Determination of the temperature field and thermal stress state of the massive of stacked concrete by finite element method

Introduction. Energy and hydraulic concrete structures, bridge structures, foundations of buildings are built with concrete blocks. Concreting of such massive structures is accompanied by the phenomenon of exothermic heating of the structure caused by the process of cement hydration. The heat released in such massive blocks under natural conditions is very slowly removed from the structure. Quite often, between the central part of the massif and its surface, there is a significant temperature drop. In the case of reaching a critical value of the temperature difference, temperature cracks occur that violate the solidity of the structure. For a preliminary assessment of the possibility of cracking and the development of measures to eliminate it, it is necessary to solve the temperature problem and the problem of determining the thermal stress state. This problem has long been in the center of attention of specialists and a large number of studies are devoted to it. Developed and used a large number of methods for solving these problems. However, in view of the great complexity of the task to be solved, caused by a multitude of operating factors and conditions, the complexity of the structures and the increased requirements for the safety of structures, the task of determining the temperature regime and the thermally stressed state of the erected concrete massif is still very relevant today. This paper presents some results of investigations in this direction, performed on the basis of the finite element method. An erected concrete block is considered, for which a non-stationary temperature problem is solved successively and the resulting temperature stresses are determined. The variants of block laying at different external temperature influences are considered. Materials and methods. The study was performed on the basis of the finite element method (FEM) using the Ansys software. Results. For the considered array concrete obtained temperature distribution and thermal stresses over time from the moment of packing to obtain a sufficient structural strength (about 30 days). On the basis of criteria assesses the possible occurrence of thermal cracks. Conclusions. Based on the numerical solution of the problems of determining the temperature regime and the thermally stressed state of the concrete block using the Ansys software complex, a detailed picture of the spatial no stationary state of the structural element, the concrete block, as part of a massive structure, has been obtained.