Recycling Dredged Sludge in Asphalt Pavement

An experimental investigation of an innovative recycling method to reuse dredged sludge in asphalt pavements is presented. According to this method, semifinished products or agglomerates, made of dried sludge and bitumen, are produced. These products may be used to partially substitute fine sand and bitumen in the asphalt mix. In this paper, the practical aspects of the manufacture, storage, and transportation of these agglomerates are simulated in order to demonstrate the feasibility of the method. The technical properties of asphalt mixes prepared with these new products are compared to those of a reference asphalt mix, in terms of Marshall characteristics, stiffness, complex modulus, permanent deformation, and water sensibility. Environmental and economic issues are also analyzed. A simplified cost factor analysis shows that this method is economically advantageous compared to the disposal of contaminated sludge.