Lothenbach’s Model of Von Mises Stress Distribution in Portland Cement in Curing and Temperature Gradient Conditions

The paper presents the two-dimensional Lothenbach's model of Portland cement curing based on the finite element method. The cement curing lasts for 7 days in the temperature gradient conditions ranging from 65 to −20 °C. A cement rod 7×70 cm in size is used for modelling the temperature and von Mises stress distributions. It is shown that in the temperature gradient and curing conditions, the stress maximum in Portland cement shifts toward the hot edge of the cement rod and exceeds the minimum stress level more than two times. The stress growth is significant at the interfaces between the concrete timber and the cement rod, especially at its cold edge. Such a distribution of von Mises stress is connected with the heat flow generation and their superposition with reverse heat flows. At the interfaces, superposition of the negative heat flows generates higher stresses, than superposition of the positive heat flows. The concrete timber and the interface stability are the additional factors that increase the stress level and contribute to the fracture of the pore walls.