Effects of curing temperature and sealing conditions on the early performance of cold-recycled asphalt mixtures under repeated loading

This experimental study investigates the early performance of cold-recycled asphalt mixtures (CRAM) under repeated loading, with particular attention to curing temperature and sealing conditions. A single mixture was prepared using predominantly reclaimed asphalt pavement (RAP), with fly ash as supplementary fines, foamed bitumen, and a small amount of cement. The effects of curing temperature (10, 20 and 30 °C) and sealing condition (partially or fully sealed) on moisture loss, stiffness evolution, permanent deformation, and post-curing strength were examined. Periodic loading was applied at selected curing ages during the first 28 days using fixed loading parameters. Higher curing temperatures accelerated stiffness development under undisturbed curing. However, when loading was applied at elevated temperatures, stiffness reduction and permanent deformation increased. Sealing conditions also influenced moisture loss and early stiffness gain. Partially sealed specimens generally showed higher stiffness and greater resistance to damage than fully sealed specimens. After a further period of undisturbed curing, all specimens gained additional stiffness, although the effects of early loading and curing history remained evident. The results indicate the importance of accounting for the curing environment and surface sealing when considering early trafficking of pavement structures incorporating CRAM.