Reflective cracking: Modeling fracture behavior of hot-mix asphalt overlays with interlayer systems

Jongeun Baek, Imad L Al-Qadi

Research output: Contribution to journalConference articlepeer-review

Abstract

This study uses three-dimensional finite element modeling to investigate the fracture behavior of hot-mix asphalt (HMA) overlays that resulted in reflective cracking. The investigated pavement consists of a 57-mm-thick HMA overlay over a 200-mm-thick jointed plain concrete pavement (JPCP). Using a bilinear cohesive zone model (CZM), the crack behavior is characterized by traction-separation law. Cohesive elements are inserted directly over the transverse joints, which are potential reflective cracking locations in the HMA overlay. The viscoelastic and fracture properties of the HMA are obtained through laboratory tests. A transient moving load is applied over a transverse joint, and implicit dynamic analysis is conducted to obtain time-dependent responses of the HMA overlay pavement. To examine the performance of interlayer systems, sand mix and steel netting interlayer, respectively, are added under the overlay as substitutive and supplemental layers. The mechanism of the interlayer systems on delaying reflective cracking is inspected by means of a degradation scalar to represent a degree of damage in the cohesive elements. These results are compared to a control HMA overlay section that has no interlayer system. In the control section, reflective cracking initiates in the middle of the leveling binder under a wheel path and propagates vertically to the surface, as well as laterally to the outside of the wheel paths. The sand mix interlayer efficiently reduces reflective cracking in the leveling binder. Shear as well as tensile fracture energy of the sand mix affects the performance. Finally, the steel netting interlayer reduces reflective cracking significantly when properly installed. When steel netting was used, reflective cracking was significantly reduced in the leveling binder due to strong shear deformation support, as well as high tensile strain compensation in the overlay. This also reduces the potential of reflective cracking in the wearing surface.

Original languageEnglish (US)
Pages (from-to)789-827
Number of pages39
JournalAsphalt Paving Technology: Association of Asphalt Paving Technologists-Proceedings of the Technical Sessions
Volume78
StatePublished - Dec 1 2009
EventAsphalt Paving Technology 2009, AAPT - Minneapolis, MN, United States
Duration: Mar 15 2009Mar 18 2009

Keywords

  • Cohesive zone model
  • Finite element method
  • Interlayer systems
  • Reflective cracking

ASJC Scopus subject areas

  • Civil and Structural Engineering

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