Att asfalt går att återvinna till 100% har varit känt sedan lång tid. Slitlagerbeläggningar är mer utsatta än de övriga de strukturella lagren i vägen. Direktkontakt med däck och dubbdäck samt exponering mot syre och UV-strålning samt vatten gör att materialkraven på råmaterialen och färdig produkt är mer omfattande för slitlagerbeläggningar. Vid återvinning av asfalt är det lätt att material från olika lager i konstruktionen blandas. Det var därför inte tillåtet att använda återvunnen asfalt i nya slitlagerbeläggningar i Sverige innan 2017 då denna begränsning lyftes.  

Vi har gjort en uppföljning av hur slitlagerbeläggningar tillverkade med respektive utan återvunnen asfalt presterat på ett antal högtrafikerade vägar i Mellansverige under fem år samt även undersökt beläggningarnas slitstyrka gentemot dubbdäck i en provvägsmaskin. Slitlagerbeläggningarna som ingår i studien är tillverkade vid olika typer av asfaltverk.  

Spår- och texturutvecklingen under fem år var likartad för provsträckorna med återvunnen asfalt och referenssträckorna på de 6 testplatserna. Dubbdäckslitaget för provmaterialen och motsvarande referensmaterial i försök med provvägsmaskinen. 

Resultaten visar att med en noggrann separering och hantering av de olika återvunna asfaltsmaterialen går det att tillverka slitlagerbeläggningar baserade på återvunnen asfalt med samma kvalitet som dito baserade på 100 % nya råvaror.  

Hur ökar vi produktiviteten och innovationstakten inom infrastruktursektorn? Varför tar det lång tid för innovationer inom nybyggnation, drift och underhåll av väginfrastruktur att slå igenom? Processen att byta traditionella metoder till innovativa dito är förknippad med stora ekonomiska risker. Därför behöver nyheter valideras med fältförsök i verklig trafikmiljö. Tester utförs idag företrädesvis i det något mindre trafikerade vägnätet för att minimera riskerna för kostsamma interventioner, ifall försöken skulle leda till ett snabbt nedbrytningsförlopp.

I en provvägsanläggning som anläggs parallellt med en högtrafikerad trafikled kan man utföra fullvärdiga valideringsförsök i ett snabbt tempo. Under större delen av året leds trafiken in i anläggningen där fältförsöken utförs. När behov uppkommer eller vid schemalagda intervall leds trafiken tillbaka till det ordinarie körfältet. Behoven kan t.ex. vara att man behöver göra olika typer av åtgärder på försökssträckan när ett eller flera försöksfält börjar närma sig slutet av sin livslängd. En provvägsanläggning skulle gynna och påskynda processen från idé till implementering.

Förstudien belyser tekniska och organisatoriska förutsättningar samt undersöker några möjliga affärsmodeller och driftsformer för en provvägsanläggning, vilket innefattar exempel på hur den kan finansieras dels initialt, dels över tid. Syftet med en fast provvägsanläggning är att erbjuda möjligheter för validering av kostnadseffektivare och/eller miljövänligare vägkonstruktioner och underhållsmetoder. Anläggningen ger en möjlighet att studera eller validera de nya tekniklösningarna i en verklig trafikmiljö. Ett överslag för vad en 3 km lång provvägsanläggning kan kosta har genomförts med förslag på hur anläggningen kan byggas etappvis samt hur den kan drivas på ett smart sätt för att erhålla god nytta av försök och låg kostnad ifall man har aktivitet i anläggningen. Ett antal förslag på försök och exempel på projekt som kan genomföras vid anläggningen presenteras. Sammantaget så uppskattar vi att nyttokostnadskvoten för förslagen och anläggningen är mycket god.

This study highlights technical and organizational conditions for a test road facility. The study will also highlight possible business models and operation and management of the facility, which includes initial financing at the beginning and over time. The purpose of a fixed test road facility is to offer opportunities for validation of more cost-effective or more environmentally friendly road structures. The facility will also provide the opportunity to study or validate new maintenance and technological solutions in a real traffic environment.

The study started with external monitoring and mapping of existing demo and test track facilities. A more detailed analysis has been provided to show specific needs and expected upcoming challenges in the field. Analysis of the business model and organization for similar test facilities have presented the possible business models for organization, ownership, operation and maintenance. Investment costs and profitability analysis have been presented, for establishing and operation of a Nordic test track facility over two five-year periods, together with a market demand and profitability analysis. 

Results from the study show great potential for a Nordic test road facility. There is also great interest from construction industries for a test road facility. MnROAD is the only test facility with the ability to manage traffic and test in a real traffic environment which is very extensive. Evaluation of the research activities at MnROAD has shown great profitability with a profit ratio of 9 (profits / costs) during the first phase. A test road facility, which is designed for Nordic challenges would contribute to increased productivity and increased innovation within this area in Sweden. 

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.

There is an increasing interest among road authorities in studying sustain ability assessment of road infrastructure. The durability of the surface course is a critical factor in these calculations and must be carefully considered in the analysis. New types of asphalt mixes with the potential to improve the results in the sustainability assessment have no proven track record and are thus more likely not to be used until solid perform ance data is available. To bridge the gap and diminish the uncertainty about the durability of Green asphalt mixes for surface courses, a combination of laboratory tests and tests in a circular road simulator were performed. Eight mixes were tested in total, four stone mastic asphalt mixes and four porous asphalt mixes. Each group contained a reference mix with well-established performance. The mixes were characterized with dynamic IDT, com plex shear modulus and water sensitivity using MiST (moisture induced stress test). Part of the loose mixes was oven aged at 85 °C simulate long term ageing. Plates of aged and virgin mixes were then tested in a circular road simulator in a program set up to check their sensitivity towards rutting, raveling, freeze-thaw cycles, polishing and fatigue. A combination of expert’s opinion from academia and national road administrations together with the data from the tests were used to estimate the performance of the new Green mixes.

