Abstract: In order to study the creep characteristics of concrete under the complex conditions of seawater corrosion, load and hydraulic seepage, we conducted triaxial staged-loading creep test on port concrete immersed in seawater for different days. Test results demonstrate that: 1) seawater corrosion has a significant weakening effect on the strength of port concrete. The long-term strengths of concrete immersed for 0,30,60,120 days are 12.8 MPa, 11.5 MPa, 10.6 MPa, and 10.2 MPa, respectively. 2) As the time of immersion elongates, the initial permeability of concrete increases gradually. The initial permeability of concrete immersed for 0,30,60,120 days are 8.15×10^-17 m², 1.12×10^-16 m², 1.49×10^-16 m², and 1.60×10^-16m², respectively. However, the corrosion effect of seawater attenuates gradually, and the initial permeability is negatively correlated with the corrosion time. 3) The non-linear creep constitutive equation of improved Nishihara model has an ideal fitting effect with the test data, and the determination coefficients are up to 0.98, 0.96, 0.95, and 0.92, respectively, well reflecting the stage characteristics and aging characteristics of creep deformation of port concrete under the coupled action of stress, seepage and corrosion. The research results can provide guidance for the long-term operation of port project in China.

Key words: creep of concrete, multi-field coupling, creep test, permeability rate, constitutive model, Longkou port project