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  • 1.
    Afridi, Amjad
    et al.
    Skellefteå Municipality, Sweden; Department of Building Materials, KTH Royal Institute of Technology, Stockholm, Sweden.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Sjögren, Leif
    Swedish National Road and Transport Research Institute, Infrastructure.
    Management of municipal street network in Sweden: results from a national survey2024In: Sammanställning av referat från Transportforum 2024 / [ed] Fredrik Hellman; Mattias Haraldsson, Linköping: Statens väg- och transportforskningsinstitut , 2024, p. 395-396Conference paper (Other academic)
    Abstract [en]

    Management of street networks is different from state roads due to its multifunctional role in society. This requires timely maintenance of the street network to improve socioeconomic development. Municipalities in Sweden are responsible for the management of about 42000 km of street network in their jurisdiction. Maintenance budget and resources vary from municipality to municipality depending on their network size, geographical location, and population density. 

    A questionnaire was sent to all 290 municipalities across the country to investigate the street network and pavement management practices at the municipal level. An in-depth interview of 14 municipalities took place afterwards. A total of 51% of responses were officially received to highlight the frequently and infrequently occurring pavement distresses and their causes. Furthermore, the study highlights the maintenance approaches and allocation of budget to manage the street network. Lastly, the study highlights the factors which need to be addressed to improve street network management.   

    Visual assessment of pavements is common and the use of pavement management system (PMS) is not only limited but also lacks pavement performance prediction models. Common pavement distresses are excessive formation of potholes, surface unevenness and alligator distress among the municipalities. Frequent causes of distress include the ageing of the street network, heavy vehicles, patching and high traffic flow. Furthermore, cold climate and population density are important factors in the degradation process. Allocation of maintenance and reconstruction budget is relatively high in municipalities located in the north. Densely populated municipalities have higher taxpayers’ contributions to maintenance and reconstruction. Other major issues are limited resources and maintenance of budget, which adversely affect the maintenance backlog and the choice of maintenance alternatives, ultimately the decision-making. This restricts the use of preventive maintenance among the municipalities. 

    Municipalities are required to improve the frequency and quality of pavement data collection, enhance the sophistication of PMS by using pavement deterioration models, and increase the maintenance budget and resources. An insight into the capabilities of municipalities would help in long-term strategic planning and effective utilisation of the maintenance budget to improve the street network across the country.  

  • 2.
    Afridi, Muhammad Amjad
    et al.
    KTH, Sverige.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. KTH, Sverige.
    Sjögren, Leif
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Municipal street maintenance challenges and management practices in Sweden2023In: Frontiers in Built Environment, E-ISSN 2297-3362, Vol. 9, article id 1205235Article in journal (Refereed)
    Abstract [en]

    The municipal street network acts as a multifunctional asset by providing people, vehicles and public services with a well-functioning infrastructure. To keep it in good condition, optimal maintenance measures are required which would result in an efficient use of taxpayers' money. This paper investigates the street network deterioration processes and the management practices that the municipal administrations have applied in Sweden. The study is based on a survey with Swedish municipalities using questionnaires and complementary interviews. The answers provide insight into a wide range of common pavement distresses and deterioration factors, along with pavement management practices. The study identifies that potholes, surface unevenness and alligator cracking are the most cited challenges, while pavement ageing, heavy traffic and patches are the most noted causes. Similarly, the cold climate and population density are influential factors in pavement deterioration. Allocation of the maintenance and rehabilitation and reconstruction budget is higher in the northern part of the country as well as in densely populated municipalities. Condition data collection and use of commercial Pavement Management Systems (PMS) are limited. Addressing the challenges effectively may be possible through the enhancement of the budget, feasible/clear guidelines from municipal councils/politicians, and reducing the gap between street network administrations and utility service providers.

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  • 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
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Rahman, Shafiqur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Iron sand as a frost protection layer: thickness design charts2022Report (Other academic)
    Abstract [en]

    Frost depths and frost heaving calculations were performed to prepare design charts and tables for the iron sand (järnsand) layer thickness design for roads typically used for residential area, parking lots and other low to medium traffic roads, and for ground insulation. 

