Waterproof concrete extends life span of tunnel

The Hong Kong-Zhuhai-Macao Bridge, one of the most massive infrastructure projects ever undertaken, is being hailed as a remarkable achievement in cutting-edge civil engineering. International tunnel expert Tommy Olsen, from COWI, a leading infrastructure consulting company in Denmark, said its immersed tunnel sets a standard that may be copied in other projects around the world.

One concept that Olsen's team brought to the Chinese project was watertight concrete, keeping the concrete tunnel safe from high hydraulic pressure without the need for waterproofing membranes.

Such membranes cannot be guaranteed to last as long as 120 years, the designed life span of the bridge, Olsen said, but good quality concrete can.