Evaluation Method for the Structural Performance of Semi-Rigid Base Asphalt Pavement Based on Deflection Basin Indices

Damage to semi-rigid base asphalt pavements, caused by factors such as poor construction quality and repeated vehicle loads (e.g., base layer cracking, fragmentation, and subgrade weakening), can induce various distresses that further develop into structural failures, severely compromising driving safety. Non-destructive testing and accurate evaluation of the current structural performance of pavements are crucial for the proper diagnosis and repair of highway distresses. Given the limitations of existing evaluation indices for semi-rigid base asphalt pavement structures, this study first employs three-dimensional finite element simulations to construct pavement structural models and analyze the effects of structural damage at different locations on deflection basin indices, specifically D0-D300, D300-D600, and D1800. Subsequently, an evaluation index, (D300-D900)/(D600-D900), is proposed to assess the interlayer bonding condition between the base and surface layers of semi-rigid base pavements. Field tests were conducted to validate the method, and core sampling results indicate that when D0-D300 is set to 100 and D300-D600 to 40, the proposed deflection basin index-based evaluation method achieves an accuracy exceeding 85% in assessing surface and base layer damage in semi-rigid base asphalt pavements.