Theoretical Analysis on the Effect of Surface Horizontal Traction on Top-Down Cracking of Flexible Pavement
Fatigue cracking of flexible pavement is one of the most important elements that should be considered due to the damage occurs in asphalt layer under the effect of wheel load repetitions. This research demonstrated theoretical study on top-down fatigue crackingusing the finite element method. A three- dimensional finite elastic structural element is used to modal pavement using (ABAQUS ver. 6.12.1) program. The results obtained from this studydemonstrated that maximum value of tensile strain developed at the surface of asphalt layer for flexible pavement due to the horizontal traction generated from wheel load application at contact area. Also, the horizontal tensile strain ( ) at surface of asphalt layer is increasing rapidly with load repetitions with values greater than that generated at bottom by (94%) at failure. This prescribed the basic or inherent features of top crack initiation and down propagates within asphalt layer in flexible pavement. The top horizontal tensile strains obtained from the finite element model is higher than the empirical relations by (20%); since the finite element analysis of flexible pavement considered the surface horizontal tensile strains due to contact traction force at tire pavement interface. Finally, according to the results of this study the horizontal tensile strains at the top of asphalt surface significantly increase the damage intensity of fatigue failure for flexible pavement.