DOT600Roadbed Water-Content Meter

The DOT600 includes a sample chamber, CR850 datalogger, PC200W software, wall charger, and a rugged case. Samples collected from laboratory or field sites are placed in the chamber and compacted to a chosen pressure (15 to 45 psi). The water content is then calculated using dielectric permittivity sensitive methods. A separate scale and magnetic linear sensors measure the sample volume. The CR850 then calculates of bulk density, converts the measured volumetric water content to gravimetric water content, and stores the measurement results in a data table for permanent record.

Water Content Measurement Accuracy/Calibration

精度is defined by comparing DOT600 measured water contents to independently determined values. The independent method is water content by gravimetric method (weighing wet and after oven drying).

The DOT600 water content measurement uses a calibration to convert sensor output period to volumetric water content. This calibration was derived at the factory based on different types of soil. The calibration coefficients will be determined by the Matrl type selected. Repeated measurements on the sandy loam soil over the water content range from air dry to about 70% saturation show deviations from independent measurements of less than ±1.5% volumetric water content.

Since the gravimetric water content measurement uses sample volume and weight to convert from measured volumetric water content, the accuracy of the gravimetric water content will be less than the volumetric value because of inherent errors of the volume and weight measurements.