Laboratory Conditioning Protocols for Warm-Mix Asphalt

摘要

Economic, environmental, and engineering benefits have led to the rapid implementation of Warm-Mix Asphalt (WMA) across the world during the past decade. While WMA technologies have been successfully utilized as a paving material, standard mix design protocols remain under development. A study of the effect of laboratory conditioning protocols (prior to compaction) on the performance of HMA (Hot-Mix Asphalt) and WMA mixtures made with chemical additives, wax additives, or a foaming process was performed. Resilient Modulus (MR), Dynamic Shear Rheometer (DSR), and image analysis techniques were used to evaluate the properties of the extracted binders and mixtures conditioned with different protocols. Laboratory mixed laboratory compacted (LMLC) specimens conditioned for 2 hours at 240°F (116°C) for WMA and 275°F (135°C) for HMA had stiffnesses similar to those of cores collected during the early life of field pavements. For off-site plant mixed laboratory compacted (PMLC) specimens, different conditioning protocols are recommended to simulate the stiffness of plant mixed field compacted (PMFC) cores at construction: reheat to 240°F (116°C) for WMA with additives and reheat to 275°F (135°C) for HMA and foamed WMA.