Introduction. The modeling of temperature fields and stresses used to prevent the risk of early cracking of massive monolithic reinforced concrete structures determines the relevance of improving the algorithm for calculating temperature stresses due to the «center-top» temperature difference depending on the magnitude and kinetics of heat dissipation of concrete, autogenous shrinkage, heat transfer conditions and ambient temperature. Purpose of the study: modeling of temperature fields and stresses of massive structures using the example of a flat foundation slab 1.5 m thick based on the proposed dependencies of the kinetics of strength, heat dissipation, autogenous shrinkage, and deformation properties of concrete of various classes. Methods. Modeling of temperature fields and stresses taking into account specific heat dissipation and properties of concrete. Results: A system of equations is proposed, identical in structure to the strength kinetics equation according to EN 1992-1-1, to describe the kinetics of autogenous shrinkage and heat dissipation of hardening concrete depending on the type of cement according to the hardening kinetics. Modeling of the formation of temperature fields and stresses of a massive flat foundation slab 1.5 m thick was carried out depending on the class of quick-hardening concrete and the specific heat dissipation of cement. It is substantiated that it is insufficient to prevent early cracking by limiting only the «center-top» temperature difference without taking into account the specific properties of concrete. It has been shown that autogenous shrinkage, when dependent on the strength of concrete according to the EN 1992-1-1 equation, can slightly reduce the level of tensile stresses in the early period of concrete hardening of a massive foundation slab. An approach to normalizing the heat dissipation of concrete and cement is proposed in order to limit the stress level under the conditions of the problem considered. The values of the permissible values of the «center-top» temperature difference taking into account the properties of concrete were obtained.
