Mechanical behaviour of cement-bitumen treated materials containing different amounts of reclaimed asphalt

Cold recycling techniques have become one of the main sustainable solutions in road construction and maintenance. The use of reclaimed asphalt (RA) as a constituent material for bound mixtures offers two main advantages: it eliminates problems concerning disposal and it allows natural resources to be preserved. Among the most widespread recycled mixtures, the use of cement–bitumen-treated materials (CBTM) for subbase courses has rapidly increased over the last 10 years. This paper deals with the influence of RA content on the mechanical characteristics of CBTM. Several mixtures were produced by combining different dosages of binders (cement and bituminous emulsion) and RA contents. The behaviour of recycled mixtures was evaluated and compared in terms of indirect tensile strength, water sensitivity and stiffness modulus. In addition, the effects of temperature on the stiffness properties were investigated. Experimental results showed that the RA content did not significantly affect the compactability and the strength properties of CBTM. The presence of RA determined an increase in mix deformability and thermodependence, but the effect can be inhibited by increasing cement dosage. The findings offer good prospects for increasing the use of RA and encourage administrations to employ this material as an effective construction solution.