This section will define micromechanics as the study of the behavior of materials at the microscale, specifically focusing on how the microstructural components of concrete, such as cement paste, aggregates, and the interfacial transition zones, interact under various loads and environmental conditions. It will detail how micromechanics helps to understand the fundamental aspects of material behavior by examining the stress, strain, and failure processes at the microscopic level and how these affect the macroscopic properties of concrete.