Joint design for concrete pavement on cement stabilized base at Zürich airport

On the concrete pavements of the runways 14 - 32 and 16 - 34, built in 1975 and 1976, cracks developed along the tongue-and-groove longitudinal joints. Investigations into the service conditions of the joints showed that they were overstressed unde r extreme loads and that damage to them could be obviated only by suitable reinforcement of the concrete in the region of the joints. For the concrete pavements of the apron extension and tbe west runway, prior to their construction in 1983- 1985, the effect of load transfer at the longitudinal joints on the stress conditions in the pavement structure was investigated, and various joint designs were developed, tested and compared. For longitudinal joints capable of transmitting shear force, the form of construction with reinforced tongue-and-groove was found to offer the best solution. In this case it is possible to dispense with shear transfer devices. If the joint is formed with plain faces (butt joint), the cement-stabilized base has to be made 10 cm thicker to ensure tbat the stresses in the concrete slab and in the sub-base are not higher than in the form of construction with shear transfer at the longitudinal joints. Technically the two alternatives are equally effective. For reasons of economy the solution with plain longitudinal joints and thickened sub-base was chosen ,