Analysis of Asphalt Geogrid Reinforced Pavement Rutting by Finite Element Method

Abstract Pavement is a complex structure consisting of several layers of different materials that influence its stressful behavior. Permanent deformation can occur in pavement layers of insufficient hardness at high temperatures. Significant rutting normally only occurs during hot weather, especially when the flexible pavement surface temperature is 60 ° C or higher. 2D model analysis using ABAQUS software can predict the rutting behavior. The modeling procedure assumes that all materials performance is a linear elastic. Surface, base, subbase and subgrade layers consist of models. Models in every pavement model, subgrade layers are supposed to have endless depth. This paper presents an element-finite model (FE) for the behavior analysis of the dynamic loading unreinforced and geogrid reinforced paving. Increased loading of the model and critical pavement responses for unreinforced or geogrid-reinforced flexible paving, such as vertical stress and vertical surface deflection, were determined. The results indicated a difference in the displacement results when adding the geogrid layer. The results also showed a significant improvement in the behavior of the pavement system. A parametric study was carried out on a type of Truck (3-S1) and the applied pressure was 36 tons with different thicknesses of the asphalt layer once 150 mm and again 25 cm at different temperatures of 20, 40 and 60 ° C. It was found that the higher the temperatures, the higher the displacement as well.

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Effect of Rubberized Bitumen Blending Methods on Permanent Deformation of SMA Rubberized Asphalt Mixtures

Advances in Materials Science and Engineering ◽

10.1155/2016/4395063 ◽

2016 ◽

Vol 2016 ◽

pp. 1-14 ◽

Cited By ~ 4

Author(s):

Herda Yati Katman ◽

Mohd Rasdan Ibrahim ◽

Mohamed Rehan Karim ◽

Suhana Koting ◽

Nuha Salim Mashaan

Keyword(s):

Creep Behaviour ◽

Permanent Deformation ◽

Asphalt Mixtures ◽

Creep Model ◽

Materials Testing ◽

Wet Process ◽

Test Conditions ◽

Dynamic Creep ◽

Different Temperatures ◽

Stone Mastic Asphalt

This study aims at comparing the permanent deformation of Stone Mastic Asphalt (SMA) rubberized asphalt mixtures produced by the wet process. In this study, rubberized binders were prepared using two different blending methods, namely, continuous blend and terminal blend. To study the creep behaviour of control and rubberized asphalt mixtures, the dynamic creep test was performed using Universal Materials Testing Apparatus (UMATTA) at different temperatures and stress levels. Zhou three-stage creep model was utilized to evaluate the deformation characteristics of the mixtures. In all test conditions, the highest resistance to permanent deformation is showed by the rubberized mixtures produced with continuous blend binders. This study also reveals that the permanent deformation of rubberized mixtures cannot be predicted based on the characteristics of the rubberized binders.

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Influence of Drying in Hyptis pectinata Essential Oil

Journal of Agricultural Science ◽

10.5539/jas.v10n4p96 ◽

2018 ◽

Vol 10 (4) ◽

pp. 96

Author(s):

Núbia Angélica de Ávila Branquinho ◽

Fabiano Guimarães Silva ◽

Osvaldo Resende ◽

Luiz Cláudio Almeida Barbosa ◽

Daniel Emanuel Cabral de Oliveira ◽

...

Keyword(s):

Essential Oil ◽

Anhydrous Sodium Sulfate ◽

Fixed Bed ◽

Chemical Characterization ◽

Automated System ◽

Caryophyllene Oxide ◽

System A ◽

Different Temperatures ◽

Drying Conditions

The present study assessed the effects of drying at different temperatures (35, 45 and 55 °C) and air velocities (1 and 2 m s-1) on the content and chemical characteristics of Hyptis pectinata essential oil. Drying was conducted in a fixed-bed dryer, and the temperatures and air velocities were controlled and recorded by an automated system. A 350±0.12 g quantity of fresh leaves was used for each of the four repetitions in each dryer. From the material obtained after drying, 60 g of each repetition was used to extract essential oil by the hydrodistillation method. Dichloromethane was used as the solvent, and anhydrous sodium sulfate was used as the desiccating agent. Gas chromatography in the forms of GC-MS and GC-FID were used for the chemical characterization of the essential oil compounds. Decreasing drying times and decreasing concentrations of essential oils were observed with increasing temperatures. A GC-MS analysis of the essential oil from H. pectinata leaves led to the identification of 19 compounds. A sesquiterpene called caryophyllene oxide was the most abundant compound under all drying conditions, with the highest concentration at a temperature of 55 °C, ranging from approximately 42 to 53%.

