Modeling and numerical analysis of concrete specimen under dynamic and thermal loading taking into account non-linearity

In this study, we propose a model describing the mechanical behavior of basalt aggregate concrete under high temperatures. Basalt aggregate concrete is formulated. The bulk density, residual mechanical (compressive strength, tensile strength and elastic modulus) and microscopic properties of basalt aggregate concrete specimens are analyzed. The damage basalt aggregate concrete, the geometry and nonlinear behavior of the material is investigated. Based on Newton's second law, the investigation is conducted on the simultaneous effects of mechanical loading and thermal treatment. The finite difference method is used for the numerical solution of the problem to determine the peak stress and strain of normal basalt aggregate concrete as a function of temperatures and time. It follows from the results obtained that, after [3-5 min] the critical temperature at which material damage, for both stress and strain, is observed to be 350 degrees C at the center, corresponding to a 30% reduction in peak stress on the value initially obtained experimentally; And 300 degrees C at the free and fixed end of basalt aggregate concrete specimen respectively, corresponding to a 38 and 30% reduction in stress in the z-axis direction. Beyond these temperatures, it is observed that the amplitude of the deformations continues to increase whatever the position announcing an imminent collapse of the material, probably due to the loss of stiffness of the cement paste which significantly reduces the mechanical performance of the normal basalt aggregate concrete observed experimentally.