Prediction of dynamic mechanical behaviors of coral concrete under different corrosive environments and its enhancement mechanism

The marine structures are usually exposed to dynamic loadings within short periods and chemical attacks, resulting in severe dynamical damage or failure to concrete structures. The study of the time-dependent changes in the dynamic mechanical behavior of coral concrete under different corrosive environments and low-frequency waves is limited. For the safety and reliable use of coral concrete in the marine environment, different corrosion environments (chloride ions, sulfate ions, and mixed chloride-sulfate ions) and low-frequency waves (0.5-2.0 Hz) were designed to evaluate the dynamic properties of concrete. A model considering the effect of corroded age is formulated to predict the damping capacity of coral concrete. Testing results indicate that sulfate attack shows the most significant effect to influence the dynamic behaviors of coral concrete, while the effect of chloride ion penetration is negligible. The loss factor of coral concrete under corroded environments increases by 59.5% compared with ordinary concrete, even though the loss modulus and storage modulus of coral concrete reduce by 38.5% and 51.8%. It was attributed to coral concrete showing a low ability to resist sulfate attack, resulting in more cracks and pores in the matrix. Coral aggregate with high porosity and interconnected pores in coral concrete works like a cushion to dissipate more external energy. The proposed prediction model (R2 = 0.89) can accurately describe the relationship between erosion age and damping capacity in different corrosion environments, which can guide the application of coral concrete in marine and vibration environments.