Comparative study on the mechanical and durability performance of concrete incorporating nanomaterials

This study investigated the influence of nano-SiO 2 , nano-Al 2 O 3 , and nano-CaCO 3 on the workability, strength, and durability of cementitious composites at 1 %, 3 %, and 5 % replacement levels of OPC. The slump test results showed a steady decline in workability with increasing nanoparticle content due to their ultrafine size and large surface area, which raised water demand. Among the additives, nano-SiO 2 produced the greatest reduction in slump, while nano-CaCO 3 had the least effect. Compressive strength improved in all nano-modified mixes, with the highest enhancement at 3 % replacement viz. 26.3 % for nano-SiO 2 , 24.6 % for nano-Al 2 O 3 , and 12.3 % for nano-CaCO 3 compared with the control. After 360 days of exposure to tap, saline, and acidic media, the nano-modified concretes exhibited superior strength retention and durability. Electrical resistivity tests confirmed higher resistivity for all nano-concretes, particularly for the 3 % nano-SiO 2 mix (NS3), indicating a denser and less permeable structure. Electrochemical analysis revealed that NS3 had the lowest corrosion rate and current density, providing maximum protection to steel reinforcement. Microstructural observations demonstrated denser microstructures, reduced porosity, and increased calcium silicate hydrate (C–S–H) gel formation in nano-modified mixes, particularly NS3. These findings establish the potential of nano-engineered concretes in enhancing mechanical performance and durability for infrastructure exposed to aggressive environments.