Sverige har länge använt beläggningsytor av asfalt på grund av dess flexibla egenskaper som är lämpliga för det svenska klimatet. Historiskt sett har Sverige haft låg trafikmängd vilket inte gett utrymme för utvecklingen av betong som beläggning i vägar. Trafikmängden har sedan ett par år tillbaka ökat markant och det kan därför hända att det kommer att byggas betongvägar i huvudleder. Emellertid är erfarenheten i Sverige så pass låg att utveckling av nuvarande metoder fordras. USA har länge brukat betongvägar i stor skala och har betydligt större mängd betongvägar i motsats till Sverige, som har mindre än 1 %. Den ökade trafikmängden speglas även på flygplatser. I den här studien jämförs den svenska dimensioneringsmetoden för betongbeläggning på flygfält (Strand, 2016) med den amerikanska dimensioneringsmetoden i syfte att optimera den svenska metoden. Den svenska dimensioneringsmetoden (Strand, 2016) som denna studie behandlar är förenklad och baserad på gamla teorier. Metoden framställs genom äldre litteraturstudier men kombineras även med aktuell litteratur. Den amerikanska metoden används genom dess egna datorprogram kallad FAARFIELD där alla beräkningar görs med hänsyn till dess normer och krav. Dimensioneringen sker för lasten från Airbus A380 med 365 avgångar per år enligt Swedavias förväntningar. Oarmerade betongplattor med 350 till 450 mm tjocklek med betongkvaliteten C35/45 klarar inte av utmattningskriteriet. Däremot klarar likadana plattor med betongkvalitén C60/75 utmattningskraven och fungerar utmärkt som beläggning på uppställningsplatser och rullbana. Vid dimensionering enligt den amerikanska metoden visar resultaten att plattorna blir både tjockare och tunnare än den svenska metoden beroende på vilken betongkvalite som används. Den svenska metoden förutsätter en del förenklingar vid dimensionering av betongbeläggningar och därför blir inte beräkningen helt korrekt. Resultaten som denna studie visar är därför preliminära. Optimering av den svenska beräkningsgången är ett steg i rätt riktning men det praktiska utförandet av arbetet och erfarenheten av detta är något som måste byggas ut för en fulländad och fungerande metod i praktiken.

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Conventional construction of Jointed Plain Concrete Pavements (JPCP) in Canada consists of placing a round steel epoxy-coated dowel at the mid height of the pavement. Steel dowels reduce stepping at the joint to improve comfort and reduce the stress concentration on the support layer beneath the pavement. Most importantly they transfer load and are commonly referred to as load transfer devices. Problems with dowel bar deterioration, including corrosion causes the slab joint to lock and cause stress concentrations as the slab expands and or contracts and curls due to thermal and shrinkage straining occurring in the concrete. In this research, alternative joint load transfer devices are presented and compared to conventional steel dowels. Four device alternatives are developed and evaluated: a Glass Fibre Reinforced Polymer (GFRP) I-beam placed directly on the base material; GFRP tapered plates; a continuous horizontal V device; and a continuous horizontal pipe device both placed directly on the support layer. The two devices that are continuous run the length of the joint similar to a shear key. The GFRP tapered plate and I-beam, as well as conventional steel dowels, were analyzed in a wheel path sized three dimensional finite element model for wheel loading and static loading applied to either side of the joint. An experimental testing program was developed to test joint load transfer capabilities of each device when subjected to a static wheel load applied to either side of the joint. The GFRP tapered plates and I-beams were shown to transfer load based on the results from the wheel path finite element model and experimental testing program. The differential joint deflection, stress concentrations and plastic straining occurring in the concrete is not reduced with either the tapered plate or I-beam compared to a dowel under wheel loading. In addition, a similar plastic straining area identified in the finite element models were noticed as an area of damage in the experimental testing program. All of the devices developed are analyzed in a quarter slab three dimensional finite element model with shrinkage and thermal strains as well as wheel loading applied to the slab to simulate service loading. A detailed investigation into the stress distribution around the devices and the differential deflection at the joint through the service loading applied is presented in this paper. Similarly to the wheel path investigation the stress concentration in the tapered plate and I-beams are greater than conventional dowels and also have greater differential deflection occurring at the joint. Both the continuous Horizontal V and Horizontal Pipe device reduce stress and plastic straining in the concrete during the service load analysis compared to dowels. During daytime wheel loading the differential deflection in the joint is the lowest with no noticeable stepping occurring at the joint with the Horizontal V device; however is greater than conventional steel dowels under nighttime wheel load application. The differential deflection with the Horizontal Pipe during day and night straining and wheel loading is similar to conventional steel dowels.

