SUMMARY
Concrete is a brittle material with high compressive strength, low tensile strength and poor toughness, where cracks of different degrees and different forms can be developed, which compromises the durability and the lifetime of concrete structures. The crack starts to propagate in concrete when the crack tip stress intensity factor reaches the fracture toughness value (critical stress intensity factor KC or fracture energy GC). Many studies were carried out on the fracture of concrete to measure KC and GC based on LEFM (Linear Elastic Fracture Mechanics).This paper uses tow approaches to analyze the crack propagation of cracks three-point bending concrete beam and Brazilian disk with initial crack based on determination of stress intensity factor analytically starting from weight functions and numerically using the finite element software platform Abaqus.