Structural Assessment using Deflection Parameter for Thin Asphalt Surfaced Pavement

Abstract

The surface deflection measurement is the widely used nondestructive test to investigate the structural strength of flexible pavement. Traditionally the test is conducted using the Benkelman Beam which is equipped in all district offices of Thailand’s Department of Rural Roads. At present, the modern equipment “Falling Weight Deflectometer (FWD)” becomes more popular to measure the deflection due to the improvement in fast processing time and amount of data obtained. The important thing of using the FWD data is to have a sound interpreting technique that is capable of evaluating the pavement structural condition correctly. This work presents the study of using the deflection to evaluate the structural strength of newly constructed asphalt pavement. Based on the field testing data, it was found that the deflection at load center (D₀) and the total thickness of pavement correlated well with the modified structural number, or SNC which represented the structural capacity of pavement for carrying traffic loading.