Publications
Change search
Refine search result
1234 1 - 50 of 198
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Adesiyun, Adewole
    et al.
    Bezuglyi, Artem
    Bidnenko, Natalya
    Laszlo, Gaspar
    Golovko, Sergyi
    Kraszewski, Cezary
    Krayushkina, Kateryna
    Kushnir, Olexander
    Kuttah, Dina K
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Niska, Anna
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Sörensen, Gunilla
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic safety, society and road-user.
    Szpikowski, Miroslaw
    Andrezj, Urbanik
    Voloshyna, Iryna
    Vozniuk, Andrii
    Vyrozhemsky, Valeriy
    Short-term Research Visits2014Report (Other (popular science, discussion, etc.))
  • 2.
    Ahmed, Abubeker
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Carlsson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Measurement technology and engineering workshop.
    Lundberg, Thomas
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Utvärdering av gummiasfalt: provväg E22 Mönsterås : etapp 12019Report (Other academic)
    Abstract [en]

    Laboratory and filed investigations have been carried out to evaluate the performance of rubber modified asphalt test road on E22 Mönsterås.

    The laboratory investigations indicated that there are no significant differences in stiffness and shear modulus between the reference and rubber modified mixtures. The rubber modified mixture however showed slightly lower phase angle compared to the reference mixture which indicate that the rubber modified mixture is more elastic. The rubber modified mixtures also showed lower modulus at lower temperatures and slightly higher modulus at higher temperature which are desired properties for resistance against low temperature cracking and permanent deformation respectively. The fatigue tests indicated that the rubber modified asphalt mixture has slightly better fatigue cracking performance. But the difference is not significant.

    The road surface profile measurements indicated no significant differences between the reference and asphalt rubber sections. It is however early to draw conclusions after one year of traffic therefore additional follow-up of the test sections is needed to draw a conclusion.

  • 3.
    Ahmed, Abubeker
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Hellman, Fredrik
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Full scale accelerated pavement tests to evaluate the performance of permeable and skeletal soil block pavement systems2016In: The Roles of Accelerated Pavement Testing in Pavement Sustainability: Engineering, Environment, and Economics, Springer International Publishing , 2016, p. 131-144Chapter in book (Other academic)
    Abstract [en]

    The increasing proportion of paved surface due to urbanization means that the conditions for urban trees and vegetation to survive have deteriorated. Factors such as air pollution, poor drainage, and the lack of usable soil for root growth contribute to the short life expectancy of urban trees. To meet this challenge, several permeable and "structural" or "skeletal soils" have been developed as alternatives to the typical compacted soil required to bear the weight of vehicular traffic in urban areas. The main objective of this study is to evaluate the resistance to permanent deformation of permeable and skeletal soil pavement structures based on full scale accelerated pavement tests (APT) using a heavy vehicle simulator (HVS). Interlocking paving stones of various types were used as permeable surface layer for the test structures. The results demonstrated that the permeable test structures exhibited higher permanent deformation than the corresponding impervious structures. The skeletal soil with bituminous base layer, however, produced performance comparable to the impervious reference test structures.

  • 4.
    Ahmed, Abubeker W.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. KTH.
    Mechanistic-Empirical Modelling of Flexible Pavement Performance: Verifications Using APT Measurements2014Doctoral 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.

    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: 2017-12-05Bibliographically 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: 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, 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: 2017-12-05Bibliographically 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: 2017-12-05Bibliographically 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)
    Keywords
    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)
    Keywords
    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
  • 5.
    Ahmed, Abubeker W.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Biligiri, Krishna Prapoorna
    Department of Civil Engineering Indian Institute of Technology Kharagpur .
    Hakim, Hassan
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    An Algorithm to Estimate Rational Values of Phase Angles and Moduli of Asphalt Mixtures2013In: International Journal of Pavement Research and Technology (IJPRT), ISSN ISSN 1997-1400, Vol. 6, no 6, p. 745-754Article in journal (Refereed)
    Abstract [en]

    The objective of this study was to develop and evaluate an algorithm based on Fast Fourier Transform (FFT) that can calculate rational values of phase angle (f) and moduli of the variants of asphalt mixtures for the data obtained from the different frequency sweep tests. f and moduli for ten different asphalt mixtures resulting in over 690 data points collected from both USA and Sweden were computed using FFT. Theoretical observations revealed that there were significant differences for f between FFT and other methods to the order of 10-50%; however, there was no difference in moduli estimates for any mix and was independent of the test. Precisely, the FFT method produced rational f for mixtures that deviate from conventional mixture properties. Furthermore, statistical comparisons corroborated the predicted f estimates indicative of significant differences between the analysis techniques; but, the moduli were unaffected by the analysis methods. The study successfully illustrated the FFT technique, a user-friendly analytical procedure that can obviate the errors in the rational estimation of the acutely sensitive viscoelastic parameters.

  • 6.
    Ahmed, Abubeker W.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Characterization of heavy traffic axle load spectra for mechanistic-empirical pavement design applications2015In: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268X, Vol. 16, no 6, p. 488-501Article in journal (Refereed)
    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.

  • 7.
    Ahmed, Abubeker W.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Evaluation of a permanent deformation model for asphalt concrete mixtures using extra-large wheel-tracking and heavy vehicle simulator tests2015In: 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)
    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.

  • 8.
    Ahmed, Abubeker W.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Evaluation of permanent deformation model for asphalt concrete mixtures by means of extra-large wheel tracking and full scale accelerated pavement testsManuscript (preprint) (Other academic)
  • 9.
    Ahmed, Abubeker W.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Evaluation of permanent deformation models for unbound granular materials using accelerated pavement tests2013In: 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)
    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.

  • 10.
    Ahmed, Abubeker W
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Mechanistic modelling of HVS flexible pavement structure2012In: EPAM 2012: Malmö, Sweden, 5–7 September: 4th European pavement and asset management conference, Linköping: Statens väg- och transportforskningsinstitut, 2012, , p. 13Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    A response model to be employed in a mechanistic-empirical pavement performance prediction model based on multilayer elastic theory has been developed. An iterative approach using a method of successive over-relaxation of stress dependency model is used to account for the nonlinear behaviour of unbound materials. Asphalt and subgrade materials are assumed as linear elastic. The response model is verified using heavy vehicle simulator (HVS) response measurements made under variety of wheel load configurations and at different pavement temperatures. The permanent deformation behaviours of the HVS structure is also modelled using mechanistic empirical approach and by employing permanent deformation prediction models. A time hardening approach has been applied to combine permanent deformation contributions from stress levels of different magnitude. The response model outputs and the predicted permanent deformations are in general in good agreement with the measurements.

  • 11.
    Ahmed, Abubeker W.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Modeling of flexible pavement structure behavior: Comparisons with Heavy Vehicle Simulator measurements2012In: 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 (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.

  • 12.
    Ahmed, Abubeker W.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Numerical validation of viscoelastic responses of a pavement structure in a full-scale accelerated pavement test2015In: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268XArticle in journal (Refereed)
    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.

