Research On Water Stability And Crack Resistance Of Polyester Fiber Gravel Asphalt Mixture

China is rich in gravel resources,and it is mostly used in the pavement base and bottom base of China’s pavement construction.If it can be applied to asphalt pavement,it will help to save high-quality stone resources and have a positive economic and social benefit price for the construction area,which is in line with the national The strategy of sustainable development,but the gravel has limited the application of gravel in the asphalt pavement because of its acidity.In order for polyester fiber gravel asphalt mixture to be effectively used in the lower layer of asphalt pavement,the material should have sufficient water stability to resist the impact of scouring on the mixture.And consider that if the polyester fiber asphalt mixture is used in the lower layer,the material should have good anti-reflection crack performance and fatigue crack resistance.Therefore,the paper analyzes the water stability and crack resistance test of polyester fiber gravel asphalt mixture,and the research results are as follows:First of all,the paper analyzes the ability of polyester fibers to hold asphalt,and recommends that polyester fibers with a diameter of 20 μm and a length of 6 mm have the best shear resistance.The quality loss rate of polyester fiber asphalt mortar on the surface of gravel aggregates can be effective Decrease;according to the DSR test results,when the content of polyester fiber is 0.3～0.5%,the high temperature shear deformation resistance of polyester fiber asphalt mortar is higher,and the phase angle is lower than that of the original asphalt mortar.The increase in the phase angle of the temperature increase is small.Secondly,through the rutting test,low temperature bending test,submerged Marshall test,freeze-thaw splitting test,and scouring performance test,the paper analyzes the influence of polyester fiber on the road performance of gravel asphalt mixture.The results show that the incorporation of polyester fibers can increase the dynamic stability of the gravel asphalt mixture by 72%,the maximum bending strain of 28%,the residual stability of 16%,and the freeze-thaw splitting strength ratio of 25%.With the increase of polyester fiber,the erosion mass loss of gravel asphalt mixture shows a decreasing trend.When the fiber is mixed with0.45%,the erosion mass loss drops to the lowest value of 0.056%,and the recommended optimal amount of polyester fiber is 0.45%.Thirdly,the thesis studies the anti-reflective cracking capacity of polyester fiber gravel asphalt mixture through anti-cracking simulation test.The test results show that: with the increase of the content of polyester fiber,the cracking life of the composite plate specimen is increasing;the crack development rate K is decreasing,and the cracking life of the gravelasphalt mixture with polyester fiber is less than that of the unmixed The average high is 38%,and the crack development rate K is 19% lower on average.The evaluation index of anti-cracking of polyester fiber gravel asphalt mixture is proposed,namely cracking life n,crack development rate k;recommended cracking life n ≥20,000 times,crack development rate k<3.2mm/h,as polyester fiber gravel asphalt The recommended value of the anti-cracking performance standard of the mixture.Finally,the thesis studied the fatigue characteristics of polyester fiber gravel asphalt mixture through fatigue test.The results show that with the increase of the amount of polyester fiber,the a value of the gravel asphalt mixture gradually increases,and the |b| value gradually decreases.The incorporation of the polyester fiber improves the anti-fatigue properties of the gravel asphalt mixture.Reduces the sensitivity of the material to changes in stress.