Role of nano-Al2O3 in modifying the properties of ultra high performance concrete

The purpose of this study is to use cutting-edge nano modification technology to provide a crucial foundation for utilizing new-generation cementitious materials with extremely high strength and extremely extended service life. This research addresses the effects of nano Al2O3 particles replacement on the UHPC. In this research, nano Al2O3 particles mixes were used as additive ranges from 0, 0.5, 1, 1.5, 2, 2.5, and 3 percent from cement weight in UHPC. Concrete was prepared to perform slump cone, strength, modulus of elasticity, water permeability, and SEM analysis. The results indicated that the nano Al2O3 particles enhanced the flowability and increased the heat of hydration with the increase of their contents. It shows that nano Al2O3 particles can significantly accelerate the setting and hardening process of UHPC. The optimal dosages to enhance mechanical and durability properties were 2% nano Al2O3 particles. The compressive strengths of specimen increased by 26.86% compared to the control mix., it also reduced the 37.04% depth of water penetration under pressure, respectively in comparison to control concrete. The results exhibit that the nano Al2O3 particle is an excellent filler material, reducing porosity regions and accelerating cement hydration via the pozzolanic effect. The SEM analysis demonstrated that adding nano Al2O3 particles may also effectively enhance the interfacial transition zone.