Concrete Pavement on a Crushed Aggregate Unbound Roadbase a New Design for Heavy Traffic Motorways

The construction method involving the placement of a 30 cm-thick concrete roadway pavement on a 30 cm-thick crushed aggregate unbound roadbase instead of a 2.6 cm-thick concrete pavement on a bound roadbase has proved its worth in Germany for more than 10 years, generally for heavy-traffic motorways. It has several important advantages compared with a concrete pavement on a hydraulically bound base course, these being, in particular, the better load-support conditions for the concrete pavement, the opportunity to recycle old road construction concrete and the more economical construction sequence. Unbound roadbases under concrete pavements have to fulfill additional demands compared to conventional crushed aggregate unbound base courses. These rlrniancjs are intended to ensure a sufficient resistance to redistribution, permeability to water, and uniformity. Above all the demands concern the grading curve of the mineral aggregate mix.