A recurrent challenge on cycle paths are edge cracks, which affect the traffic safety and accessibility of cyclists and produce high maintenance costs. Being both structurally thinner and narrower structures than roads, the cycle paths are extra prone to this problem. A few passages of heavy vehicles in unfavourable conditions might be enough to break the edge. The load-bearing capacity of eight municipal cycle paths in Linköping, Sweden, were assessed by falling weight deflectometer (FWD) and light falling weight deflectometer (LWD) measurements during a year-long cycle. A set of alternative Deflection Bowl Parameters (DBPs), better adapted to the structural design of cycle paths, were suggested and evaluated. The results of the FWD measurements showed that these suggested DBPs are a promising approach to evaluate the load-bearing capacity of cycle paths. From the results of the LWD measurements, it was found that the load-bearing capacity varies considerably with lateral position. The conclusion is that it might be more fruitful to measure the load-bearing capacity by LWD close to the edge, rather than the traditional approach of FWD measurements along the centre line of the cycle path.

Cyclists’ riding comfort, related to pavement texture and unevenness, has not been thourougly investigated, partly due to the lack of condition assessment methods specifically adapted to the speed and space limits on cycle paths. Metrics that better describe the perceived comfort of cyclists, rather than that of car users, are needed. In this paper a novel method, the Bicycle Measurement Trailer (BMT), is proposed to bridge this gap. Eight different cycle path surface types have been assessed with regards to pavement texture and for four of these surfaces the longitudinal evenness was assessed. 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 and a high level of repeatability at normal cycling speed. The surfaces could be ranked according to texture, and the evenness was successfully analysed. In conclusion, the BMT could be a valuable tool to assess the cycle path surface condition in relation to bicycle riding comfort.

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.

This article presents a model for the permanent deformation (PD) behavior of unbound granular materials (UGMs) used in the base and subbase layers of pavement struc- tures. The model was developed based on multistage (MS) repeated load triaxial (RLT) test- ing. This is essentially a modified version of a previously developed model to better suit to field conditions in a simple and effective manner. The model was calibrated for eight com- monly used UGMs using MSRLT tests with a range of moisture contents. For validation, the calibrated models were used to predict the PD behavior of three of the UGMs in MSRLT tests with stress levels and moisture contents different from those used during the calibrations. This model showed better quality of fit when compared with another widely used PD model. The model was further tested successfully for field conditions by capturing the PD behavior of an instrumented pavement test section in a controlled environment using a heavy vehicle simu- lator (HVS) based accelerated pavement testing (APT). Inputs for calibrating the model were based on the readings from the instrumentations. The parameters of the model were adjusted to match the measured data with the predictions. Based on these results for various design conditions, some ranges of values of the material parameters of the model were suggested.

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.

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 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.

Detta notat beskriver laboratorieprovningar av provkroppar tagna från fyra vägsträckor på E45 nära Svappavaara i Norrbottens kommun. Sträckorna ligger omkring 100 kilometer norr om polcirkeln i ett klimat som kännetecknas av långa kalla vintrar och korta milda somrar. De fyra teststräckorna är byggda på konventionellt sätt. Varje delsträcka är omkring 200–250 meter lång med en central del på 100 meter som utgör den egentliga teststräckan. Alla konstruktionerna har en överbyggnadstjocklek på 60 centimeter och ligger ovanpå en gammal vägkonstruktion som uppskattas till 70 centimeter i tjocklek. Den bitumenbundna delen består av fyra lager, ett ytlager, bindlager samt två bundna bärlager. Huvudskillnaden i strukturerna ligger i sammansättningen av bindlagret samt de två bundna bärlagren. Hösten 2013 togs borrade kärnor från alla sträckorna som sedan testades i VTI:s laboratorium i Linköping. Dessutom togs det prov från det obundna bärlagret som också testades. Denna rapport presenterar resultaten av laboratorietesterna. För de bundna lagren bestämdes sammansättning, styvhet samt utmattningsmotstånd. Alla tester utfördes enligt svensk eller ekvivalent europeisk norm. För det obundna bärlagret bestämdes några fundamentala egenskaper samt styvhet och permanenta deformationsegenskaper vid olika fuktkvoter.

Excess moisture presence in pavement unbound layers can result in lower structural stiffness and reduce the service life of road systems. A field study was conducted along the county road 126 near Torpsbruk to investigate the effect of the moisture content on the bearing capacity of a flexible pavement structure and its unbound layers stiffness. The subsurface drainage system of the test road was clogged during a three-month period in summer 2010, raising the groundwater level under pavement structure and therefore increasing the moisture content of the pavement unbound layers. During this period, the groundwater level and the volumetric moisture content of the pavement was continuously monitored using the instrumentations at test site and the structural response of the pavement was evaluated by conducting frequent Falling Weight Deflectometer (FWD) tests with multilevel loads. Using the FWD data, the unbound layers stiffness were back-calculated and their sensitivity to the moisture content and load level were studied. The field measurements showed that the groundwater level can significantly affect the moisture condition of the unbound layers and therefore their stiffness. Both the unbound granular layer and the subgrade showed stress dependent behavior to multilevel FWD loads.

