STRUCTURAL STRENGTH INDEX FOR HIGHWAY PERFORMANCE EVALUATION

Abstract

This paper presents the analysis and evaluation of the structural performance of highway pavements using the Falling Weight Deflectometer (FWD) on major highways in Thailand. The study includes: (1) the relationship between the normalized deflection (d_o/d_{o, doh}) and pavement structural design parameters e.g. T_A, SN, and h_e according to Asphalt Institute (AI), American Association of State Highway and Transportation Officials (AASHTO), and Odemark's Method of Equivalent Thickness (MET), respectively, (2) the comparison between the modulus ratio (MR) obtained from the empirical approach by Wimsatt and that obtained from the Evaluation of Layer Moduli and Overlay Design (ELMOD), and (3) the comparison between the structural capacity index (SCI) obtained from the empirical approach by Rohde and that obtained from AASHTO. Results suggested that the normalized deflection required the maximum deflection (d_{o, DOH}) obtained from typical Department of Highways’ pavement structure. Conventional pavements were generally weaker than semi-rigid pavements. Both MR and SCI exhibited similar trends with respect to road engineering and maintenance management aspects. Higher MR and SCI values indicated stronger and safer pavements.