scholarly journals Effect of Graphene Nanoplatelets (GNPs) on Fatigue Properties of Asphalt Mastics

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4864
Author(s):  
Ke Li ◽  
Haisheng Ren ◽  
Weirong Huang
Keyword(s):  
Growth Rate ◽  
Fatigue Life ◽  
Graphene Nanoplatelets ◽  
Fatigue Properties ◽  
Modified Asphalt ◽  
Good Linear ◽  
Asphalt Mastics ◽  
Time Sweep ◽  
Time Sweep Test ◽  
Good Linear Correlation

To investigate the effect of graphene on the fatigue properties of base asphalt mastics, graphene nanoplatelets (GNPs)-modified asphalt mastics and base asphalt mastics were prepared. A dynamic shear rheometer (DSR) was used to conduct the tests in the stress-controlled mode of a time-sweep test. The results showed that GNPs can improve the fatigue life of asphalt mastic. Under a stress of 0.15 MPa, the average fatigue life growth rate (ω¯) was 17.7% at a filler-asphalt ratio of 0.8, 35.4% at 1.0, and 45.2% at 1.2; under a stress of 0.2 MPa, the average fatigue life growth rate (ω¯) was 17.9% at a filler-asphalt ratio of 0.8, 25.6% at 1.0, and 38.2% at 1.2. The growth value (ΔT) of fatigue life of GNPs-modified asphalt mastics increased correspondingly with the increase of filler–asphalt ratio, the correlation coefficient R2 was greater than 0.95, and the growth amount showed a good linear relationship with the filler–asphalt ratio. In the range of 0.8~1.2 filler–asphalt ratio, the increase of mineral powder can improve the fatigue life of asphalt mastics, and there is a good linear correlation between filler–asphalt ratio and fatigue life. The anti-fatigue mechanism of GNPs lies in the interaction between GNPs and asphalt, as well as its own lubricity and thermal conductivity.

Research on the Fatigue Properties of Organo-Montmorillonite Modified Bitumen Mortar

2012 ◽  
Vol 509 ◽  
pp. 175-180
Author(s):  
Xing Liu ◽  
Shao Peng Wu ◽  
Ling Pang ◽  
Pei Da Guo
Keyword(s):  
Asphalt Pavement ◽  
Weight Ratio ◽  
Fatigue Properties ◽  
Dynamic Shear ◽  
Modified Bitumen ◽  
Dynamic Shear Rheometer ◽  
Modified Montmorillonite ◽  
Time Sweep ◽  
Time Sweep Test ◽  
Test Result

This study investigated the fatigue properties of organo-montmorillonite modified bitumen mortar. Organo-modified montmorillonite（OMMT）with a content of 5 wt% was used to modified one base bitumen mortar which consist of filler and bitumen at a weight ratio of 0.8:1. The fatigue properties of these bitumen mortars have been determined using a dynamic shear rheometer（DSR）through time sweep test. Result indicated that, due to the addition of the OMMT, the fatigue properties of modified bitumen mortar was superior to those of pristine mortar. Therefore, the OMMT would be an alternative to modifiers used in the bitumen to improve the lifetime of asphalt pavement. Meanwhile, some fatigue equations were estabilished.

scholarly journals Fatigue of Friction Stir Welded Aluminum Alloy Joints: A Review

2018 ◽  
Vol 8 (12) ◽  
pp. 2626 ◽  
Author(s):  
Hongjun Li ◽  
Jian Gao ◽  
Qinchuan Li
Keyword(s):  
Growth Rate ◽  
Fatigue Life ◽  
Crack Growth Rate ◽  
Crack Growth ◽  
Process Parameters ◽  
Welded Joints ◽  
Welding Process ◽  
Life Assessment ◽  
Fatigue Properties ◽  
Friction Stir

The application fields of friction stir welding technology, such as aerospace and transportation, has high safety requirements and fatigue is the dominant failure mode for weldments. It is of great significance to understand the fatigue properties of friction stir welded joints. This paper provides an overview of the fatigue mechanism, influencing factors, crack growth rate, and fatigue life assessment. It is found that the fatigue performance of friction stir welded joints can be affected by welding process parameters, test environment, stress ratio, residual stress, and weld defect. The optimized process parameters can produce high quality weld and increase the weld fatigue life. Laser peening is an effective post weld treatment to decrease fatigue crack growth rate and improve material fatigue life.

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.

scholarly journals Investigation of Changes in Fatigue Damage Caused by Mean Load under Block Loading Conditions

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2738
Author(s):  
Roland Pawliczek ◽  
Tadeusz Lagoda
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Strain Curve ◽  
Mean Value ◽  
Fatigue Properties ◽  
Stress Strain ◽  
Reference Case ◽  
Block Loading ◽  
The Mean ◽  
Mean Strain

