Numerical simulations of flexible pavement (KR category) were carried out in the paper. The special attention was put on modelling of a friction behaviour between structural layers. Three types of models were prepared: no possibility of slide, contact with a friction factor 0,65, contact with a friction factor 0,8. In the models in which the slip was made possible the fatigue strength was one order of magnitude smaller then in a traditional model used in mechanistic design method.NUMERICAL ANALYSIS OF THE INFLUENCE OF INTERLAYER BOND ON THE FATIGUE STRENGTH OF FLEXIBLE PAVEMENTS
Abstract
The paper investigates the influence of modelling slip between layers of a flexible pavement of the KR category on the results of mechanistic design. A numerical analysis was performed using the commercial Abaqus software.
Three cases of road pavement construction were modelled: no possibility of slip, contact with a friction coefficient of 0.65, and contact with a friction coefficient of 0.8. Subsequently, fatigue life was calculated in accordance with the mechanistic design procedure for flexible pavements. In the case of models where sliding between asphalt concrete layers was possible, the fatigue life was an order of magnitude lower than in the traditional model used in mechanistic design.
1. INTRODUCTION
Research shows that interlayers’ contact has a significant impact on the fatigue strength of a pavement and thus on the number of loads until the first signs of the pavement’s destruction. In the paper [1], an experimental segment of a pavement was prepared on which several levels of bond (tackiness) were simulated. The stiffness moduli were calculated on the basis of the FWD (Falling Weight Deflectometer) deflections. The authors observed that the moduli changed throughout the entire experimental section of the road. In the section where sliding between the asphalt concrete layers was made possible (no bond), the elastic modulus significantly decreased. This decreased value of the modulus is connected only with the possibility of slip between layers. Thus, this modulus should not be used when calculating strains for fatigue strength criteria. The lack of bond between layers should be taken into account in the FEM software used for strain calculations. (…)
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Source: Logistyka Magazine