Impacts of Load Distribution and Lane Width on Pavement Rutting Performance for Automated Vehicles
Ali Yeganeh, Universiteit HasseltShow Abstract
Bram Vandoren, Universiteit Hasselt
Ali Pirdavani (firstname.lastname@example.org), Hasselt University
With ongoing improvements in technical possibilities and availability of faster computers and communication systems, considerable attention has been drawn to smart driving technologies and particularly to automated vehicles (AVs). The deployment of AVs would provide the opportunity to have more control over the dynamics of the vehicle including its lateral movement, which can affect the pavement long-term rutting performance. The controlled lateral movement of the AVs may also imply a reduced lane width. This paper evaluates the impacts of dedicating a reduced lane width to automated vehicles on pavement rutting performance, considering two lateral movement modes for AVs; zero and uniform wander distribution. A finite element model was developed using ABAQUS software based on the Indiana Department of Transportation/Purdue University accelerated pavement tester (APT) facility. The rutting simulation results of this study show that using a dedicated lane for AVs with zero and uniform wander distribution would cause greater rutting depth when compared to the rutting induced by non-AVs following a normal load distribution. Furthermore, the comparison between rutting depths in different lane widths reveals that when dedicating the narrower lane widths for AVs with a uniform wander distribution, the total rutting depth of the pavement would remarkably increase compared to the wider lanes.
Development Of A Methodology To Estimate Widebase Steering Tire Load Equivalency In Canada
Papa Thiam, FPinnovationsShow Abstract
Allan Bradley, FPinnovations
Canadian regulators, such as British Columbia Ministry of Transportation and Infrastructure (TRAN), utilize the ESAL concept for vehicle impact evaluations and(or) pavement design. TAC’s ESAL equations originally were developed in RTAC’s Heavy Vehicle Weights and Dimensions Study (RTAC, 1986) and are widely accepted by the Canadian transportation industry. Unfortunately, TAC’s ESAL equations do not account for tire size and, consequently, overestimate steering axle impacts when those axles are equipped with widebase steering tires. Most new vehicles proposed for use in many Canadian provinces feature tridem drive tractors which, by regulation, must carry at least 25% - 27% of the drive group weight on the steering axle—these heavy loads necessitate the use of widebase steering tires. In order to optimize high efficiency truck configurations in Canada, therefore, accurate estimates of widebase steering tire ESALs are needed. This paper describes a methodology that was recently developed by FPInnovations, in consultation with TRAN, to estimate ESALs for widebase tires. Using layered elastic pavement modeling, FPInnovations evaluated key strain responses to widebase steering tire traffic in the 14 RTAC-86 test pavement sections. The results were transformed to estimates of pavement life and then calibrated to RTAC-86’s single-axle/single-tire ESAL model to develop ESAL relations for eight popular North American steering tire sizes, including four widebase steering tires. The ESAL relations produced in this research extend the TAC ESAL equations to all popular North American widebase steering tire sizes and offer regulators, academics, and consultants a means to more accurately estimate steering tire pavement impacts
Dynamic Pavement Response Analysis under Wide-Base Tire Considering Vehicle-Tire-Pavement Interaction
Jingnan Zhao, Rutgers UniversityShow Abstract
Hao Wang (email@example.com), Rutgers University
The new generation of wide-base tires shows sustainable benefits in trucking operations and environment impacts due to less rolling resistance at tire-pavement interface. However, it was critical to estimate the influence on pavement response and performance. The objective of this study is to analyze dynamic responses of flexible pavements induced by wide-base tires using an integrated vehicle-tire-pavement interaction approach. A full-truck model was adopted to estimate dynamic tire forces considering different axle and tire configurations and pavement surface roughness conditions. The impulse response method was used to calculate critical pavement responses under moving loads with random amplitudes. The impact of wide-base tire was evaluated through the ratio of critical pavement responses between wide-base tire and dual-tire assembly, respectively, for the potential of fatigue cracking, near-surface cracking and subgrade rutting. In general, wide-base tire caused greater tensile strain but similar compressive strain and near-surface shear strain as compared to dual tire assembly. However, the pavement response ratios caused by two tire configurations show considerable variations as the truck configuration, speed, or pavement surface roughens changes. This suggests that the prediction of long-term pavement performance under the impact of wide-base tire need consider the evolution of pavement surface condition and different failure mechanisms. The study findings emphasize the importance of considering vehicle-tire-pavement interaction in analyzing dynamic pavement responses.
