"Brine contains magnesium minerals. Kemal Celik, an assistant professor of civil and urban engineering at New York University Abu Dhabi and part of a team at the university's AMBER Lab, extracted a magnesium compound from the liquid, and used it to make the cement.
Celik says the cement was cast into blocks, which were then placed in a carbon dioxide chamber to set -- an innovation which speeds up the production process. The cement was subjected to testing in the UAE before being sent to Japan, where blocks went through further strength and rigidity tests. In addition, an algorithm was developed to calculate how safe the blocks would be if used in construction, Mika Araki, a structural designer at the University of Tokyo, told CNN."
This looks great, although brine can be corrosive so it can't be used with just any other material for construction.