Effect of free water on fatigue performance of concrete subjected to compressive cyclic load

To clarify the effect of free water on the fatigue behaviour of concrete, dry, saturated, and water-submerged concretes were subjected to different stress levels of cyclic loads. The failure modes and S-N curves were determined. The evolution of fatigue deformation, the energy dissipation characteristics, and the impact mechanism were discussed. Water content was observed to affect the fatigue life of concrete. Owing to the interaction of free water, the fatigue life of concrete in saturated and water-submerged conditions reduced significantly compared to that of dry concrete. The compressive fatigue failure mode shifted from splitting failure in dry concrete to combined splitting and shearing failure in saturated concrete and shear failure in watersubmerged concrete. The strain rate and dissipated energy of concrete in fatigue stage II increased with the water content and maximum stress level. The strain rate in stage II and the dissipated energy were logarithmically and linearly correlated with the fatigue life of concrete.

Automated summary

The research investigated the impact of water on the fatigue behavior of concrete, revealing that water content reduces the fatigue life of concrete, significantly decreasing the fatigue life of saturated and water-submerged concrete. Additionally, the failure modes shifted with the presence of water. Energy dissipation and strain rate in stage II of fatigue were found to increase with water content and maximum stress level, showing logarithmic and linear correlations with the fatigue life of concrete.