Experimental Study on Axial Compression of Concrete with Initial Crack under Hydrostatic Pressure

The axial compression test of concrete with different initial cracks under hydrostatic pressure is carried out. The fracture propagation is analyzed based on the bearing state as well as the apparent phenomena of the specimens, and the failure modes and morphologies are further elaborated. The test results show that with the increase of the hydrostatic pressure, the peak strength growth rate of different crack dip angle specimens tends to be larger or smaller. The development of the hydrostatic pressure leads to the remarkable growth of the plasticity of initially cracked post-peak plastic specimens. Due to the influence of the crack inclination angle, various rates of variation of the elastic modulus after strain softening are detectable. Under the combinational effects of the crack inclination angle and the hydrostatic pressure, the failure modes of the concrete with different initially inclined cracks are different, leading to fracturing failure and shearing shear failure. The crack propagation morphologies of the initially cracked specimens are also dissimilar. With the increase of the hydrostatic pressure as well as the inclination angle of cracks, the crack propagation pattern gradually changes from I-shaped cracks to II-typed cracks, even I-II composite cracks would appear.