LOW-TEMPERATURE REFLECTION CRACKING THROUGH ASPHALT OVERLAYS. SIXTH INTERNATIONAL CONFERENCE, STRUCTURAL DESIGN OF ASPHALT PAVEMENTS, VOLUME I, PROCEEDINGS, UNIVERSITY OF MICHIGAN, JULY 13-17, 1987, ANN ARBOR, MICHIGAN

The problem of cracks in old, underlying pavements quickly propagating up through new overlays is a serious problem in many areas. It is generally termed "reflection cracking" and is caused by thermal contraction cycles, by repeated traffic loads or by some combination of the two mechanisms. Overlay design methods should consider reflection cracking and should be able to evaluate the effectiveness of treatments such as interlayers, reinforcement, fabrics, and increased overlay thickness for any given situation. Fracture mechanics principles with strain energy and strength criteria can be effectively used. In particular, finite element analyses combined with a blunt crack band theory are employed in this paper to evaluate typical overlay situations under thermal cycling conditions. These situations are for no treatment and with geogrid reinforcement, stress absorbing membrane interlayer (SAMI), and composite interlayer treatments. Temperature cycling and gradients are modelled from The Ste. Anne Test Road. Results of the analyses illustrate that stress concentrations around the crack front can vary widely. Moreover, they can be significantly reduced with a SAMI or geogrid reinforcement. However, under very cold conditions, cracks may initiate at the top of the overlay and propagate down. The results also show that a composite interlayer offers potential for reduced overlay thickness compared to the other treatments. A laboratory simulation study, involving specially designed equipment for thermal cycling down to -40 deg C, has been initiated. It will be used to verify or calibrate the analytical modelling, to screen treatments and to plan field trials. Example preliminary results show that a geogrid reinforced overlay was able to withstand 7 times more thermal cycles before fracture than the control overlay.

• Corporate Authors:

  University of Michigan, Ann Arbor

  Department of Civil Engineering
  Ann Arbor, MI  United States  48109
• Authors:
  • JOSEPH, P
  • Haas, R
  • Phang, W A
  • Rothenburg, Leo
• Publication Date: 1987

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 935-945
• Serial:
  • Publication of: Michigan University, Ann Arbor
  • Publisher: University of Michigan, Ann Arbor

Subject/Index Terms

• TRT Terms: Asphalt pavements; Conferences; Energy absorbing materials; Finite element method; Fracture mechanics; Geogrids; Geotextiles; Laboratory studies; Low temperature; Measures of effectiveness; Overlays (Pavements); Reflection cracking; Stresses; Thickness
• Uncontrolled Terms: Effectiveness; Stress concentration; Treatment
• Old TRIS Terms: Composite interlayer; Stress absorbing membrane interlayer; Thermal cycling
• Subject Areas: Design; Geotechnology; Highways; Materials; Pavements; I22: Design of Pavements, Railways and Guideways; I33: Other Materials used in Pavement Layers;

Filing Info

• Accession Number: 00485654
• Record Type: Publication
• Files: TRIS
• Created Date: Jul 31 1989 12:00AM