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Unique technology and process of subway prestressed concrete track slab
Application of water-based high-permeability epoxy in subway shield segment
Release time:
2021-07-08 08:38
Source:
The 100-year design life of the subway in my country's subway design code must first solve the problem of anti-corrosion and waterproofing of the underground concrete, especially the shield plate.
The deterioration of concrete structure is caused by water penetration, internal carbonization, corrosion of salt ions, etc. Therefore, the surface uses high-penetration epoxy to isolate air, moisture, and salt to prevent steel corrosion and concrete damage!
The oily high-penetration epoxy resin uses a large number of solvents such as acetone and furfural, which damage the environment and cause harm to the human body!
Although acetone furfural can partially participate in the reaction of epoxy resin, the larger volatilization content leads to a larger shrinkage rate of the epoxy cured product, and the resulting stress leads to a significant decrease in the bonding strength.
The use of water-based epoxy resin can greatly reduce VOC emissions. By involving a functional curing agent with surfactant characteristics, the surface tension of the water-based system can be greatly reduced, the permeability can be enhanced, and the rigidity and toughness, water emulsion and water resistance can be achieved. Unified, can completely replace oily epoxy for the painting of shield segments.
Using self-emulsifying epoxy resin emulsion EP380 and curing agent MH3150, without solvent, by adding small molecular group water as diluent, brush twice on the surface of C40 concrete with an interval of 30 minutes, and the penetration thickness reaches 1.5-2 mm, which is good for concrete. Positive tensile bonding strength>5.4Mpa. The strength of concrete is increased by 30%, and the impermeability is greatly improved!
The system is modified by cyclic aliphatic amine, acid and alkali resistance, salt spray resistance, weather resistance, water resistance, chemical resistance and ion erosion resistance! Rigid and flexible, high flexural and compressive strength, good freeze-thaw resistance. Replacing oily epoxy for shield segment can fully meet the requirements of industry standards.