Zollinger, Corey James (2005-05). Application of surface energy measurements to evaluate moisture susceptibility of asphalt and aggregates. Master's Thesis. Thesis uri icon

abstract

  • Moisture damage in asphalt mixes can be defined as loss of strength and
    durability due to the presence of moisture at the binder-aggregate interface (adhesive
    failure) or within the binder (cohesive failure). This research focuses on the evaluation
    of the susceptibility of aggregates and asphalts to moisture damage through
    understanding the micro-mechanisms that influence the adhesive bond between
    aggregates and asphalt and the cohesive strength and durability of the binder.
    Moisture damage susceptibility is assessed using surface energy measurements
    and dynamic mechanical analysis (DMA). Surface energy is defined as the energy
    needed to create a new unit surface area of material in vacuum condition. Surface
    energy measurements are used to compute the adhesive bond strength between the
    aggregates and asphalt and cohesive bond strength in the binder.
    DMA testing is used to evaluate the rate of damage accumulation in asphalt
    binders and mastics. The DMA applies a cyclic, torsional strain controlled loading to
    cylindrical asphalt mastics until failure. The DMA results are analyzed using continuum
    damage mechanics that focuses on separating the energy expended in damaging the
    material from that associated with viscoelastic deformation. A new approach is
    developed to analyze the DMA results and calculate the rate of damage.
    The developed approach is used to evaluate six asphalt mixtures which have
    performed either well or poorly in the field. The resistance of the field mixes to
    moisture damage is shown to be related to the calculations of bind energies and the
    accumulated damage in the DMA.

publication date

  • May 2005