Coupled thermo-hydro-mechanical analysis of reinforced concrete beams under the effect of frost damage and sustained load

Frost damage is an important deterioration parameter for reinforced concrete (RC) structures in cold and humid environment, which usually acts simultaneously with sustained load caused by self-weight, immobile weight, and so forth. This article conducts a thermo-hydro-mechanical simulation on the structural behavior of RC beams under the coupled effect of frost damage and sustained load. This simulation approach starts from the microscale material-based frost damage model of multicomponent substance to the macroscale structural-based performance evaluation of RC beam. On the basis of this approach, the damage accumulation of RC beam model under both frost action and sustained load is simulated. Afterward, flexural bending load is applied to investigate the structural performance of the RC beam which has suffered coupled damage. Laboratory experiments also show a satisfactory agreement with numerical simulation. Parametric study is also conducted to further evaluate the influence by different parameters on the structural deterioration, for example, reinforcement arrangement, water to cement ratio, and so on. Finally, the equivalent frost-damaged strength with respect to the damaged region is adopted to calculate the flexural capacity according to the design code, and a simple method is proposed to verify or predict the properties of RC beam under the coupled effect of frost damage and sustained load.