Due to limited land area in Singapore, it has been necessary to develop innovative solutions for creating additional space. A proposal from Nanyang Technological University suggested using underwater space by building offshore concrete structures that are based in the seabed and extend above sea level. Sections below sea level can be used for industrial purposes, while upper levels would serve as additional land area. This proposal requires concrete of the highest possible durability and longest service life. Testing began in 2011, and it was necessary to develop a concrete mixture with a high resistance to chloride ingress. Concrete mixtures were designed and tested, and the requirements for a mixture with the necessary characteristics were identified.