Conventional construction of Jointed Plain Concrete Pavements (JPCP) in Canada consists of placing a round steel epoxy-coated dowel at the mid height of the pavement. Steel dowels reduce stepping at the joint to improve comfort and reduce the stress concentration on the support layer beneath the pavement. Most importantly they transfer load and are commonly referred to as load transfer devices. Problems with dowel bar deterioration, including corrosion causes the slab joint to lock and cause stress concentrations as the slab expands and or contracts and curls due to thermal and shrinkage straining occurring in the concrete. In this research, alternative joint load transfer devices are presented and compared to conventional steel dowels. Four device alternatives are developed and evaluated: a Glass Fibre Reinforced Polymer (GFRP) I-beam placed directly on the base material; GFRP tapered plates; a continuous horizontal V device; and a continuous horizontal pipe device both placed directly on the support layer. The two devices that are continuous run the length of the joint similar to a shear key. The GFRP tapered plate and I-beam, as well as conventional steel dowels, were analyzed in a wheel path sized three dimensional finite element model for wheel loading and static loading applied to either side of the joint. An experimental testing program was developed to test joint load transfer capabilities of each device when subjected to a static wheel load applied to either side of the joint. The GFRP tapered plates and I-beams were shown to transfer load based on the results from the wheel path finite element model and experimental testing program. The differential joint deflection, stress concentrations and plastic straining occurring in the concrete is not reduced with either the tapered plate or I-beam compared to a dowel under wheel loading. In addition, a similar plastic straining area identified in the finite element models were noticed as an area of damage in the experimental testing program. All of the devices developed are analyzed in a quarter slab three dimensional finite element model with shrinkage and thermal strains as well as wheel loading applied to the slab to simulate service loading. A detailed investigation into the stress distribution around the devices and the differential deflection at the joint through the service loading applied is presented in this paper. Similarly to the wheel path investigation the stress concentration in the tapered plate and I-beams are greater than conventional dowels and also have greater differential deflection occurring at the joint. Both the continuous Horizontal V and Horizontal Pipe device reduce stress and plastic straining in the concrete during the service load analysis compared to dowels. During daytime wheel loading the differential deflection in the joint is the lowest with no noticeable stepping occurring at the joint with the Horizontal V device; however is greater than conventional steel dowels under nighttime wheel load application. The differential deflection with the Horizontal Pipe during day and night straining and wheel loading is similar to conventional steel dowels.

The need for modern transportation systems together with the high demand for sustainable pavements under applied loads have led to a great deal of research on concrete pavements worldwide. Development of finite element techniques enabled researchers to analyse the concrete pavement under a combination of axle group loadings and environmental effects. Consequently, mechanistic approaches for designing of concrete pavements were developed based on results of finite element analyses. However, unpredictable failure modes of concrete pavements associated with expensive maintenance and rehabilitation costs have led to the use of empiricalmechanistic approach in concrete pavement design. Despite progressive knowledge of concrete pavement behaviour under applied loads, concrete pavements still suffer from deterioration due to crack initiation and propagation, indicating the need for further research. Cracks can be related to fatigue of the concrete and/or erosion of materials in sub-layers. Although longitudinal, midedge and corner cracks are the most common damage modes in concrete pavements, Austroads method for concrete pavement design was developed based on traditional mid-edge bottom-up transverse cracking introduced by Packard and Tayabji (1985). Research presented in this thesis aims to address the most common fatigue related distresses in concrete pavements. It uses comprehensive finite element models and analyses to determine the structural behaviour of concrete pavements under vehicular loads and environmental effects. Results of this research are supported by laboratory tests and an experimental field test. Results of this research indicate that the induced tensile stresses within the concrete pavement are significantly affected by vehicle speed, differential temperature gradient and loss of moisture content. Subsequently, the interaction between the above mentioned factors and concrete damage modes are discussed. Typical dynamic amplifications of different axle groups are presented. A new fatigue test setup is also developed to take into consideration effects of pavement curvature on fatigue life of the concrete. Ultimately, results of the research presented in this thesis are employed to develop a new guide for designing concrete pavements with zero maintenance of fatigue damage.