scholarly journals Study of Asphalt-Concrete Pavement Fatigue Modeling

2021 ◽  
Vol 16 (1) ◽  
pp. 24-36
Author(s):  
Peteris Skels ◽  
Viktors Haritonovs ◽  
Pavel Akishin ◽  
Andris Freimanis
Keyword(s):  
Fatigue Cracks ◽  
Fatigue Cracking ◽  
Element Model ◽  
Fatigue Behaviour ◽  
Asphalt Pavements ◽  
Fatigue Properties ◽  
Surface Loading ◽  
Asphalt Concrete Pavement ◽  
Cyclic Surface

Deterioration of asphalt pavements due to fatigue cracking is one of the most common highway pavement failure types. If the fatigue cracks are allowed to develop and grow, the driving comfort and safety, i.e., serviceability of the pavement, decreases. Pavement fatigue behaviour is not a straightforward mechanism and involves many factors and effects, thus computational methods are developed in order to help understand how the pavement works. This paper explores the accuracy and applicability of a less computational resource demanding procedure that uses transient material mechanical behaviour to model the long-term behaviour of a pavement structure. First, the mechanical and fatigue properties of asphalt were determined at the laboratory. Then a four-layer finite-element model was created using Ansys software. Two different models – with and without infinity elements – and two different fatigue simulation procedures – full and simplified – were considered. Material parameters were obtained by the laboratory tests and material properties degraded over time. Cyclic surface loading was applied to simulate the passing of a truck – 6 million fatigue cycles were simulated.

Influence of corrosion on fatigue behaviour of old crane runway steel

2019 ◽  
Vol 54 (7-8) ◽  
pp. 416-423
Author(s):  
Stanislav Seitl ◽  
Petr Miarka ◽  
Pavel Pokorný ◽  
Jan Klusák
Keyword(s):  
Crack Initiation ◽  
Cross Sections ◽  
Fatigue Cracks ◽  
Element Model ◽  
Fatigue Behaviour ◽  
Fatigue Properties ◽  
Experimental Measurements ◽  
Stress Concentrations ◽  
The Finite Element Model ◽  
Surface Crack Initiation

Experimental measurements of fatigue properties of old steel used for a crane runway were performed to capture the influence of corrosion on fatigue life of the material. Basquin’s law was used to quantify the fatigue properties of old steel with different cross sections and with different surface of specimens (polished and corroded). The finite element model was prepared to assess and quantify the various stress distribution in specimens with circular and rectangular cross sections. Fracture surfaces of the three kinds of specimens (circular polished, rectangular polished and rectangular corroded) were studied and they showed the surface crack initiation. The following fatigue cracks developed from the surface and expanded into specimen with radiation pattern. Observed crack initiation areas confirmed the ones expected according to stress concentrations.

Effect of Hydrated Lime on Long-Term Oxidative Aging Characteristics of Asphalt

2002 ◽  
Vol 1810 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Shin-Che Huang ◽  
J. Claine Petersen ◽  
Raymond Robertson ◽  
Jan F. Branthaver
Keyword(s):  
Phase Angle ◽  
Fatigue Cracking ◽  
Hydrated Lime ◽  
Age Hardening ◽  
Asphalt Binders ◽  
Asphalt Pavements ◽  
Initial Stiffness ◽  
Oxidative Aging ◽  
Useful Lifetime

An experiment involving neat asphalts AAD-1, ABD, and their mixtures with two different grades of hydrated lime was conducted to investigate the effect of lime on the long-term aging characteristics of asphalt binders. Rheological properties of unaged and aged asphalt-lime mixtures were measured with a dynamic shear rheometer at 25°C (77°F) and 60°C (140°F). The addition of hydrated lime to one asphalt (AAD-1) effectively reduced oxidative age hardening. In addition, the phase angle reached the same value as aging time reached after approximately 800 h at 60°C in the pressure-aging vessel for AAD-1 and its mixtures with lime. After 800 h of aging, the phase angle was greater for the limetreated asphalt than for the untreated asphalt, and it continued to decrease at a slower rate. This result indicates that the addition of lime to this asphalt increases the initial stiffness of the binder, but, more importantly, it preserves elasticity during long-term oxidative aging. Thus, for this asphalt, at a level of oxidation typical of pavements, limetreated and untreated asphalts arrived at the same viscosity with time, but the lime-treated asphalt had better viscous flow properties than the untreated asphalt. It could then be predicted that the aged, lime-treated asphalt would be more resistant to fatigue cracking. The other asphalt tested (ABD) did not exhibit substantial effects of lime on the rate of oxidative age hardening. This highly compatible, low-asphaltene asphalt is not typical of most paving asphalts. Because hydrated lime has been shown to reduce oxidative age hardening both in the laboratory and during the first few years in the pavement, adding hydrated lime should extend the useful lifetime of most asphalt pavements.

