Development And Application Of Waterborne Polyacrylate Waterproof Coatings For Tunnels

Tunnel waterproofing problem,tunnel water hazard is the interference and harm of water encountered in the construction or operation of tunnels.Water hazard is a common disease in tunnels.Investigation data show that most tunnels have different degrees of water hazard.At present,the main types of waterproof materials for tunnels at home and abroad are waterproof membrane,waterproof board and waterproof coating.Waterproof coil and waterproof board have more welds and can not be close to the wall.Waterproof coating also has flammable and harmful components.Each type of material has its own shortcomings.In this paper,a waterborne polyacrylate waterproofing coating was prepared by free radical polymerization of acrylate,methacrylate and other monomers under the action of initiator in water environment,the material has the advantages of fast construction,no weld,environmental protection and so on.In this paper,the following aspects are studied:?1?The formulation of waterborne polyacrylate waterproofing coatings was studied.The influence trend of waterproofing monomers was judged by the theory of polymer free radical polymerization and orthogonal experiment.According to the influence trend,20 formulations were determined.The tensile properties,bonding properties and tear strength of 20 formulations were evaluated comprehensively by rank sum ratio method.Finally,M15 was obtained as the best formulation with comprehensive properties.?2?The application performance indexes of M₁₅ were tested.The results of experiments and SEM pictures showed that water-borne polyacrylate waterproof coatings hydrolyzed in alkaline solution with PH value of 13-14,broken in acid solution with PH value of 1-2,maintained good waterproof performance in acidic and alkaline solution with PH value of 5-6 and 11-12,and maintained flexibility of waterproof materials in low temperature environment with 6?.It can withstand high temperature of 70?,keep water impermeability at 0.3 MPa water pressure for 30 minutes without leakage and tear strength??5KN/m?;the higher the solid content of monomer solution,the higher the degree of polymerization,the better the mechanical properties,and the best tensile properties when the solid content is 70%;Cl^-has no corrosion effect on it in NaCl solution with concentration not exceeding 7%.?3?Joints will occur in the construction process.In this paper,the production of construction joints,tensile properties,bonding strength,acid-alkali resistance and water permeability of construction joints are tested and determined by SEM micro-analysis.The results show that the construction joints have no effect on waterproofing efficiency of waterproof materials and will not fall off in weak acid-alkali tunnel environment.The equipment mixes and sprays waterproof coating A liquid and B liquid simultaneously,so the construction is convenient and fast.?4?The test results show that this kind of film is mainly used in open-cut tunnel and mine tunnel structure,which is in the middle of the second lining and shotcrete.This waterproof material has the advantages of fast aggregation speed,environmental protection,convenient construction and good integrity.It can effectively guarantee the quality of tunnel waterproof system and reduce the risk of seepage.It has good economic and social value.