FIELD VERIFICATION OF ASPHALT AGING IN HOT MIX PLANTS (WITH DISCUSSION)

Asphalt concrete pavement tenderness, due to inadequate aging or unexpected soft consistency of the asphalt, has caused problems such as rutting over the past ten years in Oregon. In order to identify the causes of the pavement tenderness, data were gathered from various construction projects throughout the state. As a measure of aging in the mixing and placement process, the following formula was developed to determine the percentage of the expected change in asphalt viscosity at the time of paving: C=[(R-A)/(B-A)]x100%, where A=absolute viscosity of the original asphalt, B=absolute viscosity of the asphalt residue after rolling thin film oven aging, and R=absolute viscosity of the asphalt recovered from the mixture. This field study as a follow-up to the original 1981-83 evaluation does verify the conclusions of that report. The 30 to 50 "C" value range appears to be a critical area. It appears from this study that the minimum acceptable value should be 40. In early 1985, the Oregon Highway Department raised the minimum acceptable "C" value from 30 to 40. Mixes with a value less than 40 are to be removed, or at the discretion of the engineer they may be left in place and a reduction in a Composite Pay Factor calculated (OSHD Specification 403.39). This specification is reproduced in an Appendix to this paper.

• Corporate Authors:

  Association of Asphalt Paving Technologists (AAPT)

  400 Selby Avenue, Suite I
  St Paul, MN  United States  55102
• Authors:
  • Lund, J W
  • Wilson, J E
• Conference:
  • Association of Asphalt Paving Technologists Proc
• Publication Date: 1986

Language

• English

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: p. 92-119
• Serial:
  • Volume: 55

Subject/Index Terms

• TRT Terms: Aging (Materials); Asphalt pavements; Asphalt plants; Construction; Field studies; Specifications; Viscosity
• Uncontrolled Terms: Construction specifications
• Geographic Terms: Oregon
• Old TRIS Terms: Asphalt pavement specifications
• Subject Areas: Construction; Design; Highways; Materials; Pavements; I22: Design of Pavements, Railways and Guideways; I23: Properties of Road Surfaces; I31: Bituminous Binders and Materials; I52: Construction of Pavements and Surfacings;

Filing Info

• Accession Number: 00739640
• Record Type: Publication
• Files: TRIS
• Created Date: Aug 5 1997 12:00AM