  • 13.
    Ahmed, Abubeker W.
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. Kungliga Tekniska Högskolan.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. Kungliga Tekniska Högskolan.
    Viscoelastic modelling of pavement structure behaviour in a full scale accelerated pavement testManuscript (preprint) (Other academic)
  • 14.
    Ahmed, Abubeker W
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Viscoelastic Response Modelling of a Pavement under Moving Load2016In: Transportation Research Procedia, 2016, Vol. 14, p. 748-757Conference paper (Refereed)
    Abstract [en]

    This paper demonstrates the application of a generalized layered linear viscoelastic (LVE) analysis for estimating flexible pavements' structural response. The procedure is based on the Multi-Layered Elastic Theory (MLET) and the elastic-viscoelastic correspondence principle using a numerical inverse Laplace transform. A comparison of the direct layered viscoelastic responses with approximate solutions based on the elastic collocation method was also carried out. Furthermore, it is proposed to use the collocation method using LVE solutions at selected time durations in order to improve the accuracy of the elastic collocation method. The LVE collocation method was further extended for analysis of moving loads. The method was 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 different pavement temperatures, were measured using various types of sensors installed in the structure. The LVE calculations agreed very well with the measurements.

  • 15.
    Ahmed, Abubeker W
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Rahman, Mohammad Shafiqur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Impact of longer and heavier vehicles on the performance of asphalt pavements: A laboratory study2018In: Bearing Capacity of Roads, Railways and Airfields - Proceedings of the 10th International Conference on the Bearing Capacity of Roads, Railways and Airfields, BCRRA 2017, CRC Press/Balkema , 2018, p. 483-490Conference paper (Refereed)
    Abstract [en]

    Historically, Longer and Heavier Vehicles (LHVs) have been permitted to operate in Sweden. Since 1996 and as of the beginning of 2015, the maximum gross vehicle weight of 60 tons and a length of up to 25.25 m have been permitted. The Swedish Transport Administration has decided to further increase the maximum gross vehicle weight to 74 tons and studies are undergoing to evaluate the impact of the proposed LHVs on existing transport infrastructure. To this end, repeated load triaxial tests and indirect tensile fatigue tests were conducted on selected conventional asphalt mixtures to investigate and quantify the impact of single, tandem and tridem axle configurations on permanent deformation and fatigue performances of conventional asphalt pavements. In addition, fatigue tests for selected LHV scenarios were conducted. This paper presents the results of the laboratory tests and simulations conducted. The test results have clearly demonstrated the impact of the different axle configurations on the rutting and fatigue performances of the mixture. Furthermore, such results can explain the significance of axle configuration on modelling the rutting and fatigue performances of asphalt pavements.

  • 16.
    Ahmed, Abubeker W
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Rahman, Mohammad Shafiqur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Impact of tire types and configurations on responses of a thin pavement structure2018In: Advances in Materials and Pavement Performance Prediction: Proceedings of the International AM3P Conference, 2018, London: CRC Press , 2018, p. 271-274Conference paper (Refereed)
    Abstract [en]

    The objective of this study was to assess the impact of tire and tire configurations on the responses of a thin asphalt pavement structure by means of full-scale tests using a Heavy Vehicle Simulator (HVS). A total of six different types of tires, four single and two dual tire configurations, were investigated. The structure was instrumented to measure tensile strains at the bottom of the asphalt layer and vertical stresses and strains in the unbound base, subbase and subgrade layers. The results indicated that, in general, single tire configurations produced higher tensile strain at the bottom of the asphalt layer and higher vertical stresses and strains in unbound base, subbase and subgrade layers.

  • 17.
    Ahmed, Abubeker W
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Said, Safwat F.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Lu, Xiaohu
    Nynäs AB.
    Carlsson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Measurement technology and engineering workshop.
    Pavement performance follow-up and evaluation of polymer-modified test sections2018In: The international journal of pavement engineering, ISSN 1029-8436, E-ISSN 1477-268X, p. 1-14Article in journal (Refereed)
    Abstract [en]

    Between 2003 and 2006, a test road consisting of several conventional and polymer-modified structures was built on a motorway. Different combinations of styrene–butadiene–styrene (SBS) and ethyl vinyl acetate (EVA) polymer-modified binders were used. The test structures have been in service since then and have been monitored for over 9 years. The resistance of the different types of asphalt concrete mixes to rutting and cracking was measured and predicted. The impact of ageing on the mixes was also evaluated. Although all the sections are in good condition after 9 years of traffic, the predicted differences between the test sections based on the PEDRO (Permanent Deformation of asphalt concrete layers for Roads) approach and laboratory evaluations are noticeable. Lateral wander and transverse profile measurements indicated that studded winter tyre wear contributed to most of the rutting compared to permanent deformation due to heavy traffic. The unmodified mixes exhibited considerable ageing and the SBS-modified mixes were least affected by ageing. Furthermore, the SBS-modified base mix produced significantly better fatigue resistance than the conventional base mix. However, further investigations of the relationships between bitumen and mix properties and further follow-ups of the test sections are recommended to validate the findings.

  • 18.
    Alfredsson, Magnus
    et al.
    NCC.
    Karlsson, Robert
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Sjögren, Leif
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Hintze, Staffan
    NCC.
    Johansson, Bo
    NCC.
    Lundström, Robert
    NCC.
    Winnerholt, Tomas
    Trafikverket.
    Funktionskriterier för vägkonstruktioner: Förstudie2010Report (Other academic)
    Abstract [sv]

    Det projekt som här rapporteras har som syfte att identifiera och beskriva de svårigheter och möjligheter som totalentreprenader medför, respektive erbjuder, för alla parter. Målet är att utveckla totalentreprenader på ett sådant sätt att branschens effektivitet ökas. Denna rapport är en förstudie där det studerats vilka krav som byggherren ska ställa på utföraren av en vägkonstruktion i en totalentreprenad med funktionsansvar och hur utföraren ska verifiera kraven. Arbetet har genomförts med medlemmar från olika aktörer i branschen och omfattat främst litteraturstudier och intervjuer. Kunskaper och erfarenheter har sammanställts och analyserats för att slutligen kondenseras ned till ett antal förslag till fortsatt arbete.

    Förstudien har pekat ut ett antal områden som viktiga för att påskynda framtida utveckling av totalentreprenader:

    Terminologi – idag råder viss begreppsförvirring

    Analys av funktionella krav i tidigare projekt

    Trafikantkrav

    Miljökrav

    Utveckling av funktionella krav i samverkan

    Väghållarekonomi

    Regelbetingade begränsningar av funktionella krav

    Uppföljning och underlättande av erfarenhetsackumulering

    Implementering av nya mått och mätmetoder

  • 19.
    Andersson, Anders
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Driving Simulation and Visualization.
    Lidström, Mats
    Peters, Björn
    Swedish National Road and Transport Research Institute, Traffic and road users, Driver and vehicle.
    Rosberg, Tomas
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Thorslund, Birgitta
    Swedish National Road and Transport Research Institute, Traffic and road users, Driver and vehicle.
    Framtagning av loktågsmodell för VTI:s tågsimulator2017Report (Other academic)
    Abstract [en]

    Allowing higher speeds for freight trains would provide opportunities for a higher prioritization in the traffic flow by rail traffic management, which in itself is a capacity gain and should generate better flows and higher capacity on the Swedish rail network, especially on the major railways. Simulators are an effective and safe way to investigate the effects of changes in both driver behavior and capacity.

