Mechanistic Temperature–Frequency Correction of Deflectometer-Based Moduli for Cement-Bitumen Treated Materials

The mechanical behaviour of Cement–Bitumen Treated Materials (CBTM) depends on temperature, loading frequency, and curing time, requiring temperature correction for reliable modulus interpretation. Existing approaches often oversimplify these effects, limiting their use for CBTM. This study proposes a mechanistic correction model for elastic moduli from deflectometer testing, applied in a rehabilitation project in Trois-Rivières (Québec, Canada) with a 200 mm CBTM layer produced by in-place stabilization. Light Weight Deflectometer (LWD) tests at different curing ages were backcalculated with BackCAP and validated by Indirect Tensile Stiffness Modulus (ITSM) tests. The model incorporates the dominant LWD loading frequency (≈35 Hz) from Fourier analysis and master curve parameters from dynamic modulus tests. Results show stable correction factors within ΔT −10 °C to 20 °C and agreement between backcalculated and ITSM moduli. The model outperforms Godenzoni’s formula but requires further validation with field and laboratory data from other roads to confirm its broader applicability.