New concepts for the assessment of concrete slab interfacial effects in pavement design and analysis

Abstract

For many years, concrete pavement construction, whether new or overlay, has been done with a variety of layer interfaces ranging from strongly cemented having a high degree of shear strength to completely unstabilised having only internal frictional resistance between the individual particles. In this regard, both past and present design methodologies have been limited in their capability to address the bond between the slab and the underlying layers – essentially considering either unbonded or fully bonded conditions for design purposes. However, this limitation ignores a wide range of partially bonded conditions that can exist between these two limits that may consist of a variety of combinations of different levels of friction and adhesion. For most instances of design, unbonded conditions are principally hypothetical where qualification of the amount of adhesive strength and frictional restraint that develops along the interface between the slab and the underlying layer is the key to the characterisation of slab behaviour resulting in varying degrees of partial bond. This paper addresses a framework to model the effects of the concrete pavement slab–subbase interface for design purposes based on research relative to these and other factors as they may pertain to the prediction of short- and long-term performance.