Determining Specimen Geometry of Cylindrical Specimens for Direct Tension Fatigue Testing of Asphalt Concrete

2016 ◽  
Vol 45 (2) ◽  
pp. 20140357 ◽  
Author(s):  
Jong-Sub Lee ◽  
Amirhossein Norouzi ◽  
Y. Richard Kim
Keyword(s):  
Asphalt Concrete ◽  
Fatigue Testing ◽  
Specimen Geometry ◽  
Direct Tension

scholarly journals An Overview of Fatigue Testing Systems for Metals under Uniaxial and Multiaxial Random Loadings

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 447
Author(s):  
Julian M. E. Marques ◽  
Denis Benasciutti ◽  
Adam Niesłony ◽  
Janko Slavič
Keyword(s):  
Fatigue Testing ◽  
Local State ◽  
Specimen Geometry ◽  
Present Review ◽  
General Criterion ◽  
Classification Criterion ◽  
Test Type ◽  
State Of Stress ◽  
The Relationship

This paper presents an overview of fatigue testing systems in high-cycle regime for metals subjected to uniaxial and multiaxial random loadings. The different testing systems are critically discussed, highlighting advantages and possible limitations. By identifying relevant features, the testing systems are classified in terms of type of machine (servo-hydraulic or shaker tables), specimen geometry and applied constraints, number of load or acceleration inputs needed to perform the test, type of loading acting on the specimen and resulting state of stress. Specimens with plate, cylindrical and more elaborated geometry are also considered as a further classification criterion. This review also discusses the relationship between the applied input and the resulting local state of stress in the specimen. Since a general criterion to classify fatigue testing systems for random loadings seems not to exist, the present review—by emphasizing analogies and differences among various layouts—may provide the reader with a guideline to classify future equipment.

Watertightness, cracking resistance, and self-healing of asphalt concrete used as a water barrier in dams

2013 ◽  
Vol 50 (3) ◽  
pp. 275-287 ◽  
Author(s):  
Yingbo Zhang ◽  
Kaare Höeg ◽  
Weibiao Wang ◽  
Yue Zhu
Keyword(s):  
Asphalt Concrete ◽  
Leakage Rate ◽  
Strain Rates ◽  
Self Healing ◽  
Test Results ◽  
Direct Tension ◽  
Coefficient Of Permeability ◽  
Tension Tests ◽  
Laboratory Test Results ◽  
Cracked Specimens

The coefficient of permeability of hydraulic asphalt concrete is in the range 10−8–10−10 cm/s. Laboratory test results show that triaxial specimens in axial compression can undergo axial strains up to 18% without any significant increase in permeability until approaching the compressive strength. For temperatures between 5 and 20 °C and strain rates between 2 × 10−3%/s and 5 × 10−3%/s, conventional hydraulic asphalt concrete can tolerate 1%–3% tensile strains before cracking in direct tension tests and strains up to 3%–4% in bending. At 20 °C the tensile and bending strains at cracking are 2–4 times higher than those at 0 °C, and at −20 °C they are approximately 0.2% and 0.8%, respectively. Asphalt concrete possesses pronounced crack self-healing properties. In the experiments, the crack leakage rate dropped 1–4 orders of magnitude within a few hours and the cracked specimens regained 55% of the intact tensile strength after only 1 day of self-healing. In summary, the comprehensive series of laboratory tests documents that asphalt concrete has characteristics that make the material extremely well suited for use in impervious barriers in dams, and the test results reported herein can be of great use in barrier design.

Specimen Geometry Study for Direct Tension Test Based on Mechanical Tests and Air Void Variation in Asphalt Concrete Specimens Compacted by Superpave Gyratory Compactor

2000 ◽  
Vol 1723 (1) ◽  
pp. 125-132 ◽  
Author(s):  
Ghassan R. Chehab ◽  
Emily O’Quinn ◽  
Y. Richard Kim
Keyword(s):  
Asphalt Concrete ◽  
Tensile Testing ◽  
Complex Modulus ◽  
Specimen Geometry ◽  
Uniaxial Tensile ◽  
Void Content ◽  
Uniaxial Tensile Testing ◽  
Superpave Gyratory Compactor ◽  
Air Void ◽  
Air Void Content

Reliable materials characterization and performance prediction testing of asphalt concrete requires specimens that can be treated as statistically homogeneous and representative of the material being tested. The objective of this study was to select a proper specimen geometry that could be used for uniaxial tensile testing. Selection was based on the variation of air void content along the height of specimens cut and cored from specimens compacted by the Superpave gyratory compactor (SGC) and on the representative behavior under mechanical testing. From measurement and comparison of air void contents in cut and cored specimens, it was observed for several geometries that sections at the top and bottom and those adjacent to the mold walls have a higher air void content than do those in the middle. It is thus imperative that test specimens be cut and cored from larger-size SGC specimens. Complex modulus and constant crosshead-rate monotonic tests were conducted for four geometries—75 × 115, 75 × 150, 100 × 150, and 100 × 200 mm—to study the effect of geometry boundary conditions on responses. On the basis of graphical and statistical analysis, it was determined that there was an effect on the dynamic modulus at certain frequencies but no effect on the phase angle. Except for 75 × 115 mm, all geometries behaved similarly under the monotonic test. From these findings and other considerations, it is recommended that the 75- × 150-mm geometry, which is more conservative, and the 100- × 150-mm geometry be used for tensile testing.

Fatigue Life Analysis of Asphalt Mixture Coupling with Loading Intermittent Time

2012 ◽  
Vol 204-208 ◽  
pp. 3852-3858 ◽  
Author(s):  
Li Qiang Luan ◽  
Xiao Ge Tian
Keyword(s):  
Asphalt Concrete ◽  
Fatigue Testing ◽  
Testing Machine ◽  
Asphalt Mixture ◽  
Time Factor ◽  
Repeated Loading ◽  
Self Healing ◽  
Effect Factor ◽  
Higher Temperature ◽  
Fatigue Life Analysis

Repeated loading will produce cumulative damage to asphalt concrete, because of the visco-elastic property of asphalt concrete, a certain degree of self-healing may occurred in case the loads being taken away.( the healing effect is more obvious under higher temperature or pressure),this process can be indicated through adding the intermittent time factor to fatigue test of asphalt concrete .This study adds intermittent time factor to asphalt concrete fatigue testing through universal testing machine,, deeply analyzing the effect of intermittent time, confirming that 0.5 second intermittent time is a key time point to fatigue process ,fatigue rate under 15 °C is slower than that under 20 °C,and introducing the effect factor to the fatigue equation.

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