Modeling and simulation on static and fatigue behaviors of intact and frost damaged concrete with ice-strengthening effects

Abstract

Concrete structures serving in cold and wet regions usually suffer frost damage and thus have server deterioration. Many researches have been conducted to reveal the damaging mechanism and damaged mechanical properties of concrete under the effect of frost action. It has been widely known that the strength and stiffness of frost damaged concrete without using air-entraining agent decrease under room temperature. However, there will be a different story if the frost-damaged concrete is saturated and loaded under freezing temperature. Water existing in pores and cracks will freeze into ice, which provides additional strengthening effects. This paper presents a multi-scale modeling and simulation work on the static and fatigue behaviors of frost damaged concrete with consideration of such ice-strengthening effects. The micro- mesoscale damaging and strengthening effects induced by ice formation are modeled and integrated into the mesoscale analytical approach - Rigid Body Spring Model, and the macroscale static and fatigue behaviors are simulated. It is found that the freezing temperature has a positive (strengthening) effect on the static strength, while it has a negative effect on the fatigue life for both intact and frost-damaged concrete. Test is also conducted with available experimental evidence to validate the developed approach. Satisfactory correlation is found through the comparison between simulation and experiment.