Experiment Study On Mechanical Properties And Durability Of Complex Fiber Concrete

Bridge deck pavement material requires sufficient compressive strength, flexural strength,and bending toughness. The bridge structures inevitably bear the impact of the external adverseenvironment,so pavement layer material should also have impermeability, freeze-thawresistance and corrosion resistance. Complex fiber concrete not only has good mechanism butalsohassuperiordurability.Anditisverysuitabletotakethebridgedeckpavementmaterial.This paper is on the basis of the results of previous studies. This experiment studies steelfiber concrete and polypropylenesteel-wire-like fiber concrete as well as complex fiber concrete,and makes the comparison of concrete performance, compressive strength, flexural toughness,impermeability and mechanical properties before and after freeze-thaw cycles. The results showthat: complex fiber concrete has better performance and bending toughness, superiorimpermeability and freeze-thaw resistance, and is an ideal choice as bridge deck pavementmaterial.The research results of mechanical properties show that: incorporation of steel fibers andpolypropylene steel-wire-like fiber not obviously impact the 28-day compressive strength ofconcrete, but compared with the plain concrete, fiber reinforced concrete has greater late growthpotential. Single-doped fiber reinforced concrete and steel fiber reinforced concrete has goodtoughness. The toughness index I30 of the complex fiber concrete before and after 150freeze-thawcyclesarethelargest.Sothecomplexfiberconcretehasbetterlateductility.Theresearchresultsofdurabilityshowthat:theimpermeabilityoffiberreinforcedconcreteissuperior to plain concrete. The impermeability of the complex fiber concrete reaches 29MPa.After 150 freeze-thaw cycles, despite the dynamic elastic modulus lowering and the quality lossof the concrete specimen is not significant, the concrete compressive strength has droppedsignificantly and the bending ultimate load has dropped slightly. So the concrete compressiveproperty is more sensitive to the damage of freeze-thaw cycles. The Air-entraining agentsignificantly improved the impermeability and freeze-thaw resistance of the complex fiberconcrete.