    The purpose of this project was to create capacity-enhancing opportunities and actions by developing a freight train simulator and investigating its possible application areas. The aim of the project was to provide a freight train simulator, consisting of a locomotive and a number of wagons, which can be used in studies to increase capacity through, for example, optimized speed, and thus changing braking profiles, for long trains. The project has delivered knowledge of new test methods, a freight train simulator and a software platform for further testing.

    The project was conducted in three successive stages. In the first phase, a pilot study was carried out with drivers, operators and problem owners, who gave the researchers an understanding of the driving environment. In addition, some of the data needed for the development of the freight train simulator was collected. In the second phase, a freight train (software and hardware) model was developed. Stage three was a validation study together with drivers.

    A Traxx model driver console was purchased from a German manufacturer. The vehicle model was developed from a single unit, Regina type (motorcar train), into a combination of several units. The train in the simulator consists of one or more locomotives and a number of wagons with a total length of up to 750 meters. A locomotive of Traxx model is used. For each device, locomotive and wagon, data is required: length, weight, load, brake, roll and air resistance. In addition, information about noise, driving, braking (re-electrical braking and conventional pneumatic brake) (P-brake), cab equipment and more are added. Currently, the track between Falköping - Jönköping - Forserum is modelled and will be used for ATC trains. The model is configurable using combinations of a locomotive (Traxx) and, currently, four different types of wagons. These can be linked in different combinations.

    Some applications that were discussed at the start of the project were, on the one side, those that could naturally be linked to longer and heavier trains, and, on the other, the ideas that arose because of the equipment purchased. At the Transport Administration winter meeting, a workshop was conducted where further uses were discussed. Among these are applications within education, energy efficient driving or design. Education and certain types of studies could be performed with the existing locomotive model, while others require either validation of parameters or some further development of the model.

    The project has provided knowledge of new test methods, this research report and a product in the form of a freight train simulator and software platform for further testing. The project has also delivered a national resource of simulator software. The software provides for cost-effective testing activities in the freight train domain. A freight train simulator has been developed, which will be valuable as a demonstration tool as well as a platform for training,

  • 20.
    Arvidsson, Anna K
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Blomqvist, Göran
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Hellman, Fredrik
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Jägerbrand, Annika
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Öberg, Gudrun
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Klimatanpassning av vägkonstruktion, drift och underhåll2012Report (Other academic)
    Abstract [en]

    The global climate change is a reality and affecting society and transport systems. Climate change adaptation of transport systems will make the means of transportation more resilient and decrease the risk and magnitude of disruptions. Generally, climate change adaptations in road construction, operation and maintenance will need relatively large changes, but there is a shortage of the specific knowledge required as to what steps need to be taken, when and where, before measures can actually be implemented. Since climate change effects vary among Sweden's climatic zones, the impact of climate change on the road behavior and longevity is extremely difficult to predict. The need for winter maintenance in Sweden will generally decrease due to the warmer climate. Ploughing frequency will probably decrease as well, but preparedness should not be reduced too much since occasions with more extreme instances will increase. In order to succeed in making the road transport system resilient to climate change, we conclude that there is a need to develop more knowledge about the impact on the road infrastructure system as well as the operation and maintenance of the system including how to adapt through different types of variable and flexible climate adaptation measures and the effects of extreme weather events.

  • 21.
    Arvidsson, Anna K
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Lundberg, Thomas
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Kalman, Björn
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Ekström, Camilla
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic Safety and Traffic System.
    Cruz del Aguila, Fernando
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Eriksson, Olle
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Friktions- och texturutveckling på nya beläggningar2019Report (Other academic)
    Abstract [en]

    A new pavement should be and be perceived as safe by road users, regardless of the road condition. It is therefore important that the road has a satisfactory level of friction already when the road is opened. There is limited documented knowledge of how the road change in the beginning after a paving performance.

    The purpose of this project is to determine how friction changes during the first period after road pavement is laid and traffic is permitted. The ambition is to determine if new road sections have reduced friction and provide recommendations for when a friction measurement is to be performed, and how warning signs should be displayed in connection with the pavement work. The study plan has been to follow different objects with frequent friction and texture measurements from just before the stretch is opened for traffic until the levels have stabilised.

    Initially, friction is high, and then decreases with the amount of traffic. After 1-3 weeks the lowest value was reached and then the friction increased or stabilized. Common to all investigated stretches, there are major changes in texture levels from the first vehicle and then a decreasing textural level until a stable level is reached after 1-3 weeks.

  • 22.
    Arvidsson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    HVS-test för skattning av nedbrytningseffekter från den tunga trafikens belastning: SE14, SE18 och SE202014Report (Other academic)
    Abstract [en]

    This publication describes the aim and outcome of the constructions made to estimate deterioration/degradation of roads from the load of heavy traffic. The purpose was to study three constructions with three different wheel-loads (40 kN, 50 kN and 60 kN which corresponds to axle-loads of 8 tons, 10 tons and 12 tons). To minimize the test matrix the idea was to copy older test constructions tested with the wheel-load 60 kilonewton (kN). The outcome was not to full content, especially did the thinner, older constructions differ in the bearing capacity (static plate loading). For the most modern construction (SE14), with totally of 625 millimetre of super structure including 111 millimetre of asphalt layers, that was compared with SE10 and SE11 the differences was acceptable. The wheel load was 40 kN in 600 000 passes and 50 kN for another 600 000 passes, in total 1.2 million passes. Total rut depth became approximately 6 millimetre. The ”medium” construction (SE18) had a super structure of 349 millimetre including 100 millimetre of asphalt layers and it was compared with SE06. The wheel load was 40 kN in 500 000 passes, 50 kN for 400 000 passes and 60 kN in 300 000 passes, in total 1.2 million passes. Total rut depth became just over 11 millimetre. The thinnest construction (SE20) had a super structure of 310 millimetre including 70 millimetre of asphalt layer and it was compared with SE02. The wheel load was 40 kN in 390 000 passes, 50 kN for 170 000 passes and 60 kN in 190 000 passes, in total 0.75 million passes. Total rut depth became almost 21 millimetre.

  • 23.
    Arvidsson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Jämförande provning – ballast 2015: flisighetsindex, korndensitet och kulkvarn2017Report (Other academic)
    Abstract [en]

    This report shows results, some statistical analysis and precision data for profiency testing (round-robin) performed on three materials of aggregate during 2015. The properties that was determined was Flakiness Index (EN 933-3), particle density (EN 1097-6) and Nordic ball mill (EN 1097-9). The number of participating laboratories were for Flakiness index 58 pcs., for particle density 60 pcs. and for Nordic ball mill 52 pcs.

    There are some scatter of the results which is not surprising. A few of the laboratories show clearly high or low results (for all three materials) for one of the analysis. Generally is the scatter in results varying. E.g. some of the laboratories have a clearly high result for one of the materials, a slightly low result for the second material and are quite close to the average for the third material.

    The standard deviations increase with increase in level of results (average), but not as much. The ratio of standard deviation and average decrease with increase of level.

    The precision data from this round-robin over all matches the levels from the test standards. The tests from this report has often a wider range of results. There is a correlation between reproducibility and level of average. The repeatability has not been calculated because tests actually have been performed as single tests.

    Analysis of background data, like handling, dimensions and type of model, shows that they have none or very little significance.

