The Life Cycle Assessment (LCA) of asphalt pavements are associated with significant uncertainty resulting from variability in the quantity and impact of individual components, the quality of data for each component, and variability of asphalt durability. This study presents a framework to quantify and incorporate the uncertainty of LCA and asphalt durability data into LCA of asphalt surfacings. The suggested framework includes: estimating the uncertainty of asphalt production processes by the pedigree matrix method, conducting a deterministic LCA, applying Monte Carlo Simulation (MCS) to estimate the probability density functions (PDFs) of the considered impacts using the uncertainty data, deterministic solution, and asphalt durability. This framework was applied to six asphalt mixtures; the results show that there is significant uncertainty in the processes that contribute to the environmental impacts. They also showed that considering asphalt durability and its uncertainty is critical and can significantly change the results and interpretation of LCA.

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.  

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.

Street pavements are subject to various types of distress which necessitate a cost-effective management approach. This paper presents the outcomes of a survey focusing on street pavement maintenance and the utilization of machine learning (ML) pavement performance models on a 320 km municipal street network in Skellefteå municipality, Sweden. The findings reveal that the most common types of distress on Swedish streets include potholes, surface unevenness and alligator cracking, while prevalent causes of these distress are pavement ageing, heavy traffic and pavement patches. The windshield method of assessment of street pavement is prevalent, but the use of pavement management systems (PMS) is limited and pavement performance models are rarely employed. The case study reveals that Random Forest (RF) models developed for non-residential streets perform better than residential street models. RF models based on the variables age (A) and traffic (T) emerged as the best models, with 84% prediction accuracy. However, the R-squared value for the RF model applied to residential streets was 0.53, slightly surpassing the values for all models applied to non-residential streets (0.31, 0.50, 0.49). Further evaluation of models is suggested by using additional data.  

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

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

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

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.

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.

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

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

 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.

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.

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.

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.

 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.

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.

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.

Using reclaimed asphalt (RA) in new pavements reduces the environmental impact of the new pavement. As the proportion of RA in newly paved asphalt increases, it is important to maintain or improve the quality of the mixture so as not to create an increased maintenance requirement. Rejuvenators and mixing with softer bitumen are used to compensate for the harder aged binder in RA. Rejuvenators reduce the stiffness and brittleness of the bitumen, which improves resistance to cracking. However, the risk of initial deformation associated with the use rejuvenators or mixing with softer binder in RA mixes has not been evaluated.

The objective of this project was to evaluate the stiffness changes with time of laboratory manufactured asphalt concrete mixtures having rejuvenators or softer bitumen with high percentage of RA. In this project, indirect tensile tests, modal analysis, and shear tests were conducted on five different asphalt concrete mixtures with RA, rejuvenators, and polymers.

The results showed that there are no significant differences in stiffness change with time between the different mixes was observed within 7 to 21 days after production. However, there is stiffness change with time in the long term. The stiffness modulus and shear testing showed that mixing with soft bitumen, or using rejuvenators result in small differences in stiffness and shear modulus values, respectively. Polymer modified mixes have shown lower shear modulus at low temperatures and higher shear modulus at high temperatures compared to mixes with conventional bituminous binders which increases the resistance to cracking at low temperatures and the resistance to deformation at higher temperature, respectively. Storage and conditioning of the specimens and all measurements were carried out in a laboratory environment; thus, the results represent only the stiffness change that occurs without external influence from climate and traffic.

Asphalt pavement performance is affected by the presence of water(moisture). Increased moisture within the road structure can result in substantial cost increase for the for society. Research have showed that significant portion of the road sections need early maintenance measures regardless of traffic volume due to moisture-related damages. Monitoring moisture conditions, preferably using a non-destructive continuous method, offers important information into the decision-making and selecting appropriate maintenance intervention. Furthermore, understanding moisture conditions is critical for accurately interpreting automatic road condition measurements, especially during the spring (thawing) when the roads exhibit the lowest load bearing capacity due to increased levels of moisture.

