Cracking performance predictions using index-volumetrics relationships with direct tension cyclic fatigue test and Illinois Flexibility Index Test (I-FIT)

2021 ◽  
pp. 125631
Author(s):  
Jaehoon Jeong ◽  
B. Shane Underwood ◽  
Y. Richard Kim
Keyword(s):  
Fatigue Test ◽  
Cyclic Fatigue ◽  
Index Test ◽  
Direct Tension ◽  
Performance Predictions ◽  
Cracking Performance ◽  
Flexibility Index

Evaluation of Asphalt Mixture Performance Using Cracking and Durability Tests at a Full-Scale Pavement Facility

2021 ◽  
pp. 036119812110218
Author(s):  
Amir Golalipour ◽  
Varun Veginati ◽  
David J. Mensching
Keyword(s):  
Performance Test ◽  
Asphalt Mixture ◽  
Performance Testing ◽  
Field Performance ◽  
Optimization Procedure ◽  
Cyclic Fatigue ◽  
Intermediate Temperature ◽  
Index Test ◽  
Reclaimed Asphalt ◽  
Indirect Tensile

In the asphalt materials community, the most critical research need is centered around a paradigm shift in mixture design from the volumetric process of the previous 20-plus years to an optimization procedure based on laboratory-measured mechanical properties that should lead to an increase in long-term pavement performance. This study is focused on advancing the state of understanding with respect to the value of intermediate temperature cracking tests, which may be included in a balanced mix design. The materials included are plant-mixed, laboratory-compacted specimens reheated from the 2013 Federal Highway Administration’s (FHWA’s) Accelerated Loading Facility (ALF) study on reclaimed asphalt pavement/reclaimed asphalt shingle (RAP/RAS) materials. Six commonly discussed intermediate temperature (cracking and durability) performance testing (i.e., Asphalt Mixture Performance Tester [AMPT] Cyclic Fatigue, Cantabro, Illinois Flexibility Index Test [I-FIT], Indirect Tensile Cracking [ITC, also known as IDEAL-CT], Indirect Tensile Nflex, and Texas Overlay Test) were selected for use in this study based on input from stakeholders. Test results were analyzed to compare differences between the cracking tests. In addition, statistical analyses were conducted to assess the separation among materials (lanes) for each performance test. Cyclic fatigue and IDEAL-CT tests showed the most promising results. The ranking from these two tests’ index parameters matched closely with ALF field performance. Furthermore, both showed reasonable variability of test data and they were successful in differentiating between different materials.

Impact of Specimen Configuration and Characteristics on Illinois Flexibility Index

2018 ◽  
Vol 2672 (28) ◽  
pp. 383-393 ◽  
Author(s):  
Jose Rivera-Perez ◽  
Hasan Ozer ◽  
Imad L. Al-Qadi
Keyword(s):  
Correction Factor ◽  
Loading Rate ◽  
Void Content ◽  
Displacement Curve ◽  
Specimen Thickness ◽  
Index Test ◽  
Notch Length ◽  
Air Void ◽  
Flexibility Index ◽  
Air Void Content

The Illinois Department of Transportation adopted the Illinois Flexibility Index Test (I-FIT) to evaluate the cracking vulnerability of asphalt concrete (AC) mixtures that was often shown to increase with the addition of recycled materials such as reclaimed asphalt pavement and recycled asphalt shingles. The test consists of a semi-circular AC sample that has a notch, loaded along the symmetric axis. Fracture energy (FE), post-peak slope, and the flexibility index (FI) are computed from the load displacement curve. These results can be influenced by specimen geometry and test parameters such as loading rate, AC voids content, and so forth. Therefore, this study investigated the effect of notch length, specimen thickness, loading rate, and AC air void content on the I-FIT results. It was found that an increase in the specimen thickness or loading rate resulted in a steeper post-peak slope without affecting the FE. As a result, the FI decreased. An increase in the notch length or AC air void content resulted in a flatter post-peak slope, thus, increasing the FI. From the results, it was concluded that existing correction factors to address the variations caused by specimen thickness and air void content are appropriate. A correction factor to address notch length variations is proposed. A unique correction factor for loading rate could not be developed because of the varying rate dependency of each AC mixture.

scholarly journals Comparison of the cyclic fatigue resistance of ProGlider, PathGlider and One G path-finding instruments

2019 ◽  
Vol 13 (1) ◽  
pp. 57-60
Author(s):  
Damla Özsu Kırıcı ◽  
Ertuğrul Karataş ◽  
Ahmet Demirhan Uygun ◽  
Ezgi Doğanay Yıldız ◽  
Kezban Meltem Çolak ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Fatigue Test ◽  
Fatigue Resistance ◽  
Root Canal ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Curvature Radius ◽  
System A ◽  
Post Hoc ◽  
G 14

