Experimental Research Of The Mechanical Properties Of Polypropylene Fiber Reinforced High-strength Concrete

In recent years,as the broad bridge,the tunnel and the high building's popularity,High-strength concrete with the characters of high intensity,good endurance and excellent utility is on application day by day. .However,comparing with the common concrete,the strict construction,the greater crisp character and the lower penetrability,lower firefighting properties. But adding the polypropylene fiber to improve the toughness of high strength concrete is an important direction in present study. Meanwhile, early cracking of high strength concrete hardening have a good improvement. It could well ease the early tensile stress of concrete hardening due to various factors, reduce the occurrence and development of macrco-crack ,prevent the expansion of the existing micro-cracks and delay the emergence of new cracks in the basal body and improve the ability of the matrix deformation.. Therefore the study about the mechanical properties of the high strength concrete with polypropylene fiber is a topic which has both the academic and realistic sense.Relying on shanxi university science and technology research and development program (Numbers:2007115)" polypropylene fiber of high strength concrete fire toughening components",this study of polypropylene fiber reinforced high strength concrete include cube compression tests,splitting tensile tests,elastic modulus tests,axial compression tests and bending tests refer to steel fiber concrete method. Finally, we studied the polypropylene fiber reinforced concrete fracture energy changes with three-point bending beam method in accordance with the RILEM guideline. We select six different dosages sizes and four different lengths of polypropylene fiber and determine the best content the best aspect ratio with the impact polypropylene fiber reinforced concrete. We also verify hybrid fiber mechanical properties of high strength concrete with different lengths compared to the single lengths .By the test results with the axial compressive strength and compressive strength, the impact of high-strength concrete with polypropylene fiber is very small and use high strength concrete strength directly. But for tension and compression ratio, splitting tensile strength, elastic modulus, flexural strength and fracture energy, changes in mechanical properties of polypropylene fiber reinforced high strength concrete is more obvious. It prove polypropylene fibers improve the toughness of high strength concrete and show upward changes with the content and fiber length. While hybrid fiber reinforced concrete in i flexural strength and fracture energy superior to the single length of fiber or high-strength concrete, but the advantage is not obvious. These conclusions for the study of polypropylene fibers provides a wealth of information and can also serve as the important basis of polypropylene fiber reinforced concrete structure design and practical application for the project.