This study employed a multi-receiver ground penetrating radar (GPR) and a falling weight deflectometer (FWD) devices to assess moisture levels and structural condition of field and indoor full-scale test roads. The groundwater level of the test road was varied by introducing water to the system. The results revealed an apparent correlation between the FWD and the average GPR velocity measurements. The GPR measurements provided a relative water content of the test roads. Further exploration of other GPR parameters, such as frequency, magnitude, and amplitude of the GPR signal is recommended.

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.

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.

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

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

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

Terminologi – idag råder viss begreppsförvirring

Analys av funktionella krav i tidigare projekt

Trafikantkrav

Miljökrav

Utveckling av funktionella krav i samverkan

Väghållarekonomi

Regelbetingade begränsningar av funktionella krav

Uppföljning och underlättande av erfarenhetsackumulering

Implementering av nya mått och mätmetoder

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”.

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

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

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

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

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

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

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.

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.

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.

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.

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

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

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

“Support strip”: means in this report the material that protects the edge of the (top) asphalt layer along (rural) roads. The support strip is quite narrow, around 30 cm (1 ft) and it should not be considered as the road shoulder. Normally the support strip is manufactured by crushed rock with grading 0/16 mm. 

The idea of the project is to document and evaluate a number of alternative materials to the materials described in the Swedish regulations for support strips. 

Today the material that is laid out in the support strips often does not have the functionality that it should have, especially in exposed places. 

The aim of the project is to gather experience from regions and roads where support strips work well. In addition, new materials with good properties will be developed. 

There is a need to evaluate alternative materials for support strips of crushed rock materials and to document field experiences. 

The project has been carried out through: Surveys/interviews, Field studies, Gathering of Experience and Laboratory tests 

The results include experience from surveys, field studies and procurement requirements, as well as laboratory tests carried out to verify observations in the field or to test certain theories

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

This report shows results, some statistical analysis and precision data for interlaboratory comparison (round robin) in Sweden performed on a proportioned base layer material of crushed rock for grain size distribution according to TDOK 2014:0145 (coarse material sieving) and EN 933-1:2012 (sieving on 0/16 mm).

There were 48 laboratories participating.

In the sieving on coarse material, ≥ 16 mm, the deviations are small (standard deviations approx. 0,7%) and the difference between maximum and minimum value for each sieve is only 3–4%.

The results for material finer than 16 mm (relatively to whole of the sample) are deviations wider. Especially for sieves 1/11,2 mm with difference between maximum and minimum values are up to 7% and the standard deviation for those sieves are around 1,4%. For sieves finer than 1 mm (0,5 mm and less) the differences are less than 3% and the standard deviation is less than 0,8%.

The spreading’s for the fine material sieving is wider than for the coarse sieving part. It could depend on less accurate gradings on the fractions finer than 16 mm that were used in the proportioning. For the coarse sieving the whole sample (18 kg) were the test portion, for the fine sieving the material 0/16 mm had to be divided to get the test portion (approx. 2,6 kg). The dividing can also be one of the reasons to less accurate results for the 0/16 mm-part.

Test comparisons have been carried out between road material laboratories in Sweden for particle density and water absorption according to SS-EN 1097-6:2013 in 2020. The comparison was made with four materials, two with the grading 11/16 mm and two with the grading 0/4 mm. Each participant performed double tests of each material. There were 49 laboratories participating.

Generally, are there small variations for particle density between the participants. The coefficient of variation1 is less than 1%. For the water absorption, the variations between the participating laboratories are relatively large. However, this can partly be explained with that the results consists of low values and the "natural" variation is almost as great as the results, about 0.3%. Water absorption has just under 30% in variation coefficient1for the coarser materials in grading 11/16 mm and about 60–70% for the finer ones in grading 0/4 mm.

Clearly anomalous participants for particle density for the finer materials is laboratory number 20 with very low results, where even laboratory No. 6 is located low. For water absorption, is it mainly laboratories 33, 12 and 50 that most clearly stand out in a negative way. In general, are the repeatability and the reproducibility, in this comparing analysis better or equal with SS-EN 1097-6:2013.

The objective of this project is to propose a new system for rock classification in Sweden. 

The purpose is to suggest a classification system for the use of rock material in construction and building. This new system will replace the standard for the Nordic Ball mill as classification parameter. The system is based on properties defined by testing methods that are described in European standards. 

The new system will also consider resistance to wear and resistance to fragmentation. 

