Abstract:
In order to analyze the propagation of concrete mode I crack, three crack propagation criteria, which are characterized by the initial fracture toughness, maximum tensile stress and nil stress intensity factor at the tip of the crack, are introduced to derive the load-crack mouth opening displacement curves (
P-CMOD) of three-point bending beams. The
P-CMOD curves are compared with the experimental results of concrete with variated strength including C20, C40, C60, C80 and C100. The results indicate that the peak load and the
P-CMOD curves calculated using the crack propagation criterion characterized by initial fracture toughness have best matched with the experimental ones. With the increasing of concrete strength, the
P-CMOD curves calculated by the crack propagation criteria characterized by maximum tensile stress and nil stress intensity factor at the tip of the crack show an obvious deviation from the experimental curves;while the
P-CMOD curves calculated by the crack propagation criterion characterized by initial fracture toughness are close to the experimental results. It is indicated that the crack propagation criterion characterized by initial fracture toughness is more suitable to analyze the fracture process of concrete beams with different strength.