Analysis On Hydration Heat Of Mass Concrete In Suspension Bridge Anchorage

With the process of the infrastructure construction in China,the applications of mass concrete structure in bridge engineering are more and more wide.Mass concrete is large in volume character,which easily causes the heat produced by hydration of cement to gather in internal structure and difficultly to be sent out.The result is that the temperature in internal structure of mass concrete rises sharply in a short time,and the temperature on the surface of the structure maintains a lower rising speed compared to the former,which leads to a great tensile stress on the surface,even the crack on the account of an enormous temperature difference between the inside and outside of the mass concrete structure.The finite element entity model based on a gravity anchorage of suspension bridge is studied by using element software in this paper.The specific research contents and achievements are as follows:(1)Large geometric size and high hydration heat are expounded which are the two basic characteristics of mass concrete in this paper.In addition,the present situation at home and abroad of mass concrete is also analyzed in this paper;(2)The thermal properties of concrete materials are summarized in this paper.The calculation method of adiabatic temperature rise about mass concrete is stated based on the principle of cement hydration heat.According to the principle of solid heat conduction,the theory of finite element calculation about temperature fields and stress fields in mass concrete is illustrated;(3)According to the overall and partial varying with time of hydration heat temperature fields and stress fields in suspension bridge anchorage by using finite element software,the temperature effect results of mass concrete during construction are as follows:the hydration heat of concrete by stratified pouring will have a process of accumulation.The peak temperature increases with construction and generally appears in 3 to 5 days after casting concrete,and the heating speed is larger than cooling speed.The temperature tensile stress mainly concentrates on the surface and changes in initial period;(4)Lower concrete casting temperature can reduce and delay the emergence of hydration heat peak temperature and lower temperature of cooling water can improve cooling efficiency significantly.