Fatigue Properties Of Asphalt Mixture Under Two Test Models

In recent years , the rapid development of China ’s road and highway totalmileage increased year by year , especially the highway is at an unprecedented rate ,which has entered a new era based on the construction of highways , first-classhighway and other high-grade highways. However , with the people’s living standardsimprove , the road traffic is increasing day by day and the overloaded roads ,overloading is becoming more serious. In this long-term stress and strain alternating ,the pavement strcture strength decreases very rapidly. When the load repetitionexceeds a certain number , the stess of the pavement will exceed the stength ofdecreased pavement structure , so that the pavement come to fatigue failure. Atpresent , domestic and foreign scholars have been on asphalt mixture fatigueperformance test studies , which use the most is the trabecular three-point bendingtensile fatigue tests. less commonly used semi-circular bending test methods to studythe fatigue test results and comparative the fatigue test of these two models.To thisend, I have done the following work.First , through the interpretation of the fatigue phenomenon and the analysis ofthe three fatigue mechanical response model to compare three models of difference ,and ultimately choose the phenomenological method to study. Discussion on theexisting fatigue performance test method to compare several advantages anddisadvantages of the typical indoor test methods , and ultimately select the threepoints of the repeated loading fatigue tests on trabecular and semi-circular specimen.Second , use ABAQUS finite element software to establish trabecular andsemicircle these two specimen model , and impose them half-sine load under the sameconditions.Through the comparison of two models at the bottom of the midpoint ofthe stress and deformation，analysis the two models mechanical response in 0.1seconds.Through simulation analysis , both in the 0 to 0.1 seconds of stress anddeformation of the same trend over time and predict the trabecular specimen fatiguelife is longer than semi-circular specimen fatigue life .Last , Selection of SUP - 13 , SMA - 13 , AC -13 three strain gradation style to dothe marshall mixture design , and together with 5℃, 15℃, 25℃for three temperatures ,5Hz , 10Hz , 15Hz , three kinds of frequency , 0.4,0.5,0.6 three kinds of stress ratioand three porosity these five influencing factors to do a orthogonal experimental design. Then do the fatigue test with selected orthogonal design table , and have avisual analysis and variance analysis with the test results , analysis the various factorsimpact on the fatigue life under different models. The test results showed that theimpact of various factors on the fatigue life order was that:Stress ratio > mixturegradation > test temperature > porosity>test frequency.Trabecular specimen fatiguelife is longer than the semicircle test predictions and it is the same result with finiteelement analysis ; various factors in the different test methods on the fatigue lifesignificantly is not the same.