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Sohrabi, M.R

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Thin layered systems for the repair and protection of concrete structures

PhD ThesisThin layered systems can be considered as a solution to the repair and
protection of concrete structures. This subject was studied in the current
investigation. Some common uses of these systems include protection,
upgrading and rehabilitation of the floor slabs,restoration of appearance of the
structures, impermeability, skid resistance, wear resistance, and protection of
the reinforcing steel of concrete structures against atmospheric or chemical
attack. However it can be said that protection, upgrading and rehabilitation of
floor slabs are the main uses for the design of modem thin layered systems.
For example a thin layer of a polymer concrete with a thickness of less than 3
nun can resist a very highly concentrated load resulting from a steel wheel
rolling load of 5000 N without any sign of defect.
Thin layer systems therefore include traditional screeds, externally bonded steel
plates, plasters and coatings as well as the more recent hi - tech. systems.
Like any other structure, a thin layered system may break down as the result of
many causes. Among other types of failures, delamination defect is the most
common mode of failure and particularly relevant to a thin layered system.
This phenomenon which mostly occur between the upper layer directly
subjectedto the load and the subsequent layer, is due to debonding or slippage
at the interface of the two layers. A delamination may occur at the interface of
a thin layered system even without any sign of failure in other parts of the
structure. Steel wheeled trolleys and fork - lift trucks are among the most
anticipated types of loading and causes of failures in the thin layered systems.
Different combinations of thin layered systems were prepared using some
special flooring materials, both in small and large scales. Despite the lack of
any standard test, the action of a steel wheel rolling load on the ready made and
purpose made specimens of thin layered systems was well simulated using the
Steel Wheel Rolling Load Rig. The NUROLF, Newcastle University Rolling
Load Facility, was also used for simulating the action of a tyred vehicle wheel
rolling load on the thin layered systems of large scale. Some simple ways for
detecting any possible delamination at the interface of the thin layered systems
were examined.
In addition to the available material characteristics tests, a relatively new
simple shear box test was proposed for defming the relationship between
normal stress and the correspondings hear strength for each combination of the
materials at each age of the test. The results were then used as the basis for the
subsequent structural analysis. The structural analysis of the systems was
carried out for both of the experiments using the finite element method and the
interface technique. In spite of the simplifications made in the solution, the
analytical results were consistent with the experimental results to a
considerable extent.
Based on the results of this investigation, a relatively constitutive procedure
was concluded for predicting the behaviour of a thin layered system under the
action of a wheel rolling load with regard to the delamination defect.University of Sistan and Baluchestan:
Ministry of Culture and Higher Education of the Islamic Republic of Iran

Sohrabi, Mohammad Reza

Newcastle University eTheses

http://theses.ncl.ac.uk/jspui/bitstream/10443/485/1/Sohrabi96.pdf

Thin layered systems for the repair and protection of concrete structures

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