    A segregation potential based frost design method was employed to generate the design charts and tables. The segregation potential method allows the prediction of both frost heaving and frost penetration depth of a pavement structure for a prescribed winter temperature profile or freezing index. Thus, the iron sand layer thickness design tables/charts for roads were prepared for different levels of maximum permitted heaving criteria of 50, 80, 100, and 120 mm. Whereas for ground insulation, a design chart/table was prepared to eliminate any frost action in the ground. In addition to the frost design calculations, two triaxial tests were conducted to evaluate the bearing capacity of the iron sand material. The limited test results indicated that, the bearing capacity of iron sand is similar to conventional sand both in terms of stiffness as well as permanent deformation behavior.

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  • 5.
    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.

  • 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.
    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.

  • 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 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.

  • 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.
    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.

  • 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.
    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.

  • 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.
    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.

  • 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. 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.

  • 12.
    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.

  • 13.
    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.

  • 14.
    Andersson, Anders
    et al.
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle Systems and Driving Simulation..
    Blissing, Björn
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle Systems and Driving Simulation..
    Carlsson, Håkan
    Swedish National Road and Transport Research Institute, Infrastructure, Measurement technology and engineering workshop.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Hellman, Fredrik
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Hjort, Mattias
    Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle Systems and Driving Simulation..
    Ihs, Anita
    Swedish National Road and Transport Research Institute, Infrastructure.
    Kuttah, Dina K
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Nåbo, Arne
    Swedish National Road and Transport Research Institute, Traffic and road users, Driver and vehicle.
    Thorslund, Birgitta
    Swedish National Road and Transport Research Institute, Traffic and road users, Driver and vehicle.
    Designguide för Smarta gator2022Report (Other academic)
    Abstract [sv]

    Sammanfattningsvis definierar vi i denna guide ’smarta gator’ kort sagt som mångfunktionella, levande, långsamma, ekologiska och flexibla gator. Det övergripande målet med denna guide är följaktligen ”Smarta gator för en hållbar stadsutveckling”.

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  • 15.
    Andersson-Sköld, Yvonne
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Afridi, Muhammad Amjad
    Skelleftea Municipal, Sweden; KTH, Sweden.
    Nordin, Lina
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Patrício, João
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Lindgren, Åsa
    Swedish Transport Administration, Sweden.
    Johansson, Carl-Martin
    Swedish Transport Administration, Sweden.
    Olofsson, Alexandra
    Swedish Transport Administration, Sweden..
    Andersson, Angelica
    Swedish National Road and Transport Research Institute, Society, environment and transport, Traffic analysis and logistics. Linköping University, Sweden.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. KTH, Sweden;University of Iceland, Iceland.
    Development of the SUNRA Tool to Improve Regional and Local Sustainability of the Transportation Sector2022In: Sustainability, E-ISSN 2071-1050, Vol. 14, no 18, article id 11275Article in journal (Refereed)
    Abstract [en]

    To fulfil the global sustainable development goals (SDGs), achieving sustainable development is becoming urgent, not least in the transportation sector. In response to this, the sustainability framework Sustainability National Road Administrations (SUNRA) was developed to contribute to improving the sustainability performance of national road administrations across Europe. In the present study, the framework has been tested, applied and further developed to be applicable for target setting and follow-up at the project level at both the Swedish Transport Administration (STA) and at municipal levels. The aim was a framework relevant for investment, re-investments, maintenance and operation projects and also to make it more user applicable. The study also investigated how the framework can contribute to sustainability, identified drivers and barriers for applying the framework and examined whether the framework can be applied and adapted to projects of different complexities. The adaptations and developments were done in collaboration between researchers and practitioners. The results show that the framework could easily be used and adapted for investment, re-investment, maintenance and operation projects in the planning stage, as well as for small municipal establishments, construction or reconstruction of residential areas and frequent maintenance. The framework contributes to increased awareness on sustainability, and it provides a common structure and transparency on how infrastructure project goals/targets are set and fulfilled. The framework can also be applied to follow the fulfilment of the goals/targets and thereby adapt the project to better fulfil the goals. Identified barriers include the lack of obligations and lack of experience in using sustainability frameworks.

