Production and characterization of aggregate from non metallic automotive shredder residues

In this paper the results of an experimentation on the granulation of non metallic automotive shredder residues to produce aggregates for cementitious or asphalt mixes are presented and discussed. In a preliminary separation step a fraction containing mainly inert and non metallic materials was sieved to obtain the required grading and analyzed for the metal content. In the following granulation step, performed in a pilot scale granulator, the sieved fraction was mixed with binding materials, fly ash and a superplasticizer agent, to produce granules of up to 2000 kg/m3 specific weight. The size of the produced granules, between 2 and 40 mm, proved to be a function of water content: increasing the water/solids ratio, the diameter of the particles also increased. The granules were then used as artificial lightweight aggregate for concrete mixes. Concrete samples showed a specific weight up to about 2000 kg/m3 and a compressive strength up to about 30 MPa, depending on the fluff content of the mixes, and on the nature of the binder and of the other components used. Leaching tests performed on the concrete samples showed that a good immobilization of metals and ions was achieved.