This report investigates the physical and chemical properties of the interfacial transition zone (ITZ) in concrete to determine its influence on the overall mechanical performance of cementitious materials. The text is compiled by RILEM Technical Committee 108 ICC, representing a collaborative effort by international experts in materials science and structural engineering. It synthesizes decades of research to establish a standardized understanding of how the ITZ affects concrete durability, strength, and microstructural integrity.

Experts recognize this report as a foundational technical document for researchers and structural engineers focusing on concrete durability. The text provides a high level of academic density, serving as a primary reference for those studying the microscopic mechanics of cement-based materials.