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Val av åtgärd vid spårbildning på busshållplatser

Ferati, Egzon (2016)
LTH School of Engineering in Helsingborg
Abstract
Lund Municipality, just like many other municipalities, has recurring problems with rutting at their bus stops. There is a notable problem in Lund though and the rutting occurs regardless of whether the stops are placed at high, medium or low-volume roads. In this thesis, eleven of the most vulnerable coatings in Lund Municipality were investigated. This thesis is written in collaboration with road managers Lund municipality, and contractor Peab as well as Lund University.
Surveys of the bus stops rut depth and rut width were carried out on the spot and further analysis was done on the underlying asphalt layers. What type of asphalt that was used in the construction or when these coatings were laid out has not been documented, which... (More)
Lund Municipality, just like many other municipalities, has recurring problems with rutting at their bus stops. There is a notable problem in Lund though and the rutting occurs regardless of whether the stops are placed at high, medium or low-volume roads. In this thesis, eleven of the most vulnerable coatings in Lund Municipality were investigated. This thesis is written in collaboration with road managers Lund municipality, and contractor Peab as well as Lund University.
Surveys of the bus stops rut depth and rut width were carried out on the spot and further analysis was done on the underlying asphalt layers. What type of asphalt that was used in the construction or when these coatings were laid out has not been documented, which limited the analysis of this work. The tests on the drilled core samples from the bus stops were tested with Marshall Stability Test. From the Marshall Stability Test we extracted the maximum load that causes the test specimen to fracture when subjected to a certain load and the yield value, which is a measure of the impactor deformation. These are then recorded and analyzed. The results showed that there was very little correlation between the rut depth/rut width and number of buses that drove on the roads, which was the main problem. This tells us that the root cause of the problem in all likelihood lies in the composition of the coating and that the proposed measures should not solely depend on the number of buses at the bus stop. Another problem that was visible on the cores was that the old bitumen-rich wearing course had not been milled away, but instead wearing course after wearing course had been piled on top of each other. That is what has likely caused the huge agitator seen at bus stops. A wearing course is not suited to withstand the shear stresses that occur 20-80 mm down in the structure that are caused by the heavy bus traffic. This thesis therefore proposes that the bitumen-rich coating is milled away and replaced with bitumen poor coatings on the depth, such as a traditional ABb. The underlying layers showed better correlation between the values of the Marshall test and the measured values. This may partly be because there were so few specimens to compare with, but beyond that they showed a very good correlation. (Less)
Please use this url to cite or link to this publication:
author
Ferati, Egzon
organization
year
type
M2 - Bachelor Degree
subject
keywords
marshall stability test, rutting, bus stops, lund municipality, asphalt pavement
language
Swedish
id
8886775
alternative location
https://portal.ch.lu.se/Campus.NET/Services/Publication/Export.aspx?id=2932&type=doc
date added to LUP
2016-07-06 04:08:13
date last changed
2016-07-06 04:08:13
@misc{8886775,
  abstract     = {Lund Municipality, just like many other municipalities, has recurring problems with rutting at their bus stops. There is a notable problem in Lund though and the rutting occurs regardless of whether the stops are placed at high, medium or low-volume roads. In this thesis, eleven of the most vulnerable coatings in Lund Municipality were investigated. This thesis is written in collaboration with road managers Lund municipality, and contractor Peab as well as Lund University.
Surveys of the bus stops rut depth and rut width were carried out on the spot and further analysis was done on the underlying asphalt layers. What type of asphalt that was used in the construction or when these coatings were laid out has not been documented, which limited the analysis of this work. The tests on the drilled core samples from the bus stops were tested with Marshall Stability Test. From the Marshall Stability Test we extracted the maximum load that causes the test specimen to fracture when subjected to a certain load and the yield value, which is a measure of the impactor deformation. These are then recorded and analyzed. The results showed that there was very little correlation between the rut depth/rut width and number of buses that drove on the roads, which was the main problem. This tells us that the root cause of the problem in all likelihood lies in the composition of the coating and that the proposed measures should not solely depend on the number of buses at the bus stop. Another problem that was visible on the cores was that the old bitumen-rich wearing course had not been milled away, but instead wearing course after wearing course had been piled on top of each other. That is what has likely caused the huge agitator seen at bus stops. A wearing course is not suited to withstand the shear stresses that occur 20-80 mm down in the structure that are caused by the heavy bus traffic. This thesis therefore proposes that the bitumen-rich coating is milled away and replaced with bitumen poor coatings on the depth, such as a traditional ABb. The underlying layers showed better correlation between the values of the Marshall test and the measured values. This may partly be because there were so few specimens to compare with, but beyond that they showed a very good correlation.},
  author       = {Ferati, Egzon},
  keyword      = {marshall stability test,rutting,bus stops,lund municipality,asphalt pavement},
  language     = {swe},
  note         = {Student Paper},
  title        = {Val av åtgärd vid spårbildning på busshållplatser},
  year         = {2016},
}