Laboratory analysis of hydraulically bound mixtures for road pavements made with waste foundry sand and steel slags

The paper discusses the results of an experimental study concerning the mechanical performances of hydraulically bound mixtures for road foundations, with the aggregate skeleton fully composed by industrial wastes, as foundry sands and steel slags. The laboratory investigation has been subdivided in a preliminary study of the physicalgeotechnical properties of the two different industrial wastes, and in the following mechanical characterization of the hydraulic bound mixes. The formulation of the mixes has been developed in terms of Proctor and compression tests. At the end of the study, the elastic modulus of the mixtures has been evaluated through ultrasonic tests, also at different curing periods. The results have been satisfactory, having the mixes reached a compressive strength at 7 days up to 6.63 MPa and a corresponding Elastic Modulus up to 4,120 MPa. The experimental results meet the main Italian Contract Specifications, so demonstrating the possibility to use industrial by-products as integral substitutes of natural aggregates in the production of cement bound granular material for road foundations.