Fatigue Behavior of Rubber-Modified Pavements

1998 ◽  
Vol 1639 (1) ◽  
pp. 73-82 ◽  
Author(s):  
Lutfi Raad ◽  
Stephan Saboundjian
Keyword(s):  
Fatigue Life ◽  
Fatigue Resistance ◽  
Fatigue Behavior ◽  
Dissipated Energy ◽  
Concrete Pavements ◽  
Wet Process ◽  
Displacement Mode ◽  
Asphalt Rubber ◽  
Support Conditions ◽  
Repetitions To Failure

Over the last 18 years, a number of rubberized pavement projects have been built in Alaska. Initial laboratory and field investigations sponsored by the Alaska Department of Transportation and Public Facilities (AKDOT&PF) and conducted by Raad et al. indicated improved fatigue performance of the rubberized sections in comparison with conventional asphalt concrete pavements. The results of a follow-up investigation to develop design equations for rubberized pavements in Alaska are presented. Laboratory studies were conducted on field specimens using the flexural fatigue test in the controlled-displacement mode. Specifically, the rubberized mixes included asphalt-rubber concrete with AC-2.5 (wet-process) and PlusRide RUMAC with AC-5. Tests were performed for a range of temperatures varying between 22°C and –29°C. Fatigue relationships were developed in terms of repeated flexure strain, dynamic flexure stiffness of the mix, and repetitions to failure. Relationships for the dynamic flexure stiffness as a function of temperature were also developed. Dissipated energy associated with repeated flexure stress and strain was determined and used to assess the damage behavior of conventional and rubberized mixes. The proposed fatigue equations were used to compare the behavior of the rubberized mixes with conventional AC-5 mixes at 20°C and 0°C. Results of the analysis show that at 20°C, asphalt-rubber and AC-5 mixes exhibit essentially similar fatigue resistance, whereas PlusRide has the least fatigue life. However, at 0°C, the fatigue resistance of PlusRide and asphalt-rubber exceeds that of the conventional AC-5 mix. The fatigue equations were also used to compare the fatigue life of conventional and rubberized pavements for different surface layer temperatures and foundation support conditions.

Fatigue behavior of stent in tapered arteries: The role of arterial tapering and stent material

2019 ◽  
Vol 233 (10) ◽  
pp. 989-998
Author(s):  
Xiang Shen ◽  
Hongfei Zhu ◽  
Song Ji ◽  
Jiabao Jiang ◽  
Yongquan Deng
Keyword(s):  
Fatigue Life ◽  
Fatigue Resistance ◽  
High Efficiency ◽  
Fatigue Behavior ◽  
Great Success ◽  
Term Outcome ◽  
Long Term Outcome ◽  
Minimal Invasiveness ◽  
Goodman Diagram ◽  
Stent Material

Stenting has achieved great success in treating cardiovascular diseases due to its high efficiency and minimal invasiveness. However, fatigue of stents severely limits its long-term outcome. In this article, finite element method was adopted to study the effects of arterial tapering and stent material on the fatigue performance of stents. A series of tapered vessels with different taper levels and two sets of stents with different materials were modeled. The Goodman diagram was used to evaluate the fatigue resistance of stents. Results showed that the fatigue resistance of stents can be extremely improved by simply changing stent material. In addition, the taper of the arteries had an important influence on the fatigue resistance of the stent. The fatigue life of the stent will be shortened with the increase of the arterial taper. The method that predicted stent fatigue life in tapered vessels can help clinicians select stents that are more suitable for tapered vessels and help stent engineers design stents that are more resistant to fatigue.

scholarly journals Fatigue performance evaluation of bitumen mastics reinforced with polyolefins through a dissipated energy approach

2020 ◽  
Vol 70 (338) ◽  
pp. 217
Author(s):  
C. Roman ◽  
M. A. Delgado ◽  
M. García-Morales
Keyword(s):  
Performance Evaluation ◽  
Fatigue Resistance ◽  
Fatigue Behavior ◽  
Energy Approach ◽  
Fatigue Performance ◽  
Dissipated Energy ◽  
Morphological Evidence ◽  
Polymer Distribution ◽  
Linear Viscoelastic ◽  
Dynamic Time

Polymers are known to improve the fatigue resistance of sphalt mastics. However, undesirable results can be obtained if the polymer is not successfully integrated into the bitumen binder. The goal of this work is to evaluate the effect of the addition of three selected polyolefins on their mastic’s fatigue performance. Low and high density polyethylenes (LDPE and HDPE) and polypropylene (PP) were chosen and used at the concentration of 4 wt.%. A dissipated energy approach was used in order to analyze the fatigue resistance, at 25 ºC, of the three composites studied. Dynamic time sweeps at and above the linear viscoelastic threshold were carried out. Based on that, the results demonstrated a better improvement when the LDPE was considered. For that binder, fluorescence optical microscopy observations at 25 ºC provided morphological evidence of a more homogeneous bitumen-polymer distribution which could be behind the improved fatigue behavior.

