2013 Session: 840

• Analysis of Temperature Effect on Bituminous Mixture Fatigue Behavior using the EBADE Test
  Abstract: The EBADE test has been developed at the Road Research Laboratory of the UPC-BarcelonaTech to assess the fatigue behaviour of the mixtures by applying a cyclic tensile-compression test to a prismatic specimen at different strain levels (strain sweep). The objective of this paper is to analyze the effect of the temperature variation on the fatigue behaviour of bituminous mixtures by means of this test. It has been studied a dense mixture manufactured with four different bitumens: two modified bitumens, one with polymer and the other with crumb rubber; and the other two with conventional bitumens, with same penetration but different source. The results show the difference of the mixture behaviour with the polymer modified bitumen with respect to the rest of bitumens tested at the temperature range considered. Furthermore, it has been analysed the effect of temperature variation in the mixture on the pavement design and it has been shown a certain contradiction between the results obtained from the analytical calculations and the loss of ductility experienced by the mixtures at low temperatures.
  Authors: Perez-Jimenez, Felix Edmundo; Botella Nieto, Ramon; Miró, Rodrigo; Martinez, Adriana Haydee
  Authors: Perez-Jimenez, Felix Edmundo; Botella Nieto, Ramon; Miró, Rodrigo; Martinez, Adriana Haydee
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 840
  Paper Number: 13-2477
• Effects of Shear Stress on Pavement Cracking and Interface Debonding: Case Study in Arkansas
  Abstract: Longitudinal cracking in wheelpaths and interface debonding at 2 inches underneath the surface were observed on Interstate 40 in Franklin County, Arkansas. Besides the mostly known reason, construction deficiency, this study investigated this problem from the perspective of shear stress. 3D finite element model was developed to predict structural responses for different scenarios by varying the thickness of the wearing course, the horizontal loads level, the stiffness ratio and interface condition between the wearing course and its underlying layer. Results showed that the location of the maximum shear stress was constantly between 4cm and 6cm below the surface when the horizontal force was in a low level. Much greater than tensile stresses, shear stresses at the edge of tires contributed greatly to the initiation of the longitudinal cracking in wheelpaths. In addition, it was found that the maximum shear stress took place at the interface when the interface between the wearing course and the binder course was not fully bonded. Thus, the interface could suffer large repeated shear stresses and lead to fatigue cracking in the asphalt mixture. In summary, this study concluded that shear stress at the interface could be a significant factor responsible for pavement cracking and interface debonding.
  Authors: Zou, Xiaoling
  Authors: Zou, Xiaoling
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 840
  Paper Number: 13-3506
• Nonlinear Viscoelastic Behavior of Asphalt Concrete and Its Implication on Fatigue Modeling
  Abstract: Mechanistic models for asphalt concrete (AC) can consider many different physical mechanisms. However, as more mechanisms are considered, the complexity increases, and it becomes important to balance accuracy and complexity to create a model that can be used by the engineering community. In some cases, the material response is dominated by the effects of only some key processes and smearing the effects of the minor ones is acceptable. In other cases, many different processes are important and need to be considered. In this paper, the importance of modeling the nonlinear viscoelasticity (NLVE) of AC for fatigue response prediction is assessed. Two mechanistic hypotheses are considered for describing this phenomenon; 1) linear viscoelastic with damage and 2) NLVE with damage. The importance of explicitly considering NLVE effects under fatigue loading is evaluated by using laboratory tests, the simplified viscoelastic continuum damage (S-VECD) model, and a NLVE form of the S-VECD model. These two models are characterized and used to simulate and compare AC fatigue response under constant and random controlled stress and strain conditions. It is found that while the NLVE based formulation better represents the material response in random loading and suggests less overall damage accumulation during fatigue, that the two models predict very similar amounts of modulus reduction. The primary conclusion from this study is that since the goal for fatigue assessment is to find the change in modulus over a long period of time, fatigue response modeling of AC does not need to explicitly consider NLVE.
  Authors: Underwood, Shane; Kim, Y. Richard
  Authors: Underwood, Shane; Kim, Y. Richard
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 840
  Paper Number: 13-4380
• Scanning Laser Detection of Crack Precursors in High RAP Content Asphalt Mixture with Improved Fatigue Performance
  Abstract: Formation of microcracks under fatigue conditions is a complex mechanism and difficult to detect. A microcrack is not apparent until late in fatigue life of the section. However, structural changes and microcracks can occur earlier and could be used as an originator for fatigue crack formations that lead to failure. Therefore, it is important to develop methods to promptly detect microcracks early in fatigue life well in advance of macrocrack growth. This paper presents the test procedure and analysis approach developed for a non-contact Scanning Laser Detection (SLD) for capturing and monitoring cracks in asphalt mixtures. The study focuses on utilizing SLD to investigate damage resistance of asphalt mixtures containing high Recycled Asphalt Pavement (RAP) content. Use of more RAP in asphalt materials is becoming increasingly popular due to the economic and environmental benefits of recycled materials. On the other hand, stiffer mixes resulting from RAP addition has raised concern about long term properties of pavement, therefore an accurate fatigue evaluation of these mixes are needed. The proposed scanning technique detects cracks in initiation and propagation phases and characterizes surface state with a parameter called Defect Frequency (DF). This parameter is used as direct indication of the light scattering signature of specimen and can be related to surface changes leading to crack initiation. For each mixture (50% RAP and a control), the fatigue lives determined from the SLD were compared and exhibited strong correlation with those obtained from the traditional mechanical and energy-based fatigue approaches.
  Authors: Ajideh, Hossein; Bahia, Hussain U.; Earthman, James
  Authors: Ajideh, Hossein; Bahia, Hussain U.; Earthman, James
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 840
  Paper Number: 13-5136
• Analysis of Temperature Effect on Bituminous Mixture Fatigue Behavior using the EBADE Test
  Authors: Perez-Jimenez, Felix
  Authors: Perez-Jimenez, Felix
  Year: 2013
  Document Type: Presentation
  Subject: Materials
  Session: 840
  Paper Number: 13-2477
• Effects of Shear Stress on Pavement Cracking and Interface Debonding: Case Study in Arkansas
  Authors: Zou, Xiaoling
  Authors: Zou, Xiaoling
  Year: 2013
  Document Type: Presentation
  Subject: Materials
  Session: 840
  Paper Number: 13-3506
• Scanning Laser Detection of Crack Precursors in High RAP Content Asphalt Mixture with Improved Fatigue Performance
  Authors: Ajideh, Hossein
  Authors: Ajideh, Hossein
  Year: 2013
  Document Type: Presentation
  Subject: Materials
  Session: 840
  Paper Number: 13-5136
• Nonlinear Viscoelastic Behavior of Asphalt Concrete and Its Implication on Fatigue Modeling
  Authors: Underwood, Shane
  Authors: Underwood, Shane
  Year: 2013
  Document Type: Presentation
  Subject: Materials
  Session: 840
  Paper Number: 13-4380