Study On Application Of Crack Control Technique Of Mass Concrete Used In Foundation

In recent years, with the economic development, the application of high-rise buildings is increasingly extensive, and brings new challenges to construction techniques. As the buildings are getting higher and higher, and the planceers are getting thicker and thicker, the planceers are often cracked by temperature stress in project practice. Plenty of projects and theories indicate that most cracks developing with the loading or physical and chemical factors, and bring much issue such as carbonization of the concretes,protective layer desquamation and rusting of the steel bar, which weaken the strength , rigidity and durability of the concretes, even result in collapse, and influence natural use, so it must be in control. So the research on the construction technique of the mass concrete has got very important engineering meaning.This dissertation mainly discusses the control of temperature stress and temperature strain in super thick mass concrete planceer of high-rise building. Because the cracks of super thick mass concrete planceer is usually caused by temperature stress and temperature strain, we will focus on the change of the temperature stress and explore the construction technique to prevent mass concrete planceer from cracks. Therefore, it can provide valuable insights to the studies in this field and offer practical suggestions to the further research.The main tasks of this paper are as follows:1) To give the definitions of the mass concrete and concrete's crack together with the practical meanings of crack control, and give a brief review on the studies in this field at home and abroad;2) To explain the physical mechanics characteristics of the concrete and computing methods to calculate the temperature and crack resistance of the concrete;3) To discuss the mechanism and factors resulting in temperature cracks;4) To put forward the effective measures to control the temperature cracks;5) To calculate the temperature field and temperature stress field in the case of new CCTV building (It is a representative super thick mass concrete project of which the thickness mainly contains4.5m,6.0m,7.0m,and even10.9m in local)in Beijing followed by a further analysis on the crack resistance projects, and give practical technical measures to control the crack based on the case study results, it achieve the anticipative effect. At the same time, it offers important experience for similar projects.