ABSTRACT
The recycling of demolition materials for use in roads has been developed in two parts of France where “deposits” of such materials are especially abundant : the Paris area and the Nord-Pas-de-Calais region.
The first tests were conducted in 1976 on the A1 motorway near Paris. Between 1981 and 1986, seven permanent crushing-screening plants (five in the Paris area, two near Lille) were set up, generally at locations close to mixing plants, to prepare road-building materials treated with hydraulic binders. The total output of crushed-concrete aggregates is now about 600,000 tons a year. Thanks to the work of the equipment builders and careful thinking about the design and adjustment of the crushing-screening plants, the quality of the aggregates has been significantly improved in a few years and materials that can be used in the subbase and roadbases of pavements designed for moderate traffic levels are now available.
Roadbases for pavements designed for heavy traffic have also been built, on an experimental basis, to evaluate the mechanical strength limits of these special aggregates.