The application of reclaimed asphalt is becoming increasingly important in the European Road Network. The demand for more environmentally friendly methods to construct pavements is growing constantly. Most developed countries are seeking new ways to consume less energy and virgin materials and produce less CO2-emissions and less waste. Beside the conventional recycling options (i.e. hot asphalt mixtures), cold recycling is becoming more popular and have been successfully applied in numerous road structures. However, the guidelines on when and how cold recycling can and should be applied differ from country to country. Structural design and mix design are also different in the European countries. A comparison of the use of cold recycling in road construction indicates that some countries are ahead of others and that comparing methods and approaches could be beneficial for all. In this paper, experiences and results are compared from five European countries. Each country presents 2-4 road sections where cold recycled materials are included in the asphalt base layer and where test results are available. Structural design, mix design, traffic loads and test results are compared to assess the success each road and study what could be learned for future constructions.

The applied pavement design procedures differ from country to country within Europe. Especially the use of cold recycling materials which is handled similar to hot-mix asphalt (HMA) in the most available guidelines isn’t sufficient researched. To verify developed procedures, practical trial sections are indispensable. Within this study cold recycled asphalt base layers (CRAB) were assessed according to the German procedure for monitoring and evaluation of road surface conditions. It can be concluded, that the general applied empirical design approach, in which the CRAB layer thickness is increased by 50 % compared to a HMA base will result in a feasible pavement structure. In general, the re-designing of the sections according to various national empirical pavement design approaches partly results in high differences for same layer types.

The Application of reclaimed asphalt is becoming increasingly important in the European Road Network. Beside the conventional recycling options (i. e. hot asphalt mixtures), cold recycling has been successfully applied in numerous road structures within the secondary and the main road network. However, the standard design procedures for common pavement materials as well as the approaches for cold recycling differ from one country to another. The comparison of five national pavement design procedures shows, that different design approaches may result in similar pavement structures for standard road materials (here: hot asphalt mixtures). The available specifications for pavement design with cold recycled materials indicate generally a surplus of thickness compared to standard structures. This varying surplus in thickness indicates different safety conditions applied in the analysed countries. In order to validate the existing pavement design procedures for cold recycling materials, two options will be followed. On the one hand mechanistic pavement design is applied which allows the calculation of required layer thicknesses. On the other hand, pavement design based on empirical values can be used.

The pavement engineering industry, having realized the significance of the impacts that it imposes on the environment through the production, construction and management of its products and assets, has been driven towards a more sustainable and circular way of operating. This has partly been through asphalt recycling, which is an area that many road authorities have prioritized. However, not all the National Road Authorities (NRAs) and/or sector stakeholders seem to be adequately familiar with the Circular Economy (CE) concept. This paper attempts to assist the transition of NRAs to a more circular way of doing business, by analyzing the current situation of CE within national/regional authorities and NRAs. To do so, a questionnaire was sent to different NRAs and an online search was conducted to identify the ways that NRAs communicate their CE practices. Findings indicate that, although the majority of the NRAs are familiar with CE as a concept, not many actions have been taken so far towards its holistic implementation. Finally, there is a significant lack of CE expertise and communication within these bodies.

Pavement Life Cycle Management is a 2-year international project aiming at supporting European National Road Authorities (NRAs) to introduce sustainability in their practices by providing training on Life Cycle techniques and a user-friendly package to support their widespread implementation. The first task in Pavement Life Cycle Management (PavementLCM) project is the creation of a Sustainability Assessment (SA) framework that complies with EN15643-5 and consequently include the three pillars of sustainability, use a life cycle approach and use quantifiable sustainability performance indicators. This paper presents the first steps towards the creation of the framework which includes the following steps: 1) review of the available Product Category Rules (PCRs) related to asphalt mixtures and pavement activities; 2) definition of the object of the assessment; 3) review and survey of NRAs practices of the main research efforts in Europe towards the definition of sustainability performance indicators.

En ny vägyta bör vara och upplevas som säker av trafikanterna oavsett vilket väglag som råder. Det är därför viktigt att vägbanan har en tillfredställande nivå på friktion redan när vägen öppnas. Det finns begränsade dokumenterade kunskaper hur vägen förändras den första tiden efter en beläggningsåtgärd.

Syftet med detta projekt är att fastställa hur friktionen förändras under den första tiden efter att vägbeläggningen är lagd och trafikpåsläpp sker. Ambitionen är att kunna avgöra om nylagda vägavsnitt har nedsatt friktion och ge rekommendationer för när en friktionsmätning ska utföras och hur skyltning ska ske i anslutning till beläggningsarbeten. Upplägget har varit att följa olika objekt med täta friktions- och texturmätningar från strax innan trafikpåsläpp tills nivåerna har stabiliserats.

Initialt är friktionen hög för att sen avta med mängden trafik. Efter 1–3 veckor nåddes det lägsta värdet och därefter ökade eller stabiliserades friktionen. Gemensamt för alla undersökta sträckor var att det sker stora förändringar i texturnivåerna från att det första fordonet trafikerar vägen och därefter är den starkaste tendensen en sjunkande texturnivå tills en stabil nivå uppnås efter 1–3 veckor.

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.