Exprimental Research On Frost Resistance And Fatigue Property Of Steel Fiber Reinforced Fly Ash Concrete

Based on theoretical investigation,first,experimental investigations were conducted on the compressive strength and bending strength of steel fiber reinforced fly ash concrete.Secondly,experimental investigations were conducted on the compressive strength of steel fiber reinforced fly ash concrete after 75 times freeze-thaw cycles.Finally,experimental investigations were conducted on the flexural fatigue of steel fiber reinforced fly ash concrete beams.The exprimental result indicated,volume of fly ash effect on strength of steel fiber reinforced fly ash concrete was influenced by age and volume of steel fiber.Compressive strength and bending strength of concrete decreased with the increment of fly ash incorporation.But descend trend ease up with the increment of age.Fly ash and steel fiber incarnate stronger compound effect with the increment of steel fiber volume.Compressive strength of steel fiber reinforced fly ash concrete decreased less and bending strength increased more after proper fly ash is mixed(volume under 30%).But compressive strength and bending strength lose very seriously when volume exceed 30%.When the volume of fly ash was 30%and volume ratio of steel fiber was 1.2%,28 days compressive strength of steel fiber reinforced fly ash concrete had decreased 7.6%and bending strength had improved 12.1%.But when volume of fly ash was 50%and volume ratio of steel fiber was 1.2%,compressive strength,bending strength loss rate as high as 62.3%and 36.2%. Freezing ability of concrete is worse.Compressive strength loss rate as high as 45.695%after 75 times freeze-thaw cycles.Improve antistripping and freeze-thaw properties significantly when steel fiber and fly ash are mixed.Fly ash improves frost resistance of specimen stronger then steel fiber.Compressive strength loss rate less when fly ash was mixed after freeze-thaw cycles.For example,strength loss rate of steel fiber concrete was 17.699%after 75 times freeze-thaw cycles,but loss rate of fly ash concrete was only 0.810%.Stress level has significant effect on flexural fatigue life of steel fiber reinforced fly ash concrete beam.Fatigue life under low stress is much higher than high stress.Flexural fatigue life can be divided into latency stage,stable development stage and in stability development stage in the course of flexural fatigue deformation of steel fiber reinforced fly ash concrete.Obtained curve equation of lgS-lgN which was lgS=0.11735-0.06131gN through fitting.The damage evolvement process can be divided into latency stage,stable developing stage and instability development stage.Damage developing rate of steel fiber reinforced fly ash concrete in high stress level obviously superior then low stress level.Measured fatigue life through fatigue expriment.It is obtained that the relationship between fatigue life and stress level.Analysis deformation properties and damage properties of flexural fatigue.It is can offer that the experimental gist for pavement design in heavy traffic and develop comprehensive utilization ways of fly ash.Ensure sustainable development of China's energy.