Use of nano-additions to improve the performance of UHPFRCs used in geothermal power plant infrastructures

he interest of scientific community on application of nano-additions in concrete is continuously growing due to their outstanding physical and chemical properties. These nano-additions are usually added into concrete to increase the durability in aggressive environments, such as XA environmental exposure classes. This work shows preliminary results on the use of nano-additions in an Ultra High Performance Fiber-Reinforced Concrete (UHPFRC) used as a reference. This reference UHPFRC has been modified adding three types of nano-additions: alumina nanofibers (0.25% by weight of cement), cellulose nanocrystals (0.15% by weight of cement) and cellulose nanofibrils (0.15% by weight of cement). The influence of the nano-additions has been analyzed in terms of mechanical properties, such as flexural and compressive strength and on shrinkage and durability properties, analyzed by means of sorptivity tests on uncracked, cracked and self-healed specimens