The methods used are surveys, interviews with parties in the industry have been performed as well as studies of requirements and procurement documents to figure out how the present system (2022) is used and what needs there are for the future. A survey of other countries (mainly in Europe) has also been made to find new knowledge and inspiration for the design of the new classification system. Analysis of rock material data has been done to look at relevant relationships and to look at implications of hypothetical classification systems for establishing new levels. 

Within this project there are more than 2 000 data records of samples of rock material. The data records consist of petrographic description, results from Nordic Ball mill, micro-Deval and Los Angeles tests. The data have been analyzed to calculate a general correlation between micro-Deval and the Nordic Ball mill. 

The proposed system has the most impact on primarily brittle granites, which may be classified in a lower class than in previous rock classification systems. 

This project suggests a new classification system that uses resistance to wear (micro-Deval, MDE) and resistance to fragmentation (Los Angeles, LA). The classification levels are based on the supposed usefulness of rock material in road constructions and earthworks.

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

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

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

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

Agglomeration could not be proven despite several repeated tests.

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

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

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

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

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

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

Today (at least until 2022) the general classification of rock materials for roads and earthworks is determined by the Nordic ball mill (abrasion from studded tyres) in three levels. The classification is called rock type (1 to 3). Rock type 1: Nordic ball mill-value, AN, is less than 18, Rock type 2, AN 18 to 30 and Rock type 3: AN over 30. 

Since 2004, when Sweden started to adopt European standards for building materials, it has not longer been possible to have requirements for unbound layers and aggregates to the Nordic ball mill (unless for wearing coarse aggregates). The objective of this project is to find a new way of classification according to proper properties and levels. 

This report, which is from the first part of the project, describes how the term rock type is used in Sweden. It has been investigated in requirements and procurement documents and how and to what extent the industry's actors use the term (rock type). A few persons with different roles, such as consultants, client representatives, authorities, laboratories, and higher education institutions have responded to questionnaires or have been interviewed. 

AMA Anläggning 20 is the requirement document that primarily uses the concept of rock type. Then there are some other documents that make references to the AMA Anläggning and thereby indirectly use the term. Except for some consultants and some people at the Swedish Transport Administration, the interest and use are generally low in the concept of rock type. There is greater interest in a new rock-type classification system than there is in the current one among those who have provided answers. There is also often a demand for increased usability.

Today (at least until 2022), rock type is classified into three classes using the Nordic ball mill test method (below 18, 18–30 or above 30 per cent). Since 2004, when Sweden began to comply with European product standards, Nordic ball mills have not been used as a requirement parameter for most material applications with requirements for aggregates in construction. The project aims to try to renew definitions and limits for different levels of classification of rock materials quality. The methodology for defining rock type should preferably be reasonably easy to access. 

In this report, from the second part of the project, it is shown how rock materials are classified in other countries. This has been investigated by studying national and European standards related to material classification. Many national classifications have been obtained through inquiries to the contacts of the project team and among the contacts of the contacts. 

Their responses have consisted of national standards/requirements documents/manuals etcetera. 

The classifications in the standards studied in this project have no clear or obvious proposal with the same purpose as our (Swedish) system of rock type. 

The principle of the French/Belgian classification system is appealing, but the levels should probably be reviewed for Swedish conditions and area of use. Their system is based on micro-Deval, Los Angeles, and polish stone value. We do not need to take note of polish stone value in Sweden as it is a characteristic that is tested only for the wearing course. But it is appealing to use laboratory methods which are common in Sweden, such as micro-Deval and Los Angeles. A guideline value for the sum (maximum or minimum value) of selected properties is also interesting.

In Europe, poroelastic road surface (PERS) material is being tested to a level at which it can be applied on different types of roads as a noise-reducing pavement. Traffic noise reductions of around 10–12 dB have been achieved using PERS in comparison to a conventional dense asphalt concrete. The PERS material is designed as an open-graded mix to have at least 20% air voids by volume.

