ASPHALT AND POLYMER MODIFIED ASPHALT PROPERTIES RELATED TO THE PERFORMANCE OF ASPHALT CONCRETE MIXES (WITH DISCUSSION)

Some of the physical properties of polymer modified asphalts are exceptional when compared with conventional asphalts. Does the exceptional performance in such tests equate to improved performance in asphalt mixes? To address this question, five asphalts were studied: three conventional asphalts representing the extremes of temperature susceptibility and two polymer-modified asphalts, each containing 5% polymer. The following areas were studied: rheology and physical properties; thermally induced cracking; flexural fatigue life; permanent deformation; aging - chemical and rheological changes; and binder tolerance to mix variables. Discussion of each of these research areas is presented in this paper. The study indicates that the exceptional performance of the polymer modified asphalts in tests such as temperature susceptibility, force ductility, toughness-tenacity and low temperature ductility does not correlate with exceptional performance of the modified binders in mixes. Such tests may characterize modified binders, but they do not indicate improved performance in asphalt concrete mixes. A focus of this research was to identify the properties of the binder which did correlate with mix performance properties. Some conventional tests, and parameters derived from those tests, did correlate well with the mix performance. The correlations are discussed. A major result of this research was to establish that fundamental viscoelastic properties of the binders are well correlated with and help explain the behavior of the binders in asphalt concrete. Dynamic mechanical analysis of the five test asphalts was extensively used in the course of this study. Measurements of the viscoelastic properties of the binders over a range of possible road temperatures is shown to be well correlated with the behavior of the binders in properly designed and prepared asphalt concrete. It was interesting (and unexpected) to find that a conventional asphalt included in this study performed better than the polymer modified asphalts. The proper balance of viscoelastic properties in the binder which is necessary for good mix performance is shown to exist naturally in some asphalts. Data are shown which suggest that the proper balance occurs when an effective elastic network is created by natural, molecular associations.

• Corporate Authors:

  Association of Asphalt Paving Technologists (AAPT)

  400 Selby Avenue, Suite I
  St Paul, MN  United States  55102
• Authors:
  • Goodrich, J L
• Conference:
  • Association of Asphalt Paving Technologists Proc
• Publication Date: 1988

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 116-175
• Serial:
  • Volume: 57

Subject/Index Terms

• TRT Terms: Aging (Materials); Asphalt; Asphalt concrete; Binders; Cracking; Deformation; Ductility tests; Fatigue (Mechanics); Flexural strength; Frost susceptibility; Mix design; Performance; Physical properties; Polymer asphalt; Rheology; Temperature; Thermal degradation; Viscoelasticity
• Uncontrolled Terms: Flexural fatigue; Temperature susceptibility
• Old TRIS Terms: Ductility tests (Asphalts)
• Subject Areas: Highways; Materials; I31: Bituminous Binders and Materials;

Filing Info

• Accession Number: 00749897
• Record Type: Publication
• Files: TRIS
• Created Date: Jun 4 1998 12:00AM