scholarly journals Numerical Simulation of the Effect of Repeated Load and Waste Polypropylene on the Behavior of Asphalt Layers

2022 ◽  
Vol 961 (1) ◽  
pp. 012039
Author(s):  
Hind A Akram ◽  
Miami M Hilal ◽  
Mohammed Y Fattah
Keyword(s):  
Elastic Material ◽  
Surface Deformation ◽  
Vertical Displacement ◽  
Heavy Vehicles ◽  
Modified Asphalt ◽  
Critical Response ◽  
Coulomb Model ◽  
Repeated Load ◽  
The Impact ◽  
Waste Polypropylene

Abstract Roads are utilized by many vehicle kinds and heavy vehicles among these may be seen as the most essential for cargo loading, causing paving failure and increasing expenses for rehabilitation and maintenance. In this study, in analyzing a finite element employing Abaqus 6.14, composite effects for wheel loads and temperature were addressed. The asphalt layer was designed as an elastic material, while the base and sub-bases were modeled according to the Mohr coulomb model like an elastic material. And studying the impact of wheel loads on flexible pavement settlement and the main output of analyzing pavement structure is almost represented by the vertical stresses and the surface deformation which are considered as the critical response point. A truck type 2S-2 was tried with two thicknesses of asphalt layer 140 mm and 250 mm and considering that base and subbase layer thicknesses remained constant so it does not affect the variation of displacement. It was found that the increase of asphalt layer thickness from 140 mm to 250 mm leads to a decrease in the vertical displacement of about 0.59% and studied the effect of modified asphalt with polymer and how it effect pavement vertical displacement with an obvious reduction from 0.590 mm to 0.265 mm under the repeated load of 36 ton and The vertical stress decreased from 5.036 kPa to 1.899 kPa

scholarly journals Reservoir-Induced Land Deformation: Case Study from the Grand Ethiopian Renaissance Dam

2021 ◽  
Vol 13 (5) ◽  
pp. 874
Author(s):  
Yu Chen ◽  
Mohamed Ahmed ◽  
Natthachet Tangdamrongsub ◽  
Dorina Murgulet
Keyword(s):  
Land Surface ◽  
Large Scale ◽  
Surface Deformation ◽  
Vertical Displacement ◽  
Nile River ◽  
Reservoir Volume ◽  
Novel Approach ◽  
Land Deformation ◽  
Large Scale Land ◽  
The Impact

The Nile River stretches from south to north throughout the Nile River Basin (NRB) in Northeast Africa. Ethiopia, where the Blue Nile originates, has begun the construction of the Grand Ethiopian Renaissance Dam (GERD), which will be used to generate electricity. However, the impact of the GERD on land deformation caused by significant water relocation has not been rigorously considered in the scientific research. In this study, we develop a novel approach for predicting large-scale land deformation induced by the construction of the GERD reservoir. We also investigate the limitations of using the Gravity Recovery and Climate Experiment Follow On (GRACE-FO) mission to detect GERD-induced land deformation. We simulated three land deformation scenarios related to filling the expected reservoir volume, 70 km3, using 5-, 10-, and 15-year filling scenarios. The results indicated: (i) trends in downward vertical displacement estimated at −17.79 ± 0.02, −8.90 ± 0.09, and −5.94 ± 0.05 mm/year, for the 5-, 10-, and 15-year filling scenarios, respectively; (ii) the western (eastern) parts of the GERD reservoir are estimated to move toward the reservoir’s center by +0.98 ± 0.01 (−0.98 ± 0.01), +0.48 ± 0.00 (−0.48 ± 0.00), and +0.33 ± 0.00 (−0.33 ± 0.00) mm/year, under the 5-, 10- and 15-year filling strategies, respectively; (iii) the northern part of the GERD reservoir is moving southward by +1.28 ± 0.02, +0.64 ± 0.01, and +0.43 ± 0.00 mm/year, while the southern part is moving northward by −3.75 ± 0.04, −1.87 ± 0.02, and −1.25 ± 0.01 mm/year, during the three examined scenarios, respectively; and (iv) the GRACE-FO mission can only detect 15% of the large-scale land deformation produced by the GERD reservoir. Methods and results demonstrated in this study provide insights into possible impacts of reservoir impoundment on land surface deformation, which can be adopted into the GERD project or similar future dam construction plans.

scholarly journals Stiffness Modulus of Asphaltic Concrete Incorporating Coir Fibre and Subjected to Aging