Effects of Glass-Forming Metallic Film on the Fatigue Behavior of C-2000 Ni-Based Alloy

2005 ◽  
Vol 903 ◽  
Author(s):  
F. X. Liu ◽  
C. L. Chiang ◽  
J. P. Chu ◽  
Y. F. Gao ◽  
P. K. Liaw
Keyword(s):  
Thin Film ◽  
Fatigue Life ◽  
Fatigue Resistance ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Film Coating ◽  
Fatigue Tests ◽  
Glass Forming ◽  
Four Point Bending ◽  
Coated Surface

AbstractGlass-forming Zr47Cu31Al13Ni9 (in atomic percent) films of various thicknesses were deposited on the C-2000 Ni-based alloy substrate by magnetron sputtering. Four-point-bending fatigue tests were conducted on the above system with the coated surface on the tensile side. It has been found that both fatigue life and fatigue-endurance limit can be considerably improved, while the degree of fatigue resistance enhancement depends on the maximum applied stress and the film thickness. Mechanisms of fatigue-resistance enhancements of the coated Ni-based alloy are discussed from the following aspects: reduction of surface roughness by the thin-film coating, good adhesion between thin film and substrate, development of residual compressive stress, and excellent ductility of glass-forming thin film (which would be otherwise brittle in bulk form). Of particular interest, we examine the interaction of substrate slip bands and the thin film ductile property, which would delay fatigue crack initiation process and thus extend the fatigue life.

scholarly journals Aging Influence on Fatigue Characteristics of RAC Mixtures Containing Warm Asphalt Additives

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Feipeng Xiao ◽  
Wenbin Zhao ◽  
Serji N. Amirkhanian
Keyword(s):  
Fatigue Life ◽  
Aging Process ◽  
Fatigue Behavior ◽  
Asphalt Binder ◽  
Crumb Rubber ◽  
Dissipated Energy ◽  
Negative Effect ◽  
Rubberized Asphalt Concrete ◽  
Term Performance

Aging is an important factor to affect the long-term performance of asphalt pavement. The fatigue life of a typical warm mix asphalt (WMA) is generally related to various factors of rheological and mechanical properties of the mixture. The study of the fatigue behavior of the specific rubberized WMA is helpful in recycling the scrap tires and saving energy in terms of the conventional laboratory aging process. This study explores the utilization of the conventional fatigue analysis approach in investigating the cumulative dissipated, stiffness, and fatigue life of rubberized asphalt concrete mixtures containing the WMA additive after a long-term aging process. The aged beams were made with one rubber type (−40 mesh ambient crumb rubber), two aggregate sources, two WMA additives (Asphamin and Sasobit), and tested at 5 and20ºC. A total of 55 aged fatigue beams were tested in this study. The test results indicated that the addition of crumb rubber extends the fatigue resistance of asphalt binder while WMA additive exhibits a negative effect. The study indicated that the WMA additive generally has an important influence on fatigue life. In addition, test temperature and aggregate source play an important role in determining the cumulative dissipated energy, stiffness, and fatigue life of an aged mixture.

Application of the Dissipated Energy Concept in Fatigue Endurance Limit Testing

2005 ◽  
Vol 1929 (1) ◽  
pp. 165-173 ◽  
Author(s):  
Shihui Shen ◽  
Samuel H. Carpenter
Keyword(s):  
Fatigue Life ◽  
Endurance Limit ◽  
Fatigue Behavior ◽  
Testing Procedure ◽  
Dissipated Energy ◽  
Long Time ◽  
Loading Modes ◽  
Damage Condition ◽  
Fatigue Endurance ◽  
Unique Relationship

