UHPC overlay as sustainable solution to preserve old concrete structures

Concrete structures exposed to harsh environments, especially including bridges, harbor are often suffered from durability problems. Typical external signs include surface deterioration, cracking caused by for example sulphate attack, frost action or reinforcement corrosion. All strongly linked the porous microstructure of binder matrix and chemical decomposition certain phases. Full replacement deteriorated concrete is costly can be troublesome their users. The increasing demand reduce carbon footprint prolong service life adds yet another argument restore existing structures. One alternative use very dense Ultra-High-Performance (UHPC) as an protective coating. goal this study was determine interfacial bonding characteristics between a damaged normal (NC) applied thin layer UHPC. To curb CO 2 emission, UHPC produced substituting 50 wt% Portland cement with fine limestone powder. Fresh hardened properties, shrinkage have been evaluated. Mechanical properties were determined on full-scale hybrid element using ultrasonic pulse velocity (UPV) bond test (pull-off test). results showed significant increase mechanical properties. Despite volumetric restrain substrate only limited cracks observed. UPV good excellent values.