A New Safety Factor Prediction Model for Mass Concrete Surface Cracking in Early Age

The temperature difference between mass concrete inside and outside is an important index to prevent the structure surface cracking, but the definition and the application criterion are not very clear till now. In this paper, the surface concrete temperature spatial gradient in 0.5 m deep is found as a more reasonable and feasible index. Then a new model, which can be used to calculate the surface safety factor simply, is deduced in three steps. First, a basic model is created under the simplest boundary condition. Then the feasibility of the basic model is analyzed under different boundary conditions and the model is improved. At last, according to the comparison of different concrete materials, the improved model is calibrated further. With the help of the proposed model, the surface safety factor can be adjusted by observing and controlling the temperature spatial gradient dynamically, which will bring convenience to designer and constructor.