Cold recycling with bituminous emulsion of marginal aggregates for road pavements

The paper deals with a laboratory study of bitumen emulsion bound mixtures for road pavements with an aggregate structure totally composed of waste materials, i.e. reclaimed asphalt pavement (RAP), steel slag, coal ash and glass wastes, com-bined in different ratios. The investigation was divided into a preliminary environ-mental and physical analysis of each waste material and a subsequent mechanical characterization of the bitumen emulsion bound mixtures, by means of indirect ten-sile strength, stiffness modulus and repeated load axial tests. Indirect tensile strength tests were also performed in wet conditions to evaluate the moisture resistance of the mixes. The main outcomes of the trial (indirect tensile strength at 25 °C on dry samples up to 0.37 MPa; stiffness modulus at 25 °C and 2Hz up to 4,266 MPa, de-pending on the mixture) were compared with the requisites for acceptance of the main Italian Contract Specifications, which demonstrated that the analyzed mar-ginal materials are suitable for use as integral substitutes of natural aggregates in the production of bitumen emulsion bound mixtures for road pavements