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Heat Stress and School Closings

PEDIATRICS ◽

10.1542/peds.74.2.313 ◽

1984 ◽

Vol 74 (2) ◽

pp. 313-314

Author(s):

Keyword(s):

Heat Stress ◽

Public Schools ◽

Air Conditioning ◽

Radiant Heat ◽

Excessive Heat ◽

Southern States ◽

Teachers And Students ◽

Different Temperatures ◽

Hot Weather ◽

American Society

During the last decade, the practice of opening public school in eary August has led to environmental stresses on students and teachers due to extremes of heat and humidity. In the South and Southwest, it is not unusual to have 15 to 20 days of 90°F(32.2°C) and relative humidity of 60% and higher during August. This puts a strain on teachers' and students' adaptability. In surveying eight southern states, J. W. Trieschmann (unpublished data, 1983) found that the availability of air conditioning in public schools ranged from 15% in some states to 30% in others. The smaller, poorer, usually rural school districts had the least access to cooling equipment. Thus, a large school population is at the mercy of the elements. This is especially significant because the majority of this population has been acclimatized to air-conditioned homes and stores, and extremes of heat discomfort are not well tolerated. Heat stress is defined as the overall effect of excessive heat on the human body. The important factors contributing to heat stress are air temperature, humidity, air movement, radiant heat, atmospheric pressure, physiologic factors (handicap or chronic disease), physical activity,1 and time exposure. Under normal conditions, temperature and humidity are the most important elements influencing comfort. The American Society of Heating, Refrigeration, Air Conditioning Engineers (ASHRAE) has published an index for determining heat stress based on human physiology, clothing, and standard room conditions.2 This index, called the "ET" or effective temperature (in Fahrenheit), is a measure of what hot weather feels like to the average person at different temperatures and humidities.

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Stiffness Model of the Armature Assembly in a Jet Pipe Pressure Servo Valve

10.21203/rs.3.rs-52619/v1 ◽

2020 ◽

Author(s):

Yaobao Yin ◽

Chengpeng He ◽

Jing Li

Keyword(s):

Finite Element ◽

Complex Structure ◽

Small Deformation ◽

Element Model ◽

Continuity Condition ◽

The Finite Element Method ◽

Servo Valve ◽

Linear Elastic ◽

Stiffness Model ◽

Static Performance

Abstract The armature assembly of the jet pipe pressure servo valve plays an important role in connecting the torque motor and the jet pipe amplifier. A stiffness model of its complex structure is very necessary for analyzing the dynamic/static performance of the jet pipe pressure servo valve. At the present work, the component parts in the armature assembly are simplified into linear elastic beams. The simplified armature assembly is a fourfold statically indeterminate structure under the premise of small deformation. The unknown forces and moments are solved by using the section continuity condition as the additional supplement equation, and the functional relationship between the electromagnetic torque produced from the torque motor and the armature rotation angle /the nozzle displacement is derived based on the Castigliano's Theorem. The finite element model of the armature assembly is also established to calculate the deformation under different loads and different spring tube lengths. The simulated displacements with the finite element method are consistent with the theoretical results. The experimental results of the recovery pressure of the jet pipe valve verified the theoretical model. The proposed stiffness calculation method can be used as a reference for designing and optimizing the armature assembly in the jet pipe pressure servo valve.

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Methodology for Measurement of Density of Liquid Oxides

Journal of Nuclear Engineering and Radiation Science ◽

10.1115/1.4048478 ◽

2020 ◽

Vol 7 (2) ◽

Author(s):

Jan Hrbek ◽

Bence Mészáros ◽

Mykhaylo Paukov ◽

Martin Kudláč

Keyword(s):

High Temperature ◽

Temperature Dependence ◽

Extreme Conditions ◽

Nuclear Accidents ◽

System A ◽

Different Temperatures ◽

Density Values ◽

Properties Of Materials ◽

The Difference

Abstract Measurement of physical properties of materials in extreme conditions, such as high temperature, is limited by technological challenges. Nevertheless, modeling of several phenomena relies on the existence of experimental data for their validation. In this study, a method suitable for determination of density in a liquid phase at high temperature is proposed and tested on Al2O3–ZrO2 system. A methodology for acquiring the temperature dependence of density for radioactive materials is proposed and is aimed to refine severe nuclear accidents modeling. The oxide was melted in an induction furnace with a cold crucible. The measurement was based on evaluation of the volume of the melt at different temperatures, in a range from 2100 to 2400 °C. The densities of the oxide in the solid-state and the skull-layer were measured using a pycnometer. A temperature dependence of the density was established and the results were compared with literature. The difference between existing data and the measured values in this work was less than 5%. Thus, the proposed methodology provides reliable density values in extreme conditions.

