4. Conclusion

Composite structures consisting of a concrete surfacing and a gravel-bitumen base have been developing in France since 1998. These structures are available in three different techniques:

• the BAC/GB3 Continuous Reinforced Concrete on Gravel-Bitumen composite structure;

• the structure in concrete slabs with dowelled joints on Grave-Bitume BC5g/GB3 ;

• the structure in Thin Cement Concrete Bonded to Grave-Bitumen BCMC/GB3.

The BAC/GB3 composite structure has now been validated after twenty years' service on pavements with heavy truck traffic. It consists of a concrete layer (12 to 18 cm thick, depending on traffic), and a bitumen gravel sub-base layer (minimum 8 cm thick). To ensure a service life of at least thirty years, it is imperative that...