Evaluation and Response of Aged Flexible Airfield Pavements at Ambient Temperatures Using the Falling Weight Deflectometer

摘要

A research study was conducted to evaluate the response of aged flexible airfield pavements at varying ambient temperatures using the Falling Weight Deflectometer (FWD). Eight field tests were performed on three sites at Duke Field, Florida, at pavement surface temperatures ranging from 30 to 130.F. Monthly subgrade moisture readings were taken along with the measuring of pavement temperature profiles during each test. Laboratory tests were conducted on collected asphalt concrete and sand asphalt cores. Tests included low-temperature rheology tests, indirect resilient modulus, and indirect static creep tests (fracture energy). The analysis of the test data provided a reliable and effective method for predicting the asphalt modulus and fracture energy using asphalt viscosity and air void content. Back calculation of layer moduli using measured FWD data was performed by the layered elastic computer program BISDEF. The asphalt concrete modulus (E1)was computed using the developed asphalt modulus prediction equations which BISDEF iterated for the base and subgrade layer moduli. This technique greatly reduced the errors in determining E1 from the iteration process. Uncracked segments of pavement gave good results using the prediction equations for all asphalt layers. However, adjustments to E1 were necessary to accommodate the degradation of modulus due to pavement cracking. Theses. (sdw)