Abstract:The accumulation of a large amount of phosphorus slag has seriously polluted the environment. Its application in concrete materials can realize the utilization of solid waste, but the phosphorus slag will seriously reduce the strength of cement. Therefore, introducing the nano-SiO2 into phosphorus slag concrete can realize the application of phosphorus slag resources and achieve energy saving and emission reduction. The study found that as the phosphorus slag content increases (dosage 10%, 20% and 30%), the early strength of cement mortar is greatly affected, and the strength is significantly reduced. Nano- SiO2 particles are added according to 0.5%, 1.0%, 2.0%, 4.0% and 8.0% of the cement dosage. When the content is no more than 4.0%, the water consumption of normal consistency and setting time of phosphorus slag cement are continuously reduced, and the strength is improved to some extent. However, when the dosage reaches 8.0%, the water consumption of normal consistency and setting time of phosphorus slag cement increase, and the corresponding strength decreases. Therefore, the reasonable introduction of nano-SiO2 particles can effectively improve the activity of phosphorus slag cementing materials, improve the consumption of solid waste resources, and contribute to environmental protection and resource social development