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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.ORCID iD: 0000-0002-6327-4709
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
Keywords [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
30 Road: Highway design, 32 Road: Pavement design
Identifiers
URN: urn:nbn:se:vti:diva-6950ISBN: 978-91-87353-39-0 (print)OAI: oai:DiVA.org:vti-6950DiVA, id: 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: 2022-12-09Bibliographically 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, E-ISSN 2164-7402, Vol. 14, no 1, p. 178-195Article 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
Keywords
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: 2022-10-21Bibliographically 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, p. 493-503Conference 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
Keywords
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: 2022-10-21Bibliographically 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, E-ISSN 2164-7402, Vol. 14, no 1, p. 196-210Article 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
Keywords
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: 2022-10-21Bibliographically 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, p. 488-501Article 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
Keywords
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: 2022-10-21Bibliographically approved
5. Evaluation of a permanent deformation model for asphalt concrete mixtures using extra-large wheel-tracking and heavy vehicle simulator tests
Open this publication in new window or tab >>Evaluation of a permanent deformation model for asphalt concrete mixtures using extra-large wheel-tracking and heavy vehicle simulator tests
2015 (English)In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 16, no 1, p. 154-171Article in journal (Refereed) Published
Abstract [en]

This paper evaluates a mechanistic–empirical permanent strain model for asphalt concrete mixtures. The evaluation was carried out based on two different types of tests: an extra-large wheel-tracking (ELWT) test and a full-scale accelerated pavement test using a heavy vehicle simulator (HVS). Asphalt slabs from three different types of asphalt mixtures were prepared for the ELWT test and tested at several pavement temperatures and tyre inflation pressures. Lateral wandering was also incorporated.

The measured permanent deformations in the asphalt slabs were thereafter modelled using the permanent strain model from the US Mechanistic-Empirical Pavement Design Guide and model parameters were estimated for the three types of mixes. For validation, data from an HVS tested pavement structure consisting of the same asphalt mixtures as those tested using the ELWT were used. A set of calibration factors for the three mixtures were therefore obtained between the two tests. In all cases, the calibration factors were within ±20% from unity. Differences in geometry, scale, wheel loading configuration as well as the speed of loading between the two test devices could be the possible reasons for the differences in observed calibration factors.

Keywords
Flexible pavement, Bituminous mixture, Mathematical model, Strain, Simulation, Loading
National Category
Infrastructure Engineering
Research subject
30 Road: Highway design, 32 Road: Pavement design
Identifiers
urn:nbn:se:vti:diva-9307 (URN)10.1080/14680629.2014.987311 (DOI)000349451300010 ()2-s2.0-84922800575 (Scopus ID)
Available from: 2016-03-03 Created: 2016-03-02 Last updated: 2022-12-09Bibliographically approved
6. Numerical validation of viscoelastic responses of a pavement structure in a full-scale accelerated pavement test
Open this publication in new window or tab >>Numerical validation of viscoelastic responses of a pavement structure in a full-scale accelerated pavement test
2015 (English)In: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268XArticle in journal (Refereed) Published
Abstract [en]

This paper demonstrates the application of a generalised layered linear viscoelastic (LVE) analysis for estimating the structural response of flexible pavements. A comparison of the direct layered viscoelastic responses with approximate solutions based on the linear elastic (LE) and LVE collocation methods was also carried out. The different approaches were implemented by extending a layered elastic program with an improved computational performance. The LE and LVE collocation methods were further extended for analysis of pavements under moving loads.

The methods were illustrated by analysing a pavement structure subjected to moving wheel loads of 30, 50, 60 and 80 kN using a Heavy Vehicle Simulator (HVS). The various responses (stresses and strains) in the pavement, at pavement temperatures of 0, 10 and 20°C, were measured using various types of sensors installed in the structure. It was shown that the approximated LVE solution based on the LE collocation method agreed very well with the measurements and is computationally the least expensive.

Keywords
Flexible pavement, Viscoelasticity, Unbound base, Loading, Mathematical model, Calculation
National Category
Infrastructure Engineering
Research subject
30 Road: Highway design, 32 Road: Pavement design
Identifiers
urn:nbn:se:vti:diva-9278 (URN)10.1080/10298436.2015.1039003 (DOI)2-s2.0-84929238620 (Scopus ID)
Available from: 2016-03-07 Created: 2016-03-02 Last updated: 2022-12-09Bibliographically approved

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  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
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Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
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  • asciidoc
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