Effect Of Silicon Resin On Properties Of Cement-based Materials

Almost all durability deterioration processes of concrete are closely related to the existence of water and its transmission in concrete.Water is usually used as the carrier for the invasion of harmful external media.Taking some measures to improve its waterproof performance is one of the effective ways to improve the durability of concrete.Organosilicon materials are considered as ideal waterproofing agents because of their excellent weatherability,thermal oxidation stability,biocompatibility,and can react with concrete,so that the cement-based materials have hydrophobicity while ensuring the permeability of concrete itself.Previous studies have focused on siloxane monomer and low molecular chain siloxane.In this project,polyalkyl three alkoxy siloxane(silicone resin),which is a polymer chain,is used as a waterproof treatment material for concrete surface.The surface morphology,contact angle,surface permeability,waterproof effect,chloride ion resistance and carbonization resistance of silicone resin emulsion are systematically studied.The influence of energy and drying shrinkage properties.On this basis,the effect of wear and ultraviolet aging on the waterproofing effect of silicone resin was studied.The research results provide a basis for engineering application of polymer chain siloxane.The main conclusions are as follows:(1)After the silicone resin is coated on the concrete surface,some silicone resin can enter the concrete under the action of capillary.A silicone resin-concrete waterproof layer is established within the depth of 4 mm of the concrete surface.Silicone resin which does not enter the concrete is polymerized on the surface of concrete to form a high cross-linking silicone resin waterproof layer.External silicone resin changes the micro-morphology of concrete,making the original rough concrete surface with micro-cracks become more compact and smooth,reducing the surface permeability of concrete.The contact angle increases with the increase of the amount of silicone resin coating.When the amount of silicone coating is greater than 300g/m~2,the contact angle is basically stable above 135 degrees.The penetration depth of silicone resin is lower than that of low molecular siloxane because the molecular diameter of silicone resin is larger than that of ordinary silane waterproofing agent.With the increase of the amount of silicone coating,the permeability of the concrete surface gradually decreased.(2)The silicone resin surface treatment concrete has better waterproof effect and can effectively improve the chloride ion resistance of concrete.When the coating amount is600g/m~2,the chloride diffusion coefficient is reduced by 83%.It can obviously improve the carbonation resistance of concrete and greatly reduce the drying shrinkage,thus reducing the risk of drying shrinkage cracking of cement-based materials.(3)The waterproofing layer of silicone resin on the surface of concrete is affected by the degree of wear.Taking 300g/m~2 as an example,when the surface was worn 0.5mm,the sample lost its high cross-linking silicone film,the contact angle decreased from 123.2degree to 105.5 degree,and the capillary water absorption and water absorption rate increased significantly.When the wear depth reaches 4mm,the silicone resin basically loses its waterproofing effect.When the aging time reaches 90 days,the contact angle and capillary water absorption of waterproof concrete on the surface of silicone resin have no change.It shows that the material has strong aging resistance.