Preliminary Study on Rutting Performance of Pavement Structures under the Effect of Future Autonomous Vehicle Movements
Nitish Bastola, University of Texas, TylerShow Abstract
Mena Souliman (firstname.lastname@example.org), University of Texas, Tyler
Matthew Vechione, University of Texas, Tyler
Rutting, also referred to as permanent deformation, has always been a concern in the asphalt pavement industry. The prevalence of rutting is the sign of inefficient functioning of roadways. Various studies are being performed for rutting analysis; and currently, rutting related studies are more focused on autonomous vehicles and their potential adverse impact, especially with the expected reduced wandering effect. The advent of automated vehicles on prevailing pavements may raise countless questions regarding the distress free functioning of pavement. Lateral, as well as a longitudinal wandering of autonomous vehicles, are of top concerns on the rutting related analysis of pavement structures. Therefore, there is a dire need for a better understanding of rutting related behavior of pavements when loaded with autonomous vehicles. In this study, various conditions related to automated vehicles (such as reduction of wandering effect, overall increase in traffic volume) are examined, and quantification of the rutting encountered in such circumstances is illustrated via the Permanent Deformation for Roads (PEDRO) software package. Based on the results of this preliminary study, it is anticipated that there is a potential increase in the rutting susceptibility of the affected pavement structures that may rise up to 400%.
Estimation of Automated Truck Platooning’s Impacts on the Fatigue Life of Flexible Pavements Using Machine Learning Algorithms
Michael Elwardany, FHWA-TFHRC / ESC Inc.Show Abstract
Botros Hanna, Western New Mexico University
Mena Souliman (email@example.com), University of Texas, Tyler
The concept of truck platooning is that a number of trucks are connected virtually and driving at a short following distance with minimal or designed lateral wandering. Truck platooning may cause up to 85% reduction in truck following distance compared to conventional vehicles and therefore reduces rest periods (RP) between loading cycles on pavement materials. Fatigue cracking is one of the major distresses in flexible pavement structures, and pavement fatigue life is highly dependent on RP. In this paper, Artificial Neural Network (ANN) modeling was utilized to estimate the effect of automated truck platooning on fatigue life of flexible pavements. ANN modeling was applied on the NCHRP 09-44A project’s database that included extensive laboratory beam fatigue testing results on a wide range of asphalt mixtures with various RP. The developed ANN model was used to predict number of cycles to failure as a function of RP and to estimate the impact of truck platooning on pavement fatigue life. In addition, a stand-alone equation that is based on linear multivariate regression of fatigue life was developed independently from the ANN model. Based on the results, an 85% reduction in the following distance of platooned trucks may lead to between 7% and 25% reduction in pavement fatigue life. The Platooning Fatigue Life Ratio (PFLR) was found to be dependent on temperature, applied strain level, and mixture parameters. Additionally, it was found that the applied strain level was the most significant factor on PFLR, and binder grade was the most significant mixture parameter.
A User-Friendly Mechanistic-Empirical Pavement Design Tool for Low Volume Roads
David Orr, Cornell Local Roads ProgramShow Abstract
Geoff Scott, Cornell University
Nick Kuzmik, Cornell University
Low-volume roads (LVRs) make up more than half the centerline mileage in the United States, most of which are not designed. The Cornell University Local Roads Program worked with local highway agencies to develop a mechanistic-empirical pavement design tool that overcomes the limitations of expertise and time of most LVR highway officials but takes advantage of the knowledge of their own LVRs. The tool developed, RoadPE: LHI, uses two common pavement fatigue criteria, surface tensile strain and subgrade vertical strain, with simplified inputs, and built-in trend analysis to determine the thickness of the asphalt layers for overlaid, mill and filled, rehabilitated, and reconstructed LVRs.
