Building materials, materials design and applications : 4th International Conference on Building Materials and Construction (ICBMC 2019) and 2nd International Conference on Materials, Design and Applications (ICMDA 2019) : selected, peer reviewed papers from the 4th International Conference on Building Materials and Construction (ICBMC 2019), February 25-28, 2019, Singapore and the 2nd International Conference on Materials Design and Applications (ICMDA 2019), April 13-15, 2019, Tokyo, Japan