Continuously Reinforced Concrete Roadbases

In the Netherlands Rijkswaterstaat is the authority in charge among others of the construction of highways. The department Utrecht of Rijkswaterstaat has chosen a continuously reinforced concrete roadbase for the construction of the 7 km long new highway scction between the cities of Bunnik and I Jtrecht. This choise was based on the expectation that future maintanance works would be minimal, thus a higher initial investment being acceptable. The specification of the total construction from bottom to top is as follows: 1.00 m sand for bedding, 0.25 m cement bound subbase, 0.06 m bituminous intermediate layer, 0.25 m pavement quality concrete slag and 0.05 porous asphalt surfacing. The bituminous intermediate layer should prevent the cement bound subbase from erosion. The quality of the concrctc is B45 characteristic, which means that 95% of the test results have to be 45 N/mm2 or higher. The reinforcement has been placed at mid-slab depth and consists of grade 500 deformed steel bars. The diameter of the longitudinal bars is 16 mm and 0.67% of the crosssectioiiul aie of the slab, the diameter of the transverse bars is 12 mm at 700 mm centres and at 60° to the longitudinal bars.