Xu Wen 1,2, Yan Zhigang 3, Zhang Shishan 2, Liu Jiaping 1,2
(1. School of materials science and engineering, Southeast University, Nanjing 211189, Jiangsu; 2. State Key Laboratory of high performance civil engineering materials, Nanjing 211103, Jiangsu; 3. Engineering management center of China National Railway Group Co., Ltd., Beijing 100844)
Abstract: the main channel bridge of Shanghai Nantong Yangtze River Bridge is a cable-stayed bridge with two pylons and steel truss beams with a main span of 1092 M. the tower height is 330 m, the tower body is made of C60 concrete, and the concrete volume of a single tower is more than 60000 square meters (excluding the tower base). In order to reduce the risk of cracking of bridge tower concrete, the content of cement hydration control materials and the proportion of composite expansion materials are determined by isothermal calorimetry and variable temperature deformation test. The anti cracking performance of concrete is studied by scale model test. Based on this, the anti cracking concrete is prepared and applied in the construction of 29 pier bridge tower. The results show that 0.2% hydration control material can reduce the peak value of hydration heat release rate of cement by about 50%; adding 50% CaO + 50% MgO expansion material can increase the expansion deformation of concrete at the temperature rise stage by about one time, and reduce the contraction deformation at the temperature drop stage by about 30%; compared with ordinary concrete, the peak temperature at the center of anti cracking concrete model is reduced by 6.4% The expansion deformation increased by more than one time and the shrinkage deformation decreased by 100 μ ε. The anti cracking concrete construction of 29 pier tower significantly reduced the shrinkage tensile stress and cracking risk of the solid structure.