Ökad fuktkvot i vägars obundna lager kan inverka på vägkonstruktionens strukturella styvhet och minska dess livslängd. En fältstudie gjordes längs riksväg 126 nära Torpsbruk för att undersöka de obundna lagrens fuktkvoter på vägkonstruktionens strukturella respons och styvhet. Vägkonstruktionens dräneringssystem täpptes till under tre månader under sommaren 2010. Tilltäppningen av dräneringssystemet resulterade i en snabb höjning av grundvattennivån, samtidigt ökade de obundna lagrens fuktkvot. Under studieförloppet har grundvattennivåns läge och fuktkvoten i vägkonstruktionens obundna lager mätts kontinuerligt med hjälp av fältinstrumenteringar. Dessutom gjordes frekventa fallviktsmätningar med tre lastnivåer för att mäta konstruktionens strukturella respons. På så sätt kunde lastnivåns och fuktkvotens inverkan på de obundna lagrens beteende studeras med målsättningen att bestämma egenskaperna hos de obundna materialen genom bakberäkning av fallviktmätningsdata. Enligt bakberäkningarna resulterade konstruktionens fuktökning till en betydande reducering av de obundna lagrens styvhet. Det observerades dessutom att de obundna lagren visade ett spänningsberoende beteende under de olika lastnivåerna vid fallviktsmättningarna.

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.

Denna rapport beskriver fyra nya instrumenterade vägsträckor på E45 nära samhället Svappavaara i Norrbottens län. I samband med att en ny malmgruvstäkt öppnades i Kaunisvaara 2012 kommer all malm som utvinns där att transporteras på det befintliga vägnätet längs Rv99, Rv395, E45 och E10 till Pitkäjärvi, totalt 160 kilometer. Malmen kommer därefter att omlastas till järnväg och transporteras till Narvik för vidare transport sjövägen. Malmbrytsoperatören har erhållit ett tillstånd att använda forden med den totala vikten 90 ton i stället för den 60 ton maximala tyngd som tillåts på vägnätet. Fordonen består av en 9 ton tung styraxel med singelhjul samt tre trippelaxlar där varje trippelkonfiguration väger 27 ton. När malmtäkten kommer att vara i full drift beräknas det bli omkring 66 000 överfarter av dessa fordon per år på vägsträckan. Detta motsvarar omkring 7–8 överfarter per timme eller 7½ minut mellan passagerna. Detta leder till att det är nödvändigt att förstärka det lokala vägnätet. Som ett led i processen att välja lämplig konstruktion har dessa fyra strukturer som beskrivs i denna rapport valts ut och byggts. Konstruktionerna är bestyckade med vägteknisk instrumentering samt sensorer för att uppskatta klimatets inverkan. Vägkonstruktionerna skall följas upp de närmaste åren för att ge bättre inblick i deras tillståndsutveckling, framför allt spår- och sprickutveckling. Varje teststräcka är omkring 200 meter lång och består av en 100 meter lång inre del som utgör den egentliga teststräckan. Konstruktionerna byggdes sommaren 2012 förutom slitlagret (tunnskiktet) som lades i juli 2013. Den vägtekniska instrumenteringen består av vertikala töjningsgivare (Emu-coils), jordtrycksdoser (SPC) samt dragtöjningsgivare. Klimatinstrumenteringen består av tre fuktstavar samt en tjälstav. Dessutom mäts beläggningstemperaturen på tre nivåer i teststräcka 2. En VVis klimatstation (2527 Svappavaara) finns också längs E10 på omkring 3,2 kilometers avstånd syd-öst från teststräckorna.

Terrasstabilisering är en metod som används för att förbättra bärigheten vid grundläggning på finkorniga jordar med dålig bärighet. Metoden tillämpas för att förbättra bärigheten i terrassen till exempel för byggtransporter, men framförallt för att optimera överbyggnaden för den slutliga vägen. Metoden används i stor utsträckning utanför Sveriges gränser och har där visat sig ge väl fungerande konstruktioner. Syftet med studien har varit att samanställa befintlig kunskap om metodens möjligheter och begränsningar som ett led i att skapa möjligheter till en ökad användning av metoden. Dokumentet behandlar ytstabilisering av befintlig finkorning jord i väglinjen. Stabilisering av de obundna lagren i själva vägkonstruktionen omfattats inte av studien. Eftersom huvudsyftet har varit att studera metoden i sig, har fokus lagts på konventionella bindemedel såsom kalk, cement och slagg. Några resultat:

• För att full ut kunna ta nytta av metodens fulla potential krävs utveckling och ökad erfarenhet av såväl utförande som hur kravformulering ska ske.
• Metodens ekonomiska fördelar blir mest påtagliga om man betraktar anläggningen ur ett livscykelperspektiv.
• Under vissa förutsättningar så har metoden en potential att bidra till en ökad energieffektivitet.

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.