engleski

3D Thermo-hygro-mechanical model for concrete

In the present paper numerical analysis of spalling of concrete at high temperature is discussed. For a given boundary conditions the distribution of moisture, pore pressure, temperature, stresses and strains is calculated by employing a three-dimensional transient finite element analysis. The used thermo-hygro-mechanical model accounts for the interaction between hygro and thermal properties of concrete. Moreover, these properties are coupled with the mechanical properties of concrete, i.e. it is assumed that the mechanical properties (damage) have an effect on the distribution of moisture (pore pressure) and temperature. The mechanical strain, which is due to loading, temperature induced stresses and pore pressure, is calculated by employing temperature dependent microplane model for concrete. To study spalling of concrete cover, a 3D finite element analysis of a concrete slab, which was locally exposed to high temperature, is performed. In the analysis are varied thermo-hygro and mechanical properties of concrete. It is shown that relatively high pore pressure in concrete can cause spalling of concrete cover. The results show that the governing parameter that controls spalling is the permeability of concrete.

Concrete; Fracture; Transport processes; Finite Elemens; Spalling

nije evidentirano