Background. The aim of the present study was to compare the cyclic fatigue resistance of novel nickel titanium rotary pathfinding instruments. Methods. Twenty instruments were selected for each file system. A simulated stainless steel root canal, with a 90° angle of curvature and a curvature radius of 3 mm, was used for cyclic fatigue test of the ProGlider (#16, progressive taper: 0.02‒ 0.085), PathGlider (#15, taper: .03), and One G (#14, taper: .03) instruments. Statistical analyses were performed with oneway ANOVA (P=0.05). Post hoc Tukey tests were used to determine any statistically significant differences between the groups. Results. The ProGlider instruments exhibited significantly more cyclic fatigue resistance than both PathGlider and One G instruments (P<0.001). One G instruments had significantly more resistance to fracture than PathGlider instruments (P<0.05). Conclusion. ProGlider instruments had better cyclic fatigue resistance than PathGlider and One G instruments.

Characterizing Cracking of Asphalt Mixtures with Fiber Reinforcement

2015 ◽  
Vol 2507 (1) ◽  
pp. 57-66 ◽  
Author(s):  
Nelson Gibson ◽  
Xinjun Li
Keyword(s):  
Fiber Reinforcement ◽  
Cyclic Fatigue ◽  
Full Scale ◽  
Synthetic Fiber ◽  
Continuum Damage ◽  
Polymer Modification ◽  
Direct Tension ◽  
Laboratory Observation ◽  
Fiber Modification ◽  
Better Than

This study characterized the cracking resistance of two independent sets of mixtures from the FHWA full-scale accelerated loading facility and a Pennsylvania Department of Transportation trial section. Both sets had the same selection of three types of comparative materials: an unmodified control mixture, a mixture with a binder modified with styrene–butadiene–styrene (SBS), and the same control mixture modified with synthetic fiber reinforcement. Two methods of cracking characterization that can be conducted with the Asphalt Mixture Performance Tester were evaluated: simplified viscoelastic continuum damage cyclic fatigue and direct tension monotonic strength. Dynamic modulus results showed that fiber modification had less of an effect than did polymer modification. Cyclic fatigue test results predicted that both SBS- and fiber-modified mixes performed better than did the control mixes in both sets of materials. Furthermore, the cyclic fatigue tests also indicated that the SBS-modified mix performed better than did fiber under smaller fatigue strains, but the fiber-reinforced mix performed better at higher strains. Recent performance data from the FHWA full-scale accelerated loading facility agreed with the laboratory observation. The pattern where the fiber mixtures exhibited a strain-dependent performance benefit was also observed when the same continuum damage models were used but with data from a different testing methodology by means of monotonic direct tension tests. When all test data are considered, the performance benefits of fiber modification for crack resistance appear to be subtle when observed in the laboratory, but benefits are likely at relatively higher strains.

Quantification of the Effect of Binder Source on Flexibility of Long-Term Aged Asphalt Concrete

2020 ◽  
Vol 2674 (9) ◽  
pp. 605-616
Author(s):  
Zehui Zhu ◽  
Punit Singhvi ◽  
Uthman Mohamed Ali ◽  
Hasan Ozer ◽  
Imad L. Al-Qadi
Keyword(s):  
Asphalt Concrete ◽  
Asphalt Binder ◽  
Rheological Parameters ◽  
Index Test ◽  
Performance Grade ◽  
Aged Asphalt ◽  
Aging Conditions ◽  
Aged Binder ◽  
Flexibility Index

Asphalt concrete (AC) aging reduces the resistance of flexible pavements to fatigue, thermal, and block cracking. Therefore, it is critical to understand the effects of AC aging on flexible pavement serviceability. Binder source has a significant effect on AC long-term aging. Therefore, it is necessary to develop a reliable, practical, and systematic method to quantify the effect of binder source on AC cracking resistance. Seven laboratory mixes were designed and produced at three asphalt binder replacement (ABR) levels using various binders, but same binder performance grade (PG). The AC mixes were tested using the Illinois Flexibility Index Test (I-FIT) under unaged and long-term aged conditions. Standard Superpave tests and temperature-frequency sweep tests, were conducted on virgin binders under various aging conditions. By comparing the binder rheological parameters and flexibility index (FI) of long-term aged AC specimens, the [Formula: see text] and m-value after 40-h of aging using a pressure aging vessel (PAV) were identified as valid indicators to reflect the effects of the binder source on AC long-term flexibility. A minimum [Formula: see text] of -8°C and m-value of 0.280 were proposed as the preliminary thresholds. A new parameter, [Formula: see text], which is defined as the m-value of 20-h PAV-aged binder minus the m-value of a 40-h PAV-aged binder, correlates well with the aging rate of AC. A binder with a high [Formula: see text] may induce an excessive drop in flexibility after long-term aging.

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