Mechanistic Analysis of Pavement Damage and Performance Prediction Based on Finite Element Modeling with Viscoelasticity and Fracture of Mixtures
Mohammad Rahmani, Texas A&M University, College StationShow Abstract
Yong-Rak Kim (firstname.lastname@example.org), Texas A&M University, College Station
Dallas Little, Texas A&M University, College Station
Yong Boo Park, Land and Housing Institute
Jong Suk Jung, Land and Housing Institute
This study aims to explore a purely mechanistic pavement analysis approach where viscoelasticity and fracture of asphalt mixtures are considered to predict deformation and damage behavior of flexible pavements. To do so, the viscoelastic and fracture properties of designated pavement materials were obtained through experiments, and a fully mechanistic damage analysis was carried out using a finite element method. While modeling crack development can be done in various ways, this study used the cohesive zone model, which is a well-known fracture mechanics approach to efficiently model crack initiation and propagation. To demonstrate the modeling method, different pavement configurations and traffic loads were considered based on three main functional classes of roads suggested by FHWA (i.e., arterial, collector, and local). A concept of the modeling approach was presented, and a case study where three different material combinations for asphalt surface and base layers were considered to investigate progressive damage behavior of pavements when mixture properties and layer configurations were altered. Overall, it can be concluded that mechanistic pavement modeling attempted in this study can differentiate pavement performance affected by varying design inputs. The promising results, although limited yet to be considered a practically implementable method, infer that a few mixture tests can be integrated with the finite element modeling of the mixture tests and subsequent structural modeling of pavements to better design mixtures and pavements in a purely mechanistic manner.
Pavement Fatigue Damage Simulations using Second Generation Mechanistic-Empirical Approaches
Noe Hernandez (email@example.com), Universidad Nacional Autonoma de MexicoShow Abstract
John Harvey, University of California, Davis
Benjamin Underwood, North Carolina State University
Alexandra Ossa-Lopez, Universidad Nacional Autonoma de Mexico
This article aims to demonstrate the advanced features of two second-generation Mechanistic-Empirical pavement analysis engines. First, a comprehensive review is presented of both mechanistic and empirical damage models, underlining the advanced features of CalME and FlexPAVETM over AASHTOWare Pavement ME Design. Then, the capabilities of these methodologies are demonstrated simulating the fatigue damage performance of an example study section, using the mechanical properties of four asphalt concrete mixtures with similar mix design attributes but diverse fatigue characteristics. The empirical transfer functions were initially calibrated against field cracking for the unmodified mixture cracking predictions. After that, fatigue damage simulations for the other three mixtures were performed. The results showed a similar shape and trend for the cracking growth development curves in both CalME and FlexPAVETM simulations for all asphalt mixtures. Also, it was observed that the polymer-modified mixtures exhibited higher fatigue cracking resistance, whereas the unmodified mixture showed the worst cracking
C-FLEX: Advanced Finite Element Analysis Program for Flexible Pavement Analysis and Design
Jiayi Luo, University of Illinois, Urbana-ChampaignShow Abstract
Haohang Huang, University of Illinois, Urbana-Champaign
Issam Qamhia, University of Illinois, Urbana-Champaign
Erol Tutumluer (firstname.lastname@example.org), University of Illinois, Urbana-Champaign
Jeb Tingle, U.S. Army Corps of Engineers (USACE)
The U.S. Army Engineer Research and Development Center (ERDC) of the U.S. Army Corps of Engineers has initiated an effort to modernize the Department of Defense (DOD) pavement design and evaluation procedures initially developed in the 1950s. Flexible pavement analyses are currently performed based on the elastic layered WESLEA software program to determine pavement critical responses. The DOD pavement evaluation process uses the WESDEF program to conduct back analyses to determine pavement layer moduli. To modernize the current pavement evaluation and design procedures used by the DOD, an advanced axisymmetric Finite Element Method (FEM) based analysis program, named C-FLEX, was developed and is introduced in this paper. The C-FLEX program is designed to feature accurate material models for all pavement layers with the capability to model the cross-anisotropic and nonlinear elastic properties of unbound base/subbase and subgrade layers, the viscoelastic behavior