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Cover of Development of a Binder Test to Rank the Low Temperature Cracking Resistance of Polymer Modified Binders
Development of a Binder Test to Rank the Low Temperature Cracking Resistance of Polymer Modified Binders
  • Publication no: AP-T299-15
  • ISBN: 978-1-925294-52-1
  • Published: 23 July 2015

The current Australian polymer modified binder (PMB) specification includes low temperature stiffness tests but does not include a binder test which ranks the resistance of PMBs to low temperature cracking on the road. This study investigated whether binder force ratio tests which were conducted using the ARRB elastometer could be included as a binder test in the Australian PMB specification to rank the low temperature cracking performance of binders.

The relationship between extensiometer force ratio results and the low temperature cracking performance of the binders in a single 10 mm dense graded asphalt mix was investigated using four bitumen samples and 18 different PMBs. Each of the binders was subjected to a range of conventional binder tests so that their test properties could be compared with those of specified binder grades. A good correlation was found between force ratio results and the fatigue lives of the binders in asphalt if binders did not break during extensiometer tests when they were tested under a standard set of extensiometer test conditions (i.e. test temperature = 10 °C, test speed = 0.5 mm/s and final sample displacement = 250 mm).

Based on the good correlation between force ratio results and asphalt fatigue life results observed in the current study, and studies by other researchers, extensiometer force ratio tests appear to be suitable for ranking the low temperature cracking performance of nine of the 13 binder grades which have specified test properties listed in the Australian PMB specification. The results of preliminary studies indicated that further research is required to optimise the extensiometer test conditions to be used to characterise the properties of hard PMBs as they broke during testing when standard extensiometer test conditions were used. Further work has been proposed in the fourth year of the project (2015–16) to determine whether appropriate extensiometer test conditions can be developed so that force ratio results can be used to rank the low temperature cracking performance of hard PMB grades (i.e. A35P, A25E, S15RF and S18RF grade PMBs).

  • Summary
  • 1. Introduction
    • 1.1. Background
    • 1.2. Low Temperature Binder Cracking Tests
      • 1.2.1. Dynamic Shear Rheometer (DSR) Tests
      • 1.2.2. Force Ductilometer Tests
      • 1.2.3. ARRB Extensiometer Tests
    • 1.3. This Report
  • 2. Experimental Design
    • 2.1. Materials and PMB Sample Preparation
    • 2.2. Binder Test Procedures
    • 2.3. Extensiometer Tests
    • 2.4. Asphalt Mix Design and Test Procedures
  • 3. Binder Test Results Obtained for Bitumen Samples and Laboratory-Produced PMBs
    • 3.1. Bitumen Samples
    • 3.2. PMBs Containing 3.5% w/w SBS Polymer
    • 3.3. SBS-based PMBs Subjected to Long-term Hot Storage
  • 4. Binder Test Results Obtained for Commercial PMBS
    • 4.1. Binder Test Result Summary
  • 5. Comparisons between Extensiometer and Asphalt Fatigue Results
    • 5.1. Bitumen Samples and Laboratory-produced PMBs
    • 5.2. Commercial PMBs
    • 5.3. All Binders
    • 5.4. Comparisons with Stiffness Results
    • 5.5. Discussion
  • 6. Preliminary Extensiometer Tests on Hard Binders
    • 6.1. A35P Binder
    • 6.2. 15% w/w Crumb Rubber Binder
    • 6.3. Discussion and Proposed Future Work
  • 7. Conclusions
  • References