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Design of Stress Absorbing Membrane Interlayer (Sami) and Overlay to Reduce Reflective Cracking

Taheri, Amir | 2019

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 51902 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Motamed, Arash
  7. Abstract:
  8. Cracks or construction joints in an overlayed pavement can propagate into the overlay over time due to various factors, the most important of which are traffic and temperature loading, and cause premature failure of pavement. This propagated cracks are called reflective cracks and the phenomenon of crack propagation into the overlay is called reflective cracking. Use of stress-absorbing membrane interlayers (SAMI) is one of the ways can reduce the occurrence of reflective cracking and/or delay it. One of the most common SAMIs is an asphalt mixture consists of bitumen and aggregate layed down between the old and the veneer layers. The function of the SAMI depends on several factors such as thickness and mechanical properties of the SAMI and the condition of the overlayed pavement in terms of the amount of existing damages. Numerical simulation is a powerful tool for the assessment of SAMIs. In this research by using numerical simulation and laboratory study attempted to design SAMI optimally so that reduces reflective cracking. In order to realization of this purpose, first the optimum mixture design of SAMIs and overlays (each with neat and crumb rubber modified asphalt) was determined. In the next step the dynamic modulus and the fatigue characteristics of the optimal mixtures were determined for use in numerical simulations. Then the performance of the pavements including SAMI was evaluated by wheel loading test. To compare between the results of the wheel loading test and the results of the numerical simulations and also to validate a design method introduced, the wheel loading test geometry was modeled and analyzed numerically. In the final step the possibility of replacing a new test geometry instead of wheel loading test to assessment of pavements including SAMI was evaluated. This research shows that not only the use of SAMI can reduce the reflective cracking extensively but also the introduced design method can be efficient
  9. Keywords:
  10. Reflective Cracking ; Stress Absorbing Membrane Interlayer (SAMI) ; Numerical Simulation ; Crumb Rubber Modifier ; Interface Crack ; Asphalt Pavement

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