ASPHALT VISCOSITY: AN INDICATOR OF LOW TEMPERATURE FRACTURE STRAIN IN ASPHALT MIXTURES

When flexible pavement cracking occurs with the underlying base and subgrade performing satisfactorily and no excessive large deflection in the asphalt concrete is present, thermal cracking, fatigue, or a combination of both are often the cause. It is recognized that thermal cracking occurs when creep of the asphalt is insufficient to accommodate the contraction strain resulting from fast cooling of the pavement. Asphalt viscosity-temperature behavior is recognized as the key factor in low temperature cracking. The concept of fatigue failure is often interpreted differently by investigators. Clarification of material behavior and failure mechanisms are needed before suitable design/analysis methods are developed for flexible pavements. The relation between asphalt rheological parameters and asphalt mixture parameters should be established to facilitate design of mixtures and pavements. While stiffness is an important parameter for use in design to control pavement deflections and stress, it is questioned whether it is desirable to obtain high stiffness by increasing the viscosity of the asphalt or by placing greater emphasis on aggregates and compaction. It is the intent of this paper to question the validity of conventional fatigue concepts and suggest that fracture is primarily related to a viscosity dependent creep strain limit.

• Corporate Authors:

  Association of Asphalt Paving Technologists (AAPT)

  400 Selby Avenue, Suite I
  St Paul, MN  United States  55102
• Authors:
  • Ruth, B E
  • Schweyer, H E
  • Davis, A S
  • Maxfield, J D
• Conference:
  • Association of Asphalt Paving Technologists Proceedings
• Publication Date: 1979

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 221-237
• Serial:
  • Volume: 48

Subject/Index Terms

• TRT Terms: Asphalt mixtures; Asphalt pavements; Creep; Flexible pavements; Fracture properties; Mechanical fatigue; Mix design; Pavement cracking; Pavement design; Pavement distress; Paving materials; Rheological properties; Stiffness; Viscosity
• Subject Areas: Design; Highways; Materials; Pavements; I22: Design of Pavements, Railways and Guideways; I23: Properties of Road Surfaces; I31: Bituminous Binders and Materials;

Filing Info

• Accession Number: 00934072
• Record Type: Publication
• Files: TRIS
• Created Date: Nov 4 2002 12:00AM