Research on Test of Fracture Toughness and Fracture Criterion of Crack of mixed mode I and II of Steel Fiber Concrete

摘要

Steel fiber concrete is a new-type composite material of excellent property with broad application formed by common concrete mixed with disorderly oriented short steel fiber. Main action of steel fiber is to prevent broadening of interior micro crack in concrete and restrict occurrence and growth of macro crack. Based on basic theory of concrete fracture mechanics, this treatise adopts four-point shearing sampling material to conduct experimental research, having obtained critical fracture curve of crack of composite mode I, II of steel fiber concrete, setting up experimental formula of fracture criterion, probing into difference between fracture toughness of steel fiber concrete and that of common concrete, and discussing application of maximum tension stress theory in steel fiber concrete.