Mega Project Metro
The construction of a metro under a populous city area requires rapid formwork turnaround. 500 concrete tunnels segments are produced daily to meet the targets. Sika® ViscoCrete® admixtures reduce curing time and energy consumption.
Ancient capital of China
With an urban population of over five million, Nanjing is the second-largest commercial center in the East China region after Shanghai, from which it lies 300 km to the northwest. As the capital of Jiangsu province, Nanjing has a prominent place in Chinese history and culture. Situated in one of the largest economic zones of China in the lower Yangtze River drainage basin, the city covers a total land area of 6,598 m² and is one of China's most important cities. It is recognized as one of the Four Great Ancient Capitals of China. It has long been a national center of education, research, transport networks, and tourism. In 2014 it will host the Summer Youth Olympics.
Mega project metro
The well-planned and widely extended infrastructure is a must for its inhabitants. The Nanjing metro was opened in 2005, and as of 2010 there have been two lines in operation, covering 87.0 km of track. The finished metro will be 617 km long, consisting of 17 lines. Construction is to continue for the next 20 years. Stable metro segment demand will last for another 19 years before its completion in year 2030.
Fast production of high-strength concrete
Sika China now is providing support in the form of products as well as professional technical services and reliable on-time logistics. Sika® ViscoCrete®-20 HE is the ideal solution for the challenging requirements of precast segment production, when high-strength concrete in combination with a smooth and uniform surface finish is needed. Due to a constant tunnel construction progress of 30 km per year, it is necessary to produce 500 concrete tunnel segments per day. This poses a challenge in terms of the early strength development of the concrete in order to achieve a rapid formwork turnaround. Normally, setting times must be controlled within 100 minutes and early compressive strength development over 30 km/h has to be ensured for a three-shift operation.
Reducing curing time and energy consumption
The high early strength gained has shortened the striking time and hence accelerated the turnaround of formwork and, in addition, steam curing time and energy consumption can be reduced. The overall result for the segment manufacturer is an increased production rate with significantly improved product quality.