1. Swedish Transport Administration , Gibraltargatan 7 , Malmö , Sweden .
2. Lund University , Division of Building Materials , Box 118, SE-221-00 , Lund , Sweden .
3. Université Libre de Bruxelles. École polytechnique de Bruxelles (Brussels Faculty of Engineering) , Laboratory of Image Synthesis and Analysis. Campus de Solbosch , Av. Franklin Roosevelt 50, Brussels 1000 , Belgium .