Preparation Of Silane Emulsion/Silica Sol Waterproof Material For Concrete And Its Influence On Durability Of Concrete

The failure of concrete due to lack of structural durability is a common problem in civil engineering sector, Studies have shown that the presence and migration of water are the key factors to durability of concrete. Many materials have waterproof effect, in which the introduction of silica sol can adjusted the structural of concrete surface waterproof and does not influence the breathe performance of concrete, which makes it applicative in broad prospects.This paper based on the silane monomer, tetraethylorthosilicate(TEOS), through emulsion polymerization, sol- gel method to prepare a stable emulsion of organic silane and silica sol,The reaction time, temperature, and raw materials distribution Comparative of the silane emulsion were studied.Comparative study of the effect of silane emulsion/silica sol on the cement mortar waterproof, paste surface energy, paste microstructure and mineral composition. Result showed that the silane emulsion/silica sol can reduce the amount of water absorption, the best kind of silane emulsion/silica sol can reduce about 90% of water absorption of mortar,and the surface free energy of paste reduced to 10 mN / m or so, the contact angle of water on paste were incresed to110 ° or more, The surface structure of paste were improved.Comparative study of the effect of silane emulsion / silica sol on the water absorption and frost resistance of concrete,Results showed that the capillary water absorption coefficient of concrete decreased 72.3% ~ 78.4% as a whole, The concrete treated with silan emulsion/silica sol form first of which is coated silica-coated silane emulsions is the best, amount of water absorption of concrete reduced more than 80 percent, after 100 freeze-thaw cycles the concrete almost has no cracks.Resistance to chloride ion, sulphate resistance tests have showed that the silane emulsion / silica sol form with first coated silica coating and then silane emulsion can effectively enough to prevent chloride,sulfate ion intrusion,the chlorine ion permeability coefficient decreased 88.04%(W/C= 0.4) and 88.46%(W/C = 0.5),specimen after immersion of 10% NaSO4 100 d the mass lose rate and dynamic modulus of concrete growth a little.The concrete treatedwith the silane emulsion/silica sol form with first coating of silane then coated silica sol also have a good effect in accelerated carbonation tests,the 28 d carbonation depth reduced 64.4% of the 0.5 cement ratio of concrete.