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.

scholarly journals Study on Fatigue Characteristics of Bionic Functional Surface of Hardened Steel

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4130
Author(s):  
Youzheng Cui ◽  
Minli Zheng ◽  
Wei Zhang ◽  
Ben Wang ◽  
Yonglei Sun ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Resistance ◽  
Dung Beetle ◽  
Hardened Steel ◽  
Row Spacing ◽  
Functional Surface ◽  
Analysis Software ◽  
Milling Parameters ◽  
Fatigue Characteristics

In this study, we aimed to process the biomimetic function surface by designing a prototype for modeling the pits on a dung beetle body and the abdomen of a desert viper, and by using high speed milling and controlling the ratio of row spacing to feed rate. Firstly, we conducted three-dimensional parametric modeling and static analysis of the bionic functional surface using 3D modeling software UGNX (12.0, SIEMENS AG, Munich, Germany) and finite element analysis software ABAQUS (2018, Dassault, Providence, RI, USA). Then, the analysis results were imported into the fatigue life analysis software nCode (2018, HBM United Kingdom Ltd., South Yorkshire, UK) to simulate the fatigue characteristics of different bionic pit morphology models. Per the simulated tensile fatigue testing machine, the result shows that the minimum fatigue life value of the quadrilateral pit surface of the simulated dung beetle is one and four times higher than the hexagonal pit morphology and the irregular pit morphology, respectively, whereas the maximum fatigue damage is lower by one and five orders of magnitude, respectively. The quadrilateral pit surface on the biomimetic dung beetle body has better fatigue resistance, which can considerably improve the fatigue damage distribution state and the fatigue life of hardened steel die surfaces. The influential regulation of milling parameters on fatigue performance was studied and the results show that the fatigue resistance of the model is optimal when milling parameters are: row spacing of 0.4 mm, loading space of 0.2 mm, and milling depth of 0.3 mm. The quadrilateral dimensions formed by milling are highly similar to those of a dung beetle body proving that a certain reduction in milling process depth can increase the structural fatigue resistance. From the perspective of fatigue crack growth analysis, the quadrilateral dimples on the surface of the dung beetle improve fatigue crack growth inhibition and fatigue resistance.

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 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.

Properties and Mechanism Analyse of High-Elasticity Modified Asphalt

2014 ◽  
Vol 599 ◽  
pp. 212-217
Author(s):  
Zeng Heng Hao ◽  
Bo Gao
Keyword(s):  
Fatigue Life ◽  
Bridge Deck ◽  
Asphalt Mixture ◽  
Fatigue Cracking ◽  
Fatigue Properties ◽  
Dissipated Energy ◽  
Steel Bridge ◽  
Modified Asphalt ◽  
High Elasticity ◽  
Steel Deck

Aiming at the fatigue cracking problem of the asphalt mixture on steel deck pavement surface, high-elasticity modified asphalt was developed. high-temperature properties, low-temperature properties and fatigue properties of modified asphalt and modified asphalt mixture were tested. The fatigue life of high-elasticity modified asphalt has been greatly improved, which was at least 25 times as long as that of common asphalt. The mechanism was explained clearly that the fatigue life of asphalt mixture could be improved by reducing the failure energy after each hysteresis loop of asphalt mixture, according to the dissipated energy theory for asphalt mixture. Projects proved that high-elasticity modified asphalt extremely improved the fatigue life of asphalt mixture on the steel bridge deck.

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.

scholarly journals Generalized SCF Formula of Out-Of-Plane Gusset Welded Joints and Assessment of Fatigue Life Extension by Additional Weld

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1249
Author(s):  
Yixun Wang ◽  
Yuxiao Luo ◽  
Yuki Kotani ◽  
Seiichiro Tsutsumi
Keyword(s):  
Fatigue Life ◽  
Fatigue Resistance ◽  
Welded Joints ◽  
Life Extension ◽  
Leg Length ◽  
Notch Stress ◽  
Out Of Plane ◽  
Weld Toe ◽  
Effective Notch Stress ◽  
Geometric Effects

