Effect of nonlinear stress-dependency and cross-anisotropy on the backcalculation outputs from the TSD deflection slopes and the effect on estimated pavement performance

• DOI: 10.1080/10298436.2024.2417967
• Publication Date: 2024-10-23T08:14:16Z
• Authors: Nariman Kazemi; Mofreh Saleh; Chin-Long Lee

The Traffic Speed Deflectometer (TSD) is a mobile vehicle that measures deflection slopes. Deflection slopes have been utilised in previous studies to backcalculate pavement layers' moduli. However, the nonlinear stress-dependency and cross-anisotropy of unbound granular materials fine-grained soils were overlooked those studies. Utilising Finite Element Method (FEM) based on static analysis this study evaluate three-layered flexible system with specific material properties layer thicknesses revealed neglecting base subgrade layers underestimated permanent deformation life backcalculated by more than 45%. Neglecting design anisotropy ratio 0.5 increased Asphalt Concrete (AC) modulus 21%, estimated 160%, decreased around 28%. almost 15%. results underscore necessity consider backcalculating moduli from TSD