Installation and laboratory evaluation of alternatives to conventional polymer modification for asphalt.

Details

• Creators:
  Diefenderfer, Stacey D. ; McGhee, Kevin K.
• Corporate Creators:
  Virginia Center for Transportation Innovation and Research
• Corporate Contributors:
  Virginia. Dept. of Transportation ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Binders
  • Asphalt pavements
  • Polymer asphalt
  • Styrene butadiene styrene
  • Laboratory tests
  • Evaluation
  • Deformation
  • Elasticity (Mechanics)
• Publication/ Report Number:
  VCTIR 15-R15
• Resource Type:
  Tech Report
• Geographical Coverage:
  Virginia
• Corporate Publisher:
  Virginia Center for Transportation Innovation and Research
• Abstract:
  The Virginia Department of Transportation (VDOT) specifies polymer-modified asphalt binders for certain asphalt ; mixtures used on high-volume, high-priority routes. These binders must meet performance grade (PG) requirements for a PG ; 76-22 binder in addition to elastic recovery requirements. This typically results in the use of binders containing styrene-butadiene-styrene (SBS) modifiers. However, other polymer modifiers may also be used to achieve the PG 76-22 classification. ; One of these modifiers is a copolymer of SBS and polyethylene (PE) (SBS-PE); another modifier is ground tire rubber (GTR). ; This study was undertaken to investigate the suitability of SBS-PE–modified PG 76-22 binder and GTR-modified PG 76-22 ; binder for use in Virginia. ; Each modified binder was used in a 12.5 mm nominal maximum aggregate size mixture to pave approximately 2.3 ; lane-miles. All mixtures were produced as warm mix asphalt using a foaming system. The binders evaluated included a typical ; SBS polymer-modified binder as a control and binders modified with SBS-PE and GTR. During construction, all processes ; were documented and material was sampled for evaluation. Binder and mixture tests were performed. Binder testing included ; performance grading and multiple stress creep and relaxation testing. Mixture testing included volumetric analysis, dynamic ; modulus, and flow number tests and cracking, rutting, and fatigue analysis. ; Binder testing indicated that the control binder and SBS-PE–modified binders met VDOT specifications for ; classification as a PG 76-22 binder; the GTR-modified binder graded to a PG 70-22 binder, as it did not meet the PG 76-22 high-temperature specification and did not pass the elastic recovery requirement. Laboratory mixture testing indicated that the ; performance of the SBS-PE–modified mixture should be similar to that of the control mixture. Laboratory test results for the ; GTR-modified mixture were mixed, with some indicating that the performance was similar to that of the control mixture and ; some indicating that the performance may be less than that of the control. ; Based on the study, SBS-PE–modified binders should continue to be allowed as an alternative to SBS-modified binder ; provided specifications for PG 76-22 binders are met. However, further investigation of GTR-modified binders is suggested ; before recommendations can be made. In addition, long-term evaluation of the field site is recommended for validation of the ; laboratory findings.
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• Format:
  PDF
• Funding:
  RC00052
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/28519/dot_28519_DS1.pdf
• File Type:
  [PDF - 454.26 KB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:f23f2e51af17de1afe9988d4d6b704e2b7f9044163b50ab7dbe42f9e7b2ebf88