The Method Of Raising Environment Temperature With The Application In The Mass Concrete Construction

With the rapid development of basic construction in our country, the thickness of the foundation slab in high-rise buildings is getting thicker and thicker, and the application of mass concrete is increased extensively, becoming one of the new hot in the zone of construction technology. During the construction, it is so often to find cracks due to temperature stress in the slab that the cracks in concrete have become the main hazard to the structure. A large number of project practice and theoretical analysis has shown that most of the cracks would develop with the load or the physical and chemical factors, causing many problems, such as the carbonation of concrete, the spalling of cover and the rusty of reinforcing steel, impairing the strength and stiffness of concrete, and reducing the durability, even resulting in the collapse and affecting the normal use,thus it must be paid attention. Therefore, it is meaningful to study the construction technology for the mass concrete of the foundation slab in high-rise building.In this paper, we would focus on the temperature and the controlling of the temperature difference during the mass concrete construction. According to the factor that the temperature stress and the temperature deformation are the primary reasons to make the mass concrete crack, combining with other factors, the construction technology to prevent the mass concrete from cracking would be discussed, and then the method to achieve this aim through rising the environment temperature would be tested in practice, providing the practical experience for the similar projects.The major work of this paper: (1)To explain the basic concepts of the mass concrete and the cracks in concrete, and the practical significance of controlling cracks, briefly describing the present situation of this field at home and abroad.(2)To give the chief reasons that result in the temperature cracks, and the theoretical calculation formula for the temperature.(3)To raise the primary technology method that prevents the mass concrete from cracking due to the temperature difference.(4)By the calculation procedure and technical measures above, taking the 2nd long-distance telecommunication project, Kunming for an example (the foundation slab, where the concrete grade is C40P8, is 2400mm in depth, while the distance between axis1/1-A and 1/1-C is 3400mm. The total depth of 5 tapping wells is 3400mm, and 6100mm for 2 elevator raises. The dimension of the foundation slab, which is 59.4m in length, and 43.8m in width, is the typical mass concrete.), we will compute and analyze the temperature of concrete during construction, and take the corresponding measures on this issue. Furthermore, the method of raising environment temperature would be put forward, and make it be practiced. Finally, the concrete temperature, the temperature difference and the crack would be in control effectively, achieving the expected purpose. In the meantime, valuable experience from this project could be offered to the colleagues.