Analysis of periodic cracks in surface layer of pavement structures

As a critical issue for the pavement’s quality service life, surface cracking of the pavement structure is an ongoing research topic which attracts many researchers. This paper presents a numerical study of the periodic cracks in surface layer of pavement structures based on the FEM method. The formation mechanism of the periodic cracks is analyzed and the evolving process is simulated. A parametric study, including effects of the layer thickness, tensile strength of surface layer and layer elastic modulus on the crack spacing is carried out. The numerical results indicate that the horizontal stress between two adjacent cracks decreases gradually as the crack spacing decreases. The horizontal stress transits from tensile to compressive when the crack spacing decreases to a certain value. Such a stress state transition leads to the periodic array of the surface cracks. The evolving process of the periodic cracks indicates that new cracks infill in sequence between two earlier formed adjacent cracks and the crack spacing decreases in half simultaneously. No more new crack can infill when the crack spacing reaches to a certain value even with the increasing of external load. Numerical simulations also show that the crack spacing is strongly dependent on the surface layer thickness, tensile strength of the surface layer and elastic modulus of the surface layer.