Developing a Theoretical Model for Load Transfer of Common Joints in Rigid Airport Pavement Structures

Rigid airport pavements generally comprise 4 m to 6 m approximately square plain concrete slabs separated by joints. The joints form the interface between construction Lots, relieve shrinkage stresses that develop during curing, allow movement during thermal and moisture changes, and isolate different areas of pavement from each other and from other structures. Aside from from isolation joints, all these joints rely on load transfer, most commonly through aggregate interlock at sawn contraction joints, and via steel dowels at smooth interfaced construction joints. Importantly, the determination of the concrete slab thickness depends on the assumed load transfer between adjacent slabs, and this load transfer relies on the effectiveness of the joints. To allow future analysis of the factors affecting joint load transfer, a theoretical model was developed in the finite element software ABAQUS. The development of the theoretical model is detailed, including the rigid pavement, aircraft loading and subase support characteristics, the joint types being considered, and the characteristics of those joints being theoretically represented. The developed model was calibrated against falling weight deflectometer testing of full scale rigid airport pavements performed by the Federal Aviation Administration and the resulting model was used to perform a sensivity analysis of joint response under various loading conditions. In the future, the model will be used to determine the joint detailing factors that affect joint load transfer ability, including concrete mixture aggregate size, joint gap width, underlying concrete slab support, dowel size and spacing, and concrete mixture strength. Conclusions address issues identified for future theoretical modelling of rigid airport pavement joints.