Modelling the structural behaviour of frost-damaged reinforced concrete structures

A methodology is introduced to predict the mechanical behaviour of reinforced concrete structures with an observed amount of frost damage at a given time. It is proposed that the effects of internal frost damage and surface scaling can be modelled as changes of material and bond properties, and geometry, respectively. These effects were studied and suggestions were made to relate the compressive strength and dynamic modulus of elasticity, as the indicators of damage, to the response of the damaged concrete in compression and tension, and to the bond behaviour. The methodology was applied to concrete beams affected by internal frost damage, using non-linear finite element analyses. A comparison of the results with available experimental data indicated that the changes in failure mode and, to a rather large extent, the effect on failure load caused by internal frost damage can be predicted. However, an uncertainty was the extension and distribution of the damaged region which affected the prediction of the load capacity.