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B. Edlbacher:
"Oberbaudimensionierung von Flugbetriebsflächen";
Supervisor: R. Blab, M. Wistuba; Straßenbau und Straßenerhaltung E233, 2007.

Heavily trafficked asphalt pavements often develop permanent deformation (above all
rutting) in areas subject to frequent congestion such as intersections. Conventional
maintenance of rutted asphalt pavements means substitution of the asphalt layers in
short intervals. Therefore it exists a major demand for longer-lasting and cost-effective
solutions for hot-mix asphalt pavement rehabilitation. An alternative rehabilitation
method refers to concrete overlays on existing asphalt pavements commonly known as
whitetopping, in particular thin composite concrete overlays: thin whitetopping (TWT)
and ultra-thin whitetopping (UTW).
The purpose of this master´s thesis is to describe the state-of-the-practice for the
design and construction of whitetopping and to develop better understanding of its
mechanism. The major part deals with the principles of the proper design of thin
composite whitetoppings, as different measures for achieving long-term bond between
concrete and asphalt (monolithic section), adequate overlay thickness and relatively
close joint spacing, adequate asphalt thickness and base support condition, and
adequate concrete mixtures.
The following section briefly describes existing procedures for whitetopping overlay
design. Within the scope of comparison analyses of different structures the relevant
design stresses for a combination of traffic load and temperature computed by a finite
element programm are compared with results by different published design
procedures.
Various methods and best practices of overlay construction and rehabilitation are
discussed. Especially a proper preoverlay preparation and joint construction play an
important role in the construction of whitetopping overlays.
Included in this thesis are experiences with this overlay structure. The various types of
distress documented in the literature and the most common failure modes of
whitetopping overlays are discussed. A summary of international experiences from a
number of projects is given. Besides more detailed performance descriptions and data
of several existing projects can be found.

Heavily trafficked asphalt pavements often develop permanent deformation (above all
rutting) in areas subject to frequent congestion such as intersections. Conventional
maintenance of rutted asphalt pavements means substitution of the asphalt layers in
short intervals. Therefore it exists a major demand for longer-lasting and cost-effective
solutions for hot-mix asphalt pavement rehabilitation. An alternative rehabilitation
method refers to concrete overlays on existing asphalt pavements commonly known as
whitetopping, in particular thin composite concrete overlays: thin whitetopping (TWT)
and ultra-thin whitetopping (UTW).
The purpose of this master´s thesis is to describe the state-of-the-practice for the
design and construction of whitetopping and to develop better understanding of its
mechanism. The major part deals with the principles of the proper design of thin
composite whitetoppings, as different measures for achieving long-term bond between
concrete and asphalt (monolithic section), adequate overlay thickness and relatively
close joint spacing, adequate asphalt thickness and base support condition, and
adequate concrete mixtures.
The following section briefly describes existing procedures for whitetopping overlay
design. Within the scope of comparison analyses of different structures the relevant
design stresses for a combination of traffic load and temperature computed by a finite
element programm are compared with results by different published design
procedures.
Various methods and best practices of overlay construction and rehabilitation are
discussed. Especially a proper preoverlay preparation and joint construction play an
important role in the construction of whitetopping overlays.
Included in this thesis are experiences with this overlay structure. The various types of
distress documented in the literature and the most common failure modes of
whitetopping overlays are discussed. A summary of international experiences from a
number of projects is given. Besides more detailed performance descriptions and data
of several existing projects can be found.