The present study investigates the potential of RAP for various layers of flexible and concrete pavements. Natural aggregates were replaced in different proportions by the coarse RAP and fine RAP, for preparations of granular subbase, wet mix Macadam, dry lean concrete, dense bituminous Macadam and Plain concrete mixes. Utilisation of both fractions of RAP resulted in reductions in the optimum moisture content (OMC) and maximum dry density of granular subbase and wet mix Macadam mixes, whereas, incorporation of the same was found to increase the OMC of dry lean concrete mixes. Incorporation of coarse RAP doesn’t affect much the engineering properties of base and subbase layers in comparison to fine RAP. Improving the gradation of fine RAP was found to increase its suitability in all the considered mixes. Similarly, utilisation of coarse RAP was found to improve the workability of concrete mixes, however, significant reductions in strength properties were noted. It was observed that as the strength requirement of layer increases, the negative impact of RAP on strength properties also increases linearly, suggesting incorporating a higher fraction of RAP in lower layers and a lower usage of the same for wearing course of the pavement.

Mechanical foaming of bitumen is a popular technique employed to reduce the viscosity of binder for ensuring coating of aggregates at lower temperature. The potential of this technique is being utilized widely for producing sustainable reclaimed-asphalt pavement (RAP) inclusive mixtures, but usage of recycled concrete-aggregates (RCA) in foamed technology is very scanty. The present study is the first of its kind attempting to investigate the optimum proportion of hydrophobic RAP aggregates and hydrophilic RCA (separately as well as combined) for the preparations of foam-mix asphalt (FMA). It was observed that incorporation of RCA in FMA affects the quality of mixes but RCA inclusive FMA was found to qualify the stipulated specifications for pavement applications. From the present study, it is found that up to 20% RCA and 40% RAP proportions individually could be utilized for the preparation of foam mixes. Also, it is interesting to note that delayed hydration of residual cement grains could enhance the performance of FMA. Furthermore, 30% RCA coupling with 10% RAP was found to exhibit acceptable performance. The present study suggests that 0.1% fiber reinforcement could enhance the performance of the foam mixes considerably.