  • 24.
    Arvidsson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Jämförelse mellan Los Angeles-värde och nedbrytning från hjullast2011Report (Other academic)
    Abstract [en]

    Since 2004 the Swedish Road Administration has had requirements on unbound base layer concerning the resistance to fragmentation, the Los Angeles value. To study how degradation from traffic load is affected by resistance to fragmentation five materials with different Los Angeles values were tested in VTI’s Heavy Vehicle Simulator (HVS).

    The degradation from the wheel load has been recorded by comparing the grain size distribution before and after the HVS test. Some values from the grain size distribution have been used or calculated to easier compare the grading curves with the Los Angeles value, e.g. content of fines (material < 0.063 mm) or the area under the grain size distribution curve.

    There is a clear degradation from the wheel load of the HVS in unbound base layer materials. There is, however, not a clear connection between this degradation and the resistance to fragmentation, Los Angeles value. Therefore it is not possible from this investigation to recommend a new level or category of requirements concerning the resistance to fragmentation on unbound base layer material.

    The most important conclusion is that the method that has been used in this project is working to study the degradation and particle relocation in unbound layers.

  • 25.
    Arvidsson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Stödremsa: laboratoriestudie av täthet och bärighet2018Report (Other academic)
    Abstract [en]

    When the support strip is not supposed to carry traffic load is low permeability considered as a more important property than bearing capacity. That is why the conclusion of this study is that moraine is more suitable for the support strip than crushed rock.

    “Support strip”: means in this report the unbound material that protects the edge of the (top) asphalt layer along (rural) roads. The support strip is quite narrow, around 30 cm (1 ft) and it should not be considered as the road shoulder.

    Some of the functions of support strips is that they should be non-permeable and have some bearing capacity. There are more functions the support strip should fulfill but in this project the properties of permeability and bearing capacity as California Bearing Capacity, CBR, have been studied in laboratory.

    The first tested material has been a granite (crushed rock) with the gradings 0/8 mm with content of fines (material < 0,063 mm), f, 8%, 10%, 15% and 20%; grading 0/11 mm with f = 10% and grading 0/16 with f equals to 8%, 10% and 15%. The second material has been a moraine with gradings 0/16 mm with f equals to 8%, 10%, 15% and 20%.

  • 26.
    Arvidsson, Håkan
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Eriksson, Olle
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Jämförande provning – ballast 2017: micro-Deval och Los Angeles2018Report (Other academic)
    Abstract [en]

    This report shows results, some statistical analysis and precision data for interlaboratory comparison (round robin) in Sweden performed on three materials of aggregate during 2017. The properties that was determined was resistance to wear by wet micro-Deval test (EN 1097-1) and resistance to fragmentation, Los Angeles test (EN1097-2). The number of participating laboratories were for micro- Deval 37 pcs. and for Los Angeles 34 pcs.

    There were three materials used for this comparison, the materials were called F, S and V. They were delivered to the participating laboratories in the grading 8/11 mm and 11/16 mm for each material. The laboratories should then generate the proper analyze fraction of 10/14 mm.

    The average results for micro-Deval were at the range of 6–8 for all of the materials. The standard deviations were also similar (0,43–0,50).

    For Los Angeles there were the average for one of the materials at 12 and for the other two materials the averages were around 26–27. The standard deviations are proportional to the averages.

  • 27.
    Arvidsson, Håkan
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Hellman, Fredrik
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Jämförelse mellan mekaniska egenskaper och nedbrytning av hjullast: del 22015Report (Other academic)
    Abstract [en]

    To study the correlation between the degradation of unbound base layer and mechanical properties (primarily Los Angeles test but also micro Deval test) a number of materials has been exposed by wheel load of VTI’s Heavy Vehicle Simulator (HVS). The first round was performed during the winter 2010–2011 and the second round during the following winter. In each round there were five materials tested. In the second round there were four new materials and one “old” as reference material. In this report results from round II will be presented, as well as some common results from both of the rounds, I and II. The results from round 1 are presented in VTI notat 4-2011. (Håkan Arvidsson: Comparison between the Los Angeles value and degradation from traffic load).The degradation has been defined as the difference in grain size distribution before and after HVS test. The degradation can be described in several ways. One way is as the difference in the area under the grain size distribution curve, another way is to sum the difference in percentage passing for all sieves or a few, e.g. the increase of fines by using results from the sieves 0.063–0.125 mm. The rutting has been measured by laser. The rutting is inversed proportional to the increase of fines. The increase of fines probably increases the stability in this quite coarse base layer grading. The materials with less increasing of fines have most of the hard minerals (quarts and plagioclase). The conclusion of these two tests on unbound base layer materials is that you partly can explain the degradation (change of grain size distribution) with mechanical properties (like Los Angeles and micro Deval). The correlations confirm this explanation and depend partly on an extreme material. Hellman et al (2013) show that degradation and crushing of the aggregates during compaction have a correlation with mechanical properties by studying microstructure and degree of crushing in microscope. Therefor the conclusion is that there is a degradation and crushing of aggregates in unbound base layer materials exposed by compaction and heavy traffic load.

  • 28.
    Arvidsson, Håkan
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Jansson, Samuel
    Tetra Chemicals Europe.
    Effekt av dammbindningsmedel: en laboratoriestudie2019Report (Other academic)
    Abstract [en]

    In this study, calcium chloride and magnesium chloride have been evaluated in combination with four different fine materials (granite, amphibolite, meta greywacke and naturally occurring silt), which are used for gravel road maintenance. Aqueous solutions of the two salts have been added to the fine material where after rain and drying has been simulated under laboratory conditions. Evaluation has been performed in terms of residual amount of salt after rain simulation, and SEM and optical microscopy on the fine material after drying, respectively

    It has been difficult to draw any conclusions that would yield new information from the tests. The methodology developed was not able to show agglomeration in the fine fraction of the gravel road material and it was not possible to provide recommendations regarding the dosage of dust binding agents.

    The tests show that calcium chloride is more efficient in retaining moisture than magnesium chloride when the comparison is based on the amount of flakes used.

    Agglomeration could not be proven despite several repeated tests.

    The chemical properties did not differ significantly, the salts behaved similarly and according to earlier known data.

    Differences in the origin of rock material was negligible compared with the effects of the salts.

    The added salt was for the most part (with a minimum of 80%) leached out during the rain simulation. No differences between calcium chloride and magnesium chloride or between the different fine materials were observed in terms of leaching. A small difference between leaching of cations and anions was recorded where the cations were retained in the fine material. This might be an ion-exchange effect.

    Analysis with SEM and optical microscopy did not yield any significant differences between the different combinations of salt and fine materials, respectively.

    During drying of the fine material it was observed that calcium chloride, calculated as commercial product, could absorb more water than magnesium chloride. This effect persisted also after the rain simulation.

    The experimental method that was developed during the study did not give any, previously not known, differences between the different salts and fine materials. Probably the system has been simplified to such an extent that relevant parameters were removed or do not reflect real field conditions.

  • 29. Bueche, N
    et al.
    Kalman, Björn
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Concept and design of selected innovations for interurban infrastructure: Synthesis report2008Report (Other academic)
    Abstract [en]

    The NR2C vision 2040 designates four main concepts for the road of the future. The innovations considered in WP2 all deal with solutions for one or more of the above concept needs, and mainly with the green infrastructure by reservation of rare resources via recycling and use of industrial by-products.

