Protecting Concrete on the Beijing-Shanghai Railway Bridge

Polyureas are increasingly being used as protective coatings on concrete due to their high weathering durability and good protection against corrosion. Polyurea was recently used for the protection of below-grade concrete on the Beijing-Shanghai High-speed Railway. This paper provides a brief history of polyurea use in China and describes its use in the Beijing-Shanghai High-Speed Railway project. The authors discuss the project's major coating challenges, especially coating delamination and failure, and describe the tests that led to a solution. A new type of surface preparation system was developed as a result. This priming system was a polyurethane accelerated with a catalyst to cure in winter, and adjusted to slow the cure with special solvents in summer.