Shenzhen construction on hold after alert over cheap sand in concrete

Several major property projects in Shenzhen - including what will be the city's highest building - have been ordered to suspend construction after CCTV reported that concrete used by some local developers was made from cheap, untreated sea sand.

More projects are likely to be affected as the Shenzhen government ordered a citywide inspection into the practice, which they said was common throughout the Pearl River Delta. Untreated sea sand contains high levels of salt and chloride that could corrode steel reinforcements, causing buildings to collapse.

The Shenzhen Housing and Construction Bureau called an emergency news conference yesterday and said it was conducting a blanket investigation into the city's concrete-mixing plants. So far they had found 15 of the 92 plants in Shenzhen using low-quality sea sand as the raw material. The concrete was sold to local real estate developers.

The official refused to disclose how many residential and commercial buildings were erected with problematic concrete. But it ordered three high-profile projects - including the 660-metre-tall Pingan Financial Centre, scheduled to be completed in 2016 - to suspend construction pending further notice. Pingan Financial Centre will be the tallest structure in Guangdong. Construction workers were still busy on the site after the Shenzhen government's press conference.

China Central Television reported on Thursday that many Shenzhen developers replaced expensive river sand with much cheaper sea sand as a building material. It named and shamed four concrete-mixing plants - including one owned by Hong Kong-listed China Resources Cement Holdings.

The report also accused the two largest sandpits in Shenzhen, which supply concrete-mixing plants, of using seawater instead of much more expensive fresh water to wash sand. It said sea sand was used in several government-funded projects, including subways. Shenzhen Metro insisted all its projects were safe and met national standards.

China Resources Cement Holdings said it had launched an investigation and no substandard products had been found.