The R-Value, or resistance value, of a soil is measured in a stabilometer test, and is usually estimated for pavement design.
The R-value is the ability of a soil medium to resist lateral spreading due to an applied vertical load, such as tire loads. A range
of values are established from 0 to 100, where 0 is the resistance of water and 100 is the resistance of steel. Typical
R-values are presented below (from Lindeburg):