Interpreting a three point bending test on pre-notched bitumen beam to determine cracking behavior at low temperature

Current specifications on the determination of the low-temperature cracking resistance of asphalt binders are based on empirical tests or tests involving the linear viscoelasticity (Fraass test, creep test, complex modulus). However, although these standard characteristics may work for pure bitumen but cannot be applied on all binders. A new test based on fracture mechanics principle has been standardized in Europe (CEN/TS 15963:2009). This standard, based on a three-points bending test on pre-notched bitumen beam, appears a promising solution that can be applied to all bitumnious binders. This article provides new elements for processing the results obtained by this test. Due to the viscoelastic nature of the materials tested, the concept of strain intensity factor is introduced in addition to the stress intensity factor. Hence, the description of the stress state and the shape of the pre-notch make possible to calculate easily the critical energy release rate (Gc). The theoretical approach is applied to test results obtained with 9 bitumens, non-aged and PAV aged, tested at several temperatures. Measurements show that above a certain temperature, named Limiting Cracking Temperature (LCT), crack can not propagate. A new way to rank binder is proposed using the LCT and Gc. It appears that this ranking differs from Bending Beam Rheometer output. Results highlight also the importance to test aged binder.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Pagination: 7p., schémas, graphiques, tabl.

Subject/Index Terms

Filing Info

  • Accession Number: 01729135
  • Record Type: Publication
  • Source Agency: Institut Francais des Sciences et Technologies des Transports, de l'Amenagement et des Reseaux (IFSTTAR)
  • Contract Numbers: 11R111, Réduction de l'impact climatique sur les
  • Files: ITRD
  • Created Date: Jan 28 2020 4:18PM