Research On Fatigue Performance Of Modified Polypropylene Fiber Reinforced Concrete

Concrete material use widely in construction project because of its merits including higher compressive strength,better durability and lower cost. But,as brittle material,concrete has much lower tensile strength as against of its compressive strength.This performance weakness of concrete has limited its application scope to great extent.Recently,mixing fiber in the concrete has made good progress in solving this problem,especially polypropylene fiber,which offers the advantage of light,corrosion resistance,evenly distributed and so on,has a good application prospect.Moreover,the research of fly ash in concrete has become a great important research area in the science of cement and concrete because mixes fly ash in concrete can bring important benefit in many aspects such as technology,economy,environment,society and so on.The application scope of concrete has expanded to high request domain of anti-fatigue and anti-impact along with its application getting more and more widespread in civil engineering.These projects withstand stochastic or periodic load frequently,research of fatigue performance of polypropylene fiber in concrete and fly ash concrete appears the great importance.Synthesized the situations above,this paper has selected a kind of fine performance modified polypropylene fiber which is made in China,studied performance and fundamental which was influenced on fiber in two different kinds of parent concrete.Firstly,taking plain concrete as parent concrete,studied static intensity and flexural fatigue performance which was influenced on the variation of fiber in volume,established the flexural fatigue equation of modified polypropylene fiber in concrete,searched the effects rule of flexural fatigue performance and found the best level of fibers in volume.Secondly,taking concrete with 20% (by mass) fly ash as parent concrete,further study has been made to find out the performance influence and the effects rule of fiber and fly ash in concrete.Effects of modified polypropylene fibers on performance of plain concrete:mixing a certain amount of modified polypropylene fibers into concrete has little influence upon compressive strength of concrete,but increased cleavage strength,flexural strength and flexural fatigue performance of concrete greatly.With the advance of fiber mixing level's increase,some fiber bundles can be found in concrete to certain extent which affects the performance of concrete.Considered both static intensity and flexural fatigue performance,0.10% of modified polypropylene fibers in volume is the best level mixing in concrete. Effects of modified polypropylene fibers on performance of concrete with fly ash:Mixing modified polypropylene fibers into fly ash concrete,fibers and fly ash has a good cooperative effect,further enhanced the flexural fatigue performance of concrete.Moreover,along with fiber's increase,there are no obvious fiber bundles in concrete,cleavage strength,flexural strength and flexural fatigue performance of concrete with fly ash increase greatly.