Understanding the Performance of Modified Asphalt Binders in Mixtures: Evaluation of Moisture Sensitivity

A laboratory effort is being carried out in conjunction with accelerated field performance at the Federal Highway Administration (FHWA) Pavement Testing Facility. Several modified materials, with close Superpave grade, were prepared from a common crude source. Included in this study are: three unmodified asphalt binders, an air-blown asphalt binder, and eight polymer-modified asphalt binders. The effects of polymer type and geometry (linear and branched) and, whether or not, the polymer is chemically reacted (grafted) or merely blended with the asphalt were evaluated. A discussion of the findings that pertain to moisture susceptibility of the binder and mix is presented. Also, the effect of lime at mitigating moisture damage and clays at promoting moisture damage are presented. The moisture sensitivity of mixtures was measured using the Hamburg Wheel Tracking Device. The Pneumatic Pull-Off Tester was used to evaluate the moisture susceptibility of the binders. Some of the asphalt binders provided significantly different resistances to moisture damage that were not related to differences in cohesive strength as measured by the asphalt binder parameter Complex Modulus/Phase Angle (G*/sin d) at 58°C or Pull-Off strength at 25ºC. It was concluded that polymermodified asphalt binders, having the same G*/sin d, can provide different adhesive strengths and/or different resistances to water penetration.

Language

  • English

Media Info

  • Media Type: Print
  • Pagination: pp. 399-417.
  • Monograph Title: Proceedings of the Forty-Eighth Annual Conference of the Canadian Technical Asphalt Association (CTAA): Halifax, Nova Scotia, November 2003

Subject/Index Terms

Filing Info

  • Accession Number: 01604996
  • Record Type: Publication
  • Source Agency: Transportation Association of Canada (TAC)
  • Files: ITRD, TAC
  • Created Date: Jul 26 2016 5:03PM