Patent ID: 6963205

Claim:
An Electrical Density Gauge consisting of electrode means for electrically connecting to an in-situ test spot of compacted construction material (soil), electrical means for measuring the equivalent parallel resistance and equivalent parallel capacitance of said material, and means for performing the necessary computations and display of results, is calibrated by first measuring a plurality of in-situ test spots in a field of said construction material to determine values of said equivalent resistance and capacitance, then determining with the use of geotechnical means, the in-situ wet density and in-situ weight of water of the same plurality of test spots where electrical measurements were made, and with the use of said electronic computational means, the real impedance of the measured test samples is determined, the best fit regression equation between the physical wet density data points and real impedance data points is calculated, and also with the use of said electronic computational means, the ratio of measured capacitance and measured resistance is determined for all data points, then the best fit regression equation between the unit weight of water data points and capacitance/resistance ratio data points is calculated, said Electrical Density Gauge after being thus calibrated, is used to measure field test spots of the same type of construction material with previously unknown electrical characteristics and with the newly determined values of real impedance and capacitance/resistance ratio applied to the aforementioned regression equations, to compute a value of wet density and a value of unit weight of water for said unknown test spot, and using the aforementioned electronic computational means, the dry density of the constructional material at the unknown test spot is calculated from the wet density and unit weight of water.