of the Hot Mixture Asphalt (HMA) layer, as well as mechanical reinforcement using geosynthetics in flexible pavements. The FEM formulation in C-FLEX and the program architecture and implementation details are introduced and discussed in this paper. The different analysis schemes and proper models used to characterize the cross-anisotropy and stress-dependent material nonlinearity are also described in detail. Furthermore, two conventional flexible pavements with different layer properties are analyzed to verify the solutions and reliability of the C-FLEX program. Based on this development effort with ERDC, the C-FLEX program is envisioned to serve as the flexible pavement analysis engine for the DOD’s new mechanistic design and evaluation platform.
Evaluation of Accuracy of Performance Prediction Utilizing AASHTOware PavementME Software of Composite Long-Term Pavement Performance Sections
Harshdutta Pandya, Rowan UniversityShow Abstract
Daniel Offenbacker (email@example.com), Rowan University
Yusuf Mehta, Rowan University
Composite pavements are one of the most cost-effective options of the pavement rehabilitation within the pavement management system due to its capability of supporting significant volumes of vehicle traffic. Design inputs and performance measures data from long-term pavement performance (LTPP) are used to nationally calibrate Mechanistic-Empirical Pavement Design Guide (MEPDG) pavement performance models for AASHTOWare Pavement ME design tool to minimize the differences in national and local conditions. Considering local materials, traffic data and climatic conditions, transportation agencies are required to perform further calibration and verification to implement these models. The objective of this study was to enhance the accuracy of Pavement ME design pavement performance measures of in-service composite pavements to better design and to provide long-life structural capacity performing local calibration of Pavement ME prediction models. Selected for this study are forty- two LTPP composite pavements with flexible layer over a rigid layer from wet-freeze climate zone. The measured performances, including Rutting and International Roughness Index (IRI), of the selected composite pavements were compared with those predicted from Pavement ME to determine the effectiveness of Pavement ME for predicting accurate performance. The comparisons were analyzed using multi-factor statistical analysis procedures. Effectively, for the selected LTPP composite pavements, more than 80% of rutting predictions underestimated the measured rut depth beyond 50% difference and about 50% of predicted IRI undervalued the measured IRI by less than 30% difference. Finally, the study provided decision-trees for practitioners to use to determine composite pavement types that require local calibration for accurate distress predictions.
Pavement M-E Design Preliminary Local Calibration Efforts using the Calibration Assistance Tool and Implementation Plans: MaineDOT’s Experience and Perspective
Uma Maheswar Arepalli (firstname.lastname@example.org), SRM UniversityShow Abstract
Casey Nash, Maine Department of Transportation
Derek Nener-Plante, Federal Highway Administration (FHWA)
AASHTOWare Pavement ME Design (PMED) requires local calibration of its performance models as these were developed using a national database. In 2019, AASHTO released an automated Calibration Assistance Tool (CAT) to help highway agencies with the time-consuming local calibration efforts. MaineDOT has been eager to implement PMED, and the initial efforts were started in 2016. While waiting on the qualified distress data from the test sections, a preliminary local calibration using a historical project database was planned in 2019. The primary goal of this calibration was to understand the needs for the overall calibration process and to identify any gaps with the current implementation plan. MaineDOT library values such as layer coefficient, Dynamic Cone Penetrometer (DCP), and lab measured- gradation and volumetric information were used for material design input. The CAT was used for initial verification and calibration of performance models such as rutting, roughness, bottom-up cracking, and thermal cracking. The local calibration results provided a new set of calibration coefficients – global and local for the performance models. Overall, the study recommended a PMED design guidance with the finalized calibration coefficients and improved design inputs from this effort. This paper also discusses the key limitations identified with the study as well as the improvements made for the existing implementation plan based on the lessons learned from this preliminary effort. It is believed that this paper could serve as a potential resource for the agencies planning to conduct an in-house local calibration using the CAT.
