Research on the material properties of concrete in subway stations after in service for 50 years

A new study examined concrete from Beijing's subway system after 50 years of operation to understand its material property changes. Researchers analyzed compressive strength, tensile strength, elastic modulus, Poisson's ratio, and bond strength, comparing them to original design specifications. The investigation also included a detailed look at the condition and microstructure of concrete aggregates, as well as the elemental composition and chemical properties of hydrated products within the concrete.

This research provides valuable insights for the long-term durability and maintenance of similar underground infrastructure worldwide.