A fatigue endurance limit has been postulated to exist in hot-mix asphalt pavement performance. It cannot be observed and studied with the use of traditional phenomenological approaches as seen by the totally different fatigue behavior at low strain–damage levels close to the fatigue endurance limit. The ratio of dissipated energy change succeeds in defining and investigating the existence of a fatigue endurance limit with a unique relationship between plateau value (PV) and fatigue life (Nf), regardless of strain–damage levels, mixture types, loading modes, and other testing conditions. To determine a fatigue endurance limit requires an extraordinarily long time to conduct testing. This paper applied the PV to the study of a fatigue endurance limit to validate a shortened laboratory testing procedure. Statistical analysis shows that the shortened test can predict the PV with sufficient accuracy. By applying the validated relationship between PV and Nf, the extremely long fatigue life under low strain–damage condition can be predicted without performing millions of loading cycles.

scholarly journals Preparation and Mechanical-Fatigue Properties of Elastic Polyurethane Concrete Composites

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3839
Author(s):  
Zhen Jia ◽  
Dongzhe Jia ◽  
Quansheng Sun ◽  
Yanqi Wang ◽  
Hongjian Ding
Keyword(s):  
Fatigue Life ◽  
Fatigue Resistance ◽  
Building Materials ◽  
Prediction Models ◽  
Engineering Application ◽  
Tensile Tests ◽  
Fatigue Properties ◽  
Dissipated Energy ◽  
Fine Aggregate ◽  
Rubber Particles

In order to solve issues related to bridge girders, expansion devices and road surfaces, as well as other structures that are prone to fatigue failure, a kind of fatigue-resistant elastic polyurethane concrete (EPUC) was obtained by adding waste rubber particles (40 mesh with 10% fine aggregate volume replacement rate) to conventional engineering polyurethane concrete (PUC). Based on the preparation and properties of EPUC, its constitutive relation was proposed through compression and tensile tests; then, a scanning electron microscope (SEM), an atomic force microscope (AFM) and a 3D non-contact surface profilometer were used to study the failure morphology and micromechanisms of EPUC. On this basis, four-point bending fatigue tests of EPUC were carried out at different temperature levels (−20 °C, 0 °C, 20 °C) and different strain levels (400 με~1200 με). These were used to analyze the stiffness modulus, hysteresis angle and dissipated energy of EPUC, and our results outline the fatigue life prediction models of EPUC at different temperatures. The results show that the addition of rubber particles fills the interior of EPUC with tiny elastic structures and effectively optimizes the interface bonding between aggregate and polyurethane. In addition, EPUC has good mechanical properties and excellent fatigue resistance; the fatigue life of EPUC at a room temperature of 600 με can grow by more than two million times, and it also has a longer service life and reduced disease frequency, as well as fewer maintenance requirements. This paper will provide a theoretical and design basis for the fatigue resistance design and engineering application of building materials. Meanwhile, the new EPUC material has broad application potential in terms of roads, bridges and green buildings.

The Investigations of Fatigue Characteristics of Porous Asphalt with Organomodified Montmorillonite Modified Asphalt

2007 ◽  
Vol 348-349 ◽  
pp. 929-932
Author(s):  
Shao Peng Wu ◽  
Gang Liu ◽  
Jian Ying Yu ◽  
Ting Wei Cao
Keyword(s):  
Fatigue Life ◽  
Fatigue Resistance ◽  
Dissipated Energy ◽  
Porous Asphalt ◽  
Forced Draft Oven ◽  
Modified Asphalt ◽  
Four Point Bending ◽  
Forced Draft ◽  
Fatigue Characteristics ◽  
Organomodified Montmorillonite

In this study, organomodified montmorillonite (OMMT) modified asphalt was used in porous asphalt, and fatigue characteristics of the mixtures with or without OMMT were investigated. Special attention was paid to the beam specimens aged in a forced draft oven at 60°C for 500h. Basic fatigue information, such as stiffness, dissipated energy of the material, was obtained through four-point bending beam testing under different controlled strain. The classical fatigue life definition was used to evaluate fatigue resistance of different mixtures. The research results indicate that the OMMT mixture exhibits better fatigue and ageing resistance than the neat one. It is suggested that OMMT should be an excellent alternative for the durability of porous asphalt.

