Farhad Salour Doctoral Thesis

Keywords:
Falling Weight Deflectometer (FWD), backcalculation, unbound material, 
subgrade, seasonal variation, moisture content, spring-thaw, drainage, pavement stiffness, 
field test, pavement instrumentation, resilient modulus, permanent deformation, repeated 
load triaxial test, unsaturated soil, matric suction. 

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Preface 
The work presented in this doctoral thesis aims at providing more insight into the 
influence of moisture on the structural behaviour of pavements through field and 
laboratory investigations. This project was carried out at the Swedish National Road and 
Transport Research Institute (VTI), Department of Infrastructure Maintenance in 
collaboration with the Royal Institute of Technology (KTH), Department of Transport 
Science at the School of Architecture and the Built Environment (ABE). The laboratory 
experiments were carried out at the UNSAT Geotechnical Engineering Laboratory at the 
Arizona State University (ASU). 
The Swedish Transport Administration (Trafikverket) is greatly appreciated for financing 
this research. The financial support of the Fredrik Bachman’s Memorial Foundation 
(Stiftelsen Fredrik Bachmans Minnesfond) is also acknowledged. 
I would like to express my sincerest gratitude to my supervisor, Prof. Sigurdur Erlingsson, 
for his generous support, encouragement and excellent guidance throughout the project. I 
am sincerely grateful to Assoc. Prof. Claudia Zapata at ASU for her great input and for 
providing me the opportunity to use the facilities at ASU. I would also like to thank Johan 
Ullberg, the contact person of this project at the Swedish Transport Administration, for 
his support throughout the project. 
Many thanks to my colleagues at the Pavement Technology Division at VTI for creating a 
great work environment and fellow postgraduate students for their company, assistance 
and constructive contributions. Finally, I would like to thank my family and friends for 
their support and encouragement. 
Linköping, March 2015 

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