2018 ◽  
Vol 65 ◽  
pp. 02003
Author(s):  
Abdullahi Ali Mohammed ◽  
Ramadhansyah Putra Jaya ◽  
Étienne Joseph Marie Delbrel ◽  
Choong Wee Kang ◽  
Sien Ti Kok ◽  
...  
Keyword(s):  
Stiffness Modulus ◽  
Modified Asphalt ◽  
Indirect Tensile Test ◽  
Coir Fibre ◽  
Performance Response ◽  
Short And Long Term ◽  
Indirect Tensile ◽  
Repeated Load ◽  
The Impact

The aim of this paper is to investigate the performance response of a set of coir fibre modified asphalt samples subjected different ageing conditions and containing three different fibre contents. The laboratory experimental programs are indirect tensile test at 25°C and repeated load axial test at 40°C. The results showed that the fibres improved the mixture’s performance. The main findings obtained at 25°C for short and long-term ageing reveal that low fibre content at around 0.3% per aggregate weight display a stiffness modulus up to 14% higher than that of unmodified mixtures, hence showing that fibres may improve the bearing capacity and rut-resistance of asphalt mixtures. Conversely, as the amount of fibre increases to 0.5% and 0.7%, the stiffness decreases to the point of becoming unacceptably low, almost 80% lower than unmodified mixes stiffness. However the data also reveal that high fibre contents at 0.5% and above completely neutralize the impact of ageing on the mixture, indicating that fibre-modified mixtures would yield longer lives.

Research on the Impact of Temperature on the Softening Point of SBS Modified Asphalt

2013 ◽  
Vol 365-366 ◽  
pp. 978-982
Author(s):  
Xiao Wei Feng ◽  
De Wen Zhang
Keyword(s):  
Softening Point ◽  
Heating Temperature ◽  
Road Construction ◽  
Curing Temperature ◽  
Important Indicator ◽  
Modified Asphalt ◽  
Influence Of Temperature On ◽  
Sbs Modified Asphalt ◽  
The Impact ◽  
Initial Heating

The softening point of modified asphalt is an extremely important indicator to evaluate the high-temperature performance; its the temperature of modified asphalt sample emerging shear deformation under the action of certain shear stress according to the specific heating rate. Its found that in the actual construction and testing, different temperature conditions has a larger impact on the softening point of the modified asphalt, which has adverse affect on road construction. This paper studied and researched the influence of temperature on modified asphalt softening point indicators from the different test temperature, including packing compact temperature, scraper temperature in removal of asphalt that above test mode, standing temperature, curing temperature and initial heating temperature before test.

scholarly journals EVALUATING THE EFFECT OF HEAVY VEHICLES ON TRAFFIC PARAMETERS BY USING HEAVY VEHICLE FACTOR

2018 ◽  
Vol 6 (4) ◽  
pp. 95-104
Author(s):  
Parthkumar Patel ◽  
H.R. Varia
Keyword(s):  
Travel Time ◽  
Traffic Flow ◽  
Road Traffic ◽  
Freight Transport ◽  
Heavy Vehicle ◽  
Mixed Traffic ◽  
Heavy Vehicles ◽  
Highway Traffic ◽  
Ideal Situation ◽  
The Impact

Safe, convenient and timely transportation of goods and passengers is necessary for development of nation. After independence road traffic is increased manifold in India. Modal share of freight transport is shifted from Railway to roadways in India. Road infrastructures continuously increased from past few decades but there is still need for new roads to be build and more than three forth of the roads having mixed traffic plying on it. The impact of freight vehicles on highway traffic is enormous as they are moving with slow speeds. Nature of traffic flow is dependent on various traffic parameters such as speed, density, volume and travel time etc. As per ideal situation these traffic parameters should remain intact, but it is greatly affected by presence of heavy vehicle in mixed traffic due to Svehicles plying on two lane roads. Heavy vehicles affect the traffic flow because of their length and size and acceleration/deceleration characteristics.  This study is aimed to analyse the impact of heavy vehicles on traffic parameters.

A mixed contact model for an immersed collision between two solid surfaces

2008 ◽  
Vol 366 (1873) ◽  
pp. 2205-2218 ◽  
Author(s):  
Fu-Ling Yang ◽  
Melany L Hunt
Keyword(s):  
Surface Deformation ◽  
Elastohydrodynamic Lubrication ◽  
Solid Particles ◽  
Solid Surfaces ◽  
Additional Energy ◽  
Collision Model ◽  
Dry Granular Flow ◽  
Wide Range ◽  
The Impact ◽  
Surrounding Liquid