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Effects of Shrinkage Reducing Agent and Expansive Additive on Plastic Shrinkage of Mortar at Different Temperatures

MATEC Web of Conferences ◽

10.1051/matecconf/201820602002 ◽

2018 ◽

Vol 206 ◽

pp. 02002

Author(s):

Sarapon Treesuwan ◽

Komsan Maleesee ◽

Shigeyuki Date

Keyword(s):

High Temperature ◽

Setting Time ◽

Reducing Agent ◽

Early Age ◽

Initial Setting Time ◽

Plastic Shrinkage ◽

Different Temperatures ◽

Expansive Additive ◽

Hot Weather ◽

Shrinkage Reducing Agent

In the construction, it is inevitable to perform plaster work in hot weather which causes the dehydration and rapid shrinkage on the paste during the early age. This research shows the studies of reducing the plastic shrinkage of mortar during the early age with such additives as the Shrinkage Reducing Agent (SRA), the Expansive Additive (EX), and the Fly Ash (FA) in controlled temperatures at 30°C and 40°C, with relative humidity between 60% and 70% according to the ASTM C1579-06 standard, with the strain gauge installed at 0.5 cm.from the surface. The shrinkage rate was measured starting from the Initial Setting Time and every 10 minutes afterwards for 24 hours. The results show that high temperature effects the cracking and how to use different formulas of additive under different circumstances is considerably important. To use only one additive is not sufficient in high temperature. To use the SRA in addition to the EX enhances better expansion than to use only the EX. Moreover, it is recommended to pay close attention in adding large amount of the FA into mortar with the EX and SRA added which extremely enhances the expansion and potential cracking.

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Scientific basis for definition of a fault rupture hazard in Franz Josef Glacier, West Coast, New Zealand, and the fight to see use made of this information.

10.5194/egusphere-egu2020-5316 ◽

2020 ◽

Author(s):

Virginia Toy ◽

Bernhard Schuck ◽

Risa Matsumura ◽

Caroline Orchiston ◽

Nicolas Barth ◽

...

Keyword(s):

New Zealand ◽

Fault Zone ◽

Complex Structure ◽

Scientific Basis ◽

Building Stock ◽

Near Surface ◽

Alpine Fault ◽

Different Temperatures ◽

Fault Trace ◽

Definition Of

There is currently around a 30% probability New Zealand&#8217;s Alpine Fault will accommodate another M~8 earthquake in the next 50 years. The fault passes through Franz Josef Glacier town, a popular tourist destination attracting up to 6,000 visitors per day during peak season. The township straddles the fault, with building stock and infrastructure likely to be affected by at least 8m horizontal and 1.5m vertical ground displacements in this coming event. New Alpine Fault science is presented here that adds to the strong evidence in support of moving the township northward and out of a 200m zone of deformation across the fault zone to mitigate future losses.In 2011 two shallow boreholes were drilled at Gaunt Creek, as part of the Alpine Fault Drilling Project, DFDP. In cores collected from the deeper of these boreholes (DFDP-1B), two &#8216;principal slip zones (PSZ)&#8217; were sampled, indicating the fault is not a simple geometrical structure. Subsequent studies of the recovered cores have demonstrated:<ol><li>The lower of the two PSZ in DFDP-1B has particle size distributions indicating it accommodated more coseismic strain than the shallower PSZ</li> <li>The PSZs sampled in the two boreholes have authigenic clay mineralogies diagnostic of different temperatures</li> </ol>These studies, combined with other recent outcrop studies nearby, highlight that the central Alpine Fault zone is a complex structure comprising multiple PSZ in the near surface, some of which may have been simultaneously active in past earthquakes. The results support previous studies (e.g. lidar mapping of offset Quaternary features) that underpinned definition of an &#8216;avoidance zone&#8217; around the fault trace in the town. Sadly, local government has failed to acknowledge this risk in public legislature in a way that adequately protects tourism and community infrastructure, and the >1.3 million visitors passing through the region each year. We will explain other actions consequently taken to build awareness and resilience to this hazard.

