This book addresses the need to resolve the ITZ's influence on engineering and durability characteristics of cementious composites in order to identify what systems and what properties are affected by it, and to quantify these effects in order to prepare the base for engineering design tools. This volume presents the proceedings of the Second International RILEM conference on the Interfacial Transition Zone in cementious composites, held in Haifa, Israel in 1998. A wide variety of properties of actual cementious systems are addressed enhancing the understanding of the interfacial effects on properties of cementious composites which are of practical significance. The papers presented are a mix of theoretical and experimental reports, providing basic concepts as well as identifying conditions and systems where ITZ characteristics affect the overall properties, and instances where its influence is small and need not be taken into account in material and system design. This book will be of interest to researchers and practitioners who are dealing with the design and development of cementious composites of improved performance.