The Investigation Of Temperature Crack Controlling For Large-volume Concrete Foundation Slab

The problems of temperature crack in reinforced concrete are very complicated. They not only involve geological, structural and material engineering, but also environmental engineering, heat transportation and construction technology. In this paper, the mechanisms of temperature crack and crack-prevention methods were studied through a practical foundation construction project in Wujiang city. The contents are as follows:1. On the basis of consulting a large number of references, the characteristics of temperature-shrink crack for the slab foundation of large volume concrete are introduced and discussed. The temperature-shrink crack reasons of the reinforced concrete are analyzed. From the respects of concrete reinforcement, creep, shrink, material performance of the concrete and construction, the influence factors of the slab crack are analyzed in details.2. Based on the heat-conduction equation and boundary conditions, the distribution and properties of concrete temperature field in the process of concrete cooling are investigated. Several influence factors of concrete temperature field are put forward.3. The basic conception and feature of temperature stress is briefly introduced. The calculation models of temperature stress for the foundation slab are established. The formula of maximum build-length of concrete foundation slab is derived through temperature stress analysis.4. From the respects of the design, raw materials and construction etc., the specific measures of controlling temperature shrink cracks have been put forward.5. The methods of controlling temperature shrink crack are applied in a practical concrete slab project, which shows the feasibility and rationality of these methods.