Preparation,Performance Characterization And Applied Research Of Silicone Emulsion

The durability of the concrete constructions under harsh environments like the ocean is often impaired due to the penetration of harmful ions.In order to ensure the durability of the concrete structure,silicone waterproof materials are usually used to improve the waterproof and impermeability of concrete.In this research,three types of silicone emulsions were prepared,including internal-blending,film-forming and permeable emulsions.The influence on waterproof performance of concrete structures exerted by all these silicone emulsions was studied and analyzed separately.Besides,through the application study,in which testing the influence on the properties of concrete curb by applying emulsions compounded with nano materials,the silicone emulsion with better performance was optimized and screened out.The main research contents are as follows:（1）Silicone emulsions were prepared by surfactant and polyurethane emulsified isobutyl triethoxy silane.The influence of surfactant dosage on the stability of emulsion was studied.The effects of emulsion on compressive strength,water absorption and contact angle of cement mortar and steam curing concrete were tested.The results show that adding 1%GW-4 silicone emulsion into cement mortar reveals better performance,the compressive strength ratio of cement mortar in 28 days is 85.78%,the water absorption ratio in 48 hours is 36.25%,and the contact angle is 102.2°;The compressive strength ratio of steam cured concrete in one day is 94.4%,and the water absorption ratio in 48 hours is 77.34%.（2）The polyurethane silicone hybrid emulsion was prepared by introducing hydroxyl silicone oil and silane coupling agent（KH550）into polyurethane（PUD）.The effect of silicone emulsion amount on the water absorption and contact angle properties of the film was studied,and a better proportion of emulsion was selected for cement mortar.The results show that when the dosage of hydroxyl silicone oil is 30%and the dosage of KH550 is 10%,the performance is better.The particle size of this emulsion is 147.7nm,and the contact angle of rubber film is 99.68°,the water absorption is 16.67%.After brushing two layers on the surface of cement mortar,the water absorption ratio of cement mortar is 43.12%in 48h,and the contact angle is 95.20°.（3）silicone emulsion was prepared by emulsifying isooctyl triethoxy silane with surfactant,and nano materials including Ca CO₃,Ti O₂and Si O₂were introduced to further improve the properties of the permeable silicone emulsion.Through the test of water absorption,penetration depth and contact angle of cement mortar,the effects of external coating and impregnation technology,dosage of silicone emulsion,solid content and type and amount of nano material added on the performance of cement mortar were compared.The results show that the water absorption ratio of cement mortar in 48 hours with impregnation technology,solid content of 25%and dosage of 350g/m²is 13.68%,and the contact angle is 108.16°,The penetration depth is 3.2mm;The performance of the mortar is improved after adding 2%nano-Ca CO₃,2%nano-Ti O₂and 4%nano-Si O₂in the emulsion,especially after mixing with 4%nano-Si O₂,the cement mortar has the best performance,the48h water absorption ratio is 10.43%,and the contact angle is 124.5°,The penetration depth is 3.2mm.（4）The preparation of permeable silicone emulsion was applied to the study of durability enhancement of concrete curb.The effects of impregnated emulsion on concrete water absorption,chloride penetration resistance,salt resistance（slow freezing）and freeze-thaw（quick freezing）durability were analyzed.The results show that the impregnated nano-Si O₂modified silicone emulsion has better performance,the water absorption ratio within 48 hours is 19.39%,the chloride ion absorption reduction rate is 76.13%,the salt freezing cycle times are more than 90,which is one more time than the blank group.The number of freeze-thaw cycles is 375,150 more times than that of the blank group.It shows that nano materials modified osmotic silicone emulsion can significantly improve the durability of curb.