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:
  Asphalt Pavements Binders Deformation Elasticity (Mechanics) Evaluation Laboratory Tests Polymer Asphalt Styrene Butadiene Styrene
• 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.
  
  
• Format:
  PDF
• Funding:
  RC00052
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:f23f2e51af17de1afe9988d4d6b704e2b7f9044163b50ab7dbe42f9e7b2ebf88
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/28519/dot_28519_DS1.pdf
• File Type:
  [PDF - 454.26 KB ]