ABSTRACT
An extensive study has been undertaken on 7 test roads and, in the laboratory, on 84 samples coming from 10 different Belgian crushing installations, to evaluate crushed concrete, in comparison with classical stone, as a road base material.
To produce a good crushed concrete aggregate, measures are to be taken already during the demolition of the concrete pavement : sufficient reduction of the concrete slabs, selective excavation, separation of the fine fraction before the crusher, and continuous maintenance of the crusher installation to obtain a grain size distribution as for classical base materials.
The density of the compacted material will be lower than for classical crushed stone, due to the internal voids of the concrete. The bearing capacity is often lower immediately after compaction, but may improve and even become superior because of the residual cement liberated during crushing.
The recycling of crushed concrete can be economically very advantageous on account of the reduction in transport costs and the avoidance of dumping costs. It has been shown that a reduction of the maximum size of the crushed concrete to the classical limits will increase only slightly the total cost and has important technical advantages.