    Innovation 2.1 A Design of high performance layer with raw material (EPFL-Switzerland, BRRC Belgium, and other FEHRL-laboratories as VTI, KTI, DRI). The goal is to evaluate if the growing share of recycled aggregate used in asphalt high stiffness base courses influences the asphalt mechanical properties. It is the aim of this study that no significant loss in asphalt fatigue, deformation and durability characteristics counterbalances the environmental and economic benefits coming from the use of recycled material. Comprehensive laboratory and Accelerated Loading Tests (ALT) are performed in the project.

    Innovation 2.1B Crack free semi-rigid pavement incorporating industrial waste (LCPC-France) The goal is to evaluate if the natural cement concrete shrinkage can be compensated by adding industrial by-products (steel slag, fly ash) with swelling ability to the mixture. The consequences of the use of additional CaO are also tested. The main idea is to minimise (even to stop) the cracking of hydraulically bound layers and so, to avoid the reflection cracking in the asphalt layers built on them. The innovation is closely connected to the concept "safe infrastructure".

    Innovation 2.2. Use of the infra-red characteristics of materials to improve drivers' visibility (LCPCFrance). The goal is to enhance the traffic safety by improving the drivers' visibility among unfavourable conditions (darkness, fog etc.). The use of infrared image technique can be the solution. Simulation and real test site measurements are applied for the validation of the innovative technique. It can contribute to the concept "reliable infrastructure".

    Innovation 2.3. Optimisation of the maintenance process (Eurovia-France) The goal is to evaluate whether asphalt laying activities can be performed without detrimental consequences under extreme weather conditions (too low or too high temperature, rain etc.). The proposed innovative techniques are supposed to ensure the required asphalt quality and not to increase the construction costs considerably. The success of the project can contribute to the lengthening of the construction season without quality compromise. It was to contribute to the concept "reliable infrastructure".

    Innovation 2.4. Improving the mechanical properties of a low noise section (VTI-Sweden, ZAGSlovenia) The goal of this innovation initiated in a later phase of NR2C WP2 activities is to evaluate (and eventually to improve) the functional and the mechanical properties (durability) of low-noise poroelastic layers built on cement concrete blocks. Laboratory and site tests are to be performed for the evaluation of these properties. So, it contributes to the concept "green infrastructure", by the reduction of noise nuisance coming from traffic.

  • 30.
    Canon Falla, Gustavo
    et al.
    Technische Universitat Dresden.
    Leischner, S.
    Technische Universitat Dresden.
    Blasl, A.
    Technische Universitat Dresden.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Characterization of unbound granular materials within a mechanistic design framework for low volume roads2017In: Transportation Geotechnics, ISSN 2214-3912, Vol. 13, p. 2-12Article in journal (Refereed)
    Abstract [en]

    Unbound granular materials (UGM), used in base and subbase layers, play a major role in the structural performance of low volume roads (LVR) with a thin asphalt surface layer. A prerequisite for a proper design of such roads is the development of reliable testing techniques to simulate the behavior of UGMs under conditions similar to those that occur when subjected to traffic. Therefore, there is a need for simple and economical test methods to characterize the mechanical behavior of UGM under the action of high traffic loads. This paper presents a methodology for the experimental characterization of UGMs with a focus on mechanistic design. The results of a test campaign aimed at characterizing the elastic and plastic behavior of UGM are shown. The laboratory tests were performed using a new volumetric compaction tests and the triaxial test. Based on the results of the tests, a new classification method for UGMs intended to be used in the base course of thin asphalt pavements is suggested. 

  • 31.
    Carswell, Ian
    et al.
    TRL.
    Karlsson, Robert
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Raaborg, J.
    DRI.
    Kuttah, Dina K
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Main Report on Results of Comparative Site Monitoring2012Report (Other academic)
    Abstract [en]

    The objective of WP 2 is to analyse the potential use of reclaimed asphalt (RA) in new asphalt surface layer mixes and particularly the use of modified binders. Therefore the chemical compatibility of new binders with old bitumen in RA and the physical performance of the resulting binder and asphalt mixes have been examined separately to develop mix-design guidelines to ensure a long service life of asphalt mixes with reclaimed asphalt.

    In new bituminous bound courses, especially in base asphalt layers, the use of up to 40 % of RA is state of the art in most of the European countries. In surface layers, RA is currently used in relatively small amounts (10 to 20 %) if at all, because the demands on the properties of surface courses are very high. Surface courses need good deformation resistance at high temperatures as well as a high resistance against top-down cracks at low temperature and good skid resistance. The aggregates and binder used in surface courses are therefore of premium quality.

    The objective of WP 2 is to analyse the potential use of reclaimed asphalt (RA) in new asphalt surface layer mixes including the use of penetration grade and polymer modified binders (PmB’s). In lower asphalt layers (e.g. bituminous base courses) the use of high quantities of RA is common in most European countries. In surface course layers this occurs less frequently due to the high demands on the surface course.

    Incorporation of RA into asphalt layers can reduce the demand for added binder to the new mixture, depending on the residual binder content and recovered binder properties of the RA. Using RA in new asphalt mixtures has the potential to reduce costs and reduce energy requirements through reduced demand for raw materials and reduced transport of raw materials. This report covers the performance RA sites monitored which include both plant mixed RA sites (with and without polymer modified binder); and in situ hot recycling sites. The performance of sites is compared with control sections where no RA has been used.

  • 32.
    Dolk, Ellen
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Byggnads- och underhållsmetoder för CBÖ-vägar2017Report (Other academic)
    Abstract [en]

    Pavement structures with a cement-bound granular material (CBGM) road base and an asphalt wearing course are relatively rigid and suitable for roads with heavy traffic. The road pavement type known as cement bitumen pavement (CB) is common in many European countries and was previously also widely used in Sweden, but has been used very little here in recent years. One reason for this is that many roads have had problems with reflection cracks in the asphalt due to crack formation arising in the cement-bound granular material road base (CBGM). This crack formation consists mainly of thermal cracks that continue up though the asphalt layers. Crack formation in the cement-bound layers arises at different distances, with wider cracks at a distance of 15–20 metres, and it is these that continue up through the overlying asphalt layers.

    This report examines seven well known road objects that have been paved with CB and that have been trafficked for between 2 and 30 years. Because the roads have different traffic loads, the thickness of the CBGM layer has varied from 160 mm to 240 mm. Depending on when the roads were built, they have been subject to different building requirements for CB. The strength requirement for CBGM has varied from 8.5 MPa to 17 MPa. The thickness of the asphalt binder course between CBGM and the asphalt wearing course has varied from 50 mm to 115 mm and the type of binder course has varied from bitumen stabilized gravel (BSG) to various types of softer or harder asphalt types, and overlying this there has always been a 40 mm asphalt wearing course.

  • 33.
    Dolk, Ellen
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Betongbyggnad.
    Silfwerbrand, Johan
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Byggvetenskap, Betongbyggnad.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Concrete pavement Falkenberg, Sweden: a 20 year review2016Conference paper (Refereed)
    Abstract [en]

    The majority of the road network in Sweden consists of flexible pavements. Only a small fraction is rigid pavements and the most recent concrete structure was built ten years ago. This creates a problem as the national experience and knowledge in terms of design and maintenance of rigid pavements is not maintained. It is therefore important to gather and adequately document the performance of existing concrete structures.

