Preparation Of Silicone Microemulsion And Its Application In Concrete Protection

In winter,most parts of China,in order to prevent road congestion caused by snow,a large number of deicing salt was sprayed on the road,the snow melt into the concrete structure,with the temperature decreases,the water in concrete pore freeze,resulting in concrete structure cracks,salt solution contact with the steel surface,so that steel was rusted,concrete structure strength decreased.It is one of effective methods to improve the durability of concrete and enhance its resistance to invasion of harmful substances by brushing the waterproof coating on the surface of concrete structure,and it is more convenient to operate.Silicone micro emulsion can penetrate into the concrete structure to a certain depth,both to maintain the permeability of concrete pores and prevent the environment from entering the water inside the structure,to avoid some of the film coating the bubble or rupture and other issues,it is suitable for the deck and road works that needs a higher demand for anti-corrosion ability and wear resistance.OP-10,Span-80,Span-60 and Tween-60 were selected as the non-ionic surfactants,three combinations are designed as OP-10/Span-80,Span-60/Tween-60,Span-80/Tween-60,adjust the ratio of two emulsifiers respectively,the composite non-ionic emulsifier was prepared.usephase inversion emulsification method,with dimethyl silicone as the dispersed phase,the effects of stirring time,temperature and emulsifier content on the stability of the micro emulsion and the droplet size of the separated phase were investigated.The micro-emulsion with good performance was selected and applied to the surface of C50 concrete.The durability of the concrete specimen after brushing was evaluated,its water resistance,resistance to chloride ion penetration capacity,single-sided anti-salt freeze capacity were mainly studied,and compared with the concrete without brushing silicone micro emulsion,The effect of silicone micro emulsion on the durability of concrete was systematically studied.The results show that with the increase of the content of emulsifier,the emulsification reaction is more and more complete,the emulsion particle size will be reduced;but too much emulsifier will make the emulsion unstable,the residual emulsifier of the system caused to the emulsion turbidity,stratification.When emulsion particle size was in a certain range,it would decreased with the increase of stirring time.The effect of temperature on the particle size of the silicone micro emulsion is also significant.Within a certain range,the increase of temperature will reduce the emulsion particle size and make the emulsion fine and uniform.But too high temperature will make the emulsifier failure,affect the emulsifying effect,resulting in emulsion instability,layered after centrifugation.Silicone micro emulsion can greatly improve the freeze-thaw resistance of concrete structures.The samples without coated silicone micro emulsions had a mass loss of more than 1500 g/m2 after 12 cycles of freeze-thaw cycles,and the samples coated with the silicone micro emulsions were subjected to 24 freeze-thaw cycles,the anti-freeze-thaw ability of the samples coated with silicone micro emulsions was twice that of the uncoated silicone micro emulsion.It is found that the loss of A3 is the smallest and the loss of dynamic elastic modulus is 4.30%.After the silicone micro-emulsion treated concrete block,waterproof significantly improved,compared with samples without coated silicone micro emulsions,the water absorption was reduced by about 75%.The concrete samples treated by organic silicon micro emulsion had good resistance to chloride ion penetration,the content of chloride ions in the samples was greatly reduced,compared with samples without coated silicone micro emulsions,the chloride content of the test piece was reduced by about 62%.Through the silicone micro emulsion performance test and durability test of the concrete coated silicone micro emulsions.Prepared the best performance silicone micro emulsion:The micro emulsion of silicone emulsion with particle diameter of 103.5nm was obtained after stirring for 70 min under the conditions of emulsifying temperature of 80 ? and emulsifier content of 7%.