Physico-chemical characterization of asphalt-aggregate interactions under the influence of freeze-thaw cycles

Huang et al. 2 Experiments were conducted to investigate the impact of different freeze-thaw cycling on the mechanical strength of eight different types of asphalt-aggregate mixtures. In these experiments, cylindrical specimens prepared by gyratory compactor were subjected to different freeze-thaw cycling. The indirect tensile strength at 25°C (77°F) was determined after different numbers of freeze-thaw cycles. All broken samples were contacted with cyclohexane to elute asphalt from the mixtures. Polar organic fractions were isolated from each of the mixtures using a solvent extraction method. It was observed that mild oxidation of asphalt results in recovery of large amounts (compared with unaged asphalts) of polar organics from the aggregate surface of all mixtures. Presumably these strongly bonded materials are important factors in protecting mixtures against the action of moisture. Test results also indicated that mixtures prepared from asphalt, which had been pre-aged, resisted freeze-thaw action more than unaged asphalt, and showed higher retained tensile strength than the unaged mixtures. In addition, results showed that mixtures prepared from dodecanophenone-treated asphalt interact with aggregates differently