The  300kt/a phosphoric acid plant (EPC) of Inner Mongolia Dadi Yuntian Chemical Co.,  Ltd. has a schedule encompassing 2 winters. In previous years, air temperature  during the middle of November is -6 to 5℃.  Per regulations by the local construction authority, concrete work shall be  suspended in the mid November.

In  order to perform the winter activities, based on the weather conditions of  Chifeng, the PMT prepared a complete method statement for construction in  winter. A steering group is established for winter construction. Freezing  protective materials for the winter are purchased. Detailed technical  explanation is made for construction work in winter, which defines job  responsibilities for the organization members in winter work.  On November 1, concrete  pouring for the foundation cap of the reactor is successfully completed.  Concrete work for the reactor belongs to winter work for large-area concrete,  which should consider detrimental cracking caused by temperature variance due to  hydration of cementing material in the large-area concrete and shrinkage, and  also need to consider freezing protective measures for concrete construction in  winter. In order to ensure construction quality, the PMT assigned dedicated  personnel to carry out temperature test and freezing protective covering, and  check provision of measures for work in winter every day on site. On Nov. 4,  after removing formwork for the reactor, the concrete foundation axial lines are  straight, the dimensions are accurate, the edges are perpendicular, the surfaces  are flat, smooth, clean and have consistent luster,  which meets the standard for as-cast concrete, and received recognition by the  owner and supervisor, the successful completion of concrete pouring paved the  way for subsequent activities.