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  • 16.
    Andersson-Sköld, Yvonne
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Mirzanamadi, Raheb
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Nyberg, Erik
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Torstensson, Peter
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment. Swedish National Road and Transport Research Institute, Traffic and road users, Vehicle Systems and Driving Simulation..
    Göransson, Gunnel
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Nordin, Lina
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Ramverk för att prioritera och bedöma nyttan av klimatanpassningsåtgärder2023Report (Other academic)
    Abstract [en]

    Even if the greenhouse gas emissions are rapidly reduced, the ongoing climate change will result in extensive and costly climate-related events that will occur more frequently. The costs in the Swedish transport sector for such events damaging streets, roads, rail/railways, and other vulnerable parts of the infrastructure are high today and are expected to increase. The consequences of weather-related events are, among other things, reduced accessibility, and increased risk of accidents. To maintain the functioning of the transport system, it is important to undertake risk-reducing measures related both to today's climate, but above all, to manage future climate-related events. It is necessary to ensure the functioning of the transport system during extreme weather events, and during periods of prolonged precipitation, prolonged heatwaves and changing precipitation patterns. It is also important to enable adaptation measures to deal with long-term changes such as rising sea levels which affect the accessibility and lifespan of the infrastructure.

    This report presents a summary of results and a summary of how a framework for evaluating climaterelated impact relationships has been used. Effect relationships refer to identifying, assessing, and evaluating climate-related risks and risk reduction measures. In this report, the focus is on identifying, assessing, and evaluating the effectiveness of climate-related measures. The results is a framework for assessing the effect of risk-reducing measures, i.e., to assess whether it is relevant to implement a measure, when in time it should be implemented and to assess which measure is most relevant to implement. The risks have considered in case studies and include fire risk, risk of accidents on streets and roads due to zero crossings or heat, flooding, erosion and landslides and impact on road construction (rutting, bearing capacity and fatigue), track buckling and risks related to high winds. The tests have included hazard and risk identification, risk analysis, identification, and evaluation of possible measures. Examples of case studies are a torrential rain in Kungsbacka municipality in 2019, erosion-related changes over a long period of time at Österdalälven and calculations of climate impact on the road construction at the E10 at Svappavaara. A case study has also included monetary valuation and sensitivity analysis. The framework has also formed the basis for a discussion regarding climaterelated risks linked to electricity supply.

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  • 17.
    Andersson-Sköld, Yvonne
    et al.
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Nordin, Lina
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Polukarova, Maria
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Afridi, Muhammad Amjad
    Skellefteå kommun; KTH.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Nyberg, Erik
    Swedish National Road and Transport Research Institute, Society, environment and transport, Environment.
    Sunra för lokal och regional infrastruktur: prototypen Sulri : Version 20222022Report (Other academic)
    Abstract [en]

    Sunra (Sustainability: National Road Administration) is a decision support tool developed to be used in road projects by setting the level of ambition for different sustainability aspects and following up the work towards these in a structured way. 

    This memo describes the results of continued development of Sunra adapted for local and regional infrastructure. The result is the prototypes Sulri (Sustainability Local and Regional Infrastructure) and Sulri-frequent. Sulri-frequent is intended to be used for more frequent projects, such as paving existing streets, and Sulri is intended for projects that are a little more complex such as rethinking or replanning such as improving for active travel, climate adaptation of an area or adapting a street, a place or an area to other needs, but Sulri can in principle also be used for more frequent or smaller projects. This report describes a first version of Sulri. The report shows how the tool should be used. Chapter 3 then presents the themes and aspects that are considered within Sulri. Appendix 2 gives the corresponding information for Sulri-frequent. Appendix 1 presents relevant documents and links for the different themes and aspects considered in Sulri.

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  • 18.
    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.

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  • 19.
    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. 

