CCTV 315 exposure: CR's response to "haishamen" is clear but not clear

Introduction: in 2007, Pingtan County of Fuzhou was exposed to use nearly eight times more sea sand than the national minimum standard of three types of sand for building houses " The above people pointed out that the theoretical construction life of housing in China is about 70 years, and the high-end buildings will be higher Therefore, 10-year and 20-year houses will become dangerous houses, and the quality of houses is unimaginable On the 14th of zf3, in response to CCTV's explosion that a large amount of sea sand was illegally used in many buildings under construction in Shenzhen, which seriously corroded the steel bars in the buildings, resulting in floor cracks and wall cracks, Shenzhen housing and Construction Bureau replied that 10 inspection teams had been set up to carry out carpet type investigation on the mixing plant in Shenzhen, and the parties concerned had been called to a meeting that night to explain the situation Zf3 also said in an interview with the media that China Resources Land, a real estate company under the involved China Resources Group, is currently conducting an internal investigation on this matter and will make relevant explanations on this report at the performance presentation meeting on the afternoon of 15th At the same time, it is pointed out that "sea sand is indeed used in construction and development, but it is treated in accordance with relevant regulations, and the treatment process is not entirely carried out on the construction site Therefore, the company cannot fully confirm the Shanghai water washing sea sand on the construction site mentioned in CCTV report, and the company needs to give formal feedback to the outside world after internal investigation." Zf3 is worth noting that, when CCTV reporters came to the concrete workshop again on the 14th, Guan Qing, general manager of Shenzhen China Resources Concrete Co., Ltd., said that the working manual of China Resources clearly pointed out that sea sand is not allowed, so there is no sea sand used by China Resources, but sand from Xijiang, Dongjiang, Zhujiang and other places When the reporter asked him by telephone again, his staff and sand transport driver were both called Haisha Who said it? "I don't know much, I have to investigate," Guan said In fact, zf3, just like the "consensus in the industry" in the report, the use of sea sand in Shenzhen is not an example In April 2002, 23 residents of Huaxiu Lane in Ningbo complained to the developers that the concrete pouring slab on the top of their houses fell off and the stressed steel bars were severely rusted After the appraisal by Ningbo housing safety appraisal office, the appraisal report was provided on April 10, 2002, and it was determined that the risk level of the appraised house was level B the developer finally admitted that the house was built with sea sand without desalination Zf3 in 2007, Pingtan County of Fuzhou was exposed to use sea sand which was nearly eight times higher than the national minimum standard of three types of sand for building houses At the end of 2012, four high-end residential buildings in Foshan were also revealed to use sea sand to build houses, and some owners asked to check out Some insiders pointed out that 80% of the buildings in Foshan are built with sea sand Zf3 is understood that if the sea sand is desalinated and meets the relevant standards in China, it can be used for building houses However, the use of sea sand without desalination is expressly prohibited According to the opinions on strict management of construction sea sand issued by the Ministry of construction in September 2004, sea sand must be purified and meet the requirements before it can be used to prepare concrete The chloride ion content of class I sand and class II sand used for construction shall not exceed 0.01% and 0.02% respectively, and the chloride ion content of class III sand with minimum requirements shall not exceed 0.06% If the chloride ion content is more than 0.06%, it is unqualified Regardless of the mixing ratio of cement and sand, it will cause hidden danger to the stability of the building In an interview with the economic reference newspaper, experts from zf3 China Construction Society said that the hidden danger of sea sand lies in its rich chloride ions and alkaline sodium When the chloride concentration around the reinforcement reaches a certain critical value, it will rust However, the steel bar will become thinner and weaker in its lifetime, which will not support it even for 10 years Zf3, on the other hand, even if the surface of the reinforcement is only 0.01M rusty, it is enough to make the weakest concrete cover crack After the concrete cover cracks, the carbon dioxide in the air is easy to invade, resulting in further corrosion of steel bars Such a vicious cycle will have a great impact on the safety of buildings Zf3 "since sand and stone account for about 70% of concrete, the severity of sand problems can be imagined." The above people pointed out that the theoretical construction life of housing in China is about 70 years, and the high-end buildings will be higher Therefore, 10-year and 20-year houses will become dangerous houses, and the quality of houses is unimaginable ZF3