Further developments in the use of FWD impact-stiffness moduli for determining PCN in Israel

Various technical studies have shown that the impact-stiffness modulus values, defined as the ratio of the Falling-Weight Deflectometer (FWD) impact load to its consequent central deflection, can be used to evaluate the Pavement Classification Number (PCN) of a particular flexible airport pavement. In a previous study, use was made of the old dynamic stiffness modulus procedure developed by the U.S. Army Corps of Engineers (USCOE); this procedure was correlated with various FWD measurements conducted on four major runways or taxiways in Israel, together with in-situ borings and the use of the new COMF AA-3.0 software. Note that the use of this new software in the present paper replaces the use of the old software in the author's previous paper, referred to in due course. The results obtained were also checked against the relevant results of full-scale trafficking tests conducted by the FAA at its National Airport Pavement Test Facility. In the present study, new FWD measurements and in-situ borings conducted on additional runways or taxi ways in Israel were analyzed in order to formulate an updated correlative equation. The paper concludes with an updated recommendation for the use of impact-stiffness modulus outputs from FWD measurements in order to determine the PCN of a flexible pavement directly on the basis of local experience.