Poromechanical Microplane Model with Thermodynamics for Deterioration of Concrete Subjected to Freeze–Thaw Cycles

AbstractMechanical deterioration of concrete structures by freeze–thaw cycles has been widely spotted, mainly in temperate zones. In order to incorporate the icing-induced microdefects into global damage, a poromechanical model (PM) was integrated into the latest microplane model (M7) to build a holistic model (M7p) for simultaneous evaluation of both freeze–thaw behavior and external loadings. Aligning with the PM, which associates icing-induced strain with temperature and the spacing factor, M7p extends its capability beyond conventional semistatic or dynamic simulation. The features of the M7p are as follows: (1) through a four-stage procedure, the accumulated residual icing-induced strain is evaluated; (2) by calibration of parameters with one single existing freeze–thaw cycle data, a satisfying agreement on the degradation of elastic modulus and strength with experimental data is met; and (3) after calibration, deterioration of concrete structures is reasonably captured, by which cracks were initiated and formed. Hence the stability and durability of concrete structures in freezing and thawing environments are computationally predicted and discussed.