    One such structure is along the motorway E6 close to Falkenberg on the southwest coast of Sweden built in 1993-1996. The structure is a 28 km long Jointed Plain Concrete Pavement (JPCP) resting on a cement-treated base. The climate in the area consists of a typical coastal climate with high precipitation and short, relatively warm summers and relatively cold winters with a high number of zero degree changes. Studded tire wear, normally contributing to a large extent to the total rut on the Swedish road network, is only 5 mm after these 20 years. However, the structure is suffering from longitudinal cracking along the outer wheel track that is thought to have been caused by the combined effects of erosion within the cement-treated base, resulting in cavities under the concrete slabs and the fact that the dowel bars are placed too low and thus reducing the load transfer mechanism between the slabs and acting as crack inducers.

  • 34.
    Eklöf, Ingemar
    et al.
    Novus Ecosystems.
    Brander, Linus
    CBI Betonginstitutet.
    Hedenstedt, Anders
    SP, Sveriges Tekniska Forskningsinstitut.
    Hellman, Fredrik
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Johansson, Inge
    SP, Sveriges Tekniska Forskningsinstitut.
    Johansson, Maria
    Ecoloop.
    Lövström, Monica
    Svenska EnergiAskor.
    Mácsik, Josef
    Ecoloop.
    Schouenburg, Björn
    CBI Betonginstitutet.
    Askor för konstruktionsändamål: slutrapport 2016-03-152016Report (Other academic)
    Abstract [en]

    Today in Sweden, biofuels and waste are the main fuels for the production of district heating and contributes to production of electricity. During combustion of biofuels and waste, it is also generates residues, so-called energy ashes. Large parts of the ashes have in original form or after sorting and processing good properties for construction purposes. Current use of energy ashes in Sweden are mainly as construction materials within the waste facilities as coverage of old waste dumps.. However, the need is decreasing as the coverage of many waste dump sites are about to be completed within the next 5–6 years. Therefore, there is a need for new applications for energy ashes. To deposit the ashes is a bad management of resources. Many ash producers have instead the ambition to use energy ashes for structures in society, such as in roads, parking lots and other fixed construction purposes. By using energy ashes for constructions and thus replacing virgin raw materials, the energy and waste system become more sustainable. This is an important factor for all the parts involved and shows concretely how circular economy can be created. Unless other disposal options evolve the cost will increase dramatically for ash management which stresses energy producers and ultimately also the end customer.

  • 35.
    Ekström, Camilla
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Traffic Safety and Traffic System.
    Hellman, FredrikSwedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.Haraldsson, MattiasSwedish National Road and Transport Research Institute, Society, environment and transport, Transport economics.
    Sammanställning av referat från Transportforum 20192019Conference proceedings (editor) (Other academic)
    Abstract [sv]

    VTI arrangerade Transportforum 9–10 januari 2019 i Linköping Konsert & Kongress. En konferens, som är störst i sitt slag i Norden och som 2019 innehöll 90 sessioner med en stor variation mellan ämnen. Temat för 2019 års inledande session var elektrifiering – möjligheter och utmaningar att nå klimatmålen.

  • 36.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Characterization of heavy traffic on the Swedish road network2010In: 11th International Conference on Asphalt Pavements 2010: ISAP Nagoya 2010, Tokyo: International Society for Asphalt Pavements, ISAP , 2010, , p. 8p. 1704-1711Conference paper (Other academic)
    Abstract [en]

    One of the key parameters in predicting the deterioration process of pavement structures is linked to the heavy traffic characteristics. The heavy traffic loading has been commonly expressed in pavement design methods through an equivalent number of repetitions of standard axle loads (ESAL’s). Recent pavement distress models, used in new mechanistic pavement design methods, require more detailed description of the heavy traffic. In Sweden, a Bridge Weigh-In-Motion (BWIM) system has been used to collect information about the heavy traffic on the road network. The system provides information about the vehicles’ time of passing, speed and lane, the number of axles and their configurations and weights. A national BWIM network was established in 2004, consisting of twelve locations which are measured during one week every year. The network consists of motorways, arterials or trunk roads as well as one county road. This, therefore, provides a basis to establish an Axle Load Spectra (ALS) which gives the load distribution of steering axles, other single axles, tandem and tridem axles. As very few quad axles are registered they have been neglected.

  • 37.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Impact of water on the structural performance of pavements2010In: The 11th international conference on asphalt pavements 2010: ISAP Nagoya 2010, Tokyo: International Society for Asphalt Pavements, ISAP , 2010, , p. 10p. 542-551Conference paper (Other academic)
    Abstract [en]

    An accelerated load test has been performed at VTI’s test facility in Sweden using a Heavy Vehicle Simulator (HVS). The objective was to investigate the response behaviour and performance of a commonly used flexible pavement structure in Sweden. The instrumented structure was built in a concrete test pit and consists of 10 cm bounded layer, a granular base and a subbase resting on sandy subgrade. The test was divided into three phases: a pre-loading phase, a response phase and the main accelerated loading test where 1,000,000 load cycles were applied. After the preloading phase 500,000 load cycles were applied and then the water table was raised and further 500,000 loading cycles were applied. Raising the groundwater table increased the rate of rutting developed in all unbound layers. From the sensor registrations it is clearly seen that the stiffness of all unbound layers decreased as the water table was raised, thus the pressure cells revealed lower registrations but the vertical strain gauges increased their readings. Further, it was observed that the rate of accumulation of permanent deformation accelerated. This has been interpreted as the impact of higher water content on the characteristics of the unbound layers, the subgrade, subbase and base course.

  • 38.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Mechanistic performance modelling of rutting in pavement structures2012In: EPAM 2012: Malmö, Sweden, 5–7 September: 4th European pavement and asset management conference / [ed] Gustafson, Kent, Linköping: Statens väg- och transportforskningsinstitut, 2012, , p. 10Conference paper (Other academic)
    Abstract [en]

    A mechanistic empirical (M–E) approach has been developed and thereafter used to calculate the degradation behaviour of two arterial roads in Southern Sweden. The results were then compared with measurements from the Swedish long term pavement performance (LTPP) database. The M-E approach used was a two-step procedure where the response of the structure was calculated mechanistically and thereafter the performance predicted empirically based on scaling of laboratory test results. Extensive laboratory testing was carried out on samples taken from the test roads. Traffic counting and Bridge Weigh-in-Motion data were used to determine the amount of traffic loading, and data from weather stations were used to take into account the temperature dependency of the asphalt bound layers. The analysis shows that the rutting development can be simulated adequately although the calculations show slower rate than the measurements towards the end of the simulated period. The discrepancy in the rate of rutting between the measurements and the observations that was observed after about 9 years of operation might be due to the fact that no ageing or disintegration in material characterization was incorporated in the numerical analysis but surely observed in reality.

  • 39.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Tunga trafikens samhällsekonomiska kostnader: accelererade tester av tre vägkonstruktioner2017Report (Other academic)
    Abstract [en]

    The Swedish Ministry of Enterprise and Innovation (Näringsdepartementet) has given VTI the assignment to update the knowledge about the society costs of the transport infrastructure. A part of that work is to improve our knowledge about the relationship between traffic axle loads and degradations of pavement structures.

