Prof Christopher Leung, Civil and Environmental Engineering, received a State Natural Science Award, Second Class, for his project focusing on control of cracking in concrete. The award is among the most prestigious in science and technology in China. His collaborators included members of Zhejiang University, Dalian University of Technology, and Shantou University.
The project, titled “Double-K Fracture Criterion for Crack Propagation in Concrete Structures and Fundamental Research on the Improvement of Crack-Control Performance”, set out to analyze the complex cracking process in concrete and find an experimental approach to ascertain the key governing parameters. It then sought to develop practical approaches to control cracking to improve safety and the lifespan of reinforced concrete structures. Cracking can lead to much-reduced durability and, in a worse-case scenario, catastrophic failure. It is a particularly severe problem in large concrete dams, where continuous repairs are often necessary.
The team developed and verified a double-K fracture criterion, employing two separate parameters to describe the initiation and final unstable propagation of a crack in a concrete structure. This was successfully applied to assess the stability of cracks and the structural safety of various large mainland dams, including the Wujiang Dongfeng Arch Dam, Wujiang Suofengying Roller-compacted Gravity Dam, and Three Gorges Dam (second phase).
The researchers also developed cementitious composites with very high ductility and excellent crack control ability. The concept of such composites was first presented in a paper co-authored by Prof Leung in 1992. Since then, many researchers around the world have conducted research on the material. It has also been applied in the construction of coupling beams in buildings and link slabs in continuous bridges, repair of concrete dams and retaining walls, as well as waterproofing.
Only five 2015 State Science and Technology Awards in total were presented to Hong Kong researchers, with three going to HKUST. Other HKUST academics receiving top State honors included Prof Charles W W Ng, Chair Professor of Civil and Environmental Engineering (see "Unearthing the Cleverness of Soil"
) and School of Science faculty members.