What is ultra-high-performance concrete (UHPC) and what are its applications?

UHPC has compressive strength >150 MPa, achieved through: optimized particle packing (no coarse aggregate), very low w/c ratio (0.15-0.25), high binder content with silica fume/quartz flour, steel fiber reinforcement (2-3% by volume), and special mixing procedures. Properties include: ductile behavior, very low permeability, excellent durability. Applications: bridge deck overlays (thin wearing surface), precast connections (emulative details), architectural facades, blast-resistant structures, and retrofit strengthening. Cost is 3-5 times conventional concrete but enables thinner sections.