This book is about the Ultra-high Performance Cementitious Composites (UHPCC), which is a relativity new type of cementitious materials. UHPCC has very low water-to-binder ratio, high amount of high-range water reducer, fine aggregates and high-strength steel or organic fibers. With the prominent mechanical properties, e.g., high compressive and tensile strength, high ductility, and high fracture energy, UHPCC has been becoming the most prospective construction cement-based material for both civil and military structures to resist high-speed projectile penetration, low-velocity impact and blast loadings. In this book, the related work conducted by authors on the static and dynamic mechanical properties, as well as the impact and blast resistance of UHPCC are presented. This book is written for the researchers, engineers and graduate students in the fields of protective structures and terminal ballistics.