Study on crack propagation mechanism of coal gangue concrete
In order to study the crack propagation mechanism of coal gangue concrete,three-point bending fracture test of coal gangue concrete was carried out based on DIC method.The results show that the more the amount of coal gangue,the smaller the bending degree of the failure path,the faster the crack propagation speed,and the cracks penetrate through the coarse aggregate of coal gangue.The more coal gangue content,the smaller the fracture performance index and the smaller the horizontal displacement and strain field.Before the ultimate load,the horizontal displacement on both sides of the crack tip is small.After the ultimate load,there is a jumping increase,and there is a left and right inflection point.After the inflection point,the horizontal displacement remains unchanged.After the horizontal displacement field is subjected to the ultimate load,it expands upward,and the strain field at the crack tip gradually increases.The boundary surface equations of the micro-crack generation zone of concrete with different contents of coal gangue are established.
concretecoal gangueDIC methodcrack propagationmicrofracture generation zone