The objective of this research study was to evaluate the effect of six different confinement levels on the E * dynamic modulus testing of PERS mixtures. The major aim of utilising confinement on PERS materials was specifically to simulate and assess field performance characteristics of those mixes in the laboratory. Furthermore, the choice for confinement is essential in order to obtain realistic test results for a porous or open-graded aggregate structure of the PERS mix. AASHTO TP 62-07 was utilised for dynamic modulus E * testing; for confined tests, a lateral air pressure was provided that simulated confining effect on the samples. Confined tests were conducted only on the two variants of the PERS mixtures that had about 50% or greater amount of aggregates by volume of the mix. Moduli (E *) and phase angle (φ) master curves were established using the test results.

The main purpose of this study was to characterise the fundamental material (stiffness) properties of the poroelastic road surfaces (PERS) relevant to the pavement design. The research encompassed preparation of five variants of PERS mixtures in the laboratory based on the combinations of rubber, aggregate and binder components. Two standard test procedures were utilised: stress–strain sweep test and dynamic modulus E* test. First, stress–strain sweep test was performed at 1 mm/min strain rate to investigate the PERS mixtures' elastic characteristics. Hysteresis loops were plotted between force and strain change, which indicated that in all the mixes, the samples were stable to resist against higher hysteresis losses during successive cycles of testing. Also, lower losses were observed with increasing rubber contents; the results can be used in optimising the rubber content in the PERS to further assess rolling resistance and friction. Next, dynamic modulus E* test was performed on the PERS. The dynamic moduli varied based on the blending of rubber and aggregates proportion; the PERS mixes with higher amount of aggregates and lower amount of rubber had higher moduli. A comparison of moduli between the PERS mixtures and a typical asphalt concrete (AC) mix indicated that the PERS were softer than the AC mix by about 20–1500 times; the softness characteristics of the PERS would plausibly provide higher noise-dampening response. The methods employed so far covered stress–strain, and stiffness characteristics, which could be used in pavement design and the evaluation of rolling resistance and noise-reducing properties. Although this study is just a portion of a much more comprehensive laboratory test programme, these tests along with the upcoming laboratory tests are envisaged to aid in selecting the most promising PERS materials for the application on trafficked roads

Before upcoming procurement of pedestrian and bicycle paths, The Swedish Transport Administration wishes to collect information about fall injury reducing pavements. This pilot study is aimed at collecting knowledge about the evaluation of fall injuries, which material and construction methods there are available, and what the research situation is on the topic. The risk of being injured when falling is mainly evaluated by a standardized method where the deceleration in a head shaped weight is measured when it is dropped on the studied material. The literature shows multiple examples of bicycle path pavements, and different floor material and constructions, with good shock absorbing properties. The greatest challenge is to combine these shock absorbing properties with a durability needed for a bicycle path.

Fiber mesh reinforcement is known to strengthen the road and extend its lifespan. Although the positive effects of fiber mesh reinforcement have been demonstrated through different tests, there is no Swedish design guide that allows the reinforcement to have a strengthening effect in the bearing capacity calculations. In order to reach consensus regarding the benefits of fiber mesh reinforcement and how and when it may be utilized, extensive testing along with reliable methods, developed on how to include the fiber mesh in a design model, are needed.

The use of fiber mesh reinforcement is studied in this report, when and how it is used. Representatives for clients and contractors are interviewed to collect experiences from staff that worked with fiber mesh reinforcement. A literature survey is also performed to identify what evaluations have been done and how fiber mesh is applied.

The results show that most tests are performed on specimen in a laboratory environment. Real pavement constructions have also been built abroad and instrumented with strain gauges to enable readings of stresses and strains inside the asphalt concrete (AC) where they are largest. However, comparative full scale pavement sections with and without fiber mesh reinforcement, where roads may be followed while they are exposed to real traffic and climatic loading, are still missing in Sweden. Instead, indicative data have been collected from multiple roads around Sweden. Photos and rut depth data have been sourced from the National Road Administration’s public database from before and after maintenance works containing fiber mesh reinforcements. These comparisons indicate that the fiber mesh mitigate the AC deterioration on the surface. 