Incorporating Wheel Tracking Test Results in Flexible Pavement Rutting Analysis
Mahdi Saghafi (email@example.com), University of Texas, El PasoShow Abstract
Soheil Nazarian, Center for Transportation Infrastructure Systems (CTIS)
Imad N. Abdallah, Center for Infrastructure Systems (CTIS)
Cesar Tirado, Center for Transportation Infrastructure Systems (CTIS)
Danniel D. Rodriguez, Center for Transportation and Infrastructure Systems (CTIS)
The state-of-the-practice in asphalt concrete (AC) mix design and pavement structural design are two divergent concepts. The laboratory tests that are used for mix design, especially under the balance mix design concept, are pragmatically accelerated surrogate tests developed to ensure the stability or ranking of mixes. Pavement structural design methods, being empirical or mechanistic, do not consider these laboratory test results in their analyses. As such, the selection of the type of the mix to be placed on a project is based on the local experience, and a set of consensus limits, rather than the demand of the pavement section. A harmonized strategy that integrates the results from mix tests with the pavement structure, material properties, environmental conditions and traffic levels can lead to a fully optimized pavement system. A framework is proposed to incorporate the laboratory Hamburg Wheel Tracking device indices into the rutting analysis associated with most mechanistic-empirical structural design algorithms. The proposed framework was applied to two in-service pavement test sections to demonstrate its feasibility. By balancing the rutting demand of an asphalt layer with the rutting capacity of a given mix, the proposed method can potentially lend itself to the use of local materials for a more economical and sustainable pavement structure.
Assessing Climate Change Impact on Asphalt Binder Grade: Selection and its Implications
Surya Swarna (firstname.lastname@example.org), Memorial University of NewfoundlandShow Abstract
Kamal Hossain, Carleton University
Harshdutta Pandya, Rowan University
Yusuf Mehta, Rowan University
Anthropogenic climate change is having and will continue to have adverse effects on Canadian weather. Trends in average annual temperatures have been rapidly increasing over the last 50 years. The severe climatic variations in Canada are in line with global changes in climate occurring due to increased greenhouse gas concentrations in the atmosphere. Under the current CO2 emission scenarios, scientists predict the climate trends to further intensify in the near future. It is well known that asphalt binder is highly sensitive to climate factors. Hence, reviewing asphalt binder grade is a vital step, and that can help decelerate pavement deterioration. The objective of this study was to assess the change in asphalt binder grade for the future climate and to determine the influence of change in binder grade on the performance of pavements in Canada. To achieve this, the analysis was carried out in five phases. In the first phase, statistically downscaled climate change models were gathered from the pacific Canada Climate database. Then in the second phase, the temperature and precipitation data were extracted for the selected locations. Later in the third phase, the asphalt binder grade was determined for future climate data. In the fourth phase, the pavement materials, traffic, and structural data were collected from the Long-term Pavement Performance (LTPP) database. Lastly, the pavement performance with the base binder and the upgraded binder were assessed using AASHTOware Mechanistic-Empirical Pavement Design. The results reemphasize the necessity of upgrading the asphalt binder grade in various provinces of Canada.
