1. Department of Civil and Construction, Faculty of Engineering, University of Nairobi, Nairobi 30197-00100, Kenya
2. Department of Materials Engineering and Chemistry, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague, Czech Republic
3. Institute of Cement and Concrete, Meru University of Science and Technology, Meru 972-60200, Kenya
4. Department of Physical Sciences, Meru University of Science and Technology, Meru 972-60200, Kenya