  • 20.
    Dinegdae, Yared
    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.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland, Iceland.
    Toward a Comprehensive Pavement Reliability Analysis Approach2023In: Transportation Research Record, ISSN 0361-1981, E-ISSN 2169-4052, Vol. 2677, no 7, p. 680-692Article in journal (Refereed)
    Abstract [en]

    Reliability has been incorporated in pavement design tools to account for input variability influence on predicted performance. As they are not based on a probabilistic method of uncertainty propagation, the reliability analysis methodologies that are currently implemented in pavement performance tools lack rigor and robustness. This paper investigates the potential of three reliability analysis methodologies for pavement application: the Pavement ME reliability analysis methodology, Monte Carlo simulation (MCS), and the first-order reliability method (FORM). The MCS and FORM involve a response surface method for the generation of a second-order surrogate model. The investigation was performed using inputs and performance data from accelerated pavement testing structures. Inputs that were identified as significant were characterized as random variables and their associated variability was established using measured structural and material properties. Pavement performance with respect to rutting was predicted using the ERAPave performance prediction tool, while MCS was used to generate the actual variability of the distress. The reliability analysis results have shown that a comprehensive reliability analysis methodology is required that effectively captures input variabilities and the error associated with surrogate models.

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  • 21.
    Dinegdae, Yared
    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.
    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. University of Iceland, Iceland.
    Evaluation of ERAPave PP permanent deformation models using APT2023In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402Article in journal (Refereed)
    Abstract [en]

    Permanent deformation is one of the failure modes considered in the analysis and design of flexible pavements. ERAPave performance prediction (PP) which is a mechanistic empirical (ME) pavement design tool utilises two distinct models for the prediction of permanent deformation in the bound and unbound granular layers including subgrade. This paper aims to calibrate these models using pavement response and performance data from accelerated pavement testing (APT) structures. Material properties such as layer modulus were established through an optimisation that involves both falling weight deflectometer (FWD) and pavement response measurements. Based on the predicted performance results, a separate set of calibration was performed for permanent deformation development in moist and wet moisture conditions. The calibrated models have resulted in predictions that are in good agreement with observed performances. Furthermore, the model parameters successfully captured the initial densification behaviour and the associated sensitivity with axle load level.

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  • 22.
    Dinegdae, Yared
    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 Flexible Pavements Using Accelerated Pavement Testing2020Conference paper (Refereed)
    Abstract [en]

    Several models are currently available for the prediction of permanent deformation in flexible pavements. These models are intended for different analysis conditions and require extensive calibration and validation before use. The aim of this article is to evaluate the permanent deformation models incorporated in a Swedish analysis tool (i.e., ERAPave ME) for flexible pavements. Measured response and performance data from an accelerated pavement testing using heavy vehicle simulator is used for this purpose. Pavement response is computed using a multi-layered linear elastic analysis tool while stress-dependency is accounted in the prediction of permanent deformation. A general good agreement has been observed between measured and computed responses. The same is true for observed and predicted permanent deformations. The permanent deformation prediction is achieved using model parameters that are unique to each layer and loading level.

  • 23.
    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.

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    Dolk Concrete pavement Falkenberg
  • 24.
    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.

  • 25.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Geotechnical challenges in Iceland2019In: 17th European Conference on Soil Mechanics and Geotechnical Engineering, ECSMGE 2019 - Proceedings, International Society for Soil Mechanics and Geotechnical Engineering , 2019, p. 27-51Conference paper (Refereed)
    Abstract [en]

    The geotechnical challenges in Iceland are in many aspects unusual. The geological setting of the country is unique and has a great influence on the local geotechnical conditions. Iceland lies on the divergent boundary between the Eurasian plate and the North American plate formed by the Mid-Atlantic Ridge. This has created a landmass with active volcanoes, geothermal areas and zones of high seismicity. The bedrock is relatively young and mainly basaltic. It has been built up of relatively thin lava layers during eruptions. It is frequently highly jointed with irregular interlayers. The horizontal stresses in the rock mass are furthermore very low. The soil layers consist mainly of non-cohesive materials, often created in catastrophic events such as glacial floods, and are therefore often loosely packed. This paper gives a short overview of the geotechnical conditions in the country and additionally describes several geotechnical engineering projects. Some geotechnical challenges due to climate change will also be briefly discussed. © The authors and IGS: All rights reserved, 2019

