Water absorption and chloride diffusivity of concrete under the coupling effect of uniaxial compressive load and freeze-thaw cycles

Water absorption and chloride diffusivity of concrete under the coupling effect of uniaxial compressive load and freeze-thaw cycles

In cold coastal area, the destruction mechanism of reinforced concrete structures is mainly governed by a combination of factors such as self-loading, freeze-thaw and chloride erosion. In this study, ordinary cube concretes (C30 and C50, while w/c = 0.53 and 0.35 respectively) underwent a coupling effect of pressure load with stress ratio of 0, 0.3 and 0.5 and freeze-thaw cycles, following by capillary water absorption test and chloride penetration test. Concrete samples with 0.3fc showed the best water and chloride penetration resistance under the coupling effect, followed by samples with 0.5fc and 0fc, which is consistent with the conclusion that under load only. Water and chloride ions penetration increased sharply when freeze-thaw cycles was over 100 times, which is different with samples without load. Outside part of concrete showed higher permeability and chloride content than inside part. MIP results confirmed that stress played an important role in the water absorption and chloride penetration of concrete under the coupling effect. These results provide important new insights into the permeability of concrete under a coupling effect. The applied load performed a more important role on the service life prediction of concrete structure.

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