Abstract:
For the coupled action of low frequency fatigue loading and pore water pressure, the energy for fatigue crack growth of concrete is usually divided into two aspects. The theoretical approach of energy provided by low frequency fatigue loading and pore water pressure can be derived, respectively. Based on the superposition principle of energy approach, the crack propagation model under the coupled action of low frequency fatigue loading and pore water pressure was developed considering the concept of energy release rate during the fracture of concrete. Then, the theoretical results were validated using available experimental data in the literature. The comparisons indicate that the proposed model agrees reasonably well with experimental data when the pore water pressure is ignored. Moreover, it is found that under the combined action of low frequency fatigue loading and pore water pressure, the pore water pressure can provide the energy dissipated by the opening of closed crack to accelerate the crack growth. Moreover, the crack propagation rate increases with the increase of pore water pressure, which results in the reduction of the fatigue life of concrete.