A critical review of modified concretes with different nanomaterials is presented, focusing on the effects of nano-CaCO₃, nano-clay, nano-TiO₂, and nano-SiO₂ on concrete properties. The study highlights that nanomaterials significantly enhance the hydration process and increase the production of C-S-H gel, leading to improved resistance and durability characteristics. These materials are particularly effective in environments such as coastal areas, hospitals, nuclear power plants, and structures with recycled aggregates. The review also discusses the potential of nanomaterials to reduce environmental impact by improving concrete performance while minimizing pollution and resource consumption. However, the study notes that improper use of nanomaterials can pose risks, including potential toxicological effects and environmental hazards. The review summarizes the effects of these nanomaterials on various concrete properties, including compressive strength, tensile strength, flexural strength, water absorption, chloride penetration, carbonation, acid attack, sulfate attack, freeze-thaw resistance, electrical resistivity, elevated temperature resistance, shrinkage, and microstructure. The study concludes that while nanomaterials offer significant benefits, further research is needed to fully understand their long-term effects and to ensure safe and effective application in construction.A critical review of modified concretes with different nanomaterials is presented, focusing on the effects of nano-CaCO₃, nano-clay, nano-TiO₂, and nano-SiO₂ on concrete properties. The study highlights that nanomaterials significantly enhance the hydration process and increase the production of C-S-H gel, leading to improved resistance and durability characteristics. These materials are particularly effective in environments such as coastal areas, hospitals, nuclear power plants, and structures with recycled aggregates. The review also discusses the potential of nanomaterials to reduce environmental impact by improving concrete performance while minimizing pollution and resource consumption. However, the study notes that improper use of nanomaterials can pose risks, including potential toxicological effects and environmental hazards. The review summarizes the effects of these nanomaterials on various concrete properties, including compressive strength, tensile strength, flexural strength, water absorption, chloride penetration, carbonation, acid attack, sulfate attack, freeze-thaw resistance, electrical resistivity, elevated temperature resistance, shrinkage, and microstructure. The study concludes that while nanomaterials offer significant benefits, further research is needed to fully understand their long-term effects and to ensure safe and effective application in construction.