The existing S-N curves by effective notch stress to assess the fatigue life of gusset welded joints can result in reduced accuracy due to the oversimplification of bead geometries. The present work proposes the parametric formulae of stress concentration factor (SCF) for as-welded gusset joints based on the spline model, by which the effective notch stress can be accurately calculated for fatigue resistance assessment. The spline model is also modified to make it applicable to the additional weld. The fatigue resistance of as-welded and additional-welded specimens is assessed considering the geometric effects and weld profiles. The results show that the error of SCFs by the proposed formulae is proven to be smaller than 5%. The additional weld can increase the fatigue life by as great as 9.4 times, mainly because the increasing weld toe radius and weld leg length lead to the smaller SCF. The proposed series of S-N curves, considering different SCFs, can be used to assess the welded joints with various geometric parameters and weld profiles.

scholarly journals Mechanical Characteristics of Graphene Nanoplatelets-Modified Asphalt Mixes: A Comparison with Polymer- and Not-Modified Asphalt Mixes

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2434
Author(s):  
Laura Moretti ◽  
Nico Fabrizi ◽  
Nicola Fiore ◽  
Antonio D’Andrea
Keyword(s):  
Fatigue Resistance ◽  
Graphene Nanoplatelets ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Asphalt Mixes ◽  
Modified Asphalt ◽  
Bituminous Mixtures ◽  
Water Sensitivity ◽  
Polymer Modified Asphalt ◽  
Mechanical Performances

In recent years, nanotechnology has sparked an interest in nanomodification of bituminous materials to increase the viscosity of asphalt binders and improves the rutting and fatigue resistance of asphalt mixtures. This paper presents the experimental results of laboratory tests on bituminous mixtures laid on a 1052 m-long test section built in Rome, Italy. Four asphalt mixtures for wearing and binder layer were considered: two polymer modified asphalt concretes (the former modified with the additive Superplast and the latter modified with styrene–butadiene–styrene), a “hard” graphene nanoplatelets (GNPs) modified asphalt concrete and a not-modified mixture. The indirect tensile strength, water sensitivity, stiffness modulus, and fatigue resistance of the mixtures were tested and compared. A statistical analysis based on the results has shown that the mixtures with GNPs have higher mechanical performances than the others: GNP could significantly improve the tested mechanical performances; further studies will be carried out to investigate its effect on rutting and skid resistance.

scholarly journals Impact of Graphene Oxide on Zero Shear Viscosity, Fatigue Life and Low-Temperature Properties of Asphalt Binder

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3073
Author(s):  
Abbas Mukhtar Adnan ◽  
Chaofeng Lü ◽  
Xue Luo ◽  
Jinchang Wang
Keyword(s):  
Graphene Oxide ◽  
Fatigue Life ◽  
Low Temperature ◽  
Shear Viscosity ◽  
Storage Stability ◽  
Asphalt Binder ◽  
Asphalt Binders ◽  
Test Results ◽  
Zero Shear Viscosity ◽  
Modified Asphalt

This study has investigated the impact of graphene oxide (GO) in enhancing the performance properties of an asphalt binder. The control asphalt binder (60/70 PEN) was blended with GO in contents of 0%, 0.5%, 1%, 1.5%, 2%, and 2.5%. The permanent deformation behavior of the modified asphalt binders was evaluated based on the zero shear viscosity (ZSV) parameter through a steady shear test approach. Superpave fatigue test and the linear amplitude sweep (LAS) method were used to evaluate the fatigue behavior of the binders. A bending beam rheometer (BBR) test was conducted to evaluate the low-temperature cracking behavior. Furthermore, the storage stability of the binders was investigated using a separation test. The results of the ZSV test showed that GO considerably enhanced the steady shear viscosity and ZSV value, showing a significant contribution of the GO to the deformation resistance; moreover, GO modification changed the asphalt binder’s behavior from Newtonian to shear-thinning flow. A notable improvement in fatigue life was observed with the addition of GO to the binder based on the LAS test results and Superpave fatigue parameter. The BBR test results revealed that compared to the control asphalt, the GO-modified binders showed lower creep stiffness (S) and higher creep rate (m-value), indicating increased cracking resistance at low temperatures. Finally, the GO-modified asphalt binders exhibited good storage stability under high temperatures.

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