Complex Modulus Testing and Rheological Modeling of Cold-Recycled Mixtures

摘要

This research compares the rheological behavior of different cold-recycled mixtures (CRMs)produced in-place through full-depth reclamation. Reclaimed asphalt pavement (RAP) obtainedfrom the milling of the old asphalt layers was blended with reclaimed unbound aggregatefrom the existing subgrade. Asphalt emulsion, foamed asphalt, and portland cement wereemployed as stabilizing agents. The complex modulus was measured on cylindrical cores, applyinga sinusoidal strain with an amplitude of 30 microstrain at testing temperatures rangingfrom 0°C to 50°C and frequencies ranging from 0.1 to 20 Hz. The Huet-Sayegh (HS) rheologicalmodel was applied to simulate the experimental data. The results showed that the behavior ofCRM is thermo- and frequency-dependent and that the time-temperature superposition principlecan be applied. The HS model provides an excellent fitting of the dynamic modulus data,whereas fitting of the loss angle data was improved, introducing a temperature- and frequency-independent correction. The RAP influences the rheological behavior, but viscous dissipationis mainly due to the asphalt-stabilizing agents (emulsion residue or foamed asphalt).