Experimental evidence shows that the presence of an ambient liquid can greatly modify the collision process between two solid surfaces. Interactions between the solid surfaces and the surrounding liquid result in energy dissipation at the particle level, which leads to solid–liquid mixture rheology deviating from dry granular flow behaviour. The present work investigates how the surrounding liquid modifies the impact and rebound of solid spheres. Existing collision models use elastohydrodynamic lubrication (EHL) theory to address the surface deformation under the developing lubrication pressure, thereby coupling the motion of the liquid and solid. With EHL theory, idealized smooth particles are made to rebound from a lubrication film. Modified EHL models, however, allow particles to rebound from mutual contacts of surface asperities, assuming negligible liquid effects. In this work, a new contact mechanism, ‘mixed contact’, is formulated, which considers the interplay between the asperities and the interstitial liquid as part of a hybrid rebound scheme. A recovery factor is further proposed to characterize the additional energy loss due to asperity–liquid interactions. The resulting collision model is evaluated through comparisons with experimental data, exhibiting a better performance than the existing models. In addition to the three non-dimensional numbers that result from the EHL analysis—the wet coefficient of restitution, the particle Stokes number and the elasticity parameter—a fourth parameter is introduced to correlate particle impact momentum to the EHL deformation impulse. This generalized collision model covers a wide range of impact conditions and could be employed in numerical codes to simulate the bulk motion of solid particles with non-negligible liquid effects.

scholarly journals Spatial Baseline Optimization for Spaceborne Multistatic SAR Tomography Systems

Sensors ◽  
2019 ◽  
Vol 19 (9) ◽  
pp. 2106 ◽  
Author(s):  
Jiuchao Zhao ◽  
Anxi Yu ◽  
Yongsheng Zhang ◽  
Xiaoxiang Zhu ◽  
Zhen Dong
Keyword(s):  
Surface Deformation ◽  
Design Method ◽  
Geometric Model ◽  
Three Dimensional ◽  
Optimization Method ◽  
Deformation Measurement ◽  
Experimental Simulation ◽  
Baseline Design ◽  
Imaging Performance ◽  
The Impact

Spaceborne multistatic synthetic aperture radar (SAR) tomography (SMS-TomoSAR) systems take full advantage of the flexible configuration of multistatic SAR in the space, time, phase, and frequency dimensions, and simultaneously achieve high-precision height resolution and low-deformation measurement of three-dimensional ground scenes. SMS-TomoSAR currently poses a series of key issues to solve, such as baseline optimization, spatial transmission error estimation and compensation, and the choice of imaging algorithm, which directly affects the performance of height-dimensional imaging and surface deformation measurement. This paper explores the impact of baseline distribution on height-dimensional imaging performance for the baseline optimization issue, and proposes a feasible baseline optimization method. Firstly, the multi-base multi-pass baselines of an SMS-TomoSAR system are considered equivalent to a group of multi-pass baselines from monostatic SAR. Secondly, we establish the equivalent baselines as a symmetric-geometric model to characterize the non-uniform characteristic of baseline distribution. Through experimental simulation and model analysis, an approximately uniform baseline distribution is shown to have better SMS-TomoSAR imaging performance in the height direction. Further, a baseline design method under uniform-perturbation sampling with Gaussian distribution error is proposed. Finally, the imaging performance of different levels of perturbation is compared, and the maximum baseline perturbation allowed by the system is given.

Engineering the Interaction Forces to Optimize CMP Performance

2002 ◽  
Vol 732 ◽  
Author(s):  
G. B. Basim ◽  
I. Vakarelski ◽  
P. Singh ◽  
B. M. Moudgil
Keyword(s):  
Material Removal ◽  
Surface Deformation ◽  
Defect Density ◽  
Removal Rate ◽  
Particle Interactions ◽  
Interaction Forces ◽  
High Performing ◽  
Optimal Material ◽  
Slurry Stability ◽  
The Impact

AbstractThe main objective of Chemical Mechanical Polishing (CMP) process is to planarize the metal or dielectric layers deposited on the wafer surfaces in microelectronics device manufacturing. In CMP, slurries containing submicrometer size particles and chemicals are used to achieve planarization. An effective polishing requires an optimal material removal rate with minimal surface deformation. Therefore, it is important to control the particle-substrate interactions that are responsible for the material removal and the particle-particle interactions, which control the slurry stability and consequently the defect density. This paper discusses the impact of interaction forces on polishing, and underlines the scientific guidelines to formulate consistently high performing CMP slurries.

scholarly journals Evaluating Impacts of Overloaded Heavy Vehicles on Freeway Traffic Condition by a Novel Multi-Class Traffic Flow Model

2018 ◽  
Vol 10 (12) ◽  
pp. 4694 ◽  
Author(s):  
Xiang Wang ◽  
Po Zhao ◽  
Yanyun Tao
Keyword(s):  
Traffic Flow ◽  
Flow Model ◽  
Management Strategies ◽  
Maximum Speed ◽  
Heavy Vehicles ◽  
Fundamental Diagram ◽  
Traffic Condition ◽  
Traffic Flow Model ◽  
Traffic Conditions ◽  
The Impact

Overloaded heavy vehicles (HVs) have significant negative impacts on traffic conditions due to their inferior driving performance. Highway authorities need to understand the impact of overloaded HVs to assess traffic conditions and set management strategies. We propose a multi-class traffic flow model based on Smulders fundamental diagram to analyze the influence of overloaded HVs on traffic conditions. The relationship between the overloading ratio and maximum speed is established by freeway toll collection data for different types of HVs. Dynamic passenger car equivalent factors are introduced to represent the various impacts of overloaded HVs in different traffic flow patterns. The model is solved analytically and discussed in detail in the appendices. The model validation results show that the proposed model can represent traffic conditions more accurately with consideration for overloaded HVs. The scenario tests indicate that the increase of overloaded HVs leads to both a higher congestion level and longer duration.

scholarly journals The impact of heavy vehicle’s composition to traffic performance of Jakarta Intra Urban Toll Road (JIUT) in macroscopic level

2019 ◽  
Vol 276 ◽  
pp. 03018
Author(s):  
Nahry Yusuf ◽  
Ismi Dilianda Wulandari
Keyword(s):  
Traffic Flow ◽  
Exponential Model ◽  
Flow Speed ◽  
Heavy Vehicles ◽  
Flow Models ◽  
Toll Road ◽  
Traffic Performance ◽  
Traffic Flow Models ◽  
The One ◽  
The Impact

Freight vehicle access restriction policy in 2011 has had an impact on the performance of Jakarta Intra Urban Toll way (JIUT) system. The statutory segment (Cawang-Tomang) of this toll road system seems to have better performance, but not for the advisory segment (Cawang -Ancol). Basically, heavy vehicles (HV) shift their routes to the advisory segment to avoid the statutory segment at which they are prohibited to access from 05.00 a.m. to 10.00 p.m.. This study aims to investigate the impact of the HV composition on the traffic performance of the advisory segment of JIUT. Data were obtained from 48 hours of traffic recording at a part of Cawang-Ancol segment. It was found that the Underwood Model (exponential model) can represent the relationship between the three main parameters of traffic flow on the advisory segment, i.e. volume, speed, and density. Based on the developed traffic flow models which are classified on the HV composition, it is shown that the free flow speed (uf) for HV composition < 6% (i.e. 144.91 km/h) is higher 35.41% than the one of HV > 6% (i.e. 107.02 km/h). The actual road capacity (qm) in HV composition < 6% (i.e. 4442 pcu/hour) also higher 12.83% than the one of HV > 6% (i.e. 3937 pcu/hour). The results will benefit to the transport authority to justify the truck access restriction implementation.

Simulation Modeling of Pedestrian Performance in the New Synchronized and Milwaukee B Interchanges versus Existing Designs

2018 ◽  
Vol 2672 (35) ◽  
pp. 151-160 ◽  
Author(s):  
Amirarsalan Mehrara Molan ◽  
Joseph E. Hummer
Keyword(s):  
Travel Time ◽  
Negative Impact ◽  
Heavy Vehicles ◽  
Traffic Distribution ◽  
Significant Negative Impact ◽  
Pedestrian Travel ◽  
Safe Condition ◽  
Vehicle Travel Time ◽  
Traffic Operation ◽  
The Impact

Most U.S. highway agencies recognize the importance of designing safe, short, and comfortable paths for pedestrians. Providing such an acceptable condition for pedestrians requires specific attention at intersections and service interchanges due to their interaction with other modes of transportation. The main objective of this research was to analyze pedestrian operation at two new service interchanges—the synchronized and Milwaukee B interchanges—in comparison with four existing designs. The analysis consists of three main parts: (1) a general comparison among the designs for pedestrian performances in terms of safety, travel time, and the level of service; (2) investigation of the effects of vehicles on pedestrian performance; and (3) modeling the impact of pedestrians on the traffic operation of vehicles. A comprehensive series of simulation tests were run using VISSIM and Synchro to study the pedestrian performance of interchanges in various situations of traffic volume, turning traffic ratio, traffic distribution, and percentage of heavy vehicles. The results indicated that a relatively safe condition is expected for pedestrians in the proposed new designs in comparison with the existing interchanges; however, the pedestrians’ travel time was lower in all the existing designs than in the new designs except the diverging diamond interchange (DDI). The DDI, one of the most popular alternative interchanges, showed the worst performance in all the aspects of the pedestrian analysis. Despite the very good performance of conventional diamond interchange regarding pedestrian travel time and safety, pedestrians could have a significant negative impact on vehicle travel time through a diamond.

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