Pierre-Claude Aïtcin is professor emeritus in the Department of Civil Engineering of the Faculty of Engineering at the Université de Sherbrooke, Quebec, Canada. He is the author of:- High Performance concrete published by E and FN SPON. This book has been translated in French, Spanish, Portuguese and Czech.- - Binders for Durable and Sustainable Concrete published by Taylor and Francis.- - In collaboration with Sidney Mindess he wrote Sustainability of Concrete published by Taylor and Francis. This book has been published in French by Eyrolles under the title Ecostructures en béton- Comment diminuer l’empreinte carbone des structures en béton. Robert J. Flatt is Professor of Building Materials at ETHZ. Before that he was Principal Scientist at Sika Technology AG and postdoctoral researcher at the Princeton University. He owns a master in Chemical Engineering and a PhD from EPFL. His main research interest deals with the working mechanisms of chemical admixtures, an area in which his publications are very well cited and in which he has received several awards. These include the RILEM Robert L’Hermite Medal, the Ross C. Purdy and the Brunauer awards from the American Ceramic Society, the best short presentation at the 13th International Conference on Cement Chemistry, as well an Outstanding Research Contribution in the Broad Area of Chemical Admixtures presented at the 10th International Conference on Superplasticizers and Other Chemical Admixtures. He was also nominated two years in a row among the 5 finalists for the Spark award recognizing the best invention of the year at ETH Zürich (each time among more than 100 filed patents covering all subjects). He also was awarded the best paper award in two of the four categories at the 1st International conference on concrete innovation in 2014.