    The objective of this report is to investigate if a simple relationship between axle loading and pavements degradation can be used as a tool for estimation of marginal costs for degradation of the entire road network. Three full scale test pavement structures have therefore been tested with an Heavy Vehicle Simulator using three half-axle load levels 40, 50 and 60 kN (corresponding to 8, 10 and 12 tonnes axle loads) to investigate the load intensity on the degradation progress. As a measure of the distress development has the linear rutting rate during testing been used after the initial exponential rutting phase was passed.

  • 40.
    Erlingsson, Sigurdur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Ahmed, Abubeker
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    The Svappavaara road test sections: field coring and laboratory tests2015Report (Other academic)
    Abstract [en]

    This report describes laboratory testing of specimens taken from four new instrumented test road sections that have been built on E45 close to the Svappavaara municipality in Norrbotten County in Northern Sweden. The structures are located about 100 km north of the Arctic Circle in a climate that is characterized by long cold winters and short mild summers. The four test sections were built in a conventional manner. Each structure is about 200–250-metre-long with a central 100-metre-long part defined as the actual test section. All structures are in total 60 centimetres in thickness resting on top of a 70-centimetre-thick old existing road. The bitumen bound part of all the four structures consists of four layers; a thin surface course layer, two binder layers and a road base layer. All structures have the same wearing course, TSK 16 with a standard 160/220 penetration grade bitumen. The main difference between the structures lies in the binder as well as the two road base layers. As a part of the monitoring programme drilled asphalt specimens were taken in 2013 from the road structure and tested at VTI's material testing laboratory in Linköping. Furthermore, samples were taken from the unbound base course and tested. This report presents the test results for asphalt bound layers as well as for the unbound base course. For the bound layers the testing procedure included volumetric properties, stiffness modulus and fatigue tests for the different types of conventional and polymer modified asphalt mixtures. The tests were conducted in accordance with the Swedish or the equivalent European standards. For the unbound base course fundamental properties were estimated as well as stiffness and permanent deformation properties for different moisture contents.

  • 41.
    Erlingsson, Sigurdur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Ahmed, Abubeker W.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Fast layered elastic response program for the analysis of flexible pavement structures2013In: 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)
    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.

  • 42.
    Erlingsson, Sigurdur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Ahmed, Abubeker W
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Mechanistic rutting modelling of a LTPP road structure2019In: Pavement and Asset Management: Proceedings of the World Conference on Pavement and Asset Management, WCPAM 2017, CRC Press/Balkema , 2019, p. 241-249Conference paper (Refereed)
    Abstract [en]

    A new Mechanistic-Empirical (M-E) approach is under development to predict the structural degradation of road structures as a function of time. The aim is that the method will become one of the backbones in a new pavement asset management system. The calculation scheme is based two main steps; i) a response calculation step for the different traffic loads applied taking into account the ambient climate and ii) a performance prediction step where pavement degradation is predicted in time steps and thereafter accumulated over the entire design period of the pavement structure. The paper describes the approach briefly and is thereafter demonstrated by a calculation of the degradation of an arterial road in Southern Sweden and compared with measurements from the Swedish Long Term Pavement Performance (LTPP) database. The arterial road had reached the critical 15 mm rut after 18 years in operation. The analysis shows that the rutting development can be simulated adequately although the calculations show slower rate than the measurements towards the end of the simulated period.

  • 43.
    Erlingsson, Sigurdur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Carlsson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Measurement technology and engineering workshop.
    Testplatser för 74 ton tunga fordon: två instrumenterade tunna vägkonstruktioner2018Report (Other academic)
    Abstract [en]

    This VTI note describes briefly the construction and instrumentation of two new test road structures that have been built during the autumn 2017 on Lv373 and Lv515 respectively in Norrbotten County in northern Sweden. One structure is placed on Lv373 east of the village Långträsk while the other structure is on Lv515 south if the intersection with Lv373. The distance between the two locations is about 10 km. Both structures are thin pavement structures. The main objective of the two new test sites is to estimate the impact that the new 74 tonnes vehicles have on the Swedish road network. This will be done through direct measurements of the pavement response from the road sensors. The sensors consist of horizontal strain sensors in both longitudinal and transversal direction at the bottom of the asphalt layer as well as vertical strain sensors over every layer down to 1.2 m depth. Soil pressure cells are further installed at two depths. The local ambient climate is monitored as well. A frost and a moisture rod were therefore installed. Further are temperature sensors installed in the asphalt concrete. Two weather stations are located within 20 km distances from the test structures. The first response measurements are planned in the late summer or early autumn 2018.

  • 44.
    Erlingsson, Sigurdur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Carlsson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Measurement technology and engineering workshop.
    The Svappavaara road test sections: instrumentation2014Report (Other academic)
    Abstract [en]

    This report describes four new instrumented test road sections that have been built on E45 close to the Svappavaara in Norrbotten County in Northern Sweden. The structures are located about 100 km north of the Arctic Circle in a climate that is characterized by long cold winters and short mild summers. Norrbotten County is a sparsely populated area where the pavement structures consist of thin pavements with relatively low traffic volume. A new ore deposit, the Kaunisvaara project, was opened in 2012, meaning that the ore will be transported along the existing road network about 160 kilometers to where it will be transferred to a railway. The ore operator has received a permit to use 90 ton vehicles instead of the permissible 60 tons, consisting of a single wheel steering axle and triple dual wheel tridem axles to transport the iron ore. When the ore processing will be in full operation around 66.000 journeys per year will pass over the network, or on average about 7–8 passes per hour with about seven and a half minutes between the passes. Due to this new ore transport it will be necessary to strengthen the local road network. As part of the process to evaluate the performance of a suitable pavement structure these four instrumented test road structures have been selected and built. The structures are instrumented with road performance and climate sensors. The structures will be monitored over the years to come, though the details of the monitoring programme have not yet been decided. Each test section is around 200 metres long, consisting of a 100 metres long inner part that constitutes the intrinsic test section. The structures were built and instrumented in the summer of 2012 except for the wearing course that was placed in the summer of 2013 along with the temperature sensors that are placed in the asphalt layers. The instrumentation in each section consists of Emu coils for vertical strain measurement devices, soil pressure cells for vertical stress measurements and tensile strain gauges located at the bottom of the bound road base layer. In addition there are moisture rods located in three of the structures and a temperature (frost) rod located in structure 3. A weather station (2527 Svappavaara) operated by the Transport Administration is located 3.2 kilometre south-east of the test site.

  • 45.
    Erlingsson, Sigurdur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Olafsdottir, Elin Asta
    University of Iceland.
    Bessason, Bjarni
    University of Iceland.
    Stiffness of sandy sites using the Multichannel Analysis of Surface Waves method2017In: ICSMGE 2017: 19th International Conference on Soil Mechanics and Geotechnical Engineering, 19th ICSMGE Secretariat , 2017, p. 593-597Conference paper (Refereed)
    Abstract [en]

    Multichannel Analysis of Surface Waves (MASW) is seismic exploration method to evaluate shear wave velocity profiles of near-surface soil materials based on analysis of horizontally travelling Rayleigh waves. The MASW method has been applied at four loose sandy sites in South Iceland providing shear wave velocity (VS) profiles for the uppermost 25 m at each site. The VS-profile obtained for one of the test sites was compared to empirical profiles estimated on the bases of CPT measurements carried out at the site. The results indicate that the MASW profile corresponds adequately well to the empirical estimations, strengthening the results obtained by MASW. However, further comparison of MASW and CPT data is needed in order to evaluate the overall applicability of existing CPT-VS correlations at Icelandic sand sites.

