Research On Temperature Control Technology Of Mass Concrete Of Pile Caps Of Large Bridge

A lot of hydration heat is produced as the cement condensing. Because the concrete is a kind of heat-insulating material, the hydration heat can't be released in time so that the temperature in the mass concrete gets higher and it causes the difference between internal temperature and external one. When the temperature difference is too large and the speed of rising and falling is too fast, the crack will appear in the concrete. Temperature crack will decrease bearing capacity and durability of pile caps, and cause safety hidden troubles of bridges, the crack's harm is serious. Therefore it is necessary to do a study of scheme on temperature control of the bridge's mass concrete pile caps. This paper is based on the construction of Huluhe Bridge on the Huangyan Highway and gives a deep research on the temperature control of mass concrete of large bridge platform. The main researches are involved as follows: (1). The paper expatiates on the harm and formation mechanism of temperature crack in mass concrete structure, demonstrates the feasibility of preventing temperature crack. (2). On the base of discussing heat conduction equation and the calculating method of concrete internal temperature field as well as effect factors of it, an approach is put forward which is available to reduce concrete internal maximum temperature, to control it's temperature difference between interior and exterior and to prevent it's temperature from vary rapidly. (3). Basing on the bridge's practical things, a series of temperature control measures are designed. The effect by executing it indicates that it is successful. The result show: rational matching ratio of concrete and high-quality material are the successful basis of the mass concrete temperature controlling ;By optimizing the matching ratio of material ,the inside temperature can be decreased ; Optimized construction management ,correct construction plan and the effective scheme of temperature controlling are the guarantee of the successful mass concrete temperature controlling; In addition the numerical calculation of mass concrete temperature field is sensitivity to the boundary condition ;The further study need be done on the temperature gradient and temperature difference of mass concrete.