Relationships between the Structures of Natural Rubber Vulcanizates and Their Thermal and Oxidative Aging

1970 ◽  
Vol 43 (3) ◽  
pp. 651-663 ◽  
Author(s):  
E. J. Blackman ◽  
E. B. McCall
Keyword(s):  
Fatigue Life ◽  
Fatigue Resistance ◽  
Main Chain ◽  
Fatigue Behavior ◽  
Fatigue Properties ◽  
Release Agent ◽  
Oxidative Aging ◽  
Aging Properties ◽  
Natural Rubber Vulcanizates ◽  
Sulfur Containing

Abstract Accelerated sulfur NR vulcanizate networks are known to contain poly-, di- and monosulfidic crosslinks, sulfur-containing main chain modifications including cyclic sulfides and pendent accelerator groups, and extra-network material, primarily vulcanization residues. Both oxidative and non-oxidative aging characteristics of the vulcanizate can be improved by use of an efficient or EV curing system. These systems utilize either a high accelerator to sulfur ratio or an accelerator in conjunction with a sulfur release agent to insert predominantly mono- and disulfidic crosslinks, and produce a minimum of main chain modifications. The resulting vulcanizates have excellent aging properties, but fatigue life is poor in comparison to that of a conventional vulcanizate. With a compromise between the conventional and EV curing systems, namely use of intermediate accelerator to sulfur ratios or mixtures of sulfur and sulfur donor, vulcanizates with good fatigue properties and improved aging characteristics can be obtained. Since the most obvious difference between EV and conventional vulcanizate networks is the per cent of monosulfidic crosslinks, it has been assumed that monosulfide crosslinks are responsible for the poor fatigue resistance of EV systems. Recently, it was found that a zinc dimethyldithiocarbamate (ZDC) EV system gave an NR gum vulcanizate having fatigue resistance equal to that of a conventional sulfenamide accelerated compound. The main features of the network are a high percentage of monosulfide crosslinks and extensive main chain modification. In this paper, the aging and fatigue behavior of black filled substituted phenylenediamine protected NR ZDC accelerated systems is examined. The ZDC EV vulcanizate has imaged fatigue resistance equal to that of a conventional sulfenamide accelerated vulcanizate, but oxidative aging is very poor. By decreasing the ZDC/sulfur ratio, a vulcanizate structure equivalent in every measurable way to that of a conventional sulfenamide accelerated system is obtained. Unaged fatigue properties of the two compounds are similar. However, oxidative aging resistance of the ZDC compound is again very poor, and fatigue life of an air aged specimen is virtually zero. It is concluded that fatigue life is not necessarily a function of the crosslink type distribution. Accelerator residues and possibly main chain modifications play an important role insofar as oxidative and non-oxidative aging characteristics are concerned.

scholarly journals Fatigue life investigation on a MAC engine piston

2018 ◽  
Vol 178 ◽  
pp. 06013
Author(s):  
Costel Humelnicu ◽  
Valentin Amortila ◽  
Elena Mereuta
Keyword(s):  
Fatigue Life ◽  
Optimal Design ◽  
Fatigue Resistance ◽  
Fatigue Behavior ◽  
Engine Performance ◽  
Cyclic Stresses ◽  
Piston Head ◽  
Engine Piston ◽  
Low Weight ◽  
High Fatigue

In MAC (Diesel) engines case, the shape of the piston head has an important influence on burning processes and, consequently on engine performance. Since the piston is subjected to high cyclic stresses during the blasting phase, a fatigue phenomenon occur. The piston design and material must provide a high fatigue resistance and a low weight, leading to low dynamic loading of the crank shaft and piston rod. The paper try to investigate the piston fatigue behavior, for several head shapes and materials, in order to establish an optimal design.

Factors Influencing the Fatigue Behavior of Ferrous Laminates

1987 ◽  
Vol 109 (3) ◽  
pp. 244-251 ◽  
Author(s):  
J. Wittenauer ◽  
O. D. Sherby
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Carbon Steel ◽  
Fatigue Behavior ◽  
Layered Material ◽  
Factors Influencing ◽  
Ultrahigh Carbon Steel ◽  
Processing History ◽  
Crack Blunting ◽  
Similar Processing

Laminates based on ultrahigh carbon steel were prepared and found to exhibit enhanced fatigue life as compared to a monolithic reference material. This result was achieved through the insertion of weak interlaminar regions of copper into the layered material during preparation of the laminates. The presence of these regions allowed for the operation of a delamination mechanism in advance of the propagating fatigue crack. The result was interlaminar separation and associated crack blunting. Stress-life curves show that an increase in life by as much as a factor of four is achieved for these materials when compared to monolithic specimens of similar processing history.

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