Determination of Dynamic Modulus Mastercurve of Damaged Asphalt Pavements for Pavement ME Rehabilitation Design
Zhe Zeng, North Carolina State UniversityShow Abstract
Kangjin Lee, North Carolina State University
Youngsoo Kim, North Carolina State University
For pavement rehabilitation design, the current Pavement ME guide provides three levels of analysis methodology to determine dynamic modulus mastercurves for existing asphalt pavements. First, the Pavement ME guide recommends that Witczak’s predictive equation is employed to obtain the ‘undamaged’ modulus mastercurve. Depending on the chosen level of analysis, either falling weight deflectometer testing (Level 1) or a condition survey (Levels 2 and 3) is conducted to determine the damage factor(s). The damage factor is used to shift the undamaged mastercurve downwards to match the field conditions and obtain the so-called ‘damaged’ mastercurve. In this study, two pavement structures in North Carolina Highway 96 were selected to evaluate the accuracy of the Pavement ME guide using its three analysis levels. Because this roadway is a multilayer full-depth pavement, the extracted field cores were divided into a top layer, bottom layer, and total core for investigative and comparative purposes. Accordingly, both laboratory measurements and Pavement ME predictions of the dynamic modulus values were conducted separately. The results show that the predicted undamaged mastercurves are always higher than the measured mastercurves and that Levels 1, 2, and 3 can each lead to significantly different damaged mastercurves. Considering both efficiency and accuracy for transportation agency practice, the Level 1 method is recommended, and if the existing pavement is a multilayered asphalt pavement, then a total core extracted from all the layers is recommended to generate the input properties for Witczak’s predictive equation.
Evaluation of the NCHRP 01-34 Method to Assess Rutting
Sareh Kouchaki, Wood Environment & Infrastructure Solutions, Inc.Show Abstract
Lauren Gardner, Wood Environment & Infrastructure Solutions, Inc.
Amy Simpson, Wood Environment & Infrastructure Solutions, Inc.
Pedro Serigos, Wood Environment & Infrastructure Solutions, Inc.
Gonzalo Rada, Wood Environment & Infrastructure Solutions, Inc.
Rutting is one of the major distresses in pavements with asphalt concrete surfaces. This distress may occur in multiple layers of the pavement structure, i.e., asphalt layer, base, or subgrade. Identifying the layer with the highest contribution to surface rutting would provide pavement engineers with essential information needed for selecting the right rehabilitation activity. Under the National Cooperative Highway Research Program Project 1-34A, a method has been developed to estimate the predominant layer contributing to the rutting observed in the surface from an analysis of the shape of the transverse profile. This paper presents the findings of two studies that investigated the applicability of the NCHRP 01-34 method. First, using the transverse profiles collected by the Maryland Department of Transportation State Highway Administration, it is shown that the NCHRP method results are sensible. The statistical analysis results proved the rational relationship between the results obtained by the NCHRP method with the subgrade resilient modulus and the thickness of the asphalt layer. In addition, this method showed a probability of more than 89% of getting a correct answer on composite pavements where the asphalt thickness is more than 6 inches and the rutting depth is less than 0.31 inch. Next, an investigation was conducted on the changes in the transverse profiles collected as part of the Long-Term Pavement Performance program along distance and time. The collected transverse profiles were investigated using the NCHRP method. The findings of the NCHRP method results assisted in the interpretation of the changes in transverse profiles.
Design of Snow-Melting Pavement with Electric Cable Heating System Aiming at Optimum Mechanical and Long-Term Performance
Xingyi Zhu, Tongji UniversityShow Abstract
Qifan Zhang, Tongji University
Zhao Du (email@example.com), Tongji University
The electric cable heating system (ECH) embedded in the pavement is a promising snow or ice removal technology for traffic safety guarantee. However, existing researches on the mechanical response and long-term performance of the ECH pavement are limited. To find an optimum structure, the effect of various structure parameters on the mechanical response of ECH was investigated using the finite element method in this study. Based on the stress analysis of ECH pavement structure under the temperature–vehicle coupled load, the recommended design parameters including heating power, embedded spacing and depth of cables, insulation layer, environment temperature, and surface layer type were discussed. The ECH pavement testing sections with the aforementioned parameters were constructed. The one-third-scale model mobile load simulator (MMLS3) was adopted to evaluate the rutting resistance of the ECH pavement. The rutting depth distributions of testing sections demonstrated that the cables embedded can enhance the rutting resistance of the ECH system, while the thermal conductive surface layer might weaken the rutting resistance of the ECH pavement to a certain extent. Fortunately, after continuous loading for 400,000 times, the average rutting depths of all testing sections are less than 3mm, which indicates that the long-term performance of ECH pavement can meet the basic road durability requirements.