  • 26.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute.
    Impact of Water on the Response and Performance of a Pavement Structure in an Accelerated Test2010In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 11, no 4, p. 863-880Article in journal (Refereed)
    Abstract [en]

    An accelerated load test using a Heavy Vehicle Simulator (HVS) was performed with the objective of investigating the response behaviour and performance of a commonly used pavement structure in Sweden. The structure consists of 10 cm asphalt bound layers, divided into surface course and bitumen base, over granular base and subbase resting on sandy subgrade. The structure was instrumented to register stresses, strains and deflections during loading.

    In the test more than 1,000,000 load cycles were applied. After applying the first 500,000 load cycles the water table was raised and a further 500,000 loading cycles were applied. Raising the groundwater table increased the rate of rutting developed in the structure in all unbound layers. A numerical analysis has been carried out to simulate the results.

    First the response was simulated to get a general overall agreement of the pavement response and the parameters of the model. Thereafter the permanent deformation behaviour in the main test was simulated using a simple three-parameter work hardening model with two sets of parameters for the unbound layers, before and after the groundwater table was raised. The permanent deformation behaviour of all layers was thereafter modelled separately for the two steps.

    Generally good agreement was established between the permanent deformation measurements and the calculations for all layers.

  • 27.
    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.

  • 28.
    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.

  • 29.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute. University of Iceland.
    Numerical Modelling of Thin Pavements Behaviour in Accelerated HVS Tests2007In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Road Materials and Pavement Design, ISSN 1468-0629, Vol. 8, no 4, p. 719-744Article in journal (Refereed)
    Abstract [en]

    Two thin road structures have been tested in accelerated testing by using a Heavy Vehicle Simulator (HVS). Both were surface dressed structures, one with a target 20 cm thick unbound base course layer and the other with the base divided into a 10 cm bitumen stabilized base over 10 cm unbound base. The tested road structures were instrumented to estimate deflections, strains and stresses in various locations inside the structure.

    Numerical analyses, by using two different techniques, the multilayer elastic theory (MLET) and the finite element (FE) have been carried out to simulate the response behaviour of the tested structure and compared with the actual measurements. For both techniques linear and nonlinear behaviour of the base was assumed. For the FE method both 2D axisymmetric and a 3D analysis were carried out. The results have further been used to model the permanent deformation development in each layer. The main finding of the study was that induced vertical stresses were generally well predicted in both structures. Better agreement was generally found between the vertical stresses and the actual response with the non-linear response, especially for high loading conditions.

    The best prediction of surface deflections was obtained in a three dimensional linear elastic analysis where a rectangular loading area was used instead of a circular one in the two dimensional axisymmetric solutions. Generally, poor or moderate agreement was found between the strain measurements and the numerical estimations. The simple work hardening model used to model the accumulated deformation relied on results from repeated load triaxial test results and gave generally good agreement with the results from the testing.

  • 30.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute. University of Iceland.
    On Forecasting the Resilient Modulus from the CBR Value of Granular Bases2007In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 8, no 4, p. 783-797Article in journal (Refereed)
    Abstract [en]

    The unbound granular materials (UGM), base and subbase layers, play an essential role in the overall structural performance of thin pavement structures. They show complex stress dependent elasto-plastic behaviour under external loading. Therefore the UGM are commonly tested using the Repeated Load Triaxial (RLT) testing method to estimate the stiffness of the material by applying haversine loading pulses.

    The RLT testing method represents the actual stress situation quite adequately and gives satisfactorily estimates of the stiffness characteristics of UGM. A simple test that has been used for a long time in structural design of flexible pavements is the CBR (California Bearing Ratio) test. In the CBR test, the load-deformation curve is acquired while a plunger is penetrated into the material at a constant rate. In the literature one can find a number of relationships for UGM where the CBR value is used to predict the stiffness. These connections usually do not take into account that stiffness of UGM is both stress and moisture dependent.