Scale and Surface Machining Quality Effect on Fatigue Properties for China Railway Grade B Cast Steel Wheel

2011 ◽  
Vol 480-481 ◽  
pp. 363-368
Author(s):  
Yong Xiang Zhao ◽  
Bing Yang ◽  
Y. Li
Keyword(s):  
Fatigue Cracks ◽  
Cast Steel ◽  
Fatigue Behaviour ◽  
Fatigue Properties ◽  
Surface Machining ◽  
Linear Effect ◽  
Steel Wheel ◽  
Damage Process ◽  
China Railway ◽  
Random Fatigue

Synthetic method is studied on assessing scale and surface machined effect on fatigue lives of China railway grade B cast steel wheel. Three kinds of specimens are applied for revealing the non-linear effect with scale kinetics at a least of cost. And 8 to 9 samples are applied for each kind of specimen to reveal the random fatigue behaviour. Assessing work is carried out on a phase of fatigue lives with scale kinetics at a specified strength. Results reveal that fatigue cracks were initiated from the specimen surface having a bigger site and the fatigue damage process companied with less plastic deformation than the material specimens. Random effects on fatigue lives and effect factors are constructed for measuring effects. Statistical character of the test data has been well described.

Fatigue Behaviour of Ti-6Al-4V Alloy in Vacuum and at Low Temperature

2008 ◽  
Vol 41-42 ◽  
pp. 83-90 ◽  
Author(s):  
J.H. Zuo ◽  
Z.G. Wang ◽  
En Hou Han
Keyword(s):  
Low Temperature ◽  
Fatigue Fracture ◽  
Room Temperature ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Sample Surface ◽  
Fatigue Behaviour ◽  
Fatigue Properties ◽  
Fatigue Fracture Surface ◽  
Cracks Propagation

Investigations have been conducted on the fatigue behavior of Ti-6Al-4V alloy with the bimodal microstructure in air at room temperature, in vacuum at room temperature and in vacuum at low temperature (100K), respectively. The results show that the fatigue life of this alloy is longer in vacuum and/or at low temperature than that in air at room temperature. The combination of vacuum and low temperature can much improve the fatigue properties of this alloy because of their purifying effect on fatigue cracks propagation. SEM observation of fatigue fracture surface indicates that all the fatigue cracks initiate in the sample surface when Nf ≦106 cycles. The above three testing conditions lead to different modes of fatigue crack propagation and therefore much different morphology of fatigue fracture.

Impact of Aging on the Viscoelastic Properties and Cracking Behavior of Asphalt Mixtures

2019 ◽  
Vol 2673 (6) ◽  
pp. 406-415 ◽  
Author(s):  
Runhua Zhang ◽  
Jo E. Sias ◽  
Eshan V. Dave ◽  
Reyhaneh Rahbar-Rastegar
Keyword(s):  
Viscoelastic Properties ◽  
Complex Modulus ◽  
Fatigue Cracking ◽  
Compact Tension ◽  
Asphalt Mixtures ◽  
Fatigue Properties ◽  
Cracking Behavior ◽  
Stiffness Reduction ◽  
Fracture Tests

