Characterization of HMA Moisture Damage Using Surface Energy and Fracture Properties (With Discussion)

Moisture damage in asphalt mixtures 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 study focuses on evaluating the moisture susceptibility of asphalt mixtures through understanding the mechanisms that influence the adhesive bond between aggregate and asphalt, the cohesive strength of the binder and/or mastic (binder and mineral filler), and fracture of viscoelastic materials. Adhesive and cohesive bond energies are calculated from surface energy measurements. The viscoelastic and fracture properties are obtained using cyclic, torsional strain-controlled loading on cylindrical specimens of sand asphalt mixes until failure occurs. The Dynamic Mechanical Analyzer (DMA) apparatus was used to apply this loading. A methodology is developed in this study to provide an index that is directly related to crack growth in asphalt mixtures subjected to dynamic loading. This index is a function of bond energy, viscoelastic properties, and fracture properties. The developed methodology was used to evaluate a number of asphalt mixtures that exhibited good or poor performance in the field. The resistance of the field mixtures to moisture damage was found in most cases to be related to the mixtures bond energies, the accumulated damage in DMA, and the crack growth index.

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  • English

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  • Accession Number: 01041454
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jan 22 2007 5:38PM