  • 46.
    Erlingsson, Sigurdur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Rahman, Mohammad Shafiqur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. KTH.
    Evaluation of permanent deformation characteristics of unbound granular materials from multi-stage repeated load triaxial test2013In: Transportation Research Record, ISSN 0361-1981, E-ISSN 2169-4052, no 2369, p. 17p. 11-19Article in journal (Refereed)
    Abstract [en]

    Rutting in flexible pavements is often associated with permanent deformation of the unbound granular layer. The current permanent deformation models are only applicable to a single stress path in repeated load triaxial (RLT) tests. In this paper, a simple approach using the time hardening concept was introduced to continuously model the permanent deformation of unbound granular materials (UGM) in multi-stage (MS) repeated load triaxial (RLT) tests. Three existing permanent deformation models were reconstructed to be implemented with this method and one model was slightly modified to better suit this approach. This approach was validated by calibrating these reconstructed models using data from MS RLT tests on three different UGM used in base layers of flexible pavement structures. The calibrations were done by optimizing the material parameters of the models using least square curve fitting method. The shakedown ranges were also calculated for each stress path of the MS RLT tests to compare these models in simulating these ranges. Generally, very good fits were obtained for these models where the modified model showed the best agreement.

  • 47.
    Erlingsson, Sigurdur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Rahman, Mohammad Shafiqur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Salour, Farhad
    Trafikverket.
    Characteristic of unbound granular materials and subgrades based on multi stage RLT testing2017In: Transportation Geotechnics, ISSN 2214-3912, Vol. 13, p. 28-42Article in journal (Refereed)
    Abstract [en]

    The unbound granular layers (UGM's) and the subgrade of a pavement structure provide a significant support for the structure as a whole. Hence the mechanical properties of these materials are important for the overall performance of the structure. These materials exhibit both non-linear stress dependency and their mechanical properties are highly affected by their moisture content. This paper describes two of the most important material properties of the unbound layers of the pavements, i.e. the resilient and the permanent deformation properties. The stress dependency of UGMs can be captured by the universal model or the enhanced model by Cary and Zapata (2011) for materials with high fine content. The Bishop's effective stress approach can be used for high fine content materials for estimating the effect of suction. UGMs and subgrade materials are further highly dependent on moisture content. Either the AASHTO sigmoidal model can be used to describe the moisture dependency or the simple exponential model described in this paper. The paper further discusses four models to characterize the accumulation of permanent deformation with the number of load repetitions in repeated load triaxial (RLT) testing. The models are all developed to fit single stage (SS) RLT test results but have been extended to fit multi-stage (MS) RLT test results with the aid of the time hardening scheme. The advantage of the MS RLT tests over the SS RLT tests is that it applies a range of stress paths on a single specimen, thus taking into account the effect of stress history and reducing the time and effort required to test a separate specimen for each stress path.

  • 48.
    Erlingsson, Sigurdur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Said, Safwat
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    McGarvey, Terry
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Influence of heavy traffic lateral wander on pavement deterioration2012In: EPAM 2012: Malmö, Sweden, 5–7 September : 4th European pavement and asset management conference, Linköping: Statens väg- och transportforskningsinstitut, 2012, , p. 11Conference paper (Other academic)
    Abstract [en]

    Lateral wander of the traffic has an impact on the degradation development of pavements. This is usually not accounted for in the structural design process. Facilities with wide carriageways and broad shoulders tends to have relatively large lateral spreading while narrow road facilities lacking any shoulders can have highly channelized traffic pattern. In this research lateral wander characteristics have been measured for different road facilities. They can be assumed follow a normal distribution where the standard deviation describes their lateral spreading. Rut depth has thereafter been estimated according to two new rutting calculation scheme where lateral wander characteristics has been taken into account. The first approach is based on a two step mechanistic empirical (M-E) evaluation of the permanent strain in all layer of the structure and using a time hardening approach to sum up for all wander locations. This has thereafter been used to estimate the difference in rutting development as a function of the standard deviation. The second approach concentrates on calculating the permanent strain visco-elastically in the bound layers of the structure. Both procedures can be used to estimate the rate of relative deterioration for different road facilities. Based on the same structure the first approach give around 6 % increase in the surface rut as the standard deviation of the lateral wander increases from 10 to 20 cm. The second approach estimates this difference to be around 20 %. The difference between the two approaches are partly explained due to that the first approach estimates the rut based on all layers but the second approach from the bound layers only.

  • 49.
    Erlingsson, Sigurdur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Ullberg, J.
    Trafikverket.
    Responses and performance of flexible pavements in cold climate due to heavy vehicle loading2018In: Bearing Capacity of Roads, Railways and Airfields - Proceedings of the 10th International Conference on the Bearing Capacity of Roads, Railways and Airfields, BCRRA 2017, CRC Press/Balkema , 2018, p. 451-457Conference paper (Refereed)
    Abstract [en]

    Four instrumented test road structures have been built in northern Sweden about 100 km north of the Arctic Circle. The climate consists of cold winters and mild summers with a long spring thaw period. The pavement structures differs in material quality ranging from conventional to polymer modified structures. The objective of the test structures is to see the difference in their behaviour and performance due to the heavy loading in the ambient artic climate. Each test section is instrumented that includes pressure cells and strain sensors that measure the pavement response to external loading. Climatic variables are further monitored through a weather station as well as temperature and moisture sensors installed in the road structure. Response measurements have been carried out using 90 tons vehicles consisting of a single wheel steering axle, and triple dual wheel tridem axles. Rutting development has been monitored through four years showing some difference between the structures rutting development.

  • 50.
    Franzén, Gunilla
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Lindh, Per
    PEAB.
    Åhnberg, Helen
    SGI.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Terrasstabilisering: kunskapsdokument2012Report (Other academic)
    Abstract [en]

    In situ stabilisation of sub-grade is a method used in order to improve the bearing capacity in foundations on fine-grained soils with low bearing capacity. The method is applied in order to improve the bearing capacity for, for example, temporary roads during construction, but mainly for optimizing the pavement of the final road. The method is commonly used outside of Sweden and has proved to give well-functioning constructions.

    The aim of the study has been to compile existing knowledge of the possibilities and limitations of the method to create opportunities for an increased use. The document deals with in situ stabilisation of existing fine-grained soil. Stabilization of the unbound layers in the road construction itself is not included in the study. Since the main purpose has been to study the method itself, the focus has been on traditional binders such as lime, concrete and slag. Some of the findings:

    • In order to use the full potential of the method it is necessary to further develop execution practice and requirements.
    • •The financial advantages of the method are mainly notable considering the life-cycle costs instead of investment costs.
    • •Under certain circumstances, the method has a potential to contribute to energy efficiency.
1234 1 - 50 of 198
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf