ABSTRACT
Several runway pavements at Zurich International Airport have reached the end of their service life after more than 30 years in use and are progressively being rehabilitated. The existing rigid pavements consist of concrete slabs on Cement-Treated Base (CTB). Despite its exceptional performance, the top layer of some rigid pavement sections has had to be replaced with asphalt instead of new concrete slabs for operational reasons. Based on a realized project (Stands Echo Nord and Taxiway PAPA) with rigid and flexible pavements, this paper studies the level of distress induced by aircraft loading and temperature in the CTB layer with asphalt or concrete overlays. The goal is to understand the consequences for pavement rehabilitation of replacing the concrete slabs with asphalt. Three-dimensional nonlinear finite element calculations have been performed with the commercial finite element software ABAQUS for investigating the stress–strain behaviour of the pavement layers. It is shown that if an inadequate asphalt layer thickness is chosen, the tensile stresses induced by an aircraft loading in the CTB layer are higher than the tensile strength and can potentially reduce the residual service life of the CTB layer and the whole pavement.