The concrete pavement section on E4 outside Uppsala has a few years after construction shown an accelerating rut depth increase which can not be explained by an increased traffic volume. The contactor’s self inspection protocol shows that aggregates from two different quarries with different rock qualities have been mixed in order to fulfill the ball mill value requirement. The way that the abrasive wear is affected when different proportions of a secondary aggregate quality is mixed into the pavement material is studied in this report. Seven series of laboratory specimens, consisting of asphalt concrete and cement concrete, respectively, with different parts of primary and secondary aggregates are mixed and tested according to Prall to study the resistance to wear due to studded tires. The results show an almost linear change of the abrasive wear when the proportion of the secondary aggregate is changed in the 8–16 mm fraction. It also becomes clear that the aggregates in the 4–8 mm fraction do not affect the resistance to wear.

Inom detta projekt har en ny metod för oförstörande profilerande mätningar av styvhetsmodulen på beläggningar demonstrerats och utvärderats på två kontrollerade vägsträckor. Resultaten visar att det nu är möjligt att mäta upp beläggningens styvhetsmodul och aktuell temperatur, vid en kontrollerad frekvens och töjningsnivå, genom rullande mätningar i trafik. Värdet av denna nya möjlighet är att heltäckande profilerande kvalitetskontroll av både nya och gamla vägar kan göras säkrare, från en vanlig bil, samt mer kostnadseffektivt genom att avspärrningar och stillastående provtagning kan undvikas eller minimeras. För en given beläggningstjocklek är styvhetsmodulen den viktigaste materialegenskapen i bundna asfaltlager och den egenskap som används som indata för att dimensionera beläggningens livslängd och underhållsbehov. 

Metoden bygger på kontaktlösa seismiska ytvågsmätningar med hjälp av mikrofoner. Uppmätt ytvågshastighet räknas om till dynamisk styvhetsmodul med hjälp av fundamentala viskoelastiska samband. Uppmätt ytvågshastighet och dynamisk styvhetsmodul har jämförts med konventionella stillastående mätningar och provning av borrkärnor i laboratorium. Resultaten visar på en god överrensstämmelse trots delvis okända temperaturprofiler i beläggningen. Rullande seismiska ytvågsmätningar har utförts i uppemot 50 km/h och ca 6 000 mätningar har samlats in på ungefär samma tid som en stillastående konventionell seismisk ytvågsmätning kräver.

Inom detta projekt har endast ytvågshastigheten och styvhetsmodulen analyserats och jämförts med referensmätningar. Det finns dock potential att utveckla den automatiska analysen av rådata så att också beläggningens tjocklek och den viskösa delen av beläggningens styvhetsmodul kan utvärderas.

Sufficient friction between tire and pavement is a prerequisite to ensure high traffic safety. Polishing of stones in the surface course risks causing low friction and is a problem that has gained bigger attention outside the Nordic countries. In Sweden it has been noticed that the studded tire traffic during the winter roughens the pavement surface enough to endure some polishing during the summer months. The bare ground friction has thus been allowed to vary over the year since interaction between polishing and roughening has been working well with sufficient friction even at its minimum. This interaction now seems to be out of play as repeated friction measurements on highly trafficked roads indicate an even faster polishing and in the worst case absent roughening. The background of this project is the results from repeated measurements that show critically low friction on highly trafficked road sections. The friction measurements were initiated after a car crash that got lots of attention since it was caused by lost grip and the following measurement demonstrated critically low bare ground friction. 

In this project, some possible factors are examined to why the roughening effect that earlier has been obtained during wintertime has decreased. It is presented that the traffic volume on the most heavily trafficked roads has increased, the use of studded tires has decreased substantially during the last decade and the studded tires are designed to cause less wear on pavement. The increased use of friction tires has also contributed to increased polishing during the winter months. 

The friction measurements have within the project been performed on a test section on E4 and on several highways around Stockholm. The results from the test section confirm that a harder porphyry with lower ball mill value in the surface course is more susceptible to polishing compared to softer stones. The tradeoff between abrasion resistance and polishing also becomes clear since the harder porphyry shows less abrasion wear (rutting) compared to other pavement sections. 

Measurements performed on highways around Stockholm show that the problem with low friction isn’t isolated to some single pavement section. On nine out of twelve roads, friction values below 0.5 are measured, the limit value determined by the Swedish Transport Administration under the guarantee period, on at least one 20 m section. On two out of the twelve examined highways it is demonstrated that the friction is lower than the limit value along the whole studied section.