Effect of MSCR Percent Recovery on Performance of Polymer Modified Asphalt Mixtures

Ramadan Salim, Akshay Gundla, B. Shane Underwood, Kamil Kaloush

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


The AASHTO M332 specification includes a relationship between the non-recoverable creep compliance at 3.2 kPa (Jnr3.2) and the percent of elastic recovery (R3.2) from the multiple stress creep and recovery (MSCR) test. Justification for the exact position of this curve based on binder performance is largely undocumented in the technical literature as is the singular effect of higher or lower R3.2 values on mixture performance. In this study, nine binders were tested to evaluate the effect of R3.2 on the performance of asphalt mixtures. Binders with similar Jnr3.2 and varying MSCR R3.2 were divided into four groups based on their Jnr3.2 value. Comparisons were made based on results obtained from the dynamic modulus test, Hamburg wheel tracking test, and axial fatigue test. Based on these tests, it was shown that R3.2 had a strong relationship to the dynamic modulus of asphalt mixtures especially at intermediate and high temperatures. Binders with lower R3.2 had a higher dynamic modulus but showed no correlation to phase angle. Both modulus and phase angle of the mixture correlated to the binder shear modulus and phase angle. Binders with high R3.2 had a greater fatigue resistance and the effect is quite noticeable. However, R3.2 was shown to have little to no effect on the rutting resistance of the asphalt mixtures for the temperatures tested in this study. Finally, an alternative Jnr3.2 versus R3.2 relationship based on the results of this study is also presented.

Original languageEnglish (US)
Pages (from-to)308-319
Number of pages12
JournalTransportation Research Record
Issue number5
StatePublished - May 1 2019

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Mechanical Engineering


Dive into the research topics of 'Effect of MSCR Percent Recovery on Performance of Polymer Modified Asphalt Mixtures'. Together they form a unique fingerprint.

Cite this