Due to changes in the standardisation and the construction, concerning gravel mixtures and recycled gravel mixtures, these cannot be evaluated satisfactorily with the existing requirements (new content of fines up to 12%, increasing use of recycled gravel mixtures with content of concrete or asphalt up to 30%, compaction equipment more efficient with performance much higher than "Proctor Standard").
The requirements for the load bearing capacity determined with CBR-values and the CBR-ratio should be verified and - if necessary - adjusted as follows:
- Verification and specification of requirements for natural gravel mixtures
- Specification of requirements for recycled gravel mixtures
- Confirmation or modification of the existing Swiss testing practice, concerning the aggregate size and compaction energy.