Prof. Karen Scrivener opened the 4th LC3-Doctoral School from 03rd to 06th April at EPFL, Lausanne. We are happy to welcome 35 participants from 18 countries who will learn about the use of blended cements. The programme covers aspects of hydration of blended cements and the physicochemical characterisation of supplementary cementitious materials particularly calcined clays. The focus is on practical work with two afternoons devoted to laboratory practices on microscopy, XRD and calorimetry.