| 1. |
- Erlingsson, Sigurdur, 1960-, et al.
(författare)
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The Svappavaara road test sections : instrumentation
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report describes four new instrumented test road sections that have been built on E45 close to the Svappavaara in Norrbotten County in Northern Sweden. The structures are located about 100 km north of the Arctic Circle in a climate that is characterized by long cold winters and short mild summers. Norrbotten County is a sparsely populated area where the pavement structures consist of thin pavements with relatively low traffic volume. A new ore deposit, the Kaunisvaara project, was opened in 2012, meaning that the ore will be transported along the existing road network about 160 kilometers to where it will be transferred to a railway. The ore operator has received a permit to use 90 ton vehicles instead of the permissible 60 tons, consisting of a single wheel steering axle and triple dual wheel tridem axles to transport the iron ore. When the ore processing will be in full operation around 66.000 journeys per year will pass over the network, or on average about 7–8 passes per hour with about seven and a half minutes between the passes. Due to this new ore transport it will be necessary to strengthen the local road network. As part of the process to evaluate the performance of a suitable pavement structure these four instrumented test road structures have been selected and built. The structures are instrumented with road performance and climate sensors. The structures will be monitored over the years to come, though the details of the monitoring programme have not yet been decided. Each test section is around 200 metres long, consisting of a 100 metres long inner part that constitutes the intrinsic test section. The structures were built and instrumented in the summer of 2012 except for the wearing course that was placed in the summer of 2013 along with the temperature sensors that are placed in the asphalt layers. The instrumentation in each section consists of Emu coils for vertical strain measurement devices, soil pressure cells for vertical stress measurements and tensile strain gauges located at the bottom of the bound road base layer. In addition there are moisture rods located in three of the structures and a temperature (frost) rod located in structure 3. A weather station (2527 Svappavaara) operated by the Transport Administration is located 3.2 kilometre south-east of the test site.
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| 2. |
- Saevarsdottir, Thorbjorg, et al.
(författare)
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Water impact on the behaviour of flexible pavement structures in an accelerated test
- 2013
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Ingår i: International Journal on Road Materials and Pavement Design. - : Informa UK Limited. - 1468-0629 .- 2164-7402. ; 14:2, s. 256-277
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Tidskriftsartikel (refereegranskat)abstract
- Two flexible test road structures were built and tested in an accelerated pavement test using a heavy vehicle simulator, with the aims of investigating their performance behaviour for a validation in a mechanistic performance scheme and the accuracy of repeated tests. In the test more than one million load cycles were applied, but after the first half million the water table was raised. The structures were therefore analysed in moist' and wet' states, before and after raising the water level. The increased water level had a significant effect on the structure with decreased resilient modulus and increased permanent deformation. Numerical analyses have been carried out to simulate the pavement responses, where the material properties used in the response analyses were based on field and laboratory testing. The observed accumulation of permanent deformation of the unbound layers was modelled using work hardening material models. Generally good agreement was established between the measurements and calculations.
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| 3. |
- Salour, Farhad, 1985-, et al.
(författare)
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Impact of groundwater level on the mechanical response of a flexible pavement structure : a case study at the Torpsbruk test section along county road 126 using Falling Weight Deflectometer
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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