Winter Concrete Project Job Practice Research And Application

At the beginning of the 21st century, CPC Central Committee put forward the proposal of revitalizing the northeast old industry base in the 11th Five-Year Plan, which initialized the prelude to the infrastructure development in the Northeast Area. The Northeast Area locates in the subfrigid zone where winter lasts about 5 months. In other words, the construction cycle here only covers 7 months if not taking winter construction into consideration, which can not meet the economy development and the demand of CPC Central Committee. Consequently, in order to shorten the construction cycle winter construction is the only choice. Naturally, winter construction in freezing northeast area has been becoming a hot topic.My thesis plans to carry out the relative research from the angle of the combining theory and practice:the essence of winter construction is to provide various necessary curing conditions, under natural cold temperature, for concrete so as to make it harden and increase its strength. This demands the analysis of the damage of freezing to concrete structure, the impact of early cold on concrete structure in its physical and chemical features, and finally we hope to find out the decisive element which influences concrete most.My thesis also discusses the following parts:the demands for the raw materials of concrete in winter construction, the demands for concrete in the processes of mixing, transporting and pouring, the demonstration of various winter construction methods from the angle of heating raw materials and guaranteeing positive temperature before pouring concrete into mold, and pointing out specific demonstration methods for different construction types and given winter construction methods for different construction types, and the profound analysis of different cases in accordance with the specific construction methods.My thesis is mainly about warm canopy method, steam (curing) method and the application of admixture, also including the comprehensive introduction of different construction methods, for example, the specific forms of warm canopy method and steam curing method. Our aim is to stress the principle that we should select proper winter construction methods according to construction types. We also pay attention to the extra cost in winter construction and further analyze economic benefits of every method. We hope via the way of combining the theoretical analysis of winter construction methods with construction practice to get a general winter construction theory system in Northeast Area.