Cone penetration testing has become a standard in geotechnical in situ characterization and has revolutionized the geotechnical description of the subsurface.It has shifted the focus from sampling to more economic indirect in situ methods.Cone penetration testing has special importance in the determination of relative density in granular noncohesive soils where even careful sampling is not able to derive the in situ relative density and fabric of the grain skeleton.Traditionally the relative density is derived from tedious testing in CPT calibration chambers while measuring cone resistance under varying stress and sample preparation conditions using selected model sands.Relative density data obtained via in-situ testing still requires soil sampling to be converted to absolute void ratios which are needed for advanced cyclic soil model calculations.