1. Department of Structures and Bridges, Faculty of Civil Engineering , University of Zilina , Univerzitna 8215/1, 010 26 Zilina , Slovakia .
2. GEART, s. r. o., P.O. Hviezdoslava 42A, 010 01 Zilina , Slovakia .
3. Department of Physics of Materials, Faculty of Civil Engineering and Architecture , Opole University of Technology , Katowicka 48, 45-061 Opole , Poland .
4. Institut Pascal, Clermont Auvergne INP, CNRS, Université Clermont Auvergne , F-63000 Clermont-Ferrand , France .