The literature in the area of material fatigue indicates that the fatigue properties may change with the number of cycles. Researchers recommend taking this into account in fatigue life calculation algorithms. The results of simulation research presented in this paper relate to an algorithm for estimating the fatigue life of specimens subjected to block loading with a nonzero mean value. The problem of block loads using a novel calculation model is presented in this paper. The model takes into account the change in stress–strain curve parameters caused by mean strain. Simulation tests were performed for generated triangular waveforms of strains, where load blocks with changed mean strain values were applied. During the analysis, the degree of fatigue damage was compared. The results of calculations obtained for standard values of stress–strain parameters (for symmetric loads) and those determined, taking into account changes in the curve parameters, are compared and presented in this paper. It is shown that by neglecting the effect of the mean strain value on the K′ and n′ parameters and by considering only the parameters of the cyclic deformation curve for εm = 0 (symmetric loads), the ratio of the total degree of fatigue damage varies from 10% for εa = 0.2% to 3.5% for εa = 0.6%. The largest differences in the calculation for ratios of the partial degrees of fatigue damage were observed in relation to the reference case for the sequence of block n3, where εm = 0.4%. The simulation results show that higher mean strains change the properties of the material, and in such cases, it is necessary to take into account the influence of the mean value on the material response under block loads.

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.

scholarly journals Quantitative Analysis of Inclusion Engineering on the Fatigue Property Improvement of Bearing Steel

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 476 ◽  
Author(s):  
Chao Gu ◽  
Min Wang ◽  
Yanping Bao ◽  
Fuming Wang ◽  
Junhe Lian
Keyword(s):  
Fatigue Life ◽  
Quantitative Analysis ◽  
Critical Size ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Fatigue Property ◽  
Bearing Steel ◽  
Fatigue Properties ◽  
Bearing Steels ◽  
Inclusion Distribution

The fatigue property is significantly affected by the inner inclusions in steel. Due to the inhomogeneity of inclusion distribution in the micro-scale, it is not straightforward to quantify the effect of inclusions on fatigue behavior. Various investigations have been performed to correlate the inclusion characteristics, such as inclusion fraction, size, and composition, with fatigue life. However, these studies are generally based on vast types of steels and even for a similar steel grade, the alloy concept and microstructure information can still be of non-negligible difference. For a quantitative analysis of the fatigue life improvement with respect to the inclusion engineering, a systematic and carefully designed study is still needed to explore the engineering dimensions of inclusions. Therefore, in this study, three types of bearing steels with inclusions of the same types, but different sizes and amounts, were produced with 50 kg hot state experiments. The following forging and heat treatment procedures were kept consistent to ensure that the only controlled variable is inclusion. The fatigue properties were compared and the inclusions that triggered the fatigue cracks were analyzed to deduce the critical sizes of inclusions in terms of fatigue failure. The results show that the critical sizes of different inclusion types vary in bearing steels. The critical size of the spinel is 8.5 μm and the critical size of the calcium aluminate is 13.5 μm under the fatigue stress of 1200 MPa. In addition, with the increase of the cleanliness of bearing steels, the improvement of fatigue properties will reach saturation. Under this condition, further increasing of the cleanliness of the bearing steel will not contribute to the improvement of fatigue property for the investigated alloy and process design.

Fractional viscoelastic modeling of modified asphalt mastics using response surface method

2022 ◽  
Vol 317 ◽  
pp. 125958
Author(s):  
Pouria Hajikarimi ◽  
Mehrdad Ehsani ◽  
Yassine EL Haloui ◽  
Fateh Fakhari Tehrani ◽  
Joseph Absi ◽  
...  
Keyword(s):  
Response Surface ◽  
Response Surface Method ◽  
Modified Asphalt ◽  
Surface Method ◽  
Asphalt Mastics ◽  
Viscoelastic Modeling

scholarly journals Quantifying Mold Biomass on Gypsum Board: Comparison of Ergosterol and Beta-N-Acetylhexosaminidase as Mold Biomass Parameters

2003 ◽  
Vol 69 (7) ◽  
pp. 3996-3998 ◽  
Author(s):  
M. Reeslev ◽  
M. Miller ◽  
K. F. Nielsen
Keyword(s):  
Stationary Phase ◽  
Linear Correlation ◽  
Stachybotrys Chartarum ◽  
Gypsum Board ◽  
Biomass Density ◽  
Activity Data ◽  
Good Linear ◽  
Ergosterol Content ◽  
Good Linear Correlation

ABSTRACT Two mold species, Stachybotrys chartarum and Aspergillus versicolor, were inoculated onto agar overlaid with cellophane, allowing determination of a direct measurement of biomass density by weighing. Biomass density, ergosterol content, and beta-N-acetylhexosaminidase (3.2.1.52) activity were monitored from inoculation to stationary phase. Regression analysis showed a good linear correlation to biomass density for both ergosterol content and beta-N-acetylhexosaminidase activity. The same two mold species were inoculated onto wallpapered gypsum board, from which a direct biomass measurement was not possible. Growth was measured as an increase in ergosterol content and beta-N-acetylhexosaminidase activity. A good linear correlation was seen between ergosterol content and beta-N-acetylhexosaminidase activity. From the experiments performed on agar medium, conversion factors (CFs) for estimating biomass density from ergosterol content and beta-N-acetylhexosaminidase activity were determined. The CFs were used to estimate the biomass density of the molds grown on gypsum board. The biomass densities estimated from ergosterol content and beta-N-acetylhexosaminidase activity data gave similar results, showing significantly slower growth and lower stationary-phase biomass density on gypsum board than on agar.

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