    To investigate if a relationship between the two tests exists, twenty materials have been tested with both methods and the test results compared. The materials were of varying quality and were tested at four different moisture contents. The results indicate that a simple power law can be used to forecast the stiffness if the CBR-value is known.

  • 31.
    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.

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  • 32.
    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.

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  • 33.
    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.

  • 34.
    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.

  • 35.
    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.

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  • 36.
    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.

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  • 37.
    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.

  • 38.
    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.

  • 39.
    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.

  • 40.
    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.

  • 41.
    Erlingsson, Sigurdur
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Saliko, Denis
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Correlating Air Freezing Index and Frost Penetration Depth: A Case Study for Sweden2020In: Proceedings of the 9th International Conference on Maintenance and Rehabilitation of Pavements: Mairepav9, Springer , 2020, Vol. 76, p. 847-857Conference paper (Refereed)
    Abstract [en]

    The determination of frost penetration is one of the main requirements in considering environmental effects in pavement design in cold regions. At the present time, the frost depth of pavements in Sweden is estimated computationally using computer software which approximates the heat equation by finite difference. Due to the geographical positioning of Sweden, a wide range of air freezing index and frost penetration depths were observed with lower values in the south and higher values in the north. This paper introduces a simplified design chart which is obtained by empirically correlating the air freezing index estimated from temperature measurements by 44 local meteorological stations to the maximum frost penetration depth obtained by 49 RWIS Road Weather Information Station data. The results are classified depending on their location and the climatic zones defined by the Swedish pavement design codes. Nonlinear prediction intervals are implemented to provide a range of possible frost penetration depths since local site conditions are not taken into account. Further research is required to consider local on-site effects such as frost susceptibility of pavement materials, the thermal conductivity of layers, access to water and snow covering.

  • 42.
    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.

  • 43.
    Everton, José
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Saliko, Denis
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure.
    Freeze-thaw influence on the water retention capacity of silty sand subgrades2022In: Proceedings of the 11th International Conference on the Bearing Capacity of Roads, Railways and Airfields: Volume 2 / [ed] Inge Hoff, Helge Mork, Rabbira Saba, London: CRC Press, 2022, Vol. 2, p. 122-131Conference paper (Refereed)
    Abstract [en]

    Fine-grained materials are associated with a higher water retention capacity due to their higher surface energy in comparison with coarser materials. That characteristic is connected to why fine-grained materials also yields more suction when drying. In addition, seasonal variation of the water table subjects fine-grained subgrades to different moisture contents, varying the suction built in the subgrade, consequently affecting its mechanical characteristics. As fine-grained materials are frequently frost susceptible, they can cause issues to the whole pavement cross-section related to Freeze-Thaw (F-T) actions, widely known as frost heave and thaw weakening. This study will seek to investigate if subsequent cycles of closed-system F-T can permanently alter the unsaturated behaviour of fine-grained materials, using as background their Soil Water Retention Capacity obtained using a pressure plate apparatus. Such issues may become more common with permafrost areas being subjected to freeze and thaw cycles due to climate change or extraordinary events creating the circumstances to F-T where it is currently not observed. Two silty sands with low plasticity were tested, and the results show a reduced water retention capacity (WRC) after closed-system F-T cycles. Considering that matric suction changes the state of stress of soils, the findings suggest an impact in the resilient modulus (Mr ) not only seasonally, as it is well established, but also after seasonal freezing and thaw events.

