Search On Engineering Lications And Properties Of Nano-SiO₂Modified High Performance Mortar

Facing the current need in the construction of the Marine engineering and the urgency of the repair on offshore engineering, This article mainly aims at using nano-SiO2to improve the effect on the properties of cement based material, and research in all kinds of performance on nano-SiO2modified High Performance Mortar (HPM), and the penetration of chloride ions in normal strength of mortar and nano-SiO2modified HPM under different environment. At the same time, experimental investigation and theoretic discussion are made, a feasible scheme of using nano-SiO2modified HPM in repair of Marine engineering concrete structure has been put forward. The specific research works are as follows:(1) Study the impact of different proportion of nano-SiO2on HPM’s workability, mechanical properties and resistance to the penetration of chloride ions, comparing to obtain the optimal mixture ratio in this experiment. The experimental results show that when the gelling materials, fine aggregate, admixture and component ratiostay still, Mixed with1%～5%of nano-SiO2, and control the water cement ratio (w/c=0.34), the comprehensive performance most outstanding group is HPM mixed with5%of nano-SiO2, Not only the basic mechanical performance is excellent, early strength develops highly (1day flexural strength9.7MPa, the compressive strength of57.5MPa)、Later strength develops stabily (28day flexural strength12.8MPa, the compressive strength of99.0MPa), but also the flow performance is better, and it Can meet the requirements of rehabilitation engineering. At the same time, nano-SiO2modified HPM has stronger ability to resist the penetration of chloride ions, When the HPM mixed with5%of nano-SiO2, The28day electric flux is300C,56day electric flux is as low as280C, which is far below1000C.(2) To explore the penetration of chloride ions between the ordinary strength cement mortar and nano-SiO2modified HPM under different environments. The experimental results showed that the penetration of chloride ions in the mortar under different environment:the penetration rate of chloride ion under dry-wet alternate24hours environment>the penetration rate of chloride ion under40℃water bath heating environment> the penetration rate of chloride ion under natural environment, and nano-SiO2modified HPM has early hydration rapidly、forming a dense structure、early strength develops highly and quickly,1day strength (57.5MPa)> ordinary mortar strength of28day (48.0MPa), early high strength has an obvious effect to prevent the chloride ion penetration.(3) To explore the application of nano-SiO2modified HPM in Marine engineering. the investigation of corrosion damage on concrete structure of the ore sand port in Basuo port of HaiNan Island is made, at the same time, the chloride ion content in concrete from different position are measured, According to the situation of port concrete structure corrosion presented a repair of the damaged structure reinforcement scheme with nano-SiO2modified HPM is put forward, To lay a solid foundation on achieving the engineering application of using the nano-SiO2modified high performance mortar.