Improvements in the mix design of cold-recycled bituminous mixtures

The Authors present the results of a laboratory investigation which focused on the mix design of cold-recycled bituminous mixtures. The adopted method entails the use of the gyratory compaction technique and is centred on the evaluation of the workability and density of the recycled mixtures. The optimal percentage of emulsion is estimated as a function of a fluidity index which synthesises the behaviour of the emulsion during the compaction process. In the investigation reclaimed asphalt pavement (RAP) material was sampled from a recycling plant and thereafter employed for the design of a mixture which can be used for the constitution of base or binder course layers. Its properties were assessed by performing a full volumetric characterisation and by carrying out indirect tensile strength tests after one day curing at 25°C.