Preparation Of Silane Protective Material For Concrete And Its Influence On Durability Of Concrete

Reinforced concretes are widely used nowadays, but the durability issues gainattentions as well, and most deteriorations of concrete are closely water-related.Protective materials for concrete are of variety. The low-surface-tension saline materialsare capable of penetrating into the pores in the concretes because of its wonderfulpermeability; a water-repellent alkyl film was generated on the surface of the capillarywalls after coating. With smaller surface tension, the concrete surface changed fromhydrophilic to hydrophobic. The breathability of concrete is maintained, as well as thecrack resistance, good durability and UV resistance, and the appearance remains thesame practically. The extraordinary characteristics of silane materials gain its awarenessworldwide.In this paper, silane polymers and silane emulsions were prepared through radicalpolymerization and emulsification with raw materials of vinyl-triethoxy silane, vinyltrimethoxy silane, methyl-triethoxy silane, octyl-triethoxy silane, isobutyl-triethoxysilane, etc. The preparation process was studied, including the initiator concentration,reaction time and the temperature for silane polymer, and the preparation method, thereaction temperature and the ratio of the emulsifier for silane emulsion. Thoughcomparative study of the effect of silane monomers, silane emulsions and silanepolymers on the impact of durability of concrete with different water cementratio(W/C=0.4,0.5). The capillary absorption test, capillary salt-suction test, chlorideion permeability coefficient and penetration depth test, accelerated carbonation test,rapid freeze-thaw test and sulfate corrosion test were carried out. The results indicatedthat the concrete coated polyethylene-triethoxy silane showed excellent and stableprotection in all tests, the chloride ion diffusion coefficient was only1.1×10-12m2·s-1,capillary water absorption coefficient reduced by more than87%than the untreatedconcrete, silane monomers also reduced the coefficient reduced by more than85%,silane emulsion performed poorer effect, the coefficien reduced by77%to85%, it could replace the monomer if the requirements are not harsh. Silane polymer also have goodeffects in the accelerated carbonation test, rapid freeze-thaw test and sulphate resistancetest. Polyethylene-triethoxy silane could reduce carbonation depth (28days, W/C=0.5)by88%, and the concrete showed good frost resistance and stable sulphate resistance.The test results of silane emulsion under different test conditions were very unstable.The results provided references for engineering practices in the selection silanemonomer, silane emulsions and silane polymer.Silane material can improve the durability of concrete, it has been widely used atbridges, highways and other projects have been widely used. Silane monomer has deeppenetration depth, more active ingredient and good protective effect, but its largevolatilization, toxicity and other shortcomings hindered its widespread application. Theeffect of silane emulsion was poorer, but it showed stability, low volatilization, andnon-toxicity. Although silane polymer’s penetration depth is small, it has gooddurability and stable results. The results showed that the silane materials prepared inthis topic can significantly reduce capillary water absorption coefficient, and improvethe resistances to chloride ion, sulphate, carbonation and freeze-thaw.