Abstract for presentation (Poster or Podium) with a Paper in the Conference Proceedings
Highway Pavements
Syed A. Ali, PhD
Post-Doctoral Research Associate
University of Oklahoma
Norman, OK, United States
Syed A. Ali, PhD
Post-Doctoral Research Associate
University of Oklahoma
Norman, OK, United States
David Vivanco, PE
Asphalt Branch Manager
Oklahoma Department of Transportation
Edmond, Oklahoma, United States
Kenneth R. Hobson, PE
Asphalt Lab Manager
University of Oklahoma
Norman, Oklahoma, United States
Musharraf Zaman, Ph.D., PE
David Ross Boyd and Aaron Alexander Professor in Civil Engineering
University of Oklahoma
Norman, Oklahoma, United States
Sagar Ghos, n/a
Graduate Research Assistant
University of Oklahoma
Norman, OK, Oklahoma, United States
Syed A. Ali, PhD
Post-Doctoral Research Associate
University of Oklahoma
Norman, OK, United States
Moisture-induced damage is one of the major distresses which contributes to significant premature deterioration of asphalt pavements in Oklahoma. Oklahoma Department of Transportation (ODOT) is using Tensile Strength Ratio (TSR) from the AASHTO T 283 test for screening of mixes for moisture-induced damage. Also, recently ODOT has started using Cracking Tolerance Index (CTindex) from the Indirect Tensile Asphalt Cracking Test (IDEAL-CT) for screening of asphalt mixes for fatigue cracking. The testing mechanism of the IDEAL-CT is similar to the AASHTO T 283 test method. However, the IDEAL-CT test requires specimen with a height of 62-mm, whereas the specimen height of the AASHTO T 283 is 95-mm. By using specimens of similar dimension, the data obtained from the IDEAL-CT test can be readily used for the calculation of TSR. In this study, the effect of changing the specimen height from 95-mm to 62-mm on the current AASHTO T 283 method was explored. For this purpose, three asphalt mix designs with various moisture-induced damage potentials were selected with the help of ODOT. Necessary materials to produce the asphalt mixes were collected from local sources. Asphalt mix specimens of two different heights, namely 62- and 95-mm, were compacted in the laboratory. The specimens were then divided into two different sets, namely control and AASHTO T 283-conditioned. The Indirect Tensile Strength (ITS) test was conducted on the specimens until failure. The data obtained from these tests were analyzed to determine the ITS, TSR, and CTindex of the asphalt mixes. The test results indicated that the ITS of specimens vary with specimen height. Also, the type of mix (coarser vs. finer) was observed to affect the changes in the ITS value with specimen height. The 62-mm specimens provided a more conservative estimate of moisture susceptibility, based on TSR value, than the 95-mm specimens. Similar to ITS, the CTindex value was found to vary with the height of asphalt mix specimen. It is expected that the findings of this study will help modify the current AASHTO T 283 test method and allow an integrated screening of fatigue cracking and moisture-induced damage for asphalt mixes.