Brittle materials such as, rocks, concrete and high-performance concrete, glass, ceramics, ice..., are materials abundantly present in our everyday life and materials involved in many industrial applications or in various protective solutions. Achieving a good understanding of their strain-rate sensitivity in relation with their microstructure remains a major issue. In addition, the development of micromechanics-based models is of major importance in view of improving the predictive capabilities of analytical and numerical models and in order to better explain the role of material parameters involved in the strain-rate and pressure sensitivity of brittle materials. In the present chapter the damage and fracture processes involved in various brittle materials are discussed. Several experimental techniques offering the capability to characterize and analyse these damage modes are presented. Next, some micromechanics-based models attending to describe these mechanisms are detailed. Experimental and modelling approaches allow highlighting the main microstructural parameters driving the behaviour of brittle materials at high loading rates.