This book systematically discusses the workability, mechanical properties, water stability, and material design methods of ultra-high ductility magnesium phosphate cement-based composites (UHDMC) with PVA fibers, PE fibers, or hybrid fibers. The developed UHDMC possesses strain-hardening behavior, multi-cracking, and ultra-high ultimate tensile strain, which can be used in many engineering projects, such as rapid repair and strengthening of airport runways, roads, bridges, and military ins...