Aging can significantly affect the viscoelastic properties and cracking behavior of asphalt mixtures, causing increase in stiffness, reduction in relaxation capability, and increase in brittleness. Eleven mixtures are evaluated using different laboratory conditioning protocols to evaluate how the properties of asphalt mixtures, including viscoelastic properties, fatigue, and fracture behavior will change over time. Comparisons between different aging levels and mixtures are conducted by using complex modulus (E*) (field cores are included), simplified viscoelastic continuum damage (S-VECD) approach, semi-circular bending (SCB), and disk shaped compact tension (DCT) fracture tests. The climatic aging index developed by the NCHRP 09-54 project is utilized in this study to calculate the appropriate field aging duration corresponding to the different laboratory aging protocols. Pavement evaluation tools FlexPAVETM and IlliTC are also used to predict and compare the fatigue and thermal cracking performance of these mixtures. The results of E* and S-VECD tests indicate that the mixtures are more prone to fatigue cracking with aging, and the two long-term conditioning protocols induce statistically similar changes in linear viscoelastic and fatigue properties. However, prediction of fatigue performance from FlexPAVE TM does not show a consistent trend once pavement structure and traffic are considered. Fracture tests and IlliTC predictions show the virgin mixtures and those with soft base binders will have better capability to resist cracking after long-term aging. In this study, the two mixtures with the largest difference between high and low temperature performance grade (PG) show the largest change in fracture and fatigue properties with aging.

Performance of Flexible Pavement Rehabilitation Treatments in the Long-Term Pavement Performance SPS-5 Experiment

2003 ◽  
Vol 1823 (1) ◽  
pp. 93-101 ◽  
Author(s):  
Kathleen T. Hall ◽  
Carlos E. Correa ◽  
Amy L. Simpson
Keyword(s):  
Asphalt Pavement ◽  
Fatigue Cracking ◽  
Flexible Pavement ◽  
Asphalt Pavements ◽  
Pavement Performance ◽  
Recycled Asphalt ◽  
Pavement Rehabilitation ◽  
Pretreatment Condition ◽  
Asphalt Overlay

The results of a study conducted to assess the relative performance of different flexible pavement rehabilitation treatments, including the influence of pretreatment condition and other factors, are presented. The data used in the study were drawn from the Long-Term Pavement Performance Studies' Specific Pavement Study (SPS) SPS-5 and General Pavement Study (GPS) GPS-6B experiments. The rehabilitation treatments used in the SPS-5 experiment are 2- and 5-in. overlays with virgin or recycled asphalt concrete mixes with or without preoverlay milling. Overlay thickness and preoverlay roughness levels were the two factors that most influenced the performance of the asphalt overlays of asphalt pavements in the SPS-5 experiment with respect to roughness, rutting, and fatigue cracking. Over the long term, the 5-in. overlays outperformed the 2-in. overlays with respect to roughness, rutting, and fatigue cracking. Overlay mix type (virgin versus recycled) and preoverlay preparation (with or without milling) had slight and inconsistent effects. The average initial postoverlay international roughness index of an asphalt overlay of an asphalt pavement was found to be 0.98 m/km. The data show a slight but statistically significant tendency for asphalt pavements overlaid when they were rougher to have more initial roughness after overlay than asphalt pavements overlaid when they were smoother. The data show that, on average, about 6 mm of rutting develops in the first year or so after placement of an asphalt overlay of an asphalt pavement. This is presumably due to compaction of the mix by traffic and appears to be independent of the overlay thickness, mix type, preoverlay preparation, and preoverlay rutting level.

Fracture Mechanics and Fatigue Cracks Reduction of Polymeric Asphalt Pavements

2006 ◽  
Vol 324-325 ◽  
pp. 1277-1280
Author(s):  
Akbar K. Haghi ◽  
Mahyar Arabani ◽  
Morteza Shakeri
Keyword(s):  
Performance Test ◽  
Fatigue Cracks ◽  
Asphalt Mixture ◽  
Fatigue Cracking ◽  
Asphalt Pavements ◽  
Computational Studies ◽  
Strength Tests ◽  
Asphalt Mix ◽  
Indirect Tensile ◽  
Cracking Process

The objective of this research was to advance understanding of the cracking process via laboratory and computational studies and to convey the obtained results in a form that can be utilized for the prediction of cracking in flexible pavements. The primary purpose of this project reported herein was to evaluate the effects of tire cords on the fatigue response of asphalt mix and to develop recommendations for improving the fatigue performance of asphalt pavements. Based on the results presented in this paper, the indirect tensile strength tests can propose as a simple performance test for fatigue cracking of asphalt mixture. The results clearly demonstrate a great potential procedure for the fatigue cracking evaluation of asphalt mixture.

