Durability of UHPFRC functionalised with nanoadditives due to synergies in the action of sulphate and chloride in cracked and uncracked states

This paper studies the durability of Ultra High Performance Fibre Reinforced Concrete (UHPFRC) with high Blast Furnace Slag content (BFS) and nanoadditives such as crystalline admixture (CA), alumina nanofibres (ANF) cellulose nanocrystals (CNC), exposed to different aggressive environmental conditions: 1) three media: a) deionized water (dw), b) sulphate rich solution (ss) c) simulated geothermal (sgw) containing chloride; 2) two interaction static dynamic (water impact); 3) without presence cracks. Durability was analysed over 24 months, measuring several physical chemical parameters system, recording changes in both media concrete. All UHPFRC types demonstrate good durability, showing resistance expansion deformation sulphate-rich media. A leaching process occurs all systems, sgw being most aggressive. The inside crack favours formation solid phases calcium carbonates ettringite, while affects response matrix precipitates within crack.