Abstract: In this study, polyurea based on polyaspartic esters nanocomposites were prepared by the combination of the ultrasonic dispersion method, high-speed scattering machine and silane coupling agent. The microstructure of the nanocomposites was characterized by Zetasizer, scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectra. With a 6% of silica nanoparticles amount in total, mechanic property of SiO 2-polyurea nanocomposites reaches to the best. The durability tests of the nanocomposites were completed. The results of the tests indicate the nanocomposites can significantly enhance the frost-resisting property, anti-carbonating property, as well as abrasion-resistance of hydraulic concrete. The performance of the nanocomposites is excellence and environmentfriendly tested by National Center for Quality Supervision and Test of Building Engineering. The on-site test of the nanocomposites was completed on the Three Gorges Dam and the result of the test is satisfying. The nanocomposites are expected to have promising applications in hydraulic concrete protection.

Key words: polyurea based on polyaspartic esters, nanocomposite, hydraulic concrete, durability