Fatigue Performance Of Calcium Sulfate Whisker Modified Asphalt Mixture In Forest Roads

Forest roads are indispensable infrastructure for forestry and regional development.Compared with other expressway,National Road and provincial road vehicle,the road of forest area is more heavy load vehicle and large axle load vehicle,which makes the original design unable to meet the demand of heavy load traffic.The pavement is extremely prone to fatigue damage under the integrated load and environment.In order to improve the fatigue performance of forest road,new material,new technology and new technology are used to reduce pavement damage and prolong its service life.It is an important means to improve the fatigue performance of asphalt mixture pavement.As a new type of asphalt mixture,calcium sulfate whisker has been proved to have the characteristics of wear resistance,acid and alkali resistance,corrosion resistance and high temperature resistance.It can improve the fatigue durability of the pavement and prolong the service life of the pavement,and has a wide application prospect.In this paper,the addition of calcium sulfate whiskers is applied to asphalt mixture,and the following conclusions are obtained through laboratory fatigue tests:1.Based on Marshall design method,the mix design of calcium sulfate whisker modified asphalt mixture was carried out,and the optimum asphalt content was determined to be 4.3%.2.The influence of calcium sulfate whisker content,strain level,test temperature and loading frequency on the fatigue performance of asphalt mixture is analyzed based on phenomenology.The results show that the fatigue performance of asphalt mixture is four different angles.It is found that the addition of calcium sulfate whiskers increases the fatigue life of the material,but the better the fatigue performance is,the better the fatigue life of the material is,and the fatigue life reaches the maximum when the amount of doping is 3%.3.From the strain analysis,it is found that when the strain is 400,the durability of asphalt mixture is longer,so it is more suitable for forest roads.4.From the point of view of temperature,the temperature fatigue equation is established,and the change law of temperature on fatigue performance is analyzed from the angle of stiffness modulus.5.From the angle of loading frequency,it is found that the fatigue life of the specimen increases with the increase of the loading frequency.When the loading frequency increases to more than 10 Hz,the fatigue life is gradually stable.Therefore,in the forest area,the 10 Hz design is more reasonable.The frequency-fatigue equation is established.Based on the energy consumption method,the relative energy dissipation rate and fatigue damage are analyzed respectively.From the analysis of relative change rate of dissipation energy,the material has only experienced two stages,namely initial crack formation stage and stable crack development stage.6.From the angle of relative dissipation of energy dissipation,it is proved again that the fatigue life of calcium sulfate whisker modified asphalt mixture is the largest when the dosage is 3%.7.From the fatigue damage analysis,the cumulative damage increases rapidly in the initial stage with the increase of loading times.The greater the strain is,the greater the damage is,and the fatigue damage equation is established.8.Through the saliency analysis,the influence of four factors on the calcium sulfate whisker modified asphalt mixture is: strain?temperature?frequency?calcium sulfate whisker.