Effect of Cyclic Loading Deterioration on Concrete Durability: Water Absorption, Freeze-Thaw, and Carbonation

Abstract

The effect of cyclic loading deterioration on freeze-thaw and carbonation resistances of concrete were experimentally investigated in this study. A novel loading method was designed, which simultaneously considers both mechanical loading and environmental actions for concrete. It shows that with the increase of cyclic compressive loading, the porosity and water absorption of concrete initially decrease but then increase when the stress is above a threshold level because of the cracking initiation caused by cyclic compression. With the increase of concrete porosity, both dynamic elastic modulus loss and carbonation depth obviously exhibit an increasing trend. On the other hand, under the same stress level, the freeze-thaw and carbonation resistances of high-strength concrete are relatively superior to those of low-strength concrete. Compared with the unloaded concrete, the carbonation depth and dynamic elastic modulus loss after mechanical loading below the stress level threshold are lower. This is probably due to the denser microstructure compacted by the compression. However, if the loading level becomes above the threshold level, both the carbonation depth and dynamic elastic modulus loss dramatically increase, which is due to the cracks initiation and propagation after cyclic loading deterioration. Therefore, the combination of mechanical and environmental actions is more severe than a single environmental action without considering the mechanical loading.