Fatigue crack detection method using analysis of vibration signal

2017 ◽  
Vol 1 (20) ◽  
pp. 63-74 ◽  
Author(s):  
Arkadiusz Rychlik ◽  
Krzysztof Ligier
Keyword(s):  
Crack Detection ◽  
Fatigue Cracks ◽  
Fatigue Cracking ◽  
Vibration Signal ◽  
Technical Condition ◽  
Visual Methods ◽  
Signal Characteristics ◽  
Fatigue Crack Detection ◽  
Sample Structure ◽  
Change Identification

This paper discusses the method used to identify the process involving fatigue cracking of samples on the basis of selected vibration signal characteristics. Acceleration of vibrations has been chosen as a diagnostic signal in the analysis of sample cross section. Signal characteristics in form of change in vibration amplitudes and corresponding changes in FFT spectrum have been indicated for the acceleration. The tests were performed on a designed setup, where destruction process was caused by the force of inertia of the sample. Based on the conducted tests, it was found that the demonstrated sample structure change identification method may be applied to identify the technical condition of the structure in the aspect of loss of its continuity and its properties (e.g.: mechanical and fatigue cracks). The vibration analysis results have been verified by penetration and visual methods, using a scanning electron microscope.

scholarly journals Fatigue Crack Initiation and Propagation at High Temperature of New-Generation Bearing Steel

Metals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 25
Author(s):  
Zhiwei Wu ◽  
Maosheng Yang ◽  
Kunyu Zhao
Keyword(s):  
Fracture Surface ◽  
Failure Mode ◽  
Electron Backscatter Diffraction ◽  
Fatigue Cracks ◽  
Fatigue Crack Initiation ◽  
Optical Microscope ◽  
Bearing Steel ◽  
Fatigue Properties ◽  
New Generation ◽  
Scanning Electron

The new generation of bearing steel has good comprehensive properties, which can satisfy most of the requirements of bearing steel in a complex environment. In the presented work, fatigue properties of 15Cr14Co12Mo5Ni2 bearing steel have been investigated by means of rotating bending fatigue tests on smooth bar specimens after carburization and heat treatment. Optical microscope, scanning electron microscopy, electron backscatter diffraction, and Image-Pro Plus software were used to analyze the fracture, microstructure, and carbides. The results suggest that the fatigue strength at room temperature and 500 °C is 1027 MPa and 585 MPa, respectively. Scanning electron micrographic observations on the fracture surface of the fatigue specimens at 500 °C show that fatigue cracks usually initiate from voids in the carburized case and oxide layer on the surface of steel. The failure mode in the carburized case is a quasi-cleavage fracture, and with the increase of crack propagation depth, the failure mode gradually changes to fatigue and creep-fatigue interaction. With the increase of the distance from the surface, the size of the martensite block decreases and the fracture surface shows great fluctuation.

Low-Cycle Fatigue Behaviour of Gas Turbine Alloys

1974 ◽  
Vol 188 (1) ◽  
pp. 321-328 ◽  
Author(s):  
W. J. Evans ◽  
G. P. Tilly
Keyword(s):  
Low Cycle Fatigue ◽  
Fatigue Cracks ◽  
High Stress ◽  
Cyclic Creep ◽  
Fatigue Curve ◽  
Fatigue Behaviour ◽  
Material Surface ◽  
Tension Stress ◽  
Cycle Fatigue ◽  
Stress Tests

The low-cycle fatigue characteristics of an 11 per cent chromium steel, two nickel alloys and two titanium alloys have been studied in the range 20° to 500°C. For repeated-tension stress tests on all the materials, there was a sharp break in the stress-endurance curve between 103 and 104 cycles. The high stress failures were attributed to cyclic creep contributing to the development of internal cavities. At lower stresses, failures occurred through the growth of fatigue cracks initiated at the material surface. The whole fatigue curve could be represented by an expression developed from linear damage assumptions. Data for different temperatures and types of stress concentration were correlated by expressing stress as a fraction of the static strength. Repeated-tensile strain cycling data were represented on a stress-endurance diagram and it was shown that they correlated with push-pull stress cycles at high stresses and repeated-tension at low stresses. In general, the compressive phase tended to accentuate cyclic creep so that ductile failures occurred at proportionally lower stresses. Changes in frequency from 1 to 100 cycle/min were shown to have no significant effect on low-cycle fatigue behaviour.

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