2013 Session: 374

• Linear and Nonlinear Viscoelastic Analysis of Bituminous Mortar
  Abstract: Bituminous materials exhibit either one or a combination of viscous, elastic and viscoelastic response. When applied loads are limited, their behavior can be considered linear. For higher loads they exhibit a nonlinear response. In relation to pavement performance,understanding the behavior of the binders for loads corresponding to the magnitude and frequency of the truck loading is important. With the framework of Porous Asphalt (PA)application, this paper investigates the behavior of a bituminous mortar at various temperatures and shear stress levels. A Dynamic Shear Rheometer setup (DSR) with specimen geometry specially designed for mortar testing was utilized. The mortar, which consisted of bitumen, filler and fine fractions of sand, was produced according to a standard PA mixture recipe. Various measurements conducted at the linear viscoelastic range showed the utilized setup provided very good test result repeatability. The nonlinear behavior was obtained by performing tests at high shear stress levels. The observed nonlinear behavior was described using Schapery nonlinear theory. To allow numerical use, three dimensional form of the theory was implemented in ABAQUS using user material subroutines. For code verification, time and frequency domain simulations were performed so as to reproduce the experimental data. Good comparisons between simulated and measured data were obtained. The paper thoroughly discusses the testing methods, result interpretations, description and finite element simulation works. It also discusses the implications of the results for future use in available PA design tools.
  Authors: Woldekidan, Milliyon Fekade; Huurman, Marinus; Pronk, Adriaan
  Authors: Woldekidan, Milliyon Fekade; Huurman, Marinus; Pronk, Adriaan
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 374
  Paper Number: 13-2557
• Evolution of Crossover Modulus with Oxidative Aging: Method to Estimate Change in Viscoelastic Properties of Asphalt Binder with Time and Depth on the Road
  Abstract: This study is based on recovered binders from a hot mix asphalt comparative test site constructed in Arizona in 2001 on mix collected during construction and cores collected in 2005 and 2010. The intent of the study is to evaluate the potential of using the evolution of the binder crossover modulus with time and depth in the pavement to determine the change in linear viscoelastic properties of the binder during the life of the pavement. The crossover modulus is one of three parameters in the Christensen-Anderson (CA) complex shear modulus model. The CA model is used in this study to develop complex modulus and phase angle master curves of the binder as a function of field time, depth and temperature. Based on the master curves generated the change in SHRP specification parameters such as m-value and creep stiffness as well as mix dynamic modulus with time and depth on the road are demonstrated. In addition, although asphalt dependent, a linear relationship between oxygen uptake and the log of the crossover modulus is reported.
  Authors: Farrar, Michael J.; Turner, Thomas F; Planche, Jean-Pascal; Schabron, John F; Harnsberger, P. Michael
  Authors: Farrar, Michael J.; Turner, Thomas F; Planche, Jean-Pascal; Schabron, John F; Harnsberger, P. Michael
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 374
  Paper Number: 13-3059
• Establishment of Universal Healing Evaluation Index for Asphalt Binder
  Abstract: The healing performance of asphalt binder is important to the overall performance of asphalt pavement. A suitable healing evaluation index is critical in order to compare the healing performance of different asphalt binders and choose the binder with the best healing properties. However, current studies focus primarily on the healing performance of asphalt binder and seem to ignore the importance of a healing evaluation index. In this paper, the healing performance of four different asphalt binders is analyzed. By comparing the healing curve the initial curve, a ratio that is based on the areas created by the curves is found to reflect the healing performance of the asphalt binder. Once the healing evaluation indices are established, they are used also to evaluate the mastics, and the applicability of the indices is analyzed. Also, a healing function for asphalt binder is established. The results show that the HIm-c index (based on the curve of the normalized modulus versus load cycles), the HIem-c index (based on the curve of the elastic modulus versus load cycles) and the HIvm-c index (based on the curve of the viscous modulus versus load cycles) suggest the same rankings for the healing of the study binders. The healing ranking of the binders is also the same as that of the corresponding mastics evaluated by the HIm-c index. Based on the established healing function, it is found that the effect of terminal cases on the healing performance of asphalt binder is greater than the effect of rest periods.
  Authors: Shan, Liyan; Yiqiu, Tan; Kim, Y. Richard; Xu, Yongli
  Authors: Shan, Liyan; Yiqiu, Tan; Kim, Y. Richard; Xu, Yongli
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 374
  Paper Number: 13-3587
• Evaluation of Low-Temperature Properties of Asphalt Binders and Mixtures
  Abstract: With the widespread use of modifiers and additives in asphalt bitumen, this study revisits and evaluates the adaptation of the time-temperature superposition principle that is incorporated in the low temperature Superpave™ binder specifications. The study builds on results of Bending Beam Rheometer (BBR) tests conducted on samples of asphalt binders used in seven different surface layer mixtures. Both 240-second and 2-hour BBR tests were conducted at three different temperatures: the low temperature of the asphalt PG grade (TL), 10°C higher than the low temperature grade (TL+10), and at -5°C to construct the flexural creep stiffness, S(t), master curves. Additionally, indirect tensile tests (IDT) were conducted on the surface layer mixtures to determine the low temperature properties. The BBR test results show that the methodology adopted in utilizing the equivalence principle to formulate the low temperature Superpave™ binder specifications does not accurately apply for some of the binders used in this study. Thus, modifications to the specifications with regard to loading times and test temperatures are suggested. Further, the time-temperature shift factors for the binders evaluated are compared with the universal shift factors used in the Strategic Highway Research Program (SHRP) study. The observed mismatch in the shift factor sets is in disagreement with the implicit assumption that all asphalt binders can be characterized by similar shift factors at low temperatures. The shift factors of the binders and mixtures used in this study tend to match well particularly at high testing temperatures.
  Authors: Premkumar, Laxmikanth; Chehab, Ghassan R.; Solaimanian, Mansour
  Authors: Premkumar, Laxmikanth; Chehab, Ghassan R.; Solaimanian, Mansour
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 374
  Paper Number: 13-4529
• Linear and Nonlinear Viscoelastic Analysis of Bituminous Mortar
  Authors: Woldekidan, Milliyon
  Authors: Woldekidan, Milliyon
  Year: 2013
  Document Type: Presentation
  Subject: Materials
  Session: 374
  Paper Number: 13-2557
• Evolution of Crossover Modulus with Oxidative Aging: Method to Estimate Change in Viscoelastic Properties of Asphalt Binder with Time and Depth on the Road
  Authors: Farrar, Michael
  Authors: Farrar, Michael
  Year: 2013
  Document Type: Presentation
  Subject: Materials
  Session: 374
  Paper Number: 13-3059
• Evaluation of Low-Temperature Properties of Asphalt Binders and Mixtures
  Authors: Premkumar, Laxmikanth
  Authors: Premkumar, Laxmikanth
  Year: 2013
  Document Type: Presentation
  Subject: Materials
  Session: 374
  Paper Number: 13-4529
• Establishment of Universal Healing Evaluation Index for Asphalt Binder
  Authors: Shan, Liyan
  Authors: Shan, Liyan
  Year: 2013
  Document Type: Presentation
  Subject: Materials
  Session: 374
  Paper Number: 13-3587