Assessment of the influence of cracking parameters on the condition of non-rigid highway pavements

Through and sub-surface cracks are the most characteristic and dangerous type of failure of non-rigid pavements, which has a significant impact on their stress-strain state and leads to a loss of pavement distribution capacity. Therefore, the main objective of the study is to investigate the patterns of influence of through and subsurface cracks on the stress-strain state (SSS) of a non-rigid pavement structure in order to: justify the position of the design load for calculating the pavement structure with cracks; establishing the effective crack opening width and stiffness of the filling material, at which the tensile stresses on the lower fiber of the monolithic pavement layers are reduced. The calculation was performed using the finite element method. Based on the results of the study, it is proved that the calculation of the SSS of pavements with through cracks should be carried out for the most dangerous angular position of the load relative to the T-shaped through crack, the presence of which increases the horizontal stresses in monolithic pavement layers by 239% and the tangential stresses on the upper fiber of the base by 234% compared to structures without a crack. The tensile stresses acting normal to the crack at the boundaries of the structural layers can be 2 to 2.5 times higher than the stresses directed along the crack. It was found that the effective width of crack opening, beyond which tensile stresses on the delicate fiber of a package of monolithic coating layers decrease, is 10 mm. To avoid the growth of tensile stresses, the crack should be filled with materials with an elastic modulus of more than 1000 MPa. The results obtained from the modeling of the SSS of structures with hidden cracks can be used both in assessing the condition of pavement and in the development of projects for the overhaul of non-rigid pavement.