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Mechanistic-Empirical Modelling of Flexible Pavement Performance: Verifications Using APT Measurements
Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. KTH.
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Mechanistic-Empirical  (M-E)  pavement  design  procedures  are  composed  of  a  reliable  response model to estimate the state of stress in the pavement and distress models in order to predict the different types of pavement distresses due to the prevailing traffic and environmental conditions. One of the main objectives of this study was to develop a response model based on multilayer elastic  theory   (MLET)  with  improved  computational  performance  by   optimizing  the   time consuming parts of the MLET processes. A comprehensive comparison of the developed program with  two  widely  used  programs  demonstrated  excellent  agreement  and  improved  computational performance.  Moreover,  the  program  was  extended  to  incorporate  the  viscoelastic  behaviour  of bituminous materials through elastic-viscoelastic correspondence principle. A procedure based on collocation of linear viscoelastic (LVE) solutions at selected key time durations was also proposed that improved the computational performance for LVE analysis of stationary and moving loads. A comparison  of  the  LVE  responses  with  measurements  from  accelerated  pavement  testing  (APT) revealed a good agreement. Furthermore the developed response model was employed to evaluate permanent deformation models  for  bound  and  unbound  granular  materials  (UGMs)  using  full  scale  APTs.  The  M-E Pavement  Design  Guide  (MEPDG)  model  for  UGMs  and  two  relatively  new  models  were evaluated  to  model  the  permanent  deformation  in  UGMs.  Moreover,  for  bound  materials,  the simplified  form  of  the  MEPDG  model  for  bituminous  bound  layers  was  also  evaluated.  The measured  and  predicted  permanent  deformations  were  in  general  in  good  agreement,  with  only small discrepancies between the models. Finally, as heavy traffic loading is one of the main factors affecting the performance of flexible pavement, three types of characterizations for heavy traffic axle load spectrum for M-E analysis and design of pavement structures were evaluated. The study recommended an improved approach that enhanced the accuracy and computational performance.

Place, publisher, year, edition, pages
Stockholm: US-AB , 2014.
Series
TRITA-TSC-PHD, 14:003
Keyword [en]
Performance, Deformation, Model (not math), Rutting (wheel), Viscoelasticity, Elasticity, Axle load, Flexible pavement, Laboratory (not an organization), Test, Thesis, Heavy vehicle simulator, Wheel tracking test
National Category
Infrastructure Engineering
Research subject
Road: Highway design, Road: Pavement design
Identifiers
URN: urn:nbn:se:vti:diva-6950ISBN: 978-91-87353-39-0 (print)OAI: oai:DiVA.org:vti-6950DiVA: diva2:734494
Public defence
2014-05-23, Q2, Osquldas väg 10, Stockholm, 13:30 (English)
Opponent
Supervisors
Available from: 2014-08-22 Created: 2014-07-17 Last updated: 2014-08-22Bibliographically approved
List of papers
1. Evaluation of permanent deformation models for unbound granular materials using accelerated pavement tests
Open this publication in new window or tab >>Evaluation of permanent deformation models for unbound granular materials using accelerated pavement tests
2013 (English)In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, Vol. 14, no 1, 178-195 p.Article in journal (Refereed) Published
Abstract [en]

Mechanistic-empirical (M-E) pavement design methods have become the focus of modern pavement design procedure. One of the main distresses that M-E design methods attempt to control is permanent deformation (rutting). The objective of this paper is to evaluate three M-E permanent deformation models for unbound granular materials, one from the US M-E pavement design guide and two other relatively new models. Two series of heavy vehicle simulator (HVS) tests with three different types of base material were used for this purpose. The permanent deformation, wheel loading, pavement temperature, and other material properties were continuously controlled during the HVS tests. Asphalt concrete layers were considered as linear elastic where stress-dependent behaviour of unbound materials was considered when computing responses for the M-E permanent deformation models with a nonlinear elastic response model. Traffic wandering was also accounted for in modelling the traffic by assuming it was normally distributed and a time-hardening approach was applied to add together the permanent deformation contributions from different stress levels. The measured and predicted permanent deformations are in general in good agreement with only small discrepancies between the models. Model parameters were also estimated for three different types of material.

Place, publisher, year, edition, pages
Taylor & Francis Group, 2013
Keyword
Rutting (wheel), Unbound base, Granular, Stress (in material)
National Category
Infrastructure Engineering
Research subject
Road: Highway design, Road: Pavement design; Road: Materials, Road: Aggregate and stone materials
Identifiers
urn:nbn:se:vti:diva-6941 (URN)10.1080/14680629.2012.755936 (DOI)
Available from: 2014-07-17 Created: 2014-07-17 Last updated: 2014-08-25Bibliographically approved
2. Modeling of flexible pavement structure behavior: Comparisons with Heavy Vehicle Simulator measurements
Open this publication in new window or tab >>Modeling of flexible pavement structure behavior: Comparisons with Heavy Vehicle Simulator measurements
2012 (English)In: Advances in Pavement Design Through Full-Scale Accelerated Pavement Testing / [ed] Jones, Harvey, Mateos & Al-Qadi, London: Taylor & Francis Group, 2012, 493-503 p.Conference paper, Published paper (Refereed)
Abstract [en]

 A response model to be employed in a mechanistic-empirical pavement performance predictionmodel based on multilayer elastic theory has been developed. An iterative approach using a method of successiveover-relaxation of a stress dependency model is used to account for the nonlinear behavior of unbound materials. Asphalt and subgrade materials are assumed to be linear elastic. The response model was verified against two series of Heavy Vehicle Simulator (HVS) response measurements made under a variety of wheel loadconfigurations and at different pavement temperatures. A comparison with Falling Weight Deflectometer (FWD)data was also carried out. The model was subsequently used to predict permanent deformation from the HVS testing using simple work hardening models. A time hardening approach has been adopted to combine permanentdeformation contributions from stress levels of different magnitude.The response model outputs and the predictedpermanent deformations were generally in good agreement with the measurements.

