Reflective crack mitigation guide for flexible pavements.

Details

• Creators:
  Williams, R. Christopher ; Chen, Can ; Buss, Ashley
• Corporate Creators:
  Iowa State University. Institute for Transportation
• Corporate Contributors:
  Iowa. Dept. of Transportation ; Iowa. Highway Research Board
• Subject/TRT Terms:
  • Flexible pavements
  • Reflection cracking
  • Rehabilitation (Maintenance)
  • Hot mix asphalt
  • Pavement performance
  • Bituminous overlays
  • Crack and seat treatment
  • Rutting
  • Comminution
  • Falling weight deflectometers
• Publication/ Report Number:
  IHRB Project TR-641;InTrans Project 11-424
• Resource Type:
  Tech Report
• Geographical Coverage:
  Iowa
• Corporate Publisher:
  Iowa State University. Institute for Transportation
• Abstract:
  Reflective cracks form in pavements when hot-mix asphalt (HMA) overlays are placed over jointed and/or severely cracked rigid ; and flexible pavements. In the first part of the research, survival analysis was conducted to identify the most appropriate ; rehabilitation method for composite pavements and to evaluate the influence of different factors on reflective crack development. ; Four rehabilitation methods, including mill and fill, overlay, heater scarification (SCR), and rubblization, were analyzed using ; three performance indicators: reflective cracking, international roughness index (IRI), and pavement condition index (PCI). It was ; found that rubblization can significantly retard reflective cracking development compared to the other three methods. No ; significant difference for PCI was seen among the four rehabilitation methods. Heater scarification showed the lowest survival ; probability for both reflective cracking and IRI, while an overlay resulted in the poorest overall pavement condition based on ; PCI. In addition, traffic level was found not to be a significant factor for reflective cracking development. An increase in overlay ; thickness can significantly delay the propagation of reflective cracking for all four treatments. Soil types in rubblization pavement ; sites were assessed, and no close relationship was found between rubblized pavement performance and subgrade soil condition. ; In the second part of the research, the study objective was to evaluate the modulus and performance of four reflective cracking ; treatments: full rubblization, modified rubblization, crack and seat, and rock interlayer. A total of 16 pavement sites were tested ; by the surface wave method (SWM), and in the first four sites both falling weight deflectometer (FWD) and SWM were ; conducted for a preliminary analysis. The SWM gave close concrete layer moduli compared to the FWD moduli on a ; conventional composite pavement. However, the SWM provided higher moduli for the rubblized concrete layer. After the ; preliminary analysis, another 12 pavement sites were tested by the SWM. The results showed that the crack and seat method ; provided the highest moduli, followed by the modified rubblization method. The full rubblization and the rock interlayer methods ; gave similar, but lower, moduli. Pavement performance surveys were also conducted during the field study. In general, none of ; the pavement sites had rutting problems. The conventional composite pavement site had the largest amount of reflective cracking. ; A moderate amount of reflective cracking was observed for the two pavement sites with full rubblization. Pavements with the ; rock interlayer and modified rubblization treatments had much less reflective cracking. It is recommended that use of the ; modified rubblization and rock interlayer treatments for reflective cracking mitigation are best.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/29618/dot_29618_DS1.pdf
• File Type:
  [PDF - 4.80 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:ab6f3e8bebf3ea3043c3f92bdbaece813e77210a80acde59dc12195f1e6bb7fb217485aef6e89c8ffc8a614eec191bf998ef99a9eb406104f993a9bb3ae084b1