Abstract: New time-domain response system calibration techniques are described for determining dry density and water content of soil based on electromagnetic wave propagation through it. For example, one disclosed technique use the ratio between V1, the voltage difference between the peak and trough of the response signal, and Vf, the long-term (i.e., steady-state) response of the system to the input pulse. These values are measurable, even for highly conductive soils, and calibration done in a laboratory can be applied to measurements taken in an uncontrolled field environment.

Abstract: Methods and apparatus using time domain reflectometry to determine electrical properties of concrete for calculating physical and mechanical properties of the concrete that are indicative of concrete quality and durability. The dielectric constant of a concrete is determined to calculate the gravimetric water content of the concrete for use in finding the water-cement ratio of the concrete. Electrical conductivity of curing concrete is determined to calculate compressive strength of the concrete for use in predicting strength development in the concrete.

Abstract: A method and apparatus for measuring dry density and gravimetric water content of soil includes the steps of providing a plurality of spikes adapted to be driven into the soil and driving the spikes into the soil in spaced relationship. An electrical signal is applied to the spikes and a reflected signal is analyzed using time domain reflectometry to determine an apparent dielectric constant and the bulk electrical conductivity of the soil. With these parameters, the dry density and gravimetric water content of the soil can be calculated using a predetermined relationship between apparent dielectric constant, bulk electrical conductivity, dry density and gravimetric water content. The predetermined relationship includes experimentally determined soil specific calibration constants. The calculated value of the bulk electrical conductivity as determined by time domain reflectometry is adjusted to correspond to a value for which values of the constants are known.

Abstract: A method and apparatus for measuring dry density and gravimetric water content of soil includes the steps of providing a plurality of spikes adapted to be driven into the soil and driving the spikes into the soil in spaced relationship. An electrical signal is applied to the spikes and a reflected signal is analyzed using time domain reflectometry to determine an apparent dielectric constant and the bulk electrical conductivity of the soil. With these parameters, the dry density and gravimetric water content of the soil can be calculated using a predetermined relationship between apparent dielectric constant, bulk electrical conductivity, dry density and gravimetric water content. The predetermined relationship includes experimentally determined soil specific calibration constants. The calculated value of the bulk electrical conductivity as determined by time domain reflectometry is adjusted to correspond to a value for which values of the constants are known.

Abstract: A method and apparatus for measuring in-place soil density and moisture content. A cylindrical cell is disclosed which may be used to measure the density and the dielectric constant of a soil sample placed within the cylindrical cell. Also disclosed is a multiple rod probe which is designed to contact spikes driven into the ground to measure the in-place dielectric constant of soil. The multiple rod probe includes adjustable studs which ensure complete contact with the spikes. Both measurements are performed using time domain reflectometry. The present invention develops equations for determining the density of the soil in-place from the measured dielectric constant of the soil in-place and the measured density and dielectric constant of the soil in the cylindrical cell.

Abstract: A method and apparatus for measuring in-place soil density and moisture content. A cylindrical cell is disclosed which may be used to measure the density and the dielectric constant of a soil sample placed within the cylindrical cell. Also disclosed is a multiple rod probe which is designed to contact spikes driven into the ground to measure the in-place dielectric constant of soil. The multiple rod probe includes adjustable studs which ensure complete contact with the spikes. Both measurements are performed using time domain reflectometry. The present invention develops equations for determining the density of the soil in-place from the measured dielectric constant of the soil in-place and the measured density and dielectric constant of the soil in the cylindrical cell.

Abstract: A method and apparatus for measuring in-place soil density and moisture content. A cylindrical cell is disclosed which may be used to measure the density and the dielectric constant of a soil sample placed within the cylindrical cell. Also disclosed is a multiple rod probe which is designed to contact spikes driven into the ground to measure the in-place dielectric constant of soil. The multiple rod probe includes adjustable studs which ensure complete contact with the spikes. Both measurements are performed using time domain reflectometry. The present invention develops equations for determining the density of the soil in-place from the measured dielectric constant of the soil in-place and the measured density and dielectric constant of the soil in the cylindrical cell.