If the cement contains too much free calcium oxide or magnesium oxide, especially coarse particles of cement bricks, but also in the storage facility and a shorter time cement board, it will have stability unacceptable phenomenon. Because this fire (1000 ℃ above) calcium oxide and magnesium oxide is not completely been fully matured, their hydration is very slow, after the cement setting that is under constrained conditions began to cement hydration, volume expansion after generation, It will form a cracking phenomenon. In addition, if too much cement content of sulfur trioxide, generates sulfur calcium aluminate cement, volume expansion, will also adversely stability. 20th century, people continue to improve performance while Portland cement China Cement Net, the successful development of a number of construction projects for special cement such as alumina cement, special cement. Cement variety worldwide has grown to more than 100 kinds, 2007 cement output of about 2 billion tons. China in 1952 to develop the first national uniform standards, determine cement production to more varieties designated principle, Portland cement and its main mineral composition contained renamed silicate cement, and later renamed the silicon Portland cement today. 2012, China's cement output reached 2.184 billion tons, accounting for over 50 percent of global production. _ Wuhan cement cement grade (certified) _ Wuchang cement provided by the Hongshan District of Wuhan pavilion cement operation. Hongshan District of Wuhan pavilion cement business unit (www.whltsn.com) (www.hbltsn.com) was Wuhan, cement and products leader, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, the maximum Limits to meet customer needs. Wuhan cement leadership with the staff warmly welcome all inquiries negotiations to create a better future Wuhan cement.