  Concrete subjected to combined compressive stresses and temperature loading
exhibits compressive strains, which are considerably greater than for concrete
subjected to compressive stresses alone. This phenomenon is called transient
thermal creep or load induced thermal strain and is usually modeled by
macroscopic phenomenological constitutive laws which have only limited
predictive capabilities. In the present study a meso-scale modeling approach is
proposed in which the macroscopically observed transient thermal creep results
from the mismatch of thermal expansions of the meso-scale constituents. The
meso-structure of concrete is idealized as a two-dimensional three phase
material consisting of aggregates, matrix and interfacial transition zones
(ITZ). The nonlinear material response of the phases are described by a
damage-plasticity interface model. The meso-scale approach was applied to
analyze compressed concrete specimens subjected to uniform temperature
histories and the analysis results were compared to experimental results
reported in the literature.
