Investigation of Factors Related to Surface-Initiated Cracks in Flexible Pavements

This report works to identify potential mechanisms for the occurrence of top-down cracking, as well as to investigate stress patterns and concentrations due to surface load and preexisting transverse (thermal) cracks. It attempts to provide information on surface stresses that derives from both theory and experiments. In particular, contact mechanics solutions are analyzed to gain information on loads that are subsequently used in performing numerical evaluation of surface stresses. Examples of three-dimensional computations using the finite element code ABAQUS illustrate the analysis, and comparisons of stresses for uncracked and cracked pavements are made. The report concludes that the presence of a transverse crack in the AC layer significantly increases the vertical stresses in the base. It also has a noticeable effect on the horizontal stresses in the AC layer. Keywords-longitudianal cracks, transverse cracks, flexible pavements, ABAQUS finite element analysis