A Review on GPR Applications in Moisture Content Determination and Pavement Condition Assessment

In highway engineering, GPR is a nondestructive tool for measuring pavement layer thickness, moisture content of subgrade soils, and assessing other pavement conditions, such as moisture-related pavement damage. From the reflected GPR wave information, dielectric properties of the materials, which are highly dependent on soil or aggregate-water-air systems, can be estimated. An increase in dielectric constant may indicate an increase in water content of dielectric materials. However, the relationship between dielectric value and moisture content is complex and controlled by many factors. GPR studies, which consider both real and imaginary parts of dielectric value and its frequency-dependent behavior, have shown potentials for developing more robust model to predict moisture content. This paper presents an overview of GPR applications in estimating water content and assessing pavement condition. Further investigation of GPR is also discussed.