Abstract

Full-depth reclamation with hydraulic and bituminous binders, also known as cement-bitumen treated materials (CBTMs), is a cost-effective and eco-friendly road rehabilitation method that fully reutilizes preexisting local materials. The mechanical behavior of stabilized materials changes over time due to curing, which is crucial for long-term performance, so adapted on-site quality control (QC) strategies are necessary. This article proposes a methodology for using lightweight deflectometer (LWD) experimental data to assess CBTM properties at different locations and curing times using backcalculation. Multiple data processing techniques and four backcalculation methods for modulus values are introduced: (1) the surface modulus obtained by Love’s solution using only one deflection (ES1Love); (2) the surface modulus obtained by Love’s solution using three deflections (ES3Love); (3) the surface modulus obtained by a finite element–based backcalculation approach using three deflections (ES3FEM), considering the pavement as composed as one single semi-infinite layer; and (4) the elastic modulus of the two distinct materials or layers (CBTM and subgrade), backcalculated with the finite element method and using three deflections (ECBTM3FEM and ESG3FEM). Comparisons between surface modulus (ES) and the moduli set (ECBTM and ESG) demonstrate the fourth method effectively assesses each material’s contribution to pavement stiffness, which is important in evaluating the CBTM layer. The research concludes that LWD is an efficient QC tool for CBTM and that using backcalculated elastic moduli for the separated layers provides better results than the surface modulus for monitoring material evolution over curing time, and this may be important in the case of CBTMs.

Issue Section:
Technical Papers
Keywords:
cement-bitumen treated materials, quality control, lightweight deflectometer, surface elastic modulus, backcalculation

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