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Synthesis of Imidazole End-Capped Poly(n-butyl methacrylate)s via Atom Transfer Radical Polymerization with a new functional initiator containing imidazolium group

e-Polymers ◽

10.1515/epoly.2007.7.1.89 ◽

2007 ◽

Vol 7 (1) ◽

Cited By ~ 3

Author(s):

Aihua Zhu ◽

Zhi Wang ◽

Meiran Xie ◽

Yiqun Zhang

Keyword(s):

Atom Transfer Radical Polymerization ◽

Radical Polymerization ◽

Butyl Methacrylate ◽

Polymerization Temperature ◽

Atom Transfer ◽

Molecular Weights ◽

System A ◽

Rate Of Polymerization ◽

Different Temperatures ◽

Optimal Reaction Temperature

AbstractThe synthesis of imidazole end-capped poly(n-butyl methacrylate)s via atom transfer radical polymerization (ATRP) is reported. n-Butyl methacrylate (n- BMA) was polymerized in isopropyl alcohol (IPA) at different temperatures via ATRP using a new N-heterocyclic functional initiator (1-α-bromoisobutylimidazole, BrBI) in the presence of CuBr/2,2’-bipyridine (bpy) as the catalyst. With this new initiating system, a successful ATRP of n-BMA was carried out, and imidazole endcapped polymers with predetermined molecular weights and low polydispersities (1.1<PDI<1.3) were obtained at low polymerization temperature (below 80 °C). Furthermore, the dependence of both the rate of polymerization and PDI on temperature gave the optimal reaction temperature (50 °C). However, at elevated temperature (especially above 80 °C), some different phenomena appeared in the polymerization: the conversion of monomer remains constant after reaching a maximum value (20%-30%), and the higher the temperature, the lower the conversion obtained.

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On the Reference Length and Mode Mixity for a Bimaterial Interface

Journal of Engineering Materials and Technology ◽

10.1115/1.2772340 ◽

2007 ◽

Vol 129 (4) ◽

pp. 580-587 ◽

Cited By ~ 9

Author(s):

A. Agrawal ◽

A. M. Karlsson

Keyword(s):

Interfacial Fracture ◽

Bimaterial Interface ◽

Mode Mixity ◽

Characteristic Mode ◽

Linear Elastic ◽

System A ◽

Reference Length ◽

Point Bend ◽

Arbitrary Location ◽

Bimaterial System

We investigate properties that govern interfacial fracture within the framework of linear elastic fracture mechanics, including interfacial fracture toughness, mode mixity, and the associated reference length. The reference length describes the arbitrary location where the mode mixity is evaluated, ahead of the crack tip, in a bimaterial system. A method for establishing a reference length that is fixed for a given bimaterial system is proposed. This is referred to as the “characteristic reference length,” with the associated “characteristic mode mixity.” The proposed method is illustrated with an experimental investigation, utilizing a four-point bend test of a bimaterial system.

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Dynamical Behavior of the Subsurface Region in Alloys Under Ion Bombardment at High Temperatures

MRS Proceedings ◽

10.1557/proc-7-35 ◽

1981 ◽

Vol 7 ◽

Cited By ~ 3

Author(s):

N. Q. Lam ◽

H. Wiedersich

Keyword(s):

Alloy Composition ◽

Dynamical Behavior ◽

Alloy System ◽

Model Alloy ◽

Model Calculations ◽

Enhanced Diffusion ◽

Preferential Sputtering ◽

System A ◽

Radiation Enhanced Diffusion ◽

Different Temperatures

ABSTRACTModifications of subsurface alloy composition by bombardment with ions of several keV energy were investigated theoretically, using a phenomenological model which includes the effects of various processes, such as preferential sputtering, displacement mixing, Gibbsian adsorption, radiation-enhanced diffusion, and radiationinduced segregation. The nonuniformity of damage rates, resulting from slow-down of the incoming ions, was also taken into account. The alloy composition evolution in time and space was calculated numerically for different temperatures, using concentrated Ni-Cu as a model alloy system. A good qualitative agreement between the present model calculations and recent experimental measurements was obtained.

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