Posted Mar 22, 2013, 7:53 PM
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Join Date: Aug 2002
Location: Toronto
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Poor-Quality Chinese Concrete Could Lead to Skyscraper Collapses
Poor-Quality Chinese Concrete Could Lead to Skyscraper Collapses
03.21.13
By Ian Steadman
Read More: http://www.wired.com/design/2013/03/...per-collapses/
Quote:
A sand scandal is brewing in China, with concerns that low-quality concrete has been used in the construction of many of the country’s largest buildings — putting them at risk of collapse.
- Commonly the aggregate used in many modern building projects consists of crushed gravel or other rock, including sand, and that’s the cause of so much distress in the Chinese construction industry at the moment. Inspections by state officials have found raw, unprocessed sea sand in at least 15 buildings under construction in Shenzhen, including a building which, when finished, was set to become China’s tallest.
- The Ping’an Finance Center is planned to top out at 660m, making it not only China’s tallest building but the second-tallest building in the world after the Burj Dubai. 80m has been built so far, but construction has been halted in the wake of the revelation from Shenzhen’s Housing and Construction Bureau that substandard sea sand concrete had been used in its construction. According to a notice on the Bureau’s website posted on March 16, 31 companies had had their licenses to work revoked for at least six months.
- Bloomberg reports that the financial incentive to use illegal sea sand, which is far cheaper than legal river sand, is the likely reason for the problem. Untreated sea sand is unsuitable for construction because it still contains chlorine and salt, which corrodes steel — river sand from freshwater channels doesn’t have that problem. It can take only a few decades for a building to become dangerously unsafe if untreated sea sand is used in its concrete — including the possibility of collapse. While this scandal has been confined only to Shenzhen thus far, the possibility of it spreading to other Chinese cities is cause for concern.
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Construction on the Ping’an Financial Center, slated to tower over Shenzhen when completed in 2015, has been delayed after concrete used in its construction was found to contain corrosion-causing sea sand.
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