Implementação de um modelo termo-hídrico para simular os efeitos da temperatura sobre estruturas de concreto

Abstract

Modeling the behavior of concrete structures exposed to high temperatures allows the study of different conditions that are not always possible in experimental studies, both from a physical and economic point of view, in a much shorter time interval, in addition to providing the analysis of the main constituent properties. of material. The purpose of the research is to improve a thermo-hydro model seeking, through numerical simulations, to adequately reproduce experimental results found in the literature. A review was carried out on the main aspects related to the subject, including the description of the thermal properties of concrete and its behavior as a porous medium. Among the main improvements applied to the studied model is the alteration of the time march scheme, the consideration of the porosity time derivative terms in the mass conservation equation and the change in the evolution of the latent heat of vaporization, a property used as a generating source of heat. The program used for numerical simulations was Cast3M, which is a code based on the finite element method for solid and fluid mechanics. It is a complete system that integrates calculation, model building (pre-processor) and result processing (post-processor) functions at the same time. Numerical results make it possible to assess the quality of the proposed model and serve as support for future developments. The analysis of the results is based on the comparison with the results achieved by Ferreira (2011) and Amaral (2014) for the rock-concrete bilayer. There is a clear similarity between the numerical and experimental results for temperature and an evident improvement in the saturation results. Noticed discrepancies point to the demand for more in-depth studies regarding the formulation of the water properties used.