. Soil stabilizers and soils modified with them present calibration problems for current technologies for construction control. The Purdue TDR Method uses the same equipment for both laboratory compaction testing and field quality control testing, and thus removes sources of error associated with some conventional procedures.

This paper will describe the use of the Purdue TDR method for use with fly ash, lime, cement, and other soil stabilizers and soils modified with these materials. Soil samples with varying concentrations of a given additive were mixed at different water contents and tested using the Purdue TDR Method. Measurement of the modified soil density by weight and volume measurements in the compaction mold and water content by oven drying were used to confirm the TDR results. The paper will include recommendations for procedures for establishing compaction specifications and construction control utilizing this method.

Vincent P. Drnevich
Professor, School of Civil Engineering
Purdue University
West Lafayette, Indiana

Janet Lovell
Laboratory Manager, School of Civil Engineering
Purdue University
West Lafayette, Indiana

Quanghee Yi
Graduate Research Assistant, School of Civil Engineering
Purdue University
West Lafayette, Indiana

Jody K. Tishmack
Ash Management Coordinator/Compost Researcher
Dept. of Heating and Power, Physcial Facilities
Purdue University
West Lafayette, Indiana