The Pushout Strength of Concrete Pavement Slab and Clay Soil Layers

Abstract

The frictional forces between the concrete slab and base has been combined with the movements of the horizontal slab that have been induced by variations of the moisture and temperature in concrete slabs. The frictional drag that acts on the slab bottom as a result of base friction is in an opposite horizontal slab displacement direction, and resist movements of the horizontal slab. A condition of smoother interface provides lower resistance to slab movement. On the other hand, rough interfaces are beneficial in the reduction of the load-related stresses. As bonding degree between slab and foundation affects the friction that has been mobilized at interface, a realistic evaluation of friction of the interface is required for the rational designs of the concrete pavement. In this work, push-off test has been performed. Based upon results of the friction tests, the friction characteristics of concrete and soil have been researched. The parameters that influence the maximal displacement and friction coefficient are (interface state, rate of movement) for friction and (rate of movement, interface condition) for the displacements, respectively. Finally, once the applied force reaches a stable state, the frictional force increases dramatically. The most important influence on this force is the interface state, which is accompanied by movement rate. The change of the interface from a smooth to a rough surface increases the overall coefficient of friction.