Impact of different approaches to modelling rigid pavement base layers on slab curling stresses

Abstract

The magnitude of stresses induced in jointed concrete slabs due to thermal loads is influenced by the stiffness of the underlying foundation layers (base, sub-base and subgrade). The layer that most significantly affects the Portland cement concrete (PCC) slab responses is the base. Field observations have demonstrated the increase in reflecting cracking of PCC slabs placed over relatively stiff base layers. To predict thermo-mechanical responses of jointed PCC slabs accurately, appropriate idealisation of foundation layers in finite element (FE) analysis is required. Several modelling methods have been proposed to idealise the effect of the base layer. These methods differ in the structural contribution assigned to the base layer in the pavement concrete system. Four approaches for modelling the base layer in FE analysis of jointed concrete pavements are presented in this paper. The first and second approaches involve modelling the base as a plate separate from the other foundation layer(s). In the third and fourth approaches, the base layer is modelled as part of a Winkler or Vlasov foundation, respectively. A series of parametric studies are carried out to evaluate the capability and feasibility of each modelling approach proposed in this study in reflecting the effect of the base course rigidity on the PCC slab responses under thermal loads.

Keywords::

• concrete pavement
• base course
• foundation
• finite element analysis
• curling stress
• Winkler
• Vlasov

Funding

The authors are grateful to Dr. Julian Bendaña, former research specialist in The New York Department of Transportation for supporting this study.

Notes

^1. Email: [email protected]

^2. Email: [email protected]

^3. Email: [email protected]