EVALUATION OF IN-SITU PAVEMENT MODULI FROM DEFLECTION MEASUREMENTS.

Mechanistically based typical curves are developed to evaluate the moduli of the pavement layers: surface, base, subbase, and subgrade from surface deflection measurements. The curves are developed using the Chevron N-layer computer program with a large number of typical combinations of layer thicknesses and material moduli. Twenty-four sets of curves are developed representing a wide range of layer thicknesses and deflection basin shapes. Therefore, if the layer thicknesses are known and the surface deflection measurements are determined, the four moduli of the pavement layers can be evaluated. The developed curves are simple to use without the need for previous empirical relationships or computer analysis.