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  • 44.
    Fladvad, M.
    et al.
    Norwegian Public Roads Administration, Norway.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Unbound pavement materials' response to varying groundwater table analysed by falling weight deflectometer2021In: Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields: Volume 1 / [ed] Inge Hoff, Helge Mork & Rabbira Saba, London: CRC Press, 2021, p. 409-418Conference paper (Other academic)
    Abstract [en]

    Expected climate changes will in many areas represent a shift towards increased precipitation and more intense rainfall events. This may lead to increased moisture within road structures and possible overloading of road drainage systems. Pavement design methods must therefore be able to predict the behaviour of pavement materials at increased moisture levels. An instrumented accelerated pavement test (APT) has been conducted on two thin flexible pavement structures with coarse-grained unbound base course and subbase materials using a heavy vehicle simulator (HVS). The two pavement structures were identical except for the particle size distribution (PSD) of the subbase materials, where one had a dense 0/90 mm curve with a controlled fines content, and the other had an open-graded 22/90 mm curve. The APT was conducted using constant dual wheel loading, and three different ground- water levels were induced in order to change the moisture content in the structures. Falling weight deflectometer (FWD) measurements were conducted at each groundwater level during the APT. Additional FWD measurements were conducted as the groundwater was lowered after the APT loading was finished. The moisture content in the unbound materials was con- tinuously measured throughout the test. The analysis is focussed on the response of the unbound aggregate layers to varying moisture levels in the pavement structures. Analysis results show how the dense- and open-graded materials respond to the moving groundwater table, and how this affects the deflection of the full structures.

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  • 45.
    Fladvad, Marit
    et al.
    NTNU Norwegian Univ Sci & Technol, Dept Geosci & Petr, Trondheim, Norway.;Norwegian Publ Rd Adm, Trondheim, Norway..
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Modelling the response of large-size subbase materials tested under varying moisture conditions in a heavy vehicle simulator2021In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402Article in journal (Refereed)
    Abstract [en]

    Pavement design methods must be able to predict the behaviour of pavement materials at increased moisture levels due to climate changes causing increased precipitation and more intense rainfall events. This paper intends to examine the influence of moisture and gradation on pavement response. An instrumented accelerated pavement test (APT) has been conducted on two thin flexible pavement structures with unbound base course and subbase materials using a heavy vehicle simulator (HVS). The two pavement structures were identical except for the gradation of the subbase material, where one had a 0/90 mm curve with a controlled fines content, and the other had an open-graded 22/90 mm curve. The APT was conducted using constant dual-wheel loading, and three different groundwater (GW) levels were induced in order to change the moisture content in the structures. The HVS was stopped regularly for carrying out response measurements from the instrumentation. The analysis is focussed on the response of the unbound aggregate layers to varying moisture levels in the pavement structure. The increased GW level causes a substantial increase in rutting. Conflicting results are found regarding the development of stresses and strains throughout the APT. Two models, linear elastic and non-linear elastic, is employed to model the responses from the pavement structures.

  • 46.
    Fladvad, Marit
    et al.
    Norwegian University of Science and Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology.
    Performance of unbound pavement materials in changing moisture conditions2020In: Lecture Notes in Civil Engineering, Springer , 2020, Vol. 96, p. 70-79Conference paper (Refereed)
    Abstract [en]

    Expected climate changes will in many areas represent a shift towards increased precipitation and more intense rainfall events. This may lead to increased moisture within road structures and possible overloading of road drainage systems. Pavement design methods must therefore be able to predict the behaviour of pavement materials at increased moisture levels. An instrumented accelerated pavement test (APT) has been conducted on two thin flexible pavement structures with coarse-grained unbound base course and subbase materials using a heavy vehicle simulator (HVS). The two pavement structures were identical except for the grain size distribution of the subbase material, where one had a dense 0/90 mm curve with a controlled fines content, and the other had an open-graded 22/90 mm curve. The APT was conducted using constant dual wheel loading, and three different groundwater levels were induced in order to change the moisture content in the structures. The HVS was stopped regularly for carrying out response measurements from the instrumentation. The analysis is focussed on the response and the performance of the unbound aggregate layers to varying moisture levels in the pavement structure.

