1. Former Research Student, School of Civil Engineering, College of Engineering and Physical Sciences, Univ. of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
2. School of Civil Engineering, College of Engineering and Physical Sciences, Univ. of Birmingham, Edgbaston, Birmingham, B15 2TT, UK (corresponding author).
3. School of Civil Engineering, College of Engineering and Physical Sciences, Univ. of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
4. School of Metallurgy and Materials, College of Engineering and Physical Sciences, Univ. of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.