Numerical Simulations of the Anti-Vibration Pavements with the Damping Layer Under Traffic Pulse Load
Jiandong Huang, China University of Mining and TechnologyShow Abstract
Yuantian Sun, China University of Mining and Technology
Vibrations induced by traffic are of concern for road authorities due to disturbance on the population, and the damage of buildings and structures. Different solutions to mitigate this phenomenon are under investigation. In the field of pavement engineering, the anti-vibration paving technologies are under investigation in order to avoid the generation of excessive vibration and contains propagation. To more fully examine the effectiveness of such a damping layer in the application of anti-vibration pavement, numerical simulations based on a two-dimensional (2D) finite element (FE) model is conducted. The method of determining Rayleigh damping parameters is proposed to more accurately characterize the attenuation of vibration in roads. Sensitivity analysis of varying monitored points and varying loads are performed. Several important parameters such as the damping layer position and thickness, damping ratio are evaluated as well. By the use of this FE simulation to model the vibration response induced by traffic, the costly construction mistakes and field experimentation can be avoided.
Seasonal Variation of the Structural Response of a Thin Instrumented Flexible Pavement under Heavy Vehicle Loading
Denis Saliko, Swedish National Road and Transport Research Institute (VTI)Show Abstract
Sigurdur Erlingsson, University of Iceland
The seasonal variations of the climatic factors such as temperature, moisture, and freeze-thaw cycles are known to influence the material properties and structural behavior of flexible pavement structures. Mechanistic models are required to predict the behavior of the structure throughout the entire year including the winter frost and spring thaw periods. In this study, the mechanical response of an instrumented flexible pavement structure located in the north of Sweden has been investigated at four different times during a year under loading by falling weight deflectometer and three different long heavy vehicles (~64, ~68 and ~74 ton). The mechanical response values recorded by the sensors embedded in the structure have been compared to the numerical model values obtained by 2D multilayer elastic calculations. It is shown that multilayer elastic theory provides a reasonable prediction of the mechanical behavior on the condition that the stiffness of the asphalt concrete is adjusted according to the temperature variations of the layer and the stiffness of the unbound granular layers is adjusted according to moisture content levels.
A Case Study Demonstrating the use of NDT and FEM to Quantify Pavement Response in Canada
Daniel Pickel, PSI Technologies, Inc.Show Abstract
Vimy Henderson, PSI Technologies, Inc.
Roberto Soares, PSI Technologies
Michael Becke, City of Hamilton
Taylor Lefebre, Coco Paving Inc.
Non-destructive testing (NDT) is commonly used to evaluate in-situ pavement conditions, and includes Falling Weight Deflectometer testing, LIDAR scanning, and Ground Penetrating Radar. These tests provide pavement characteristics, including structural capacity, roadway geometry, and layer thicknesses. Finite Element Modelling is a numerical calculation technique that can be used to analyze the distribution of stresses, strains, and displacements throughout a pavement structure. In this paper, a case study using NDT techniques to characterize an existing pavement under three different conditions are modelled using PSIPave3D™, a finite element software. The three conditions include: prior to rehabilitation; immediately following rehabilitation; and following rehabilitation and a dry period. The conditions are analyzed under two loading conditions corresponding to two common truck types in Ontario. The results were compared to quantify the differences experienced by the pavement structure under the different conditions. The rehabilitation treatment completed by Coco Paving on Book Road is commonly used in Ontario, including in the City of Hamilton. The success of this type of treatment has been observed through adequate pavement performance on previous projects however the use of NDT and PSIPave3D™ allows the designer, contractor, and owner to quantify the changes in behaviour of the pavement structure when this treatment is used. The ability to visualize and quantify the reaction of a pavement structure to variations in material characteristics and traffic loading provides an opportunity to select and implement the right type of treatment for a particular scenario if data is derived directly from in-situ conditions.
Mechanistic-Empirical Design of Chemical Stabilized Full-Depth Reclaimed Pavement
Xingdong Wu, Kansas State UniversityShow Abstract
Shuvo Islam, Kansas State University
Mustaque Hossain, Kansas State University
Greg Schieber, Kansas Department of Transportation
Full-depth reclamation (FDR) is an in-place recycling process that uses the entire depth of deteriorated asphalt concrete (AC) pavement to produce a uniform stabilized base course and improve AC overlay performance. This paper introduces a mechanistic-empirical pavement design (MEPDG) methodology to determine the optimum thickness of an AC overlay over a stabilized FDR base course. The stabilized FDR mixtures had recycled asphalt pavement (RAP) blended with Portland Type I/II cement and/or Class C fly ash. The mixtures were evaluated using the standard Proctor, unconfined compressive strength (UCS), vacuum saturation, and linear shrinkage tests. The UCS test results were used as inputs in the MEPDG software to determine optimum AC overlay thickness. The test results indicate that the fly ash content impacts both optimum moisture content and shrinkage. Mixtures with only fly ash showed that higher fly ash content could significantly reduce shrinkage strain. The mixtures with 5% fly ash & 5% cement and 6% fly ash & 4% cement by weight of dry FDR material were found to meet the UCS required by the US Army Corps of Engineers (USACE). The MEPDG software results predicted that for the stabilized FDR mix with a UCS of about 250 psi (as required by USACE) or higher, the optimum AC layer thickness would be 3.5 in. for 10 to 12 in. stabilized FDR layer thickness.
Long-term effects of subsurface drainage on performance of asphalt pavements
Pinyu Ji, Tongji UniversityShow Abstract
Hongren Gong, Tongji University
Xiaoyang Jia, Tennessee Department of Transportation
Baoshan Huang (firstname.lastname@example.org), University of Tennessee, Knoxville
This study investigated the effects of subsurface drainage on the long-term performance of pavements. The SPS-1 experiment of the Long-Term Pavement Performance (LTPP) program was selected to extract performance data. Four types of cracking, rut depth, and IRI were used as the performance indicators. Other relevant factors affecting the pavement performance were also considered: surface thickness, base type, base thickness, subgrade soil classification, total thickness, age, and climatic conditions. The significant factors to long-term performance were identified using two methods: exploratory data analyses and mixed-effects models. Results from the analyses showed that drainage only substantially affected the transverse cracking and rutting but had little effect on the other performance indicators. Sections in the dry and non-freeze region had the best riding quality and exhibited the least alligator cracking, NWPLC, TC, but this climatic condition worsened the WPLC. The use of drainage in sections from the wet-freeze region significantly retarded the development of distress. For drained sections, the base comprising an asphalt-treated base over a permeable asphalt-treated base better sustained the smoothness and resisted rutting. For undrained sections, the asphalt-treated base was a superior alternative. Sections on sites with fine subgrade showed less WPLC, NWPLC, and TC, while those on coarse subgrade sites showed less alligator cracking and better riding quality. Sections on sites with fine subgrade showed less WPLC, NWPLC, and TC, while those on coarse subgrade sites showed less alligator cracking and better riding quality.
DISCLAIMER: All information shared in the TRB Annual Meeting Online Program is subject to change without notice. Changes, if necessary, will be updated in the Online Program and this page is the final authority on schedule information.