  • 47.
    Fladvad, Marit
    et al.
    Norwegian University of Science and Technology.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. University of Iceland.
    Permanent deformation modelling of large-size unbound pavement materials tested in a heavy vehicle simulator under different moisture conditions2022In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 23, no 5, p. 1157-1180Article in journal (Refereed)
    Abstract [en]

    Climate changes alter the environmental conditions which pavement design is based on, invalidating empirical design methods. Transition to mechanistic design requires the ability to model the behaviour of pavement materials under relevant environmental conditions. An accelerated pavement test (APT) is designed to test two instrumented pavement structures under moisture conditions which are altered by raising the groundwater table (GWT). Open-graded and well-graded subbase materials are used to investigate the effect of gradation on moisture dependency. Pavement response behaviour is modelled using a non-linear elastic (NLE) approach. Accumulation of permanent deformation under different moisture conditions is calculated by two models and compared to measured surface rutting. Moisture transport through the structures differs due to the subbase gradation. Increased GWT accelerates the accumulation of permanent deformations in both structures, identified by both models. One model provides a significantly better fit to the subgrade deformations and the width of the rutting profile.

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  • 48.
    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.
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  • 49.
    Larsson, Martin
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance. KTH, Sweden.
    Niska, Anna
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. KTH, Sweden; University of Iceland, Iceland.
    Degradation of Cycle Paths: a Survey in Swedish Municipalities2022In: CivilEng, ISSN 2673-4109, Vol. 3, no 2, p. 184-210Article in journal (Refereed)
    Abstract [en]

    There is a need to move society in a sustainable direction. One way to contribute to this move is to change to more sustainable transport modes, such as cycling. To increase cycling, the infrastructure is important, and good quality cycle paths are needed. However, little is known about the degradation of cycle paths. This paper aims to investigate what modes of pavement distress are found on municipal cycle paths in Sweden, and what probable mechanisms lie behind such distress; these are determined based on questions from a state-of-practice survey, interviews, and a literature review. The main findings are that the most commonly stated distress modes are surface unevenness followed by longitudinal cracks, and the most commonly stated causes of distress are ageing, followed by structural interventions, and roots and vegetation. The results also show that for several distress modes, there are probable connections with climatic factors such as temperature and moisture, as well as with the population size of the urban areas. Objective data are needed regarding traffic load and the climatic factors that affect cycle paths, along with information on their structural design, to better understand their degradation.

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  • 50.
    Larsson, Martin
    et al.
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance. Byggnadsmaterial, KTH, Sverige.
    Niska, Anna
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Erlingsson, Sigurdur
    Swedish National Road and Transport Research Institute, Infrastructure, Pavement Technology. Byggnadsmaterial, KTH, Sverige.
    Thunholm, Mattias
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Andrén, Peter
    Swedish National Road and Transport Research Institute, Infrastructure, Infrastructure maintenance.
    Condition assessment of cycle path roughness and evenness using a bicycle measurement trailerManuscript (preprint) (Other academic)
    Abstract [en]

    The riding comfort of cyclists related to roughness and unevenness of cycle path surfaces has unfortunately not been given enough attention in the indices used to predict cyclists’ perceptions of roadway environments. This is partly due to the lack of condition assessment methods specifically adapted to the speed and space limits on cycle paths, and a need for developing metrics that describe the perceived comfort of cyclists rather than that of car users. In this paper a novel method, the Bicycle Measurement Trailer (BMT), is proposed to bridge this gap. Eight different surface types, ranging from gravel and different sized concrete block pavements to asphalt concrete in different conditions, have been assessed with regards to roughness. Four of these surfaces were also used for the assessment of their longitudinal evenness. The accuracy and repeatability of the BMT were evaluated. Finally, five different metrics (Dynamic Comfort Index, Evenness Coefficient, 0.5 m Straight Edge, International Roughness Index and Root Mean Square), were calculated from the collected data and assessed. The main findings suggest that the BMT has a high accuracy at normal and high cycling speeds when compared to the standardized road measuring system, Road Surface Tester, and a high level of repeatability at normal cycling speed. The surfaces could be ranked according to their roughness, and the longitudinal evenness was successfully analysed from the collected data. In conclusion, the BMT could be a valuable tool to assess the cycle path surface condition in relation to how cyclists perceive the riding comfort.

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