Assessing the Effect of Material Properties on Full-Depth Reclamation Mixtures via Compressive Strength Characterization

Full-depth reclamation (FDR) as a pavement rehabilitation technique involves pulverizing an asphalt layer with underlying materials to create a new base, offering cost savings, environmental benefits, and improved pavement performance. This study was conducted to investigate the effect of six stabilization combinations of laboratory-produced material ratios and properties on FDR mixtures by evaluating the unconfined compressive strength. Materials studied include reclaimed asphalt pavement (RAP), unbound road base material of different qualities, subgrade materials, fat clay, and low-plasticity silt. Stabilizers used were Portland cement, asphalt emulsion, and foamed asphalt. Results revealed that RAP content influences cement hydration, with a 23%–64% increase in dry strength for mixtures containing 42% RAP compared with 8% RAP. Bituminous stabilizers were more effective in mixtures with higher RAP content because of binder activation. Mixtures with 42% RAP, 1% Portland cement, and 3% asphalt emulsion showed a 290% strength increase. Cement stabilization proved ideal for FDR mixtures with clay subgrades, resulting in 13%–64% strength gains, whereas bituminous stabilizers performed better with silty subgrades, showing 14%–52% strength improvements. In conclusion, Portland cement stabilization worked with a wide range of materials and accommodated high-plasticity mixtures compared with mixtures stabilized with bituminous agents. The resistance of the cement-stabilized mixtures to moisture damage was greater than mixtures stabilized with bituminous stabilizers.