Place, publisher, year, edition, pages
London: Taylor & Francis Group, 2012
Keyword
Pavement, Simulation, Deflectograph, Model
National Category
Civil Engineering
Research subject
Road: Highway design, Road: Pavement design
Identifiers
urn:nbn:se:vti:diva-6942 (URN)10.1201/b13000-61 (DOI)ISBN 978-0-415-62138-0 (ISBN)
Conference
The 4th International Conference on Accelerated Pavement Testing
Available from: 2014-07-17 Created: 2014-07-17 Last updated: 2014-08-22Bibliographically approved
3. Fast layered elastic response program for the analysis of flexible pavement structures
Open this publication in new window or tab >>Fast layered elastic response program for the analysis of flexible pavement structures
2013 (English)In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, Vol. 14, no 1, 196-210 p.Article in journal (Refereed) Published
Abstract [en]

One of the key components in analysing pavement structural behaviour is the response model which is used to estimate the stresses, strains and displacements of the pavement structure subjected to the existing traffic, taking into account the material properties and prevailing environmental conditions. Multilayer elastic theory (MLET) is often preferred over other methods such as the finite element method, due to its computational performance for repeated applications. A new elastic response analysis program has been developed based on the Burmister MLET theory to calculate the response of flexible pavement structures. In the development of the program, the time-consuming part of MLET processes was optimised. To improve the convergence and accuracy of responses in the vicinity of the surface of the top layer, an approach based on Richardson's extrapolation was employed. Moreover, an iterative approach to model stress dependency of unbound granular materials was incorporated. A comprehensive comparison of the program with two frequently used programs demonstrated an excellent agreement and improved performance.

Place, publisher, year, edition, pages
Taylor & Francis Group, 2013
Keyword
Elasticity, Flexible pavement, Model (not math)
National Category
Civil Engineering
Research subject
Road: Highway design, Road: Surfacing
Identifiers
urn:nbn:se:vti:diva-6944 (URN)10.1080/14680629.2012.757558 (DOI)
Available from: 2014-07-17 Created: 2014-07-17 Last updated: 2014-08-25Bibliographically approved
4. Characterization of heavy traffic axle load spectra for mechanistic-empirical pavement design applications
Open this publication in new window or tab >>Characterization of heavy traffic axle load spectra for mechanistic-empirical pavement design applications
2015 (English)In: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268X, Vol. 16, no 6, 488-501 p.Article in journal (Refereed) Published
Abstract [en]

 Heavy traffic axle load spectrum (ALS) is  one of the key inputs for mechanistic-empirical analysis and design of pavement structures. Frequently, the entire ALS is aggregated into Equivalent Number of Single Axle Loads (ESAL) or assumed to have Constant Contact  Area  (CCA)  or  Constant  Contact  Pressure  (CCP).  These characterizations affect the accuracy and computational performance of the pavement analysis. The objective of this study was to evaluate these  characterizations  based  on  predicted  performances  to  rutting and fatigue cracking of several pavement structures subjected to ALS data collected from 12 Bridge-Weigh-In-Motion stations. The results indicated  that  for  layers  below  the  top  25  cm,  all  characterizations produced similar values of predicted rutting. However, for the top 25 cm, the methods differed in the predicted performances to rutting and fatigue cracking. Furthermore an improvement to the CCA approach was proposed that enhanced the accuracy while maintaining the same level of computational performance.

Place, publisher, year, edition, pages
Taylor & Francis Group, 2015
Keyword
Axle load, Heavy vehicle, Pavement design, Rutting, Cracking, Prediction, Accuracy
National Category
Infrastructure Engineering
Research subject
30 Road: Highway design, 32 Road: Pavement design
Identifiers
urn:nbn:se:vti:diva-6945 (URN)10.1080/10298436.2014.943131 (DOI)000354458200003 ()2-s2.0-84929283717 (Scopus ID)
Available from: 2014-07-17 Created: 2014-07-17 Last updated: 2016-07-06Bibliographically approved
5. Viscoelastic modelling of pavement structure behaviour in a full scale accelerated pavement test
Open this publication in new window or tab >>Viscoelastic modelling of pavement structure behaviour in a full scale accelerated pavement test
(English)Manuscript (preprint) (Other academic)
Keyword
Viscoelasticity, Full scale, Flexible pavement, Test, Performance, Deformation, Model (not math), Rutting (wheel)
National Category
Civil Engineering
Research subject
30 Road: Highway design, 32 Road: Pavement design
Identifiers
urn:nbn:se:vti:diva-6947 (URN)
Available from: 2014-07-17 Created: 2014-07-17 Last updated: 2016-01-11Bibliographically approved
6. Evaluation of permanent deformation model for asphalt concrete mixtures by means of extra-large wheel tracking and full scale accelerated pavement tests
Open this publication in new window or tab >>Evaluation of permanent deformation model for asphalt concrete mixtures by means of extra-large wheel tracking and full scale accelerated pavement tests
(English)Manuscript (preprint) (Other academic)
Keyword
Rutting, Deformation, Bituminous mixture, Flexible pavement, Mathematical model, Full scale, Test
National Category
Civil Engineering
Research subject
30 Road: Highway design, 32 Road: Pavement design
Identifiers
urn:nbn:se:vti:diva-6949 (URN)
Available from: 2014-07-17 Created: 2014-07-17 Last updated: 2016-01-25Bibliographically approved

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