Pavement Design and Performance Study:Phase B. Deflection Study. Nuclear Measurement of Subgrade Moisture.

摘要

The basic consideration in evaluating subgrade moisture conditions under pavements is the selection of a method of determining moisture contents that is sufficiently accurate and can be used with minimal effort,interference with traffic,and calibrations. In this study,the electrical resistance method and a nuclear method were tried,and the nuclear method was adopted. The devices and procedures used in both methods are described. Modified methods for eliminating errors in the measurement of moisture by nuclear depth probes were tried and some of these are recommended for use. A method of reducing the standard error of estimate in the use